Profile soil moisture (PSM), the soil water content in the whole soil layer, directly controls the major processes related to biological interaction, vegetation growth, and runoff generation. Its spatial heterogeneity, which refers to the uneven distribution and complexity in space, influences refined spatial management and decision-making in ecological, agricultural, and hydrological systems. Satellite instruments and hydrological models are two important sources of spatial information on PSM, but there is still a gap in understanding their potential mechanisms that affect spatial heterogeneity. This study is designed to identify the spatial heterogeneity and the driving factors of two PSM datasets; one is preprocessed from a satellite product (European Space Agency Climate Change Initiative, ESA CCI), and the other is simulated from a distributed hydrological model (the DEM-based distributed rainfall-runoff model, DDRM). Three catchments with different climate conditions were chosen as the study area. By considering the scale dependence of spatial heterogeneity, the profile saturation degree (PSD) datasets from different sources (shown as ESA CCI PSD and DDRM PSD, respectively) during 2017 that are matched in terms of spatial scale and physical properties were acquired first based on the calibration data from 2014–2016, and then the spatial heterogeneity of the PSD from different sources was identified by using spatial statistical analysis and the semi-variogram method, followed by the geographic detector method, to investigate the driving factors. The results indicate that (1) ESA CCI and DDRM PSD are similar for seasonal changes and are overall consistent and locally different in terms of the spatial variations in catchment with different climate conditions; (2) based on spatial statistical analysis, the spatial heterogeneity of PSD reduces after spatial rescaling; at the same spatial scale, DDRM PSD shows higher spatial heterogeneity than ESA CCI PSD, and the low-flow period shows higher spatial heterogeneity than the high-flow period; (3) based on the semi-variogram method, both ESA CCI and DDRM PSD show strong spatial heterogeneity in most cases, in which the proportion of C/(C0 + C) is higher than 0.75, and the spatial data in the low-flow period mostly show larger spatial heterogeneity, in which the proportion is higher than 0.9; the spatial heterogeneity of PSD is higher in the semi-arid catchment; (4) the first three driving factors of the spatial heterogeneity of both ESA CCI and DDRM PSD are DEM, precipitation, and soil type in most cases, contributing more than 50% to spatial heterogeneity; (5) precipitation contributes most to ESA CCI PSD in the low-flow period, and there is no obvious high contribution of precipitation to DDRM PSD. The research provides insights into the spatial heterogeneity of PSM, which helps develop refined modeling and spatial management strategies for soil moisture in ecological, agricultural, and hydrological fields.

Under global climate changes, the temperature and precipitation on the Tibetan Plateau changed significantly, causing accelerated melting of glaciers and snow and changes in runoff. The response of runoff and its components to climate change is important for water resource management and ecology conservation in the region. Therefore, the Spatial Processes in Hydrology model, a distributed cold-zone hydrological model that contains a glacial ablation module, was used to simulate runoff in the Yangtze River source located in the middle of the Tibetan Plateau during 2000-2050, and the Nash-Sutcliffe efficiency coefficient, relative error and coefficient of determination (R-2) for the calibration period and validation period revealed that the model performed well in most years. The results showed that rainfall runoff contributed the most to the total runoff (61%), followed by baseflow (23%), snowmelt runoff (12%) and glacier runoff (4%) in the Yangtze River source during 2000-2020. The runoff amounts of the three source rivers, Dangqu River, Tuotuo River and Chumar River, accounted for approximately 53% of the total runoff in the Yangtze River source basin, with rainfall runoff (52%) contributing the most and glacier runoff (6%) contributing the least. Compared to the contributions of glacial runoff in the Dangqu River (9%) and Tuotuo River (7%), the proportion of glacial runoff in the Chumar River is small (1%). Under the CMIP6 climate model, the mean runoff depth is predicted to increase by approximately 13.5 mm from 2020 to 2050 compared with that from 2000 to 2020.

为研究京津冀地区多年来的农业干旱情况,采用该地区26个监测站点2003—2017年15年的土壤水分监测资料,计算了各站点逐年和逐月的土壤水分状态指数(SMCI),并利用该指数研究京津冀地区年际、年内变化特征及其空间分布特征.结果表明:15年间,京津冀地区农业干旱平均发生3.7次/a,主要集中在河北省中部和南部地区,以轻度干旱和中度干旱为主;区域SMCI年平均值呈现上升趋势,其中2016年SMCI平均值最高,农业干旱情况加重;56.1％耕地的农业干旱程度表现出显著上升的变化趋势,集中分布在河北省东南部和北部大部分地区.研究结果可为京津冀地区干旱预警和抗旱减灾提供理论依据.

The Jinsha River Basin (JRB) is situated on the eastern edge of the Tibetan Plateau and is a significant water source for the Yangtze River. An in-depth understanding of its drought evolution and propagation is a crucial guide for drought identification and risk assessment in the plateau and the entire Yangtze River. Hence, this paper analyzed the trend pattern of meteorological elements in the JRB and explored the dynamics of meteorological and hydrological drought. The results indicated that precipitation in the JRB fluctuated and increased at a rate of 8.01 mm/10a on average, and the average temperature increased by around 1.82 °C over the past 61 years, with both indicating a higher value downstream than upstream. Meteorological droughts were mainly focused in the 1970s, 1980s, and mid-1990s, with an overall reduction in meteorological droughts on a 12-month time scales. There were differences in the hydrological drought trends at different stations, Zhimenda and Shigu stations decreased and Pingshan station increased. In addition, the JRB was dominated by mild drought, with an average frequency of 13% for meteorological drought and 30% for hydrological drought, and the correlation between SRI and SPI was most significant in the upstream area where human activities were less frequent. The hydrological drought was about 9–10 months later than the meteorological drought due to climate change, subsurface change and human activity. The findings could be utilized as a reference for regional water resource management and basin drought hazard warning.

青藏高原是受气候变化影响最为明显的地区之一,气候变化驱动下的径流变化趋势及其原因备受关注.该研究采用Mann-Kendall检验和Pettitt突变点检验,分析了西藏自治区11 个水文站1980-2016年径流深的变化规律;并采用基于Choudhury-Yang方程的气候弹性法,量化了年降水、年潜在蒸发以及下垫面变化对年径流深的影响.结果表明,研究区年径流深总体呈不显著上升趋势,多个流域在1997年左右发生突变;雅鲁藏布江下游地区年径流深对气候变化和下垫面变化的敏感性明显低于其他地区;年降水量的变化是年径流深变化的主要影响因素,导致所有站点的年径流深增加,但区域差异较为明显,其中对拉萨河流域的影响最大.

基于非一致性水文频率计算原理的频率计算方法,存在确定性成分参数选取主观性强,无法反映多影响要素的问题.提出了变化环境下基于回归分析的非一致性水文频率计算方法,将该方法应用在鄱阳湖水位非一致性频率计算中.结果表明:鄱阳湖年均水位序列呈现出下降的趋势,枯水期出现的频率有所提升,重现期缩短,导致鄱阳湖干旱情况频发.分析结果与鄱阳湖实际的水位状况较为一致,该方法具有较好的可行性和可靠性.

The analysis of drought propagation has garnered mounting attention in the changing global environment. The current studies tend to focus on the propagation characteristics from meteorological to hydrological drought in rivers. Lakes, despite being a key component of watershed ecosystems, have received little attention to their response to meteorological and hydrological droughts. To this end, here, we investigated the characteristics of propagation from meteorological to hydrological drought for a lake in a changing environment. To determine the drought propagation time from meteorological to hydrological drought, we analyzed correlations between the standardized precipitation index (SPI), standardized runoff index (SRI), and standardized water level index (SWI). Lake Baiyangdian in China served as the case study. The results showed that meteorological droughts occur at high frequency but are short in duration, indicating that not every meteorological drought will necessarily lead to a hydrological drought. By contrast, lake hydrological droughts have low frequency and long duration and feature more severe consequences. Comparing drought characteristics before and after a changing environment, we found a reduced frequency of the SPI, SRI, and SWI, yet their duration was prolonged. For the SWI especially, these results were even more pronounced, which suggests the changing environment enabled further intensification of the lake hydrological drