Environmental Science › Water Science and Technology

Environmental and Agricultural Sciences

Works Count: 72090

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Description

This cluster of papers focuses on the hydrological effects, water resource management, and environmental impact in China, particularly in relation to river basins, soil moisture, erosion control, and the influence of climate change. It also explores the use of remote sensing for monitoring and sustainability efforts.

Keywords

Hydrological Effects; Water Resources; China; Climate Change; Soil Moisture; River Basins; Erosion Control; Remote Sensing; Sustainability; Environmental Impact

Features of the extremely severe drought in the east of Southwest China and anomalies of atmospheric circulation in summer 2006

2011-04-01

Yonghua Li , Haiming Xu , De Li Liu

The use of remote sensing data for drought assessment and monitoring in Southwest Asia.

2005-01-01

Prasad S. Thenkabail , M. S. D. Nilantha Gamage , Vladimir Smakhtin

Analysis of changing pan evaporation in the arid region of Northwest China

2013-03-26

Zhi Li , Yaning Chen , Yanjun Shen +2 more

Key Points Ep decreased from 1958 to 1993 but increased since then Ep mostly due to changes in the aerodynamic component WS and VPD are both primary factors of the … Key Points Ep decreased from 1958 to 1993 but increased since then Ep mostly due to changes in the aerodynamic component WS and VPD are both primary factors of the reversion of Ep

Mathematical models of small watershed hydrology and applications.

2002-01-01

V. P. Singh , D. K. Frevert

The Analysis and Display of Real Time Surface Climate Data

1985-06-01

Chester F. Ropelewski , John E. Janowiak , M. S. Halpert

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The Large-Scale Circulation and Heat Sources over the Tibetan Plateau and Surrounding Areas during the Early Summer of 1979. Part I: Precipitation and Kinematic Analyses

1983-05-01

Luo Hui-bang , Michio Yanai

The time evolution of the large-scale precipitation, low-level (850 mb) wind, moisture and vertical motion fields over the Tibetan Plateau and surrounding areas during a 40-day period from late May … The time evolution of the large-scale precipitation, low-level (850 mb) wind, moisture and vertical motion fields over the Tibetan Plateau and surrounding areas during a 40-day period from late May to early July 1979 is studied based on the objectively analyzed FGGE Level II-b data set. During this period the general circulation over East Asia undergoes a distinct change characterizing the onset of the summer monsoon circulation. The Tibetan Plateau exerts profound orographic and thermal influences upon the low-level wind field. The inflow towards the eastern part of the Plateau with a marked diurnal change in its intensity is the most prominent feature of the low-level wind field. The areas of organized precipitation are well related to synoptic systems seen in the 850 mb flow: the quasi-stationary Burma-India trough, the disturbances forming on the trough, the "Mei-yü (Baiu)" front, and the "transverse trough" extending eastward from the Plateau. There is a sharp contrast between the western and eastern Plateau in terms of precipitation and moisture distributions. The eastern Plateau acts as a huge chimney funneling water vapor from the lower to the upper troposphere. Maxima of 40-day mean upward velocities are located above the eastern Plateau, above the Assam-Bengal region and along the Mei-yü frontal zone. The vertical motions above the Plateau are more upward in the evening than in the morning. The reverse is true in the surrounding areas. Detailed examinations of daily values of the areal mean vertical p-velocity, mixing ratio and rainfall are made for four heat source regions (the western Plateau and adjacent areas, the eastern Plateau, the Yangzi River, the Assam-Bengal region) as a preliminary to the discussion of heating mechanisms operating in these regions.

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Effects of Drought Stress on Chlorophyll Fluorescence Parameters, Chlorophyll Content and Grain Yield of Wheat Cultivars

2007-08-01

Farzad Paknejad , Mohammad Nasri , H. Mo +2 more

Chlorophyll fluorescence quick variation c:m be used as a valuable index for evaluati~n of plants tolcrance to environmental stresses. In order to evaluate chlorophyll quick fluorescence fluctuations 'of different wheat … Chlorophyll fluorescence quick variation c:m be used as a valuable index for evaluati~n of plants tolcrance to environmental stresses. In order to evaluate chlorophyll quick fluorescence fluctuations 'of different wheat cultivars under water-limited condition, a factorial experiment with a randomized complete block design was performed in Karaj, Iran. Treatments were seven different irrigation regimes and three bread wheat cultivars with four replications. The measurements of Chlorophyll fluorescence parameters were done on flag leaves about three weeks after flowering. Photo-system II photochemical capacity was calculated from the ratio of variable fluorescence to maximum chlorophyll fluorescence (FV/FM). In addition, Tin and FV were evaluated and relative water content and flag leaf chlorophyll were also measured. Results showed that different irrigation levels affected the FV, FV/FM and Tin significantly (p~O.05), but have not any significant effect on FO nnd I;M. There was a significant difference between different varieties and irrigation levels in respect to chlorophyll content, RWC and grain. The means of FV/FM, FV, TIn and FM were declined as soil water content was decrea!:ed, but FO was almost remained constant for all the treatments. High yielding varieties had higher Tin, FM, FV/FM, FV, chlorophyll content and RWC values. The FV and FV/FMhnd highest and FO had lowest correlation coefficients with grain yield. The existing synchronized pattern of variation in fluoresccnce parameters of all varieties indicates that high yielding varieties can avoid the negative effects of drought slTcss during grain filling period. The high correlation between fluorescence parameters and RWC confirm these

A geomorphoclimatic theory of the instantaneous unit hydrograph

1982-08-01

Ignacio Rodríguez‐Iturbe , Marcelo González‐Sanabria , Rafael L. Bras

The instantaneous unit hydrograph is conceived as a random function of climate and geomorphology varying with the characteristics of the rainfall excess. The probability density functions of the peak and … The instantaneous unit hydrograph is conceived as a random function of climate and geomorphology varying with the characteristics of the rainfall excess. The probability density functions of the peak and time to peak of the IUH are analytically derived as functions of the rainfall characteristics and the basin geomorphological parameters. The main characteristics of these pdf's are studied, and a new approach to hydrologic similarity is initiated under the concept of the geomorphoclimatic IUH. For a given set of geomorphologic characteristics and a particular intensity and duration of rainfall, the peak and time to peak of the IUH corresponding to those values can be easily estimated.

Soil erosion and its control in the loess plateau of China

1989-06-01

Bojie Fu

Abstract. The loess plateau in China is the most developed region of loess in the world in terms of extent, thickness and depositional sequence. It is also the region with … Abstract. The loess plateau in China is the most developed region of loess in the world in terms of extent, thickness and depositional sequence. It is also the region with the most serious soil erosion in the world. This paper reviews the factors and reasons for soil erosion in this area. The loess is prone to vertical cleavage and its surface soils are soft and loose. Rainstorms are frequent with intense rain concentrated during the summer. Irrational land use and exploitive management have been carried out for thousands of years and express themselves through the loss of grassland and natural forests. Finally, some soil conservation schemes for use in the loess plateau are suggested.

Some Characteristics of the Summer Circulation Over the Qinghai-Xizang (Tibet) Plateau and Its Neighborhood

1981-01-01

Ye Duzheng

Horizontal and vertical circulation patterns over the Qinghai-Xizang (Tibet) plateau during summer, derived from meteorological observations, are compared with results from rotating annulus experiments. There are several striking features during … Horizontal and vertical circulation patterns over the Qinghai-Xizang (Tibet) plateau during summer, derived from meteorological observations, are compared with results from rotating annulus experiments. There are several striking features during the season when the plateau acts as a huge elevated heat source: 1) a heat low dominates the planetary boundary layer over the plateau; 2) this heat low is broken up into several cells, giving rise to shear-line development; 3) surrounding the heat low is an anticyclonic belt; 4) the northern and southern portions of this belt approach each other as one proceeds into the upper troposphere and finally merge into a large anticyclone over the plateau; and 5) significant circulation cells appear in meridional and zonal cross sections, attesting to the strong influence of the plateau on the general circulation of the atmosphere.

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A catchment storage model for runoff routing

1964-01-01

Eric M. Laurenson

The impact of the development of water resources on environment in arid inland river basins of Hexi region, Northwestern China

2006-04-05

Xibin Ji , Ersi Kang , Rensheng Chen +3 more

Recent advances on the study of atmosphere-land interaction observations on the Tibetan Plateau

2009-07-09

Yuanxu Ma , Yanghua Wang , Renguang Wu +7 more

Abstract. As a unique geological and geographical unit, the Tibetan Plateau dramatically impacts the world's environment and especially controls climatic and environmental changes in China, Asia and even in the … Abstract. As a unique geological and geographical unit, the Tibetan Plateau dramatically impacts the world's environment and especially controls climatic and environmental changes in China, Asia and even in the Northern Hemisphere. Tibetan Plateau, therefore, provides a field laboratory for studying global change. With support from various agencies in the People's Republic of China, a Tibetan Observation and Research Platform (TORP) is now implementing. Firstly the background of the establishment of the TORP, the establishing and monitoring plan of long-term scale (5–10 years) of the TORP has been introduced. Then the preliminary observational analysis results, such as the characteristics of land surface heat fluxes and CO2 flux partitioning (diurnal variation and inter-monthly variation etc.), the characteristics of atmospheric and soil variables, the structure of the Atmospheric Boundary Layer (ABL) and the turbulent characteristics have also been shown in this paper.

