Satellite-based solar-induced chlorophyll fluorescence (SIF) provides novel capabilities for global vegetation monitoring, with most previous studies focusing on its relationship with gross primary productivity (GPP). Although photosynthesis and transpiration (T) are closely linked through stomatal regulation, the covariation between SIF and T remains insufficiently understood. Here, we conduct a multi-timescale assessment of the SIF-T statistical relationship across six vegetation types using three long-term reconstructed SIF datasets, including contiguous SIF (CSIF), reconstructed TROPOMI SIF (RTSIF), and China high spatial resolution SIF (HCSIF), together with tower-derived transpiration observations from 46 eddy covariance sites across China. Our findings showed positive relationships between SIF and tower-derived T across the six vegetation types based on the pooled observations at the 8-day timescale, with R2 values ranging from 0.52 to 0.78 for CSIF-T, 0.49 to 0.76 for RTSIF-T, and 0.36 to 0.70 for HCSIF-T. Temporal aggregation from 8-day to monthly resolution generally increased the explained variance of the SIF-T relationship across most ecosystems. The slopes of the linear regression (SLR) of CSIF-T and RTSIF-T were generally comparable across vegetation types, with no significant differences in most pairwise comparisons. The strength of SIF-T linear relationship in C3 crops was not superior to that in C4 crops, but the regression slopes were generally higher than those in C4 crops. Environmental conditions further affected the SIF-T relationship. Vapor pressure deficit showed a potential nonlinear influence, with weaker SIF-T relationships observed under extremely humid or dry atmospheric conditions in grasslands. The SIF-T relationship also varied along soil water content gradients across vegetation types, with stronger relationships observed in grasslands under moist soil conditions. Based on reconstructed SIF, this study clarifies the SIF-T relationship in various ecosystems, offering a critical reference to improve regional and global vegetation transpiration models.

With the continuous rise in atmospheric carbon dioxide (CO₂), the stability of forest soil carbon pools has become a key concern. However, the coupled responses of soil organic carbon (SOC) components and soil inorganic carbon (SIC), and the regulatory roles of nitrogen (N), phosphorus (P), and soluble cations, remain unclear. We conducted a soil column experiment using litter and soils from two plantation species on the Loess Plateau—Pinus tabuliformis (PT) and Quercus acutissima Carruth (QC)—under four CO₂ concentrations. Elevated CO₂ altered litter quality, with PT litter decomposing more slowly due to higher lignin content. Soil N and P responded differently to CO₂–litter interactions: QC increased nitrate-N and available P, while PT enhanced ammonium-N accumulation. Elevated CO₂ also led to losses of soluble calcium ions (Ca²⁺) and magnesium ions (Mg²⁺), along with enrichment of soluble sodium ions (Na⁺). Carbon responses showed clear differentiation between species: QC promoted minor SOC fractions and dissolved organic carbon, whereas PT favored long-term retention of plant-derived SOC and improved SIC stability. Soluble cations and N–P nutrients were identified as the main drivers of SOC and SIC variation, with Ca²⁺ and nitrate-N showing the strongest effects.,This study reveals how litter inputs, nutrients, and soluble cations jointly regulate soil carbon stability under elevated CO₂, and highlights nutrient dilution and cation loss as constraints on soil carbon sequestration. The findings support strategies to enhance forest carbon sinks in ecologically fragile regions.

