Yongqiang Zhang

Institute of Geographic Sciences and Natural Resources Research, CAS · Key Laboratory of Water Cycle and Related Processes

Baseflow is pivotal in maintaining catchment ecological health and improving sustainable economic development. The Yellow River Basin (YRB) is northern China's most important water supplier. However, it faces water shortage due to synergistic effects between natural conditions and anthropogenic activities. Investigating baseflow characteristics qua...

Plain Language Summary Water is essential to agricultural production. Increasing water consumption in water supply limited areas may result in a water crisis and threaten sustainable food security, especially in China, the most populated agricultural country in the world. There are continuous arguments regarding the matches between agricultural wat...

Extreme riverine floods and hydrodynamic response of downstream lakes are the main focus of catchment flood control, especially under climate change. In this study, future changes in the extreme floods and their hydrodynamic responses are projected by driving the external coupling of the hydrological and hydrodynamic models using the precipitation...

Recent forest fires potentially intensify flood hazards. However, forest fire amplification of floods is not well understood at a large scale due to the complex compound impacts of forest fires and climate variability, while available small‐scale cases may not represent regional changes. Here, we show that the 2019–2020 mega forest fires in southea...

[目的]探究气候因素驱动下沂河流域暴雨径流的变化规律，阐释流域暴雨径流的影响因素，为深入理解流域水文响应过程和水资源管理提供科学参考。[方法]利用改进后的Lyne-Hollick数字滤波法估算了沂河流域的暴雨径流量，通过水文信号方法与皮尔逊相关系数法，定量分析沂河流域暴雨径流的变化特征及影响因素。[结果](1) 1975—2000年，流域年均暴雨径流指数SFI呈缓慢下降趋势(R2=0.37,p<0.01),年际SFI下降率0.048/10 a,暴雨径流占河川径流比重下降；(2)年均暴雨径流量呈波动增加趋势(R2=0.04,p=0.35),于1998年达到研究时段峰值；(3)暴雨径流量年内季节分配差异显著，年内暴雨径流量峰值出现在7—9月，夏季暴雨径流Q(s(sf))与冬季暴雨径流Q(w(sf...

Heatwaves have increased significantly in recent decades, seriously affecting the biosphere. The vegetation canopy is altered by heatwaves through high temperatures and water deficit, adversely affecting the ecosystem's health. However, how the canopy resilience of different ecosystems responding to heatwaves behaves remains less understood. Canopy...

Climate change and increasing water use associated with socio-economic growth have exacerbated the water crisis in many parts of the world. Many regional studies rely on Earth System Models that, however, do not fully exploit streamflow observations. Here we offer an observation-based approach to predicting streamflow change on the basis of the ela...

以滦河山区流域为研究对象，运用趋势检验、经验正交、Budyko敏感性系数等方法，对流域气象和水文要素及土地利用数据进行分析，探讨了变化环境下滦河山区流域水文响应过程。结果表明：（1）1961-2018年滦河山区流域降水呈不显著下降趋势（-3.4mm/10a），潜在蒸散发呈显著下降趋势（-7.5mm/10a），且二者空间变化方向具有一致性；径流呈显著下降趋势（-4.1亿立方米/10a），并呈现出干湿交替的周期变化特征；（2）在人类活动影响下，整个变化期（1980-2018年）径流量减少11.8亿立方米；（3）归因分析表明，气候在径流变化的贡献中占比27.2%，人类活动的贡献度达69.6%，是引起滦河山区径流量减少的主要因素。 Trend Test, Empirical orthogonal...

Projections of future climate change for given CO2 and other greenhouse gas emission scenarios depend on the response of global climate-carbon cycle feedback, which consists of carbon-concentration feedback (e.g., CO2 physiology effect on land carbon sink) and carbon-climate feedback (e.g., CO2 radiative effect on land carbon sink). Previous studie...

Understanding the runoff response to climate change in the Tibetan Plateau (TP) is critical to water resources management since TP is the “Water Tower of Asia” and is sensitive to climate change. However, previous studies have paid more attention to the changes in annual and monthly runoff. Therefore, the changes in the characteristics of floods an...

Accurate high-resolution actual evapotranspiration (ET) and gross primary production (GPP) information is essential for understanding the large-scale water and carbon dynamics. However, substantial uncertainties exist in the current ET and GPP datasets in China because of insufficient local ground measurements used for model constraint. This study...

Vegetation greening profoundly impacts the water cycle, and recent concerns about greening impacts have focused on various hydrological cycle components. However, the impacts of greening on catchment runoff signatures reflecting magnitude, low/high flow frequency, low/high flow duration and flow dynamics remain poorly understood. To properly simula...

Inter-decadal surface solar radiation (SSR) changes are closely related to climate change, such as global or regional warming, glacial melting, hydrological and carbon cycles, anthropogenic emissions of greenhouse gases and aerosols etc. Attributing the SSR trends is important for understanding these processes, however, the relative importance of a...

Understanding and exploring hydrological or soil moisture drought due to meteorological drought under changing climate is crucial for drought early warning. Previously, different methods were used to calculate drought propagation from one state (meteorological (M)) to another (hydrological (H) or soil moisture (SM)). However, each method has its pr...

While bushfires are often regarded as a vital trigger that alters the partitioning of hydrological fluxes, their role in water balance changes remains poorly quantified, especially in regions where the impacts of frequent bushfires and climate variability overlap. Here, we estimated the fire-induced water balance changes based on a modified paired...

Irrigation cools near surface air temperature by increasing evapotranspiration from wetter soil. However, elevated evapotranspiration can also increase atmospheric albedo and enhance the local greenhouse effect via increased atmospheric water vapor. Their net effects on daily air temperature remains controversial. Here we show that in several consi...

Climate change is a significant force influencing catchment hydrological processes, such as baseflow, i.e., the contribution of delayed pathways to streamflow in drought periods and is associated with catchment drought propagation. The Weihe River Basin is a typical arid and semi-arid catchment on the Loess Plateau in northwest China. Baseflow play...

Quantitative and qualitative knowledge about the potential impacts of climate change on extreme hydrological events is crucial for water resource management and extreme risk management under climate change. This has theoretical and realistic implications to study and couple the climate system with hydrologic processes, to understand the system and...

A combination of in-situ climatic variables and remote sensing data could provide dynamic information that facilitates to get effective dryness or wetness situations for planetary ecosystems. Thus, the traditional standardized precipitation evapotranspiration index (SPEI) was revisited by drought index (DI) using satellite soil moisture data and la...

Flooding is a major natural hazard that poses serious threats to lives and property safety, but changes in the multidimensional behavior of global floods (magnitude, frequency, and duration) are still not well understood. Additionally, a quantitative assessment of drivers that control multidimensional flood changes across the globe is currently una...

Check dam is an important soil and water conservation engineering measure for the prevention and control of soil erosion on the Loess Plateau in China. However, how the check dams influence runoff at different catchments remains unclear. This study uses a modified hydrological model (SWAT-PML) to quantitatively distinguish the impact of check dams...

Accurate high-resolution actual evapotranspiration (ET) and gross primary production (GPP) information is essential for understanding the large-scale water and carbon dynamics. However, substantial uncertainties exist in the current ET and GPP datasets in China because of insufficient local ground measurements used for model constrain. This study u...

Northwest China has experienced a warming-wetting climate featured by increasing temperature and precipitation during the past six decades. Recent studies suggested that the climate may have shifted from wetting to drying after the 1990s if changes in energy supply was considered. However, how the change in energy supply affects the dryness remains...

Evaluation of peak flood magnitude and frequency in the future at a catchment scale under global warming is crucial for water resource management and flood risk management. Climate model outputs provide a leading source of information to quantify the effect of the foreseen natural and anthropogenic climate change on the environment and natural syst...

Image classification often produces large deviations between land use and land cover (LULC) datasets and the ‘real’ changes, leading to uncertainty in the results of LULC related assessments and the propagated impacts through modelling. LULC products are widely used as input for various large-scale climatic, ecological and hydrological models, but...

One of the most important factors concerning the design of earth-fill dams is the accurate seepage estimation, which is highly correlated to the permeability and hydraulic conductivity of the core material. With the geographic coordinates of 37°31'35.9,“ North and 46°07'55.6” East, Gale chay dam is located in the northwest of Iran in East Azerbaija...

Alpine grassland is the dominant land cover type of the Tibetan Plateau (TP). Previous studies suggested that TP's climate and vegetation condition have changed substantially in past few decades. However, the impacts of such changes on ecosystem water use efficiency (WUE), a vital index for depicting the tradeoff between water loss and carbon gain,...

Root zone soil moisture (RZSM) is particularly useful for understanding hydrological processes, plant-land-atmosphere exchanges, and agriculture- and climate-related research. This study aims to estimate RZSM across China by using a one-parameter (T) exponential filter method (EF method) together with a random forest (RF) regionalization approach a...

Surface soil moisture (SSM) is crucial for understanding the hydrological process of our earth surface. The passive microwave (PM) technique has long been the primary tool for estimating global SSM from the view of satellites, while the coarse resolution (usually >∼10 km) of PM observations hampers its applications at finer scales. Although quantit...

Accurately estimating actual evapotranspiration (ET) across global land surface is one of the key challenges in terrestrial hydrological cycles and energy flux balance studies. Gridded ET products have the potential for application in ungauged basins, but their uncertainties are possibly large and it remains unclear which one is best for a given ba...

In this paper two enhanced long-short-term memory (LSTM) models of sequenced-LSTM (SLSTM) and wavelet-LSTM (WLSTM), provided for multi-step-ahead simulation of solar irradiance of six stations, located in Iran and USA. In this respect, twenty-year recorded solar irradiance and climate data were employed. The proposed multi-frequency models serve al...

Large-scale afforestation program has alleviated environmental problems to some extent in China. However, the response of hydrological processes to vegetation greening at different catchments remains unclear. This study identified the impact of vegetation changes on runoff (Q), evapotranspiration (ET), and soil water storage (SW), as well as their...

Global warming and anthropogenic activities have imposed noticeable impacts on rainfall pattern changes at both spatial and temporal scales in recent decades. Systematic diagnosis of rainfall pattern changes is urgently needed at spatiotemporal scales for a deeper understanding of how climate change produces variations in rainfall patterns. The obj...

It is well known that global ecosystem water-use efficiency (EWUE) has noticeably increased over the last several decades. However, it remains unclear how individual environmental drivers contribute to EWUE changes, particularly from CO2 fertilization and stomatal suppression effects. Using a satellite-driven water-carbon coupling model—Penman-Mont...

In this study, first to identify the patterns of groundwater level (GWL) over the Ghorveh-Dehgolan plain (GDP) located in western Iran, as a data pre-processing scheme, three different types of clustering algorithms were applied to monthly GWL data sets of the piezometers. Then, the best structures of all clustering methods were integrated by Combi...

Satellite‐derived vegetation indices (VIs) provide a way to analyse vegetation phenology over decades globally. However, these data are often contaminated by different kinds of optical noise (e.g. cloud, cloud shadow, snow, aerosol), making accurate phenology extraction challenging. We present an open‐source state‐of‐the‐art R package called to ext...

While terrestrial evapotranspiration (ET) from the Tibetan Plateau (TP) plays a key role in modulating water storage change in the Asian Water Tower, the magnitude, trend, and drivers of ET remain poorly understood in this region due partially to sparse ground measurements. This study used a water-carbon coupled biophysical model, Penman-Monteith-L...

The runoff of Chandra river basin in the Himalayan India was assessed using a hydrological model combined with satellite remote sensing observations. During a test period between 2000 and 2015, in situ measurements of runoff and meteorological parameters were conducted in the glacial catchment areas of Sutridhaka and Chhotashigri. A good agreement...

Drought in the Mongolian Plateau (MP) has gradually intensified in recent decades. The energy and water cycles are key factors affecting drought. However, there are few quantitative studies on the mechanism of aridity change in this region. This study uses the ERA5, Moderate Resolution Imaging Spectroradiometer (MODIS) and Himawari 8 datasets and i...

Streamflow elasticity to precipitation, defined as the percent change of streamflow resulting from a 1% change in precipitation, is sometimes used as an alternative to rainfall‐runoff models in climate impact analyses. Elasticity is usually estimated from long streamflow and precipitation series aggregated at annual time steps while the climate imp...

Baseflow is paramount to sustain the ecological integrity of river catchments. Identifying baseflow characteristics and influencing factors can facilitate the understanding of the water budget of catchments. In this study, a revised one parameter digital filter was used to separate baseflow from total daily streamflow in 18 mountainous catchments a...

Surface soil moisture (SSM) is crucial for understanding the hydrological process of our earth surface. Passive microwave (PM) technique has long been the primary tool for estimating global SSM from the view of satellite, while the coarse resolution (usually >~10 km) of PM observations hampers its applications at finer scales. Although quantitative...

Numerous studies have projected that drought will become more severe under changing climatic conditions which will have a profound impact on terrestrial ecosystems around the world. While a wide range of drought indices has been extensively applied to assess droughts, various issues have been raised, such as over- or underestimation of drought cond...

Evapotranspiration (ET), as a key exchanging component of the land energy, water and carbon cycles, is expected to increase in response to greening land under a warming climate. However, the relative importance of major drivers (e.g., leaf area index (LAI), climate forcing, atmospheric CO2, etc.) to long-term ET change remain largely unclear. Focus...

In recent times, significant research has been carried out into developing and applying soft computing techniques for modeling hydro-climatic processes such as seepage modeling. It is necessary to properly model seepage, which creates groundwater sources, to ensure adequate management of scarce water resources. On the other hand, excessive seepage...

Wildfires are common in Australia and can cause vegetation loss and affect hydrological processes such as interception, evapotranspiration, soil water storage and streamflow. This study investigates wildfire impacts on catchment mean annual streamflow for 14 Australian catchments that have been severely impacted by the 2009 Victoria wildfire, the s...

In this study, the snowmelt runoff model (SRM) was employed to estimate the effect of snow on the surface flow of Aji-Chay basin, northwest Iran. Two calibration techniques were adopted to enhance the calibration. The multi-station calibration (MSC) and single-station calibration (SSC) strategies applied to investigate their effects on the modeling...

Light use efficiency (LUE) defines the vegetation efficiency of converting radiative energy into biochemical energy through photosynthesis. Estimating the maximum LUE (ε max) is critical yet challenging for quantifying gross primary production (GPP) using LUE-based models. This study describes an analytical method for estimating ε max based on wate...

Remotely sensed geophysical datasets are being produced at increasingly fast rates to monitor various aspects of the Earth system in a rapidly changing world. The efficient and innovative use of these datasets to understand hydrological processes in various climatic and vegetation regimes under anthropogenic impacts has become an important challeng...

While large-scale terrestrial evapotranspiration (ET) information is essential for our understanding of the Earth's water and energy cycles, substantial differences exist in current global ET products due partly to uncertainties in soil- and vegetation-related parameters and/or precipitation forcing. Here a calibration-free complementary relationsh...

Satellite-derived land surface temperature (LST) data are most commonly observed in the longwave infrared (LWIR) spectral region. However, such data suffer frequent gaps in coverage caused by cloud cover. Filling these 'cloud gaps' usually relies on statistical reconstructions using proximal clear sky LST pixels, whilst this is often a poor surroga...

Runoff signatures, including low flow, high flow, mean flow, and flow variability, have important implications on the environment and society, predominantly through drought, flooding, and water resources. Yet, the response of runoff signatures has not been previously investigated at the global scale, and the influencing mechanisms are largely uncle...

Most polar-orbit-satellite based passive microwave radiometers, e.g. AMSR-2 and the FY-3B Microwave Radiation Imager (FY3B-MWRI), have the revisit cycles of ~2 days in low latitudes. This indicates that requirement of complete global coverage on the daily basis has not been met. On the other hand, using synergistic observations from different radio...

Elevation in atmospheric carbon dioxide concentration (eCO2) affects vegetation water use, with consequent impacts on terrestrial runoff (Q). However, the sign and magnitude of the eCO2 effect on Q are still contentious. This is partly due to eCO2-induced changes in vegetation water use having opposing responses at the leaf scale (i.e., water-savin...

Over the recent decades, the increase of atmospheric carbon dioxide (CO2) concentration has caused large effects on the earth system. However, few studies have paid attention to the effects of heterogeneity of CO2 on the biosphere and the hydrosphere. Using a coupled diagnostic biophysical model (PML-V2) and comparing three heterogeneous CO2 datase...

Drought is a natural phenomenon caused by extreme and persistent precipitation shortage. This shortfall causes impacts on hydrology, agriculture, and the economy of a country. Secondly, drought/dryness has certain unique characteristics (severity, duration) among natural hazards which makes it difficult to classify the persistent and subjective net...

Development and use of global, continental, and country scale hydrological models has attracted an increasing attention over the last two decades. Though developed countries are a head in development and assessment of these models, most developing countries, if not all, even do not have their own models. Therefore, an appropriate model selection pr...

Numerous studies have separated the impacts of climate change and human activities on streamflow. However, the uncertainties of various methods applied for separating such impacts are seldom studied. Here, we comprehensively investigated the uncertainty and causality of eight methods (two statistical methods, two sensitivity coefficient methods and...