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Regional trends in recent precipitation indices in China

2005-04-05

Weihong Qian , Xiaopei Lin

The Circulation of the High Troposphere over China in the Winter of 1945–46

1950-01-01

T. C. Yeh

The paper studies the structure of the high troposphere over China in the autumn of 1945 and winter of 1945–46. The principal feature is the existence of two belts of … The paper studies the structure of the high troposphere over China in the autumn of 1945 and winter of 1945–46. The principal feature is the existence of two belts of maximum westerlies, one flowing around the southern and the other around the northern edge of the Tibetan Plateau. The southern jet stream (the main one) is extremely stationary in position. Its speed increases downstream beyond the edge of the Asiatic continent. The onset of this southern jet stream is abrupt in the middle of October over central and southwestern China and advances downstream at a speed of about 3° longitude per day. South of this main jet stream is a belt of extremely uniform absolute vorticity which is zero in December and January. In spite of the existence of zero absolute vorticity the circulation above 15,000 feet is strikingly stable. Below 10,000 feet is the regular procession of warm troughs and cold ridges. Comparison with the conditions along 76° E and the east coast of United States has also been made. The difference in the structure of the basic current along the east coasts of the two continents suggests an explanation of the observed formation of winter typhoons off the Chinese coasts versus the non-existence of such storms in the Caribbean Sea in the cold season.

Factors affecting sheet and rill erosion

1957-12-01

Dwight D. Smith , W. H. Wischmeier

This paper discusses the two principal processes by which sheet erosion occurs and the six factors which effect the magnitude of the losses. The processes are raindrop impact and transportation … This paper discusses the two principal processes by which sheet erosion occurs and the six factors which effect the magnitude of the losses. The processes are raindrop impact and transportation of soil particles by flowing water. The factors are length and per cent slope, cropping, soil, management and rainfall. The relative effectiveness of each of the three main conservation practices in control of erosion, contour farming, strip cropping, and terracing is presented. The factors and practices are combined in a rational erosion equation for calculating field soil loss for use in application of conservation practices and in assessing land program benefits.

Behavior of Corn and Sorghum under Water Stress and during Recovery

1971-11-01

Manuel Sánchez‐Díaz , Paul J. Kramer

Corn (Zea mays L.) and sorghum (Sorghum vulgare, Pers.) plants were grown in a vermiculite-gravel mixture in controlled environment chambers until they were 40 days old. Water was withheld until … Corn (Zea mays L.) and sorghum (Sorghum vulgare, Pers.) plants were grown in a vermiculite-gravel mixture in controlled environment chambers until they were 40 days old. Water was withheld until they were severely wilted, and they were then rewatered. During drying and after rewatering stomatal resistance was measured with a diffusion porometer each morning, and water saturation deficit and water potential were measured on leaf samples. The average resistance of the lower epidermis of well watered plants was lower for corn than for sorghum. When water stress developed, the stomata began to close at a higher water potential in corn than in sorghum. The stomata of both species began to reopen normally soon after the wilted plants were rewatered, and on the 2nd day the leaf resistances were nearly as low as those of the controls. The average leaf water potential of well watered corn was -4.5 bars; that of sorghum, -6.4 bars. The lowest leaf water potential in stressed corn was -12.8 bars at a water saturation deficit of 45%. The lowest leaf water potential in stressed sorghum was -15.7 bars, but the water saturation deficit was only 29%. At these values the leaves of both species were tightly rolled or folded and some injury was apparent. Thus, although the average leaf resistance of corn is little lower than that of sorghum, corn loses much more of its water before the stomata are fully closed than does sorghum. The smaller reduction in water content of sorghum for a given reduction in leaf water potential is characteristic of drought-resistant species.

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An overview of the Semi-arid Climate and Environment Research Observatory over the Loess Plateau

2008-11-01

Jianping Huang , Wu Zhang , Jinqing Zuo +7 more

Opportunities and challenges of sustainable agricultural development in China

2007-08-31

Jingzhu Zhao , Qishan Luo , Hongbing Deng +1 more

This paper introduces the concepts and aims of sustainable agriculture in China. Sustainable agricultural development comprises sustainability of agricultural production, sustainability of the rural economy, ecological and environmental sustainability within … This paper introduces the concepts and aims of sustainable agriculture in China. Sustainable agricultural development comprises sustainability of agricultural production, sustainability of the rural economy, ecological and environmental sustainability within agricultural systems and sustainability of rural society. China's prime aim is to ensure current and future food security. Based on projections of China's population, its economy, societal factors and agricultural resources and inputs between 2000 and 2050, total grain supply and demand has been predicted and the state of food security analysed. Total and per capita demand for grain will increase continuously. Total demand will reach 648 Mt in 2020 and 700 Mt in 2050, while total grain yield of cultivated land will reach 470 Mt in 2010, 585 Mt in 2030 and 656 Mt in 2050. The per capita grain production will be around 360kg in the period 2000-2030 and reach 470kg in 2050. When productivities of cultivated land and other agricultural resources are all taken into consideration, China's food self-sufficiency ratio will increase from 94.4% in 2000 to 101.3% in 2030, suggesting that China will meet its future demand for food and need for food security. Despite this positive assessment, the country's sustainable agricultural development has encountered many obstacles. These include: agricultural water-use shortage; cultivated land loss; inappropriate usage of fertilizers and pesticides, and environmental degradation.

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The impacts of human activities on the water–land environment of the Shiyang River basin, an arid region in northwest China / Les impacts des activités humaines sur l’environnement pédo-hydrologique du bassin de la Rivière Shiyang, une région aride du nord-ouest de la Chine

2004-06-01

Shaozhong Kang , Xiaoling Su , Ling Tong +6 more

Abstract Abstract The Shiyang River basin is a typical interior river basin that faces water shortage and environmental deterioration in the arid northwest of China. Due to its arid climate, … Abstract Abstract The Shiyang River basin is a typical interior river basin that faces water shortage and environmental deterioration in the arid northwest of China. Due to its arid climate, limited water resources and some inappropriate water-related human activities, the area has developed serious loss of vegetation, and gradual soil salinization and desertification, which have greatly impeded the sustainable development of agriculture and life in this region. In this paper, the impacts of human activities on the water–soil environment in Shiyang River basin are analysed in terms of precipitation, runoff in branches of the river, inflow into lower reaches, water conveyance efficiency of the canal system and irrigation water use efficiency in the field, replenishment and exploitation of groundwater resources, soil salinization, vegetation cover and the speed of desertification. The results show that human activities and global climate change have no significant influence on the precipitation, but the total annual runoff in eight branch rivers showed a significant decrease over the years. The proportion of water use in the upper and middle reaches compared to the lower reach was increased from 1:0.57 in the 1960s, to 1:0.27 in the 1970s and 1:0.09 in the 1990s. A reduction of about 74% in the river inflow to the lower reaches and a 15-m drop in the groundwater table have occurred during the last four decades. Strategies for improving the water–soil environment of the basin, such as the protection of the water resources of the Qilian Mountains, sustainable use of water resources, maintenance of the balance between land and water resources, development of water-saving agriculture, diverting of water from other rivers and control of soil desertification, are proposed. The objective of this paper is to provide guidelines for reconstruction of the sustainable water management and development of agriculture in this region.

Changes of pan evaporation and reference evapotranspiration in the Yangtze River basin

2006-12-19

Ying WANG , Tong Jiang , Oliver Bothe +1 more

Soil and water loss from the Loess Plateau in China

2000-05-01

Hui Shi , Mingan Shao

Effects of Various Factors on the Accuracy of DEMs: An Intensive Experimental Investigation

2000-09-01

Jianya Gong , Zhilin Li , Qing Zhu +2 more

A series of tests on the accuracy of DEMs is described. The effects of four factors on DEM accuracy have been tested, i.e., the accuracy, the density of source data, … A series of tests on the accuracy of DEMs is described. The effects of four factors on DEM accuracy have been tested, i.e., the accuracy, the density of source data, the characteristics of the terrain su$ace, and the modeling approaches. A large area covered by two 1 :I 0,000-scale maps was selected for testing. The terrain types range from flat to hilly to mountainous. Various sources (photographs and contour maps) were used and various measurement methods were employed. From test results, the following has been found: (1) source data measured manually with analytical plotters are the most reliable because automated measurement using image matching techniques could generate systematic errors; (2) the accuracy of DEMS decreases (or the RMsE becomes larger) with an increase in sampling interval, and the relationship is linear; (3) the inclusion of feature points and break lines improves the accuracy of DEMS significantly, especially when the terrain is rough; (4) generally speaking, the accuracy of DEMS decreases with an increase in relief;. however, this is not always the case, and the best results may be obtained in hilly areas; and (5) direct modeling from originally measured data to form a triangular network will yield better results than indirect modeling using a random-to-grid interpolation to form a grid network. The difference could be significant if the terrain is rough. From these conclusions, some advice on DEM production could be made as follows: (1) when using automated photogrammetric systems for data acquisition, editing by experienced operators should be considered; (2) in hilly areas, photogrammetric contouring can be the most efficient method for DEM data acquisition if analytical plotters are used; (3) feature points should always be measured and kept in order to reduce the data volume while retaining the fidelity of the DEM; and (4) when the terrain su$ace is rough, triangulationbased methods are recommended.

Effective rainfall in irrigated agriculture

1978-01-01

N. G. Dastane

Study on effective precipitation in irrigated agriculture. Methodology of its empirical measurement and mathematical calculation and application of effective rainfall data to irrigation and drainage projects Study on effective precipitation in irrigated agriculture. Methodology of its empirical measurement and mathematical calculation and application of effective rainfall data to irrigation and drainage projects

A new model for relationship between irradiance and the rate of photosynthesis in Oryza sativa

2007-11-26

Zi-Wu-Yin Ye

The calculated maximum net photosynthetic rate (P N) at saturation irradiance (I m) of 1 314.13 µmol m-2 s-1 was 25.49 µmol(CO2) m-2 s-1, and intrinsic quantum yield at zero … The calculated maximum net photosynthetic rate (P N) at saturation irradiance (I m) of 1 314.13 µmol m-2 s-1 was 25.49 µmol(CO2) m-2 s-1, and intrinsic quantum yield at zero irradiance was 0.103. The results fitted by nonrectangular hyperbolic model, rectangular hyperbolic method, binomial regression method, and the new model were compared. The maximum P N values calculated by nonrectangular hyperbolic model and rectangular hyperbolic model were higher than the measured values, and the I m calculated by nonrectangular hyperbolic model and rectangular hyperbolic model were less than measured values. Results fitted by new model showed that the response curve of P N to I was nonlinear at low I for Oryza sativa, P N increased nonlinearly with I below saturation value. Above this value, P N decreased nonlinearly with I.

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Soil erosion and management on the Loess Plateau

2001-01-01

Cai Qiang-guo

A gridded daily observation dataset over China region and comparison with the other datasets

2013-01-01

Gao Xue

A new gridded daily dataset with the resolution of 0.25°latitude by 0.25°longitude,CN05.1,is constructed for the purpose of high resolution climate model validation over China region.The dataset is based on the … A new gridded daily dataset with the resolution of 0.25°latitude by 0.25°longitude,CN05.1,is constructed for the purpose of high resolution climate model validation over China region.The dataset is based on the interpolation from over 2400observing stations in China,includes 4variables : daily mean,minimum and maximum temperature,daily precipitation.The anomaly approach is applied in this interpolation.The climatology is first interpolated by thinplate smoothing splines and then a gridded daily anomaly derived from angular distance weighting method is added to climatology to obtain the final dataset.Intercomparison of the dataset with other three daily datasets,CN05for temperature,and EA05and APHRO for precipitation is conducted.The analysis period is from 1961to 2005.For multi-annual mean temperature variables,results show small differences over eastern China with dense observation stations,but larger differences(warmer) over western China with less stations between CN05.1and CN05.The temperature extremes are measured by TX3D(mean of the 3greatest maximum temperatures in a year) and TN3D(mean of the 3lowest minimum temperatures).CN05.1in general shows a warmer TX3Dover China,while a lower TN3Din the east and greater TN3Din the west are found compared to CN05.A greater value of annual mean precipitation compared to EA05and APHRO,especially to the latter,is found in CN05.1.For precipitation extreme of R3D(mean of the 3largest precipitations in a year),CN05.1presents lower value of it in western China compared to EA05.

Study of Applying USLE and Geographical Information System IDRISI to Predict Soil Erosion in Small Watershed

2000-01-01

Cai Chong

Based on the field survey in the typical small watershed, the method of geographical data base building was studied. Runoff and soil loss amount from experimental plots were used to … Based on the field survey in the typical small watershed, the method of geographical data base building was studied. Runoff and soil loss amount from experimental plots were used to generate K, C and P factors of USLE. By the support of IDRISI geographical information system and integration of the GIS and USLE, the soil erosion amount of the small watershed was predicted. Results showed that the serious eroded area (sediment is higher than 8 000 t/km 2) is 20%, but contributes 80% sediments of all watershed, while no or slightly eroded area (sediment is lower than 1 000 t/km 2) is 67%, only contributes 3% sediments.

National Assessment Report of Climate Change (I): Climate change in China and its future trend

2006-01-01

Zhang De

A New Scheme for Climate Regionalization in China

2010-01-01

Bingyuan Li

A new scheme for climate regionalization in China was established based on the daily observations for 609 meteorological stations during the period 1971-2000.During regionalization,current basic theories,classification methodologies and criteria system … A new scheme for climate regionalization in China was established based on the daily observations for 609 meteorological stations during the period 1971-2000.During regionalization,current basic theories,classification methodologies and criteria system were used,besides,five principles were taken into consideration,mainly included zonal and azonal integration,genetic unity and regional relative consistent climate integration,comprehensiveness and leading factors integration,bottom-up and top-down integration,spatial continuity and small patch omission.The new scheme consists of 12 temperature zones,24 moisture regions and 56 climatic sub-regions.

Regional Flood Frequency Analysis

1987-01-01

Correction to “Observed trends in extreme precipitation events in China during 1961–2001 and the associated changes in large‐scale circulation”

2005-09-01

Wang Yu-qing , Li Zhou

Journal of Jilin Agricultural University

2004-01-01

Xiaobo Wang , Fengbin Song , Lei Zhang +2 more

Apot experiment using paddy soil in the middle area of Jinlin orovince was cinducted to investigate the effects of zinc on the late mature japonica ruce “Nongda 3”.The resukt showed … Apot experiment using paddy soil in the middle area of Jinlin orovince was cinducted to investigate the effects of zinc on the late mature japonica ruce “Nongda 3”.The resukt showed that when the concentration was under 300 mg/kg,zinc application was favorable to the growth of rice.Rice p;ant height increased by 2.4~6.9cm,the number of leaves and tillers and tillers increased by 1.7~9.7 and 17.6~48.3 respectively,and the mature period was 5 days in advance.When the rate was above 500mg/kg,lant height decreased by 11.2~13.4cm,whit leave number 17.6~48.3 and the number of tillers 4~6 inhibited.The appearance of the most leaved and the differentiation of rice spike were delayed for 10 days and 5days,respectively.Rice yield decreased by 4.91%~43.40% in high concentrations

The climate regionalization in China for 1981-2010

2013-10-01

Quansheng Ge , JuanJuan BIAN , JingYun ZHENG +3 more

The scheme of climate regionalization in China was conducted by the classification criteria of temperature zone, arid/humid region and climatic sub-region, and the variables used in the criteria were calculated … The scheme of climate regionalization in China was conducted by the classification criteria of temperature zone, arid/humid region and climatic sub-region, and the variables used in the criteria were calculated as mean values of the 30 years by using the daily meteorological data of 658 stations from 1981 to 2010. In the classification criteria, the temperature zones were classified by the general guideline of the days with daily temperature steady above 10℃, and the secondary guideline of January mean temperature, or by their referenced variables including the accumulated temperature with daily temperature steady above 10℃ and annual minimum temperature, respectively. The arid/humid regions were classified by the annual aridity index and annual precipitation amount in turn. The climatic sub-regions were classified by the July mean temperature. The result shows that China can be divided into 12 temperature zones, 24 arid/humid regions and 56 climatic sub-regions. Compared with the climate regionalization scheme for the period of 1951- 1980, several boundaries of temperature zones in eastern China shifted northward in 1981-2010 due to the climate warming. The east part of the northern boundary of warm temperate zone shifted more than 1.0° at a maximum. On average, the east part of the northern boundary of north subtropical zone shifted 1.0°. The middle part of the northern boundary of mid-subtropical zone shifted 2.0° at a maximum. The west part of the northern boundary of south subtropical zone shifted 0.5°-2.0°. In West China, the shift of temperature zone was not significant in horizontal due to the vertical landform. However, the plateau sub-cold zone was shrunk while the plateau temperate zone was enlarged in the Tibetan Plateau. Because precipitation decreased in North China, southeastern part of Northeast China and eastern part of Northwest China, the boundary of the semi-arid and sub-humid region in Northern China shifted eastward and southward, and in which, the boundary between 36°-41°N shifted 0.5°-2.5°at longitude. Moreover, the climate in the most of arid regions and semi-arid regions in Hexi Corridor, Xinjiang and the Tibetan Plateau changed to be more humid.

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Effects of Drought Stress on Photosynthetic and Physiological Parameters of Tomato

2019-11-27

Guoting Liang , Junhui Liu , Jingmin Zhang +1 more

Drought has become an important factor limiting crop yields in China. As an important greenhouse horticultural crop in China, the research of tomato ( Solanum lycopersicum L. cv. Jinpeng No.10) … Drought has become an important factor limiting crop yields in China. As an important greenhouse horticultural crop in China, the research of tomato ( Solanum lycopersicum L. cv. Jinpeng No.10) is of great theoretical and practical significance. In the study, four different relative soil moisture contents (74% to 80%, 55% to 61%, 47% to 52%, and 25% to 30%) were used to induce drought stress. We investigated changes in photosynthetic gas exchange, chlorophyll fluorescence, and other related physiological parameters in response to different relative soil moisture contents. Drought inhibited the photosynthesis of tomato significantly, as shown by a clear decline in the net photosynthetic rate. Our results indicated stomatal limitation and nonstomatal limitation were responsible for the photosynthesis reduction.

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Prediction and analysis of net ecosystem carbon exchange based on gradient boosting regression and random forest

2020-02-10

Jianchao Cai , Kai Xu , Yanhui Zhu +2 more

Effect of Vegetation Changes on Soil Erosion on the Loess Plateau

2006-01-01

Zheng , Fen-Li

Sediment Yield Computed with Universal Equation

1972-12-01

J. R. Williams , Harold D. Berndt

Sediment yield from watersheds is predicted by modifying the Universal Soil Loss Equation and using a delivery ratio. All factors of the equation except the rainfall factor are modified to … Sediment yield from watersheds is predicted by modifying the Universal Soil Loss Equation and using a delivery ratio. All factors of the equation except the rainfall factor are modified to increase computational efficiency. In addition, the erosion-control-practice factor is expanded to include the separate effect of grassed waterways. Delivery ratios are computed for five small blackland watersheds and related to watershed characteristics. Step-wise multiple regression was used to develop equations for predicting delivery ratios. The regression analysis showed that the most important watershed characteristic, slope of the main stem channel, explains about 99% of the variation in delivery ratios. The modified Universal Soil Loss Equation and the equation for predicting delivery ratios form a sediment yield model that should be useful in reservoir design and water quality studies.

Blocking Action in the Middle Troposphere and its Effect upon Regional Climate

1950-11-01

Daniel F. Rex

Soil Fertility Evaluation and Control

2013-12-29

C. A. Black

Soil Fertility Evaluation and Control presents the theoretical background for practical applications of scientific work on soil fertility. The book emphasizes the use of response curves as the basic biological … Soil Fertility Evaluation and Control presents the theoretical background for practical applications of scientific work on soil fertility. The book emphasizes the use of response curves as the basic biological standard for both evaluation and control, and it discusses soil testing and plant analysis as secondary standards. The principal application

Predicted Forage Yield Based on Fall Precipitation in California Annual Grasslands

1970-09-01

Alfred H. Murphy

The initiation of fall forage growth in the California annual grasslands is dependent upon the first half-inch of effective rainfall. Annual yield of this forage is influenced by the amount … The initiation of fall forage growth in the California annual grasslands is dependent upon the first half-inch of effective rainfall. Annual yield of this forage is influenced by the amount of precipitation received by the third week in November. At that time a determination can be made as to whether the expected annual production will be low, medium, or high. A coefficient of correlation value (r = .70), significant at the 1% level, was obtained between yield and total rainfall through November 20.

Assessment of Crop Water Resource Utilization in Arid and Semi-Arid Regions Based on the Water Footprint Theory

2025-06-24

Yuqian Tang , Nan Xia , Yuxuan Xiao +2 more | Agronomy

The arid and semi-arid regions of Northwest China, as major agricultural production zones, have long faced dual challenges: increasing water resource pressure and severe supply–demand imbalances caused by the expansion … The arid and semi-arid regions of Northwest China, as major agricultural production zones, have long faced dual challenges: increasing water resource pressure and severe supply–demand imbalances caused by the expansion of cultivated land. The crop water footprint, an effective indicator for quantifying agricultural water use, plays a crucial role in supporting sustainable development in the region. This study adopted a multi-scale spatiotemporal analysis framework, combining the CROPWAT model with Geographic Information System (GIS) techniques to investigate the spatiotemporal evolution of crop water footprints in Northwest China from 2000 to 2020. The Logarithmic Mean Divisia Index (LMDI) model was used to analyze spatial variations in the driving forces. A multidimensional evaluation system—encompassing structural, economic, ecological, and sustainability dimensions—was established to comprehensively assess agricultural water resource utilization in the region. Results indicated that the crop water footprint in Northwest China followed a “decline-increase-decline” trend, it increased from 90.97 billion m3 in 2000 to a peak of 133.49 billion m3 in 2017, before declining to 129.30 billion m3 in 2020. The center of the crop water footprint gradually shifted northward—from northern Qinghai to southern Inner Mongolia—mainly due to rapid farmland expansion and increasing water consumption in northern areas. Policy and institutional effect, together with economic development effect, were identified as the primary drivers, contributing 49% in total. Although reliance on blue water has decreased, the region continues to experience moderate water pressure, with sustainable use achieved in only half of the study years. Water scarcity remains a pressing concern. This study offers a theoretical basis and policy recommendations to enhance water use efficiency, develop effective management strategies, and promote sustainable water resource utilization in Northwest China.

Wheat yield prediction using an enhanced WOFOST with soil stratified hydrothermal module driven by GLASS and ERA5-land products over Yellow River Basin

2025-06-19

Jing Zhang , Guijun Yang , Meiling Gao +6 more | Computers and Electronics in Agriculture

Comprehensive Analysis of the Driving Forces Behind NDVI Variability in China Under Climate Change Conditions and Future Scenario Projections

2025-06-17

Ao Li , Shuai Yin , Nan Li +1 more | Atmosphere

Climate change has a significant impact on vegetation development. While existing studies provide some insights, long-term trend analysis and multifactor driver assessments for China are still lacking. At the same … Climate change has a significant impact on vegetation development. While existing studies provide some insights, long-term trend analysis and multifactor driver assessments for China are still lacking. At the same time, research on the future vegetation development under different climate change scenarios needs further strengthening. In response to these issues, this study analyzed China’s normalized difference vegetation index (NDVI) data from 2001 to 2023, exploring vegetation cover trends, driving factors, and predicting the impact of future climate change. Firstly, this study decomposed the time series data into seasonal, trend, and residual components using the Seasonal–Trend decomposition using Loess (STL) decomposition method, quantifying vegetation changes across different climate zones. Partial least squares (PLS) regression analysis was then used to examine the relationship between NDVI and driving factors, and the contribution of these factors to NDVI variation was determined through the variable importance in projection (VIP) score. The results show that NDVI has significantly increased over the past two decades, especially since 2010. Further analysis revealed that vegetation growth is primarily influenced by soil moisture, shortwave radiation, and total precipitation (VIP scores > 0.8). Utilizing machine learning with Coupled Model Intercomparison Project Phase 6 (CMIP6) multimodel data, this study predicts NDVI trends from 2023 to 2100 under four emission scenarios (SSP126, SSP245, SSP370, SSP585), quantifying future meteorological factors such as temperature, precipitation, and radiation to NDVI. Findings indicate that under high-emission scenarios, the vegetation greenness in some regions may experience improved vegetation conditions despite global warming challenges. Future land management strategies must consider climate change impacts on ecosystems to ensure sustainability and enhance ecosystem services.

Ecosystem decoupled from water as precipitation increases in a warming Tibetan Plateau

2025-06-16

Qinhuo Liu | Research Square (Research Square)

<title>Abstract</title> Greening induced by warming and wetting in the Tibetan Plateau (TP) has given rise to novel questions about whether the ecosystem constrains should be increased. The present manuscript evaluated … <title>Abstract</title> Greening induced by warming and wetting in the Tibetan Plateau (TP) has given rise to novel questions about whether the ecosystem constrains should be increased. The present manuscript evaluated the impact of vegetation modification on water and energy limitations, and the subsequent attribution of these limitations. Interestingly, water constraint, accompanied by increased evapotranspiration (<italic>ET</italic>) due to greening, was alleviated because of increased precipitation (<italic>Pre</italic>). Water constraint shows asymmetrical trend with vegetation greening in the water- and energy-limited regions, i.e., ecosystem tends to decouple from water limitation in the water-limited regions, whereas it tends to strengthen the water constraint in the energy-limited regions. Attribution analysis indicated the complex interaction between water and energy status in controlling the ecosystem function. Although the water constraint trend tended to be alleviated in most regions in the TP, available water is still the critical role in controlling the ecosystem function. The shift of water constraint induced by the warming and wetting indicated a new equilibrium to partition the <italic>Pre</italic>. These results provided novel insight to the shift of ecosystem function and its involved hydrological effects in the TP.

Investigating spatiotemporal variability of drought and its impact on grassland GPP in Inner Mongolia

2025-06-16

Jingfang Zhang , Fanhao Meng , Min Luo +5 more | Journal of Arid Environments

Spatio-Temporal Dynamics and Contributing Factors of Irrigation Water Use in the Loess Plateau

2025-06-16

Jiayu He , Yayun Hu , Lang Shi +4 more | Land

The “Grain for Green” policy has led to a reduction in cultivated land area in the Loess Plateau, intensifying the conflict between ecological conservation and food security. As a key … The “Grain for Green” policy has led to a reduction in cultivated land area in the Loess Plateau, intensifying the conflict between ecological conservation and food security. As a key strategy to mitigate this tension, irrigated farmland has undergone significant changes in both its spatial extent and water consumption, which may further exacerbate the water crisis. Hence, the spatio-temporal dynamics and driving forces behind these changes require greater attention and have not yet been comprehensively explored. This study integrates multi-source datasets and employs piecewise linear regression and the Logarithmic Mean Divisia Index (LMDI) model to analyze the spatio-temporal evolution of cultivated land and irrigation water use. Furthermore, it quantifies the contributions of key factors such as cultivated land area, irrigation intensity, and crop planting structure to irrigation water dynamics. The results show that (1) The total cultivated land area in the Loess Plateau decreased by 12.4% from 1985 to 2020, with increases primarily concentrated along the Yellow River between Hekou and Longmen, while decreases were predominantly observed around major cities such as Xi’an, Taiyuan, and Yuncheng. Conversely, the irrigated area exhibited an overall upward trend, with minor declines occurring between 1977 and 1985. (2) While the total irrigation water use increased overall, piecewise linear regression analysis identified four distinct phases, with the first three phases showing growth, followed by a decline after 2001. (3) The expansion of agricultural irrigation areas emerged as the primary driver of increased irrigation water use, whereas advancements in irrigation efficiency effectively reduced water consumption. This study provides novel insights into the spatio-temporal dynamics of irrigation water use in the Loess Plateau and offers valuable guidance for optimizing water resource management and advancing sustainable development in the region.