In order to reveal the characteristics of the runoff and sediment yield patterns of different vegetation types under erosive rainfall in purple soil, based on the daily measured data from 2017 to 2021 at the Soil and Water Conservation Experimental Station in Hengdong County, Hunan Province, four runoff plots were selected, namely bare land, forest land, agricultural land, and grassland. By using the cluster analysis method, 132 erosive rainfall events were classified into three different rainfall types: A (with large rainfall amount, large rainfall intensity, and long duration), B (with large rainfall amount, small rainfall intensity, and long duration), and C (with small rainfall amount, large rainfall intensity, and short duration). According to the analysis, among the three types of erosive rainfall, the type with the lowest occurrence frequency was type B. The rainfall amount of the three types of rainfall had a greater impact on runoff volume than on slope erosion-induced sediment yield. The rainfall type with the largest cumulative runoff and sediment yield was type B. The cumulative runoff and sediment yield of the four land types in ascending order was bare land > agricultural land > grassland > forest land. Compared with that by bare land, the runoff and sediment reduction by forest land was higher, being 20.4% and 70.4%, respectively. Moreover, the runoff and sediment reduction by various vegetation types was the highest under type B rainfall. Overall, the sediment reduction was greater than the runoff reduction.

Karst groundwater is widely distributed in China, and karst water resources are the main source of water for human life, industry, and agriculture. To scientifically understand and rationally exploit karst groundwater, it is necessary to analyze the runoff conditions of karst groundwater. This study comprehensively applied statistical methods, Shukalev classification, reverse hydrogeochemical modeling, and Kriging interpolation in ArcGIS to analyze the hydrochemical characteristics and runoff conditions of the three karst groundwater runoff belts in the Fengfeng mining area. The results show that: (1) The hydrochemical type in the study area is mainly HCO3·SO4-Ca·Mg type, and the eastern region changes greatly, while the western region changes little; (2) The chemical reactions and water-rock interactions occurring during the flow of groundwater in different runoff belts of the study area are different; (3) The runoff conditions derived from hydrogeochemical methods are consistent with existing geological data, indicating that this method is suitable for identifying groundwater runoff conditions. In this study, the hydrogeochemical reaction of karst groundwater in the flow process is quantitatively evaluated from the spatial point of view, and the runoff conditions of different runoff belts are analyzed, so as to provide new methods and new ideas for the determination of groundwater runoff conditions.

Evapotranspiration (ET) is an important part of agricultural water consumption, yet little is known about nocturnal evapotranspiration (ETN) patterns. An eddy covariance system was used to observe ET over five consecutive years (2020–2024) during the growing season in a dry farming area of the Loess Plateau. Daytime and nocturnal evapotranspiration were partitioned using the photosynthetically active radiation threshold to reveal the changing characteristics of ETN at multiple time scales and its control variables. The results showed the following: (1) In contrast to the non-significant trend in ETN on the diurnal and daily scales, monthly ETN dynamics exhibited two peak fluctuations during the growing season. (2) The contribution of ETN to ET exhibited seasonal characteristics, being relatively low in summer, with interannual variations ranging from 10.9% to 14.3% and an annual average of 12.8%. (3) The half-hourly ETN, determined by machine learning methods, was driven by a combination of factors. The main driving factors were the difference between surface temperature and air temperature (Ts-Ta) and net radiation (Rn), which have almost equivalent contributions. Regression analysis results suggested that Ta was the main factor influencing ETN/ET at the monthly scale. This study focuses on the nighttime water loss process in dry farming fields in Northwest China, and the results provide a basis for rational allocation and efficient utilization of agricultural water resources in arid regions.

Water, food, and energy are essential resources for human survival and socio-economic development. The complex interconnections have positioned the Water-Food-Energy Nexus (WFEN) as a critical framework for achieving integrated and effective resource allocation, while maintaining the stable operation of coupled systems. This study, for the first time, proposes a novel WFEN-based multi-objective optimization framework that integrating system dynamics (SD) modeling, the non-dominated sorting genetic algorithm III (NSGA-III), and the weighted technique for order preference by similarity to ideal solution (TOPSIS) approach. This integrated framework enables dynamic, year-by-year optimization and comprehensive performance assessment across multiple scenarios, thereby facilitating rational resource allocation and enhancing overall system sustainability. The framework quantifies the impacts of key decision variables such as crop planting areas, irrigation quotas, and energy quotas on the system mechanisms, thereby revealing the complex coupling between feedback loops and policy regulation. A regional case study in Ningxia, northwest China, was conducted to implement and validate the proposed method. The SD model demonstrated high reliability, with simulation relative errors consistently below 10 % during the study period, indicating its suitability for representing the real-world conditions in the study area. The solution sets obtained from the multi-objective optimization exhibited substantial diversity and convergence, underscoring the effectiveness of the proposed integrated method. Under the top1 ranked solution selected by the weighted TOPSIS method, from 2011 to 2022, regional security indicators improved significantly: the Water Security Indicator (WSI) increased from 1.31 to 1.76, the Food Security Indicator (FSI) increased from 0.31 to 0.80, the Energy Security Indicator (ESI) increased from 0.51 to 1.05, and the Water-Food-Energy Security Indicator (WFESI) increased from 0.59 to 1.14. Incorporating integrated management principles into policymaking enables this study to break away from conventional single-sector policy frameworks. Moreover, by adjusting key variables that link across sectors, the proposed framework offers a promising pathway toward win-win synergies and sustainable prosperity in the regional water, agriculture, and energy systems.

[Objective]To explore the variation of extreme precipitation in Xiangjiang River basin and its influencing factors on sediment transport.[Methods]Daily precipitation data from 13 meteorological stations in Xiangjiang River basin and its surrounding areas during 1965-2018 were collected,and seven extreme precipitation indices were selected and calculated using the RClimDex model.The spatial distribution characteristics were analyzed by linear fitting method and five-year moving average method,and the Cv value of each index,Spearman correlation coefficients and Kendall correlation coefficients were calculated.The temporal characteristics were observed from the linear exponential change and the five-year moving average process line.M-K mutation test,Lee-Heghinian test and ordered clustering method were used to test the mutation of the average annual sediment transport in Xiangjiang River basin.The contribution rate of extreme precipitation index to the variation of sediment transport during this period was quantitatively analyzed by double accumulation curve.[Results]1)The interannual variation trend of extreme precipitation indices in the basin during 54 years showed an increasing trend except for CWD(consecutive wet days).The duration of extreme precipitation events was prolonged,and the precipitation and precipitation intensity increased significantly.2)The spatial distribution of each precipitation index was basically consistent with the topographic characteristics,and the trend was gradually increasing from the southwest to the northeast of the basin,and the maximum values of the seven indices were found at Nanyue Station.3)Abrupt changes occurred in 1984 and 1997.During 1985-1997,the extreme precipitation index R99P(extremely wet days)had the greatest impact on the reduction of sediment transport in the basin,with a contribution rate of 10.5%.During 1998-2018,the same extreme precipitation index R95P(very wet days)had a change in the reduction of sediment transport.The contribution rate was 18.1%,but the influence of extreme precipitation index on sediment transport reduction was less than 20%.[Conclusion]Extreme precipitation has a certain effect on the reduction of sediment transport in the basin,but human activities are still the main factor leading to the reduction of sediment transport.

Soil erosion is undeniably a significant cause of a variety of problems in the Upper Yangtze River (UYR), including floods, land degradation, and sedimentation in rivers. Recognizing alterations in soil erosion and its influencing variables in this area recently is a crucial scientific challenge requiring prompt solutions in regional soil erosion control. This study examines soil erosion and its influencing factors in the Jialing River Basin (JRB) from 1990 to 2018 using RUSLE and geographical detector. It focuses on the relationship between land use, landscape patterns, and soil erosion in this typical basin in the UYR. The results indicated that: (1) The average soil erosion modulus of the JRB decreased during 1990-2018, with predominant slight (< 500 t·km−2·a−1) and light (< 2,500 t·km−2·a−1) erosion intensity. Moderate and higher grades of erosion mainly occurred in the middle and lower JRB. (2) Cultivated land, forest land, and grassland accounted for over 97% of the JRB’s land use from 1990-2018, with cultivated land dominating the middle and lower areas. Over the years, there was an increase in forest land and construction areas, while cultivated land decreased. The landscape pattern was characterized by diversity, fragmentation, and decentralization. (3) The soil erosion control area (SECA), primarily situated in the middle and lower JRB, was predominantly cultivated land. Between 1990 and 2018, the SECA area underwent significant changes, with the most notable changes occurring in the lower Fujiang River Basin (FRB) and the western and middle parts of the Qujiang River Basin (QRB). The area experienced more fluctuations on the left bank of the JRB and the right bank of the JRB, specifically in the QRB and FRB. The research can serve as a reference for future decision-making on land use planning and soil erosion management in the UYR.