Study of the Applicability of CMADS Data Based on the BTOPMC Model in the South Yunnan Region—An Example from the Jinping River Basin

2025-06-16

Hongbo Zhang , Chunyong Li , Junjie Wu +5 more | Water

Data-driven distributed hydrological models utilizing atmospheric assimilation are crucial for simulating hydrological processes, particularly in regions lacking historical observational data, and for managing and developing local water resources due to … Data-driven distributed hydrological models utilizing atmospheric assimilation are crucial for simulating hydrological processes, particularly in regions lacking historical observational data, and for managing and developing local water resources due to the impacts of climate change and human activities. The southern part of Yunnan is located at the southwestern border of China, and the small number of observation stations poses a major obstacle to local water-resource management and hydrological research. This paper carries out an evaluation of the accuracy of the China Atmospheric-Assimilation Dataset (CMADS) in southern Yunnan and uses CMADS data and measured data to drive the BTOPMC model to investigate hydrological processes in the Jinping River basin, a representative local sub-basin. The study shows that the probability density function statistic (SS) between CMADS data and the measured precipitation data is 0.941, and their probability density curves of precipitation are basically the same. The relative error of daily precipitation is −19%, with 90% of the daily precipitation error concentrated within ±10 mm/day, which increases as daily precipitation increases. This paper examines three precipitation scenarios to drive the hydrological model, resulting in Nash–Sutcliffe efficiency (NSE) coefficients of 66.8%, 81.0%, and 83.9% for calibration, and 54.5%, 70.2%, and 74.5% for validation. These results indicate that CMADS data possesses a certain degree of applicable accuracy in southern Yunnan. Furthermore, the CMADS-driven BTOPMC model is suitable for simulating hydrological processes and conducting water-resource research in the region. The integration of CMADS data with actual measurement data can enhance the accuracy of hydrological simulations. Overall, the CMADS data have good applicability in southern Yunnan, and the CMADS-driven BTOPMC model can be used for hydrological modeling studies and water-resource management applications in southern Yunnan.

Differences in the effects of 10-30-day oscillations on persistent precipitation across diverse Meiyu climate regions in China

2025-06-13

Wei Qi , Suxiang Yao , Qian Huang | Weather and Forecasting

Abstract The Meiyu season is marked by persistent precipitation, often leading to floods and landslides. Due to significant spatial variability, the China National Climate Center has defined three Meiyu monitoring … Abstract The Meiyu season is marked by persistent precipitation, often leading to floods and landslides. Due to significant spatial variability, the China National Climate Center has defined three Meiyu monitoring zones: south of Yangtze River (SYR), Yangtze River valley (YRV), and Yangtze-Huaihe valley (YHV). Analyzing the differences of persistent precipitation event (PPE) across these regions is crucial for accurately understanding precipitation patterns and effectively predicting natural disasters. This study employs ground-based observations, ERA5 reanalysis data and RegCM5.0 to examine PPE characteristics and its physical processes concerning sub-seasonal oscillation in these three Meiyu climate regions, aiming to reveal how oscillation affects the PPEs. The observations indicate PPEs last about 4-5 days on average in all three regions, while the dominant sub-seasonal scales demonstrate a period of 10-30 days. However, notable disparities exist in the fundamental mechanisms influencing PPEs, and the trajectories of oscillations also differ. In SYR, PPEs are mainly influenced by mid-high latitude oscillations, whereas in YRV and YHV, they are influenced by both mid-high and low latitudes. Numerical simulation, consistent with observed results, which further elucidates the relative significance of 10-30-day oscillations at different latitudes on PPEs across three regions. The PPEs of SYR are primarily influenced by mid-high latitude oscillations. The response of PPE in YRV to 10-30-day oscillations is consistent across mid-high and low latitudes, with a slightly stronger effect at mid-high latitudes, while in YHV, low-latitude oscillations are the primary influence. The aforementioned results can provide a fundamental basis of precursor signals for predicting Meiyu precipitation.

Spatiotemporal variation in net primary productivity and factor detection in arid and semiarid regions of China

2025-06-01

Yuru Wang , Liping A. Cai , Guoliang Liu +1 more | Deleted Journal

Analysis of Groundwater Level Dynamic Variation Characteristics and Associated Influencing Factors in the Huang-Qin Alluvial Plain

2025-06-01

Minmin Ma , Yao-Zhong Zhang , Yong Xiao +5 more | Journal of Salt Lake Research

Uncovering scale- and location-dependent variations and drivers of soil nutrients along a southeast-northwest transect of the Qinghai-Tibetan plateau using wavelet analysis

2025-05-31

Ziwei Wang , Yanwu Pei , Laiming Huang +2 more | Soil and Tillage Research

Synergistic Impact of Midlatitude Westerly and East Asian Summer Monsoon on Mid-Summer Precipitation in North China

2025-05-29

Ke Shang , Xiaodong Liu , Xiaoning Xie +4 more | Atmosphere

Midlatitude westerly and East Asian summer monsoon (EASM) are crucial circulation systems in the upper and lower troposphere of East Asia that significantly influence mid-summer precipitation pattern. However, their synergistic … Midlatitude westerly and East Asian summer monsoon (EASM) are crucial circulation systems in the upper and lower troposphere of East Asia that significantly influence mid-summer precipitation pattern. However, their synergistic effect on mid-summer precipitation in North China (NC) remains unclear. In this study, the concurrent variations of mid-summer westerly and EASM are categorized into two configurations: strong westerly–strong EASM (SS) and weak westerly–weak EASM (WW). At the synoptic timescale, the SS configuration significantly enhances precipitation in NC, whereas the WW configuration suppresses mid-summer rainfall. The underlying mechanism is that the SS pattern stimulates an anomalous quasi-barotropic cyclone–anticyclone pair over the Mongolian Plateau–Yellow Sea region. Two anomalous water vapor channels (westerly-driven and EASM-driven water vapor transport) are established in the southern and western peripheries of this cyclone–anticyclone pair, ensuring abundant moisture supply over NC. Meanwhile, frequently occurring westerly jet cores in northern NC form a jet entrance region, favoring strong upper-level divergent pumping and deep accents in its southern flank. This synergy between strong westerlies and EASM enhances both the moisture transports and ascending movements, thereby increasing precipitation over NC. Conversely, the atmospheric circulation associated with the WW pattern exhibits opposite characteristics, resulting in decreased NC rainfall. Our findings elucidate the synoptic-scale influences of westerly–monsoon synergy on mid-summer rainfall, through regulating moisture transports and westerly jet-induced dynamic uplift, potentially improving predictive capabilities for mid-summer precipitation forecasting.

Vegetation net primary productivity variation characteristics and optimization path in inland river basins of arid areas driven by ecological water conveyance: A case study of the mainstream of the Tarim river

2025-05-29

Ayong Jiao , Jia Xu , Mingjiang Deng +1 more | Ecological Indicators

Twenty-Year Variability in Water Use Efficiency over the Farming–Pastoral Ecotone of Northern China: Driving Force and Resilience to Drought

2025-05-28

Xiaonan Guo , Meng Wu , Zhijun Shen +5 more | Agriculture

Water use efficiency (WUE), as an important metric for ecosystem resilience, has been identified to play a significant role in the coupling of carbon and water cycles. The farming–pastoral ecotone … Water use efficiency (WUE), as an important metric for ecosystem resilience, has been identified to play a significant role in the coupling of carbon and water cycles. The farming–pastoral ecotone of Northern China (FPENC), which is highly susceptible to drought due to water scarcity, has long been recognized as an ecologically fragile zone. The ecological restoration projects in China have mitigated land degradation and maintain the sustainability of dryland. However, the process of greening in drylands has the potential to impact water availability. A comprehensive analysis of the WUE in the FPENC can help to understand the carbon absorption and water consumption. Using gross primary production (GPP) and evapotranspiration (ET) data from a MODerate resolution Imaging Spectroradiometer (MODIS), alongside biophysical variables data and land cover information, the spatio-temporal variations in WUE from 2003 to 2022 were examined. Additionally, its driving force and the ecosystem resilience were also revealed. Results indicated that the annual mean of WUE fluctuated between 0.52 and 2.60 gC kgH2O−1, showing a non-significant decreasing trend across the FPENC. Notably, the annual averaged WUE underwent a significant decline before 2012 (p < 0.05), and then showed a slight increased trend (p = 0.14) during the year afterward (i.e., 2013–2022). In terms of climatic controls, temperature (Temp) and soil volumetric water content (VSWC) dominantly affected WUE from 2003 to 2012; VPD (vapor pressure deficit), VSWC, and Temp showed comprehensive controls from 2013 to 2022. The findings suggest that a wetter atmosphere and increased soil moisture contribute to the decline in WUE. In total, 59.2% of FPENC was shown to be non-resilient, as grassland occupy the majority of the area, located in Mu Us Sandy land and Horqin Sand Land. These results underscore the importance of climatic factors in the regulation WUE over FPENC and highlight the necessity for focused research on WUE responses to climate change, particularly extreme events like droughts, in the future.

Long-term Simulation of Gross Primary Productivity and its Impact Evaluation Based on a Mechanism and Data Co-Driven Model

2025-05-28

Xiaojing Zhang , A Yinglan , Guoqiang Wang +6 more | Water Resources Management

Assessing the Accuracy and Consistency of Cropland Datasets and Their Influencing Factors on the Tibetan Plateau

2025-05-27

Fuyao Zhang , Xue Wang , Liangjie Xin +1 more

With advancements in cloud computing and machine learning algorithms, an increasing number of cropland datasets have been developed, including the China land-cover dataset (CLCD) and GlobeLand30 (GLC). The unique climatic … With advancements in cloud computing and machine learning algorithms, an increasing number of cropland datasets have been developed, including the China land-cover dataset (CLCD) and GlobeLand30 (GLC). The unique climatic conditions of the Tibetan Plateau (TP) introduce significant differences and uncertainties to these datasets. Here, we used a quantitative and visual integrated assessment approach to assess the accuracy and spatial consistency of five cropland datasets around 2020 in the TP, namely the CLCD, GLC30, land-use remote sensing monitoring dataset in China (CNLUCC), Global Land Analysis and Discovery (GLAD), and global land-cover product with a fine classification system (GLC_FCS). We analyzed the impact of terrain, climate, population, and vegetation indices on cropland spatial consistency using structural equation modeling (SEM). In this study, the GLAD cropland area had the highest fit with the national land survey (R2 = 0.88). County-level analysis revealed that the CLCD and GLC_FCS underestimated cropland areas in high-elevation counties, whereas the GLC and CNLUCC tended to overestimate cropland areas on the TP. Considering overall accuracy, GLC and GLAD performed the best with scores of 0.76 and 0.75, respectively. In contrast, CLCD (0.640), GLC_FCS (0.640), and CNLUCC (0.620) exhibited poor overall accuracy. This study highlights the significantly low spatial consistency of croplands on the TP, with only 10.60% consistency in high and complete agreement. The results showed substantial differences in spatial accuracy among zones, with relatively higher consistency observed in low-altitude zones and notably poorer accuracy in zones with sparse or fragmented cropland. The SEM results indicated that elevation and slope directly influenced cropland consistency, whereas temperature and precipitation indirectly affected cropland consistency by influencing vegetation indices. This study provides a valuable reference for implementing cropland datasets and future cropland mapping studies on the TP region.

Analysis of Key Influencing Factors of Water Quality in Tai Lake Basin Based on XGBoost-SHAP

2025-05-27

Weiling Li , Menghua Deng , Chang Liu +1 more

Tai Lake Basin, a key freshwater resource in eastern China, has garnered attention due to widespread cyanobacterial blooms. Effective water quality management is vital for the region’s sustainable development. Investigating … Tai Lake Basin, a key freshwater resource in eastern China, has garnered attention due to widespread cyanobacterial blooms. Effective water quality management is vital for the region’s sustainable development. Investigating the seasonal variations of water quality parameters (WQPs) in Tai Lake Basin is essential for devising targeted strategies to enhance water quality. This study employs an interpretable machine learning model (XGBoost-SHAP) to identify the most important factors of water quality using daily monitoring WQP data from 2023 to 2024. Results revealed that dissolved oxygen (DO), total phosphorus (TP), permanganate index (CODMn), and ammonia nitrogen (NH3-N) are primary determinants of water quality in the basin, while water temperature, pH, total nitrogen (TN), and turbidity showed minimal impact (SHAP value < 1). Seasonal analysis demonstrated that DO exerts a substantial influence on water quality during spring, summer, and autumn; TP and CODMn have a stable and negative impact on water quality throughout the year; NH3-N has a relatively significant negative impact on winter water quality. Recommendations include enhancing DO levels in spring and summer, fortifying TP and NH3-N concentrations in winter, and implementing tailored strategies in response to seasonal variations. This research offers valuable insights to guide decision-making processes aimed at enhancing water quality and safeguarding the water environment in the Tai Lake Basin.

Ecological projects affect ecosystem resistance and resilience to drought stress: evidence from the Yellow River Basin

2025-05-26

Donglin Fan , Wei We

Research on Interval Probability Prediction and Optimization of Vegetation Productivity in Hetao Irrigation District Based on Improved TCLA Model

2025-05-23

Jie Ren , Delong Tian , Hexiang Zheng +2 more

Vegetation productivity, as an essential global carbon sink, directly influences the variety and stability of ecosystems. Precise vegetation productivity monitoring and forecasting are crucial for the global carbon cycle. Traditional … Vegetation productivity, as an essential global carbon sink, directly influences the variety and stability of ecosystems. Precise vegetation productivity monitoring and forecasting are crucial for the global carbon cycle. Traditional machine learning algorithms frequently experience overfitting when processing high-dimensional time-series data or substantial numbers of outliers, impeding the accurate prediction of various vegetation metrics. We propose a multimodal regression prediction model utilizing the TCLA framework—comprising the Transient Trigonometric Harris Hawks Optimizer (TTHHO), Convolutional Neural Networks (CNN), Least Squares Support Vector Machine (LSSVM), and Adaptive Bandwidth Kernel Density Estimation (ABKDE)—with the Hetao Irrigation District, a vast irrigation basin in China, serving as the study area. This model employs TTHHO to effectively navigate the search space and adaptively optimize network node positions, integrates CNN-LSSVM for feature extraction and regression analysis, and incorporates ABKDE for probability density function estimation and outlier detection, resulting in accurate interval probability prediction and enhanced model resilience to interference. Experimental data indicate that the TCLA model improves prediction accuracy by 10.57–26.47% compared to conventional models (Long Short-Term Memory (LSTM), Transformer). In the presence of 5–15% outliers, the fusion of multimodal data results in a substantial drop in RMSE (p < 0.05), with a reduction of 45.18–69.66%, yielding values between 0.079 and 0.137, thereby demonstrating the model’s high robustness and resistance to interference in predicting the next three years. This work introduces a scientific approach for precisely forecasting alterations in regional vegetation productivity using the proposed multimodal TCLA model, significantly enhancing global vegetation resource management and ecological conservation techniques.

Impact Prediction of Climate Change on Crop Yield and It’s Solutions

2025-05-21

Vishal A. Bhosale , Tejas Nirmal , Aayush Bhakare +1 more

Climate change (temperature rise, erratic rainfall, humidity swings) threatens yields of wheat, rice, maize, cotton and sugarcane in Maharashtra. We integrate 25+ years of historical yield & weather data (State … Climate change (temperature rise, erratic rainfall, humidity swings) threatens yields of wheat, rice, maize, cotton and sugarcane in Maharashtra. We integrate 25+ years of historical yield & weather data (State Ag. Dept.), IoT sensing (NodeMCU ESP8266 + DHT11 + soil-moisture + NEO-6M GPS) and AI (Random Forest Regressor, CNN disease detection, Gemini chatbot). The Random Forest model achieved R² ≈0.91 (rice), 0.93 (cotton); RMSE ~0.3 t/ha. IoT-driven irrigation alerts saved 12–15% water; pilot trials showed 6–8% yield gains. Economic analysis predicts 20–25% income loss under moderate warming, half recoverable via our AI-IoT solutions. Adaptive strategies include crop recommendations, optimized sowing, disease alerts, and conversational guidance

Influence of Qinba Mountains on Summer Precipitation in the North-South Transition Zone based on WRF Simulation

2025-05-21

Bin Wang , Yiru Yang , Peter D. Clift +7 more

Abstract The Qinba Mountains (QBM) as the natural geographic and climatic boundary between north and south China, play an important role in changing the climate and ecological of the North-South … Abstract The Qinba Mountains (QBM) as the natural geographic and climatic boundary between north and south China, play an important role in changing the climate and ecological of the North-South transition zone (NSTZ). However, the influence of the QBM on precipitation in NSTZ and its process are still unclear. To reveal the influence of the QBM on the NSTZ, this study conducted topographic sensitivity experiments for Qinling Mountians, Daba Mountians and their combined effects over the NSTZ using the Weather Research and Forecasting (WRF) high-resolution numerical model. The results reveal that the elevation changed of the Qinling and Daba Mountains regulate the precipitation pattern in summer over the NSTZ. The combined effects of the Qinling and Daba Mountains have the most significant regulatory impact on precipitation, intensifying the climatic pattern of dryness in the north and wetness in the south. The uplift of the QBM resulted in a significant increase in precipitation over the Qinling and Daba Mountain regions (125.52 mm and 177.68 mm, respectively). It also resulted in a decrease in precipitation in north of the QBM (113.68 mm), causing a significant aridification of the Loess Plateau. In contrast, the change in precipitation in south of QBM is relatively small (89.21 mm). The driving mechanisms include altering the pathways of water vapor transport and vertical motion. In the QBM sensitivity experiments, the southeast-northwest oriented positive water vapor transport pathway becomes more pronounced, with the changes in terrain-induced disturbances reaching their peak, thereby modifying the pathways and directions of water vapor transport. These findings deepen our understanding of the climatic effects of mountain uplift.

Optimization of crop planting strategies in mountainous areas of North China based on mixed integer programming and Monte Carlo simulation

2025-05-18

Xinyuan Xie , Yutong Xu , Ying Qiu

In this paper, a mixed integer programming model (MIP) and Monte Carlo simulation model were established to optimize the crop planting strategy of a village in the mountainous area of … In this paper, a mixed integer programming model (MIP) and Monte Carlo simulation model were established to optimize the crop planting strategy of a village in the mountainous area of North China, considering the planting restrictions of different plots, crop growth laws and the uncertainty of external conditions. First, under stable market conditions, the MIP model can obtain the optimal planting plan for the next seven years by optimizing factors such as cultivated land area, land type restrictions, cropping constraints, legume crop planting requirements and field management. Secondly, the Monte Carlo simulation model considers the uncertainty of expected crop sales, per mu yield, planting cost and selling price, and obtains the optimal planting plan under uncertain conditions by simulating various market scenarios, effectively reducing risks and improving the robustness of returns. The results showed that the village should actively develop efficient cash crops, optimize planting structure, and adopt diversified planting strategies to cope with market risks and promote sustainable agricultural development.

Exploration of Synergistic and Redundant Information Sharing from Hydrometeorological Variables to Net Ecosystem Exchange

2025-05-14

Elizabeth Eldhose , Subimal Ghosh

Abstract Terrestrial ecosystems play a vital role in mitigating climate change by absorbing a substantial fraction of anthropogenic CO₂ emissions, with Net Ecosystem Exchange (NEE) serving as a critical metric … Abstract Terrestrial ecosystems play a vital role in mitigating climate change by absorbing a substantial fraction of anthropogenic CO₂ emissions, with Net Ecosystem Exchange (NEE) serving as a critical metric of land-atmosphere carbon flux. While individual climate variables like temperature, precipitation, and radiation are well-studied drivers of NEE, their interactions in multivariate contexts remain poorly understood. This study leverages the O-Information framework to disentangle the synergistic and redundant contributions of temperature, precipitation, vapor pressure deficit, terrestrial water storage, and photosynthetically active radiation to NEE variability. Analysing global and regional dynamics, we reveal the nature of multivariate interactions governing NEE. Globally, pairs like VPD-PAR consistently exhibit synergy, underscoring their complementary roles in driving carbon exchange, while T-VPD and T-TWS interactions are predominantly redundant. Regional analyses highlight distinct patterns of information sharing: temperate forests and semiarid regions are synergy-dominated, whereas tropical ecosystems and Arctic regions exhibit unique spatial variability in synergy and redundancy. These findings advance our understanding of how complex climate-ecosystem interactions shape carbon fluxes and offer insights for improving predictive models of NEE under changing climatic conditions.&#xD;

Regional simulation of water-carbon fluxes and winter wheat yield with assimilation of multi-source remote sensing data in the Haihe River Basin

2025-05-10

Gangqiang Zhang , Tongren Xu , Shaomin Liu +7 more

Contribution of the Northeast China Cold Vortex to the Persistent Extreme Precipitation Events over the Yangtze–Huaihe River Basin

2025-05-09

Shi Chen , Panmao Zhai , Shangfeng Li

Abstract Persistent extreme precipitation events (PEPEs) have dramatic socioeconomic impacts in the Yangtze–Huaihe River basin (YHRB). However, the possible role of the Northeast China cold vortex (NEC-CV) in modulating the … Abstract Persistent extreme precipitation events (PEPEs) have dramatic socioeconomic impacts in the Yangtze–Huaihe River basin (YHRB). However, the possible role of the Northeast China cold vortex (NEC-CV) in modulating the PEPEs over the YHRB remains unresolved. In this study, the contribution of NEC-CVs to summer precipitation is first examined over central-eastern China, which is characterized by a local and long-distance effect, along with distinct geographic variability. Limited influence is found for the areas outside a threshold of 4× radius of NEC-CV. The YHRB is one of the regions significantly affected by the NEC-CVs, which accounts for about 35%–40% of the total extreme precipitation. During 1961–2022, about 27.7% of the total PEPEs are found to be closely related to the NEC-CVs. In addition, two types of PEPEs (type W/type E) are identified based on the position of corresponding NEC-CV tracks. Significant impacts are found for the opportune configurations of NEC-CVs. The PEPEs are found to be located more westward/eastward for type W/type E, with the anomalous moisture mainly coming from the western North Pacific/South China Sea. The two PEPEs exhibit the anomalous eastward/westward extension of the South Asian high/western North Pacific subtropical high and anomalous southward shift of the upper-level jet with respect to the climatology. Meanwhile, the lower troposphere is dominated by a large-scale low pressure, strong wind shear, and intense moisture transport in the YHRB. The concurrent combinations of the upstream Ural blocking and the downstream Okhotsk blocking are favorable for the development and southward intrusion of NEC-CVs to the YHRB in type W. However, the counterparts in type E are closely associated with the upstream Baikal blocking. The precursor signals of the NEC-CVs can be detected 12/8 days prior to the peak PEPE occurrence at 500 hPa for type W/type E. Significance Statement Persistent extreme precipitation events (PEPEs) can cause catastrophic flooding. This study demonstrates the role of the Northeast China cold vortex (NEC-CV) in influencing such high-impact weather events in the Yangtze–Huaihe River basin (YHRB). Using the latest reanalysis datasets and neural network technology, we quantitatively conclude that the NEC-CVs have contributed to about 35%–40% of the total extreme precipitation and 27.7% of the total PEPEs in the YHRB over the past 60 years. The relevant PEPEs are dominated by the NEC-CVs, with the opportune configuration of the upper and lower circulation systems. These key findings present a new perspective on the meteorology of the PEPEs with implications for the medium-range weather forecasts.

Direct and indirect effects of climatic factors on ecosystem carbon and water fluxes and water use efficiency across different climatic zones in China

2025-05-09

Weiru Zhao , Junliang Jin , Zhenxin Bao +4 more

Increasing atmospheric evaporative demand across the Tibetan plateau and implications for surface water resources

2025-05-09

Shiqin Xu , Dennis P. Lettenmaier , Tim R. McVicar +7 more

Spatiotemporal Dynamics of Drought–Flood Abrupt Alternations and Their Delayed Effects on Vegetation Growth in Heilongjiang River Basin

2025-05-08

Hongjun Ma , Jiang Jing , Changlei Dai +3 more

Drought–flood abrupt alternations (DFAAs) have a greater impact on ecosystems and socioeconomic environments than lone droughts or floods. Despite the significant impact of DFAAs, research has paid little attention to … Drought–flood abrupt alternations (DFAAs) have a greater impact on ecosystems and socioeconomic environments than lone droughts or floods. Despite the significant impact of DFAAs, research has paid little attention to their evolutionary characteristics, particularly in relation to vegetation growth in the Heilongjiang River Basin. Therefore, this study focuses on the Heilongjiang River Basin and employs the DFAA Index to identify and analyze abrupt alternation events from 1970 to 2019. It also examines the annual and interannual distributions of vegetation growth changes from 2000 to 2019, based on the Normalized Difference Vegetation Index. Lastly, it utilizes correlation analysis to investigate the responsive relationship between vegetation growth and DFAA events. The results indicate the following: (1) Within the Heilongjiang River Basin, the number of drought-to-flood events increased over time, whereas the number of flood-to-drought events decreased over time. The frequency of mutation was relatively high in the northern region, low in the eastern region, elevated in spring and summer, and reduced in winter. (2) The Normalized Difference Vegetation Index was lowest in January, highest in July, and approximately 0 during the winter. The vegetation coverage reached its peak during the summer. (3) Vegetation changes in response to DFAAs exhibited a significant time lag. Vegetation changes in spring–summer lagged behind DFAA events by 3–4 months, while in summer–autumn, the lag was approximately 3 months. These results are of great significance for the early warning and prevention of DFAAs in the Heilongjiang River Basin.

Characteristics and Mechanisms of Heavy Precipitation in Spring of Eastern Himalayas

2025-05-05

Wei Peng , Xin Xu

Abstract In spring, Eastern Himalayas (EH) receives the largest amount of rainfall in South Asia. However, the characteristics and formation mechanisms of spring precipitation, especially heavy precipitation (HP), in this … Abstract In spring, Eastern Himalayas (EH) receives the largest amount of rainfall in South Asia. However, the characteristics and formation mechanisms of spring precipitation, especially heavy precipitation (HP), in this region remain poorly understood. Based on 10-yr IMERGE precipitation and the clustering approach of self-organizing map, two types of HP are revealed with the rainfall center located at the northern coast of the Bay of Bengal (BOB) and the Gangetic Plain near the foot of EH, respectively. Despite low occurrence frequency, HP contributes importantly to the total rainfall, especially after the onset of South Asian summer monsoon. The coastal and inland HP are of opposite diurnal cycles which peak in the early-afternoon and midnight, respectively. Composite analyses are conducted for the synoptic circulation patterns using the ERA5 reanalysis. The occurrence of HP is promoted by the moisture transport and uplifting of southwesterly boundary layer jet (BLJ) associated with an anomalous lower-tropospheric cyclonic circulation over BOB, which is dynamically induced by the excessive surface sensible heating (SH) over the Indian subcontinent. When the surface SH is enhanced in northwestern-central India, BLJ terminates near the northern coast of BOB, resulting in coastal-type HP. By contrast, when the enhanced surface SH mainly occurs in northwestern India, BLJ penetrates further northward to the foot of EH and thus produces inland HP. In the latter case, the interaction between BLJ and EH topography helps increase the water vapor convergence and dynamical lifting, leading to heavier precipitation than the former.