Study region Dali River Basin, a typical basin on the Loess Plateau (LP) in China Study focus The LP has undergone extensive ecological management in recent decades, significantly altering runoff in the region. For more scientific management of basins, it is useful to study runoff variations at multiple scales quantitatively. Dali River Basin (DRB) was used as the model basin. The impacts of climate change (CC) and human activity (HA) were quantitatively analyzed based on the features of runoff changes at multiple scales using observed hydrological data from to 1960–2020. The characteristics of potential factors influencing HA were further analyzed. New hydrological insight for the region The study showed that basin runoff was mainly concentrated during May-October. Spatially, most of the runoff originated from the middle and lower reaches, with little change in the upper reaches. Both CC and HA affected runoff variation, but their effects shifted from upstream to downstream. Apart from the upper reaches, HA was dominant in summer and autumn, whereas CC was dominant in spring and winter. Changes in runoff might be caused by temporal and spatial differences in HA, such as converting cultivated land into forests and grasslands, increasing NDVI, and constructing dams. This analysis of runoff variations at multiple temporal and spatial scales in a representative basin provides a reliable reference for the ecological management of the LP.

As advanced oxidation processes (AOPs) is considered to be a highly effective approach for degrading organic pollutants, the simultaneous coagulation and oxidation process by the Fenton-like reaction of nanoscale zero-valent iron (NZVI) and hydrogen peroxide (H2O2) is investigated to eliminate the harmful cyanobacterium Microcystis aeruginosa in this study, and the process conditions are optimized using the central composite design of response surface methodology (RSM); in addition, the removal efficiency of M. aeruginosa (in terms of chlorophyll a, Chl a) and the verifications of the antioxidant abilities, as well as extracellular organic matters (EOM) and intracellular organic matters (IOM) are investigated under the optimized conditions. Results indicate that H2O2 concentration is the key factor affecting the Chl a removal efficiency, and the maximum Chl a removal reaches 98.10% under the optimized conditions: NZVI concentration 62.82 mg L-1, H2O2 concentration 54.2 mmol L-1, pH 4.38 and rotating speed 67 rpm. The high correlation coefficient (R-2 > 0.80) of analysis of variance (ANOVA) demonstrates the RSM model is extremely significant and suitable for experimental results. Moreover, the total organic carbon (TOC) and fluorescent substances (soluble cyanobacteria metabolic byproducts, aromatic proteins II, humic and fulvic acid-like compounds) for both EOM and IOM are enhanced removal. It is speculated the removal mechanisms of the Fenton-like process of NZVI/H2O2 for cyanobacterium belongs to the combined actions of the oxidation of Fe(II)/H2O2 and the coagulation of Fe(III), which destroy the defense system and result in the removal of M. aeruginosa.