Simulation of carbon flux in tea plantation based on an improved Biome-BGC model in hilly areas of Southeast China.

2025-05-01

Yun Shao , Hengpeng Li , Jianwei Geng +3 more | PubMed

The rapid expansion of tea plantations in the hilly regions of southeastern China significantly impacts regional carbon cycle. The Biome-BGC model, commonly used to quantify carbon fluxes, lacks sufficient representation … The rapid expansion of tea plantations in the hilly regions of southeastern China significantly impacts regional carbon cycle. The Biome-BGC model, commonly used to quantify carbon fluxes, lacks sufficient representation of artificial management processes. We integrated the measured and remote-sensed leaf area index (LAI) to improve the Biome-BGC model, enhancing its simulation capabilities for the artificial management processes in tea plantations. The results showed that LAI was a crucial intermediate variable in the Biome-BGC model. Accurate simulation of LAI was the key to improve the model's precision in simulating carbon fluxes in tea plantations. The improved model significantly enhanced the simulation accuracy of gross primary productivity (GPP) and ecosystem respiration (RE), with 5-year average GPP and RE values of 1.26 and 1.19 kg C·m-2, respectively. The daily-scale R2 values reached 0.55 and 0.80, representing an increase of 44.5% for GPP and a decrease of 0.9% for RE compared to the original model. The root mean square error (RMSE) values were 0.887 and 1.030 g C·m-2·d-1, representing reductions of 50.3% for GPP and 68.4% for RE compared to the original model, respectively. At the month scale, the improved model significantly reduced the overestimation of original model resulted from insufficient representation of artificial pruning for tea plantations. The improved model could dynamically depict the impact of LAI fluctuations caused by pruning on the carbon cycle and its applicability across different time scales had been verified, which would provide technical support for quantitative research on carbon cycling in tea plantations with high-intensity anthropogenic management.

Response of gross primary productivity to compound dry-hot events in Xilingol Grassland, China.

2025-05-01

Yuan Zhang , Enliang Guo , Rui Wang +2 more | PubMed

We explored the impacts of compound dry-hot events on gross primary productivity (GPP) of the Xilingol Grassland. Based on MODIS GPP data and TerraClimate datasets, including potential evapotranspiration, maximum temperature, … We explored the impacts of compound dry-hot events on gross primary productivity (GPP) of the Xilingol Grassland. Based on MODIS GPP data and TerraClimate datasets, including potential evapotranspiration, maximum temperature, and precipitation, from 2000 to 2023 during the vegetation growing season (May to October), we constructed a standardized compound dry and hot index (SCDHI) by using the standardized temperature index (STI) and the standardized precipitation evapotranspiration index (SPEI). We then used Theil-Sen trend analysis and the Mann-Kendall non-parametric test to analyze the spatiotemporal variations of SCDHI and GPP, and used partial correlation analysis and ridge regression analysis methods to quantitatively assess the relationships between STI, SPEI, SCDHI, and GPP, as well as their relative contribution. The results showed that GPP of the study area during the growing season showed a non-significant upward trend (0.79 g C·m-2·a-1) from 2000 to 2023, while the SCDHI decreased at a non-significant rate of 0.005·a-1. In 84.3% of the study area, there was a positive correlation between SPEI and GPP, and the area with a significant negative correlation accounted for only 0.2%. In 69% of the study area, STI was negatively correlated with GPP, while in a few areas, it was positively correlated, with the area of significant positive correlation accounting for 1.8%. In most areas, SCDHI was negatively correlated with GPP, and the significant negative correlation areas were mainly distributed in the central and western parts, accounting for 47% of the area. In the study area, SPEI had the significant dominant regulatory effect on GPP in the northeastern and southern regions, STI had a relatively significant contribution to GPP in the northwestern part of Sunite Left Banner and Duolun County. Meanwhile, GPP in the western and southern regions was greatly affected by compound dry and hot events. This study is of importance for deepening the understanding of the formation mechanisms of compound dry-hot events and guiding the development of disaster prevention and mitigation strategies in the region.

Modelling and evaluation of net ecosystem productivity and its driving factors in Inner Mongolia

2025-04-30

Shuang Cui , Shuixia Zhao , Chao Li +3 more

Net ecosystem productivity (NEP) is a critical indicator for characterizing the carbon cycle dynamics within terrestrial ecosystems. This study employs six different combinations of methods for calculating Net Primary Productivity … Net ecosystem productivity (NEP) is a critical indicator for characterizing the carbon cycle dynamics within terrestrial ecosystems. This study employs six different combinations of methods for calculating Net Primary Productivity (NPP) and heterotrophic soil respiration <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m1"><mml:mrow><mml:mfenced open="(" close="" separators="|"><mml:mrow><mml:msub><mml:mi>R</mml:mi><mml:mi>h</mml:mi></mml:msub></mml:mrow></mml:mfenced></mml:mrow></mml:math> ) to estimate monthly NEP values in Inner Mongolia from 2001 to 2021. The carbon flux observation data obtained through the eddy covariance method are used to validate and evaluate these combinations, and the best NEP estimation model combination is selected, and the spatiotemporal distribution patterns of NEP along with its primary driving factors are analyzed. Results show that: 1) The NEP estimates derived from MODIS NPP combined with the Global Soil Respiration Model (GSMSR) and Bond-Lamberty’s <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m2"><mml:mrow><mml:msub><mml:mi>R</mml:mi><mml:mi>s</mml:mi></mml:msub></mml:mrow></mml:math> - <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m3"><mml:mrow><mml:msub><mml:mi>R</mml:mi><mml:mi>h</mml:mi></mml:msub></mml:mrow></mml:math> relationship model exhibit a strong correlation with validated data; 2) The NEP in Inner Mongolia shows a significant increasing trend, with an annual average value of 168.73 gC·m −2 ·a −1 , or 177.57 gC·m −2 ·a −1 when excluding barren. Forests, croplands, and grasslands are identified as the primary carbon sinks during the growing season, with average NEP values of 84.81, 46.41, and 32.95 gC·m −2 ·mth −1 , respectively; 3) Precipitation is the dominant meteorological factor driving the spatiotemporal variations of NEP across the region, contributing 72.29% to NEP during the growing season. Additionally, over 80% of areas influenced by human activities exhibit a positive impact on NEP; 4) The interannual and growing season increases in NEP are primarily attributed to climate change and anthropogenic activities, which account for 57% and 66.3% of NEP variations, respectively. These effects are particularly pronounced in the eastern forested regions and central grasslands of Inner Mongolia. The findings of this study provide valuable insights for regional carbon sink management and ecological environment protection.

Assessment of CMIP6 models for precipitation simulation and prediction of future extreme precipitation in China

2025-04-29

<p>This article evaluates the performance of 20 models from the Coupled Model Intercomparison Project phase 6 (CMIP6) in simulating precipitation over China from 1981 to 2014, with a focus on … <p>This article evaluates the performance of 20 models from the Coupled Model Intercomparison Project phase 6 (CMIP6) in simulating precipitation over China from 1981 to 2014, with a focus on interannual and seasonal variations. The evaluations results varying levels of performance among the models, with CNRM-CM6-1 identified as the best model for simulating summer extreme precipitation. Based on CNRM-CM6-1,&nbsp;future projections of extreme precipitation in China have been conducted. The results indicate that under the SSP245 scenario, maximum rainfall is projected to increase primarily in southern China and southeastern Tibet.&nbsp;Across all extreme indices, a distinct spatial pattern emerges, characterized by a "Southeastern High–Northwestern Low" distribution throughout the study period. Under the SSP585 scenario, the spatial distribution of extreme indices mirrors that of the SSP245 scenario. However, in the late 21st century, peak values of extreme rainfall indices under the SSP585 scenario are significantly higher than those observed under the SSP245 scenario.&nbsp;For total precipitation, the differences between the SSP585 and SSP245 scenarios are not significant prior to 2070. However, for other indices (SDII, RX1day, R95p), the differences between the two scenarios remain minimal before 2050. After 2050, extreme precipitation indices under the SSP585 scenario become significantly higher than those under the SSP245 scenario.</p>

Research on the optimization of crop planting strategy under multi-dimensional uncertainty —— Based on Monte Carlo simulation, linear planning and crop correlation analysis

2025-04-28

J. Y. Wang , Yang Lei , Mengjing Chen

Crop cultivation in rural areas faces challenges from diversification, plot constraints, and fluctuating market demands, posing threats to farmers' economic income stability. To address this, this paper proposes a crop … Crop cultivation in rural areas faces challenges from diversification, plot constraints, and fluctuating market demands, posing threats to farmers' economic income stability. To address this, this paper proposes a crop planting optimization model based on Genetic Algorithm (GA) for the planning period from 2024 to 2030. This model encodes planting schemes as chromosomes, simulates the natural evolution process, and maximizes economic returns through selection, crossover, and mutation operations. Additionally, nine gradient mutation rate experiments are designed to explore their impact. Meanwhile, optimal schemes are simulated and calculated for situations of crop surplus and price reductions. To address parameter uncertainty, a strategy combining Monte Carlo simulation and Linear Programming (LP) is employed to assess risk correlations and solve for optimal schemes under various scenarios. Experimental results demonstrate that this model outperforms traditional methods in enhancing returns and reducing risks, providing robust support for formulating crop planting strategies.