In recent years, the acceleration of urbanization in the Yangtze River Economic Belt (YREB) has brought about problems such as soil erosion, ecosystem degradation and decline in ecological service functions. Therefore, this paper selects the Fujiang River Basin (FRB) in Upper Yangtze River (UYR), and analyzes the relationship between runoff erosion power (REP) and sediment transport (ST) on the basis of analyzing the variation characteristics of hydrological elements. Based on SWAT model, a variety of scenarios are set up to quantitatively analyze the impact of different land use changes on runoff and ST and REP in the basin. The results indicated that: (1) The annual precipitation in FRB from 1960 to 2018 did not change significantly, while the annual runoff, annual ST and annual REP decreased significantly. Compared with runoff and runoff depth, the relationship between sediment transport modulus (STM) and REP is the best, especially the power function between them is better than the linear function. (2) The results of the evaluation indexes of the simulation results of the SWAT model based on the measured runoff and sediment data from 2008 to 2018 are pass and above, that is, the simulation results are considered reliable. (3) Under the five scenarios of conversion of sloping farmland to forest, conversion of dry land to paddy field and conversion of grassland to bushland and forest land, the runoff and ST in the basin decreased but the overall range was small. The simulation results of SWAT model show that the erosion of specific areas in the basin shows the greatest degree of weakening with the decrease of REP.

It is essential to systematically consider social, economic, and natural endowments in managing and allocating water resources. However, few studies have comprehensively quantitatively evaluated the allocation of regional water resources from a socio-hydrology perspective and provided recommendations. To explore this research gap, we have constructed a tightly coupled framework that integrates system dynamics models and optimization algorithms to carry out an innovative redistribution of water resources in Shaanxi Province. The system dynamics model simulation results showed that the error was almost always within 10% over the research period, indicating robust simulation capability and laying a solid foundation for subsequent model coupling. The coupled model achieves convergence in approximately 30 generations by formulating the optimization problem with four individual objectives. Optimizing four objectives concurrently results in convergence around the 150th generation. The optimized Pareto solution sets visually demonstrate the trade-offs between different objectives. In the optimized water allocation schedule, the water consumption in Yulin exhibits a change of 1.22 ×108m3, reflecting the most significant optimization effects on agricultural and domestic water allocation. The results indicated that the comprehensive Gini coefficient typically ranged between 0.2 and 0.3. Over the period from the year 2010-2021, the Gini coefficient exhibited a declining trend, signifying a positive trajectory in water resource allocation throughout the research period and a high level of fairness. The annual total green WF of grain in Weinan was the highest at 14.26 ×108m3, followed by Xianyang at 9.52 ×108m3, and the lowest in Tongchuan at 0.54 ×108m3. The annual average amount of blue WF of grain is the highest in Hanzhong, at 11.33 ×108m3, followed by Weinan at 9.60 ×108m3, and the lowest in Tongchuan at 0.14 ×108m3. The coupled framework proposed in this study exhibits significant innovation, scalability, and practical efficiency. It can inspire future research and decision-making and holds the potential for application in other regions.

Plant phenology is an important indicator of the impact of climate change on ecosystems. We have continuously monitored vegetation phenology using near-surface remote sensing, i.e., the PhenoCam in a gully region of the Loess Plateau of China from March 2020 to November 2022. In each image, three regions of interest (ROIs) were selected to represent different types of vegetation (scrub, arbor, and grassland), and five vegetation indexes were calculated within each ROI. The results showed that the green chromatic coordinate (GCC), excess green index (ExG), and vegetation contrast index (VCI) all well-captured seasonal changes in vegetation greenness. The PhenoCam captured seasonal trajectories of different vegetation that reflect differences in vegetation growth. Such differences may be influenced by external abiotic environmental factors. We analyzed the nonlinear response of the GCC series to environmental variables with the generalized additive model (GAM). Our results suggested that soil temperature was an important driver affecting plant phenology in the Loess gully region, especially the scrub showed a significant nonlinear response to soil temperature change. Since in situ phenology monitoring experiments of the small-scale on the Loess Plateau are still relatively rare, our work provides a reference for further understanding of vegetation phenological variations and ecosystem functions on the Loess Plateau.

[Objective]This study examines the impact of climate change and human activities on baseflow variability across four representative watersheds within the Loess Plateau:the Wuding River,Kuye River,Yan River,and Tutai River.[Methods]Utilizing daily flow data from 1965 to 2017 for the Wuding,Kuye,and Yan rivers,and from 1983 to 2017 for the Tutai River,alongside multi-site meteorological data,we evaluated the applicability of nine baseflow separation methods and characterized baseflow variations.Contributions of climate change and human activities to baseflow changes were quantified using the elasticity coefficient method within the Budyko framework.[Results]The F4 digital filtering method exhibited superior performance in terms of stability,dispersion,and error metrics,making it the most suitable method for the typical watersheds of the Loess Plateau.Trends in annual baseflow depth,annual runoff depth,and annual baseflow index were consistent across the four watersheds,with multi-year average baseflow indices(BFI)of 0.64,0.42,0.28,and 0.49,respectively.Significant decreasing trends(p＜0.01)were observed in both annual baseflow depth and runoff depth,while the annual baseflow index showed increasing trends.The contributions of precipitation,potential evapotranspiration,and human activities to the changes in baseflow ranged from-56.72％to 33.92％,-0.81％to 55.16％,and 10.92％to 104.37％,respectively.[Conclusion]The findings underscore that human activities are the principal drivers influencing baseflow evolution in the Loess Plateau area,offering theoretical support for integrated water resource management in the region.

To tackle ecological problems, many ecological restoration projects have been implemented in northern China. Identifying the drivers of vegetation change is critical for continued ecological engineering. In this study, three typical ecological reserves in the Three-North Shelter Forest Program Region (TNSFR) were selected to identify their vegetation development characteristics and driving mechanisms using the normalized difference vegetation index (NDVI), climate factors, and land use data. The results show that (1) NDVIs increased in the range of human activities of all of the three ecological reserves, indicating an obvious effect of the vegetation restoration projects. (2) In the planting period, vegetation restoration was mainly correlated with human activities. After entering the tending period, the impact of climate changes on vegetation dynamics was enhanced. (3) Temperature and precipitation provided approximate driving effects on vegetation dynamics in Region I, while vegetation dynamics in Regions II and III were more strongly correlated with precipitation. (4) The proportion of areas with ecological measures exceeded 50% in all three regions. In short, ecological projects in the three ecological reserves dominated the quantity of vegetation restoration, while climate changes influenced the quality of vegetation restoration.

As an erosion dynamic index considering the three elements of flood, runoff erosion power (REP) can better reflect the influence of precipitation, underlying surface, and other factors on the erosion and sediment transport (ST) of flood events. Therefore, it is of great significance to study the variation characteristics of the REP and its relationship with ST in the basin for soil erosion control. In this paper, the Fujiang River Basin (FRB) was selected to analyze the characteristics of runoff and ST at four hydrological stations in the basin from 2009 to 2018, including Santai, Jiangyou, Shehong, and Xiaoheba. Combined with the concept of the REP, six kinds of water–sediment relationship were compared and analyzed. Furthermore, by constructing the SWAT model, the spatial distribution characteristics of runoff, ST, and REP in the FRB were analyzed in depth, and the spatial scale effect of the REP in the basin was explored. The conclusions are as follows: (1) The power function relationship between REP and sediment transport modulus (STM) is better than the other five kinds of water–sediment relationship. (2) Based on the SWAT model, the evaluation indexes of the monthly runoff and ST of the four hydrological stations are credible, good, and excellent in the rating period (RP) and the validation period (VP). (3) The annual REP in the main stream from upstream to downstream is mostly a single change trend, while in each primary tributary, the overall value is larger than that of the main stream and the interannual difference is obvious. The average annual REP generally shows the distribution characteristics of ‘large at the junction of the upper and middle reaches and small in the rest of the area’. With the increase in the control area, the multi-year average REP has a decreasing trend, especially when the catchment area above the sub-watershed is >7318 km2; the change of the multi-year average REP is single and obviously slows down, with an average value of 23.8 mm·m3·s−1·km−2.

Yudiba dam serves as an effective measure for controlling gully erosion and mitigating soil and water loss in the Loess Plateau.Its role in reducing sediment yield and transport in watersheds is achieved by temporarily obstructing or slowing down floodwaters,thereby retaining sediment and preventing silting into the river.With the ecological protection of the basin becoming more and more scientific and reasonable,it is necessary to quantitatively and accurately analyze the sediment retention of Yudiba dams in different stages in order to evaluate their real and specific benefits in the control of water and soil loss,which can provide a reference for the precise implementation of high-quality development in the Yellow River Basin.By consulting the literature and data of related research on Yudiba dams at home and abroad,combined with field investigation and sampling,laboratory instrument testing and subsequent related research experience,this paper systematically summarizes seven methods for analyzing the sediment retention of Yudiba dams:field investigation,topographic mapping method,mathematical attribution method,cause analysis method,weight coefficient method,model simulation method and dating analysis in fingerprint identification technology.The principle,steps,applicability and problems to be solved of each method are described,and the follow-up sediment retention analysis of Yudai Dam is prospected,with a view to providing reference for further accurate quantitative analysis of sediment retention of Yudiba dams.

受气候变化和人类活动影响,近几十年黄土高原地表环境和水碳通量发生显著变化,对区域水资源和生态系统格局产生深刻影响.基于植被界面过程(VIP)遥感蒸散发模型,对退耕还林(草)工程实施以来黄土高原蒸散量(ET)时空变化格局进行模拟研究,揭示了近 20 年黄土高原水碳通量时空演变特征及其原因.结果表明:(1)2000-2019 年黄土高原ET总体呈显著上升趋势(P＜0.05),倾向率为 3.77 mm/a,其中黄河中游黄土丘陵沟壑区ET增长最为显著,而陕西关中平原东部、宁夏银川平原南部等农业区则呈显著下降趋势,倾向率为-5.68 mm/a;(2)气候变量和归一化植被指数(NDVI)对ET显著上升区的区域平均贡献分别为 14.7%和 78.6%(其中人类活动贡献为 70.5%),而对ET显著下降区的区域平均贡献分别为-58.4%和-31.5%(其中人类活动贡献为-31.6%),表明人类活动和气候变化分别主导了ET显著上升区和ET显著下降区的蒸散变化;(3)在气候变化主导区域,气温和降水量分别为能量受限区和水分受限区ET增加的主导气象因子,而气溶胶浓度升高导致的日照时数和地表风速下降对作物碳同化和蒸腾具有显著的抑制作用,成为农业区ET下降的主导气象因子.

河川径流变化受到人类活动和气候变化影响,探究其主要影响因素与影响过程是当前学科研究的热点问题之一.本文以陕北黄土高原区佳芦河为研究对象,采用 Mann-Kendall 线性回归法对干、湿季水文气象要素进行趋势分析;采用滑动F检验法、滑动T检验法和Lee-Heghinian检验法等进行径流变异性分析;采用abcd模型与基于扩展的 Budyko 模型的季尺度垂直分解法进行径流变化影响因素量化分析.结果表明:佳芦河流域干季和湿季降水均有不显著上升趋势,气温均呈显著上升,潜在蒸散发干季显著上升、湿季不显著上升,而干湿两季径流都具有显著下降趋势.干季和湿季径流序列分别在 1972 年和 1984 年发生突变.人类活动是佳芦河流域干季和湿季径流减少的主要原因,人类活动和气候变化对干季径流的影响分别为减少 2.2 mm∕月和增加 0.07 mm∕月,对湿季径流序列的影响分别为减少7.84 mm∕月和增加0.92 mm∕月.模型模拟效果较好,适用于佳芦河流域径流变化研究.

全面深入提升高校教师能力素养，是新时代推进科教兴国战略、培养符合社会发展要求的高素质人才的客观需要。青年教师是高校师资力量的重要组成部分，本文从新时代高校青年教师担当使命的能力需求出发，设计了能力素养指标框架，从而以此为支撑，提出了全面培养新时代高校青年教师能力素养的基本策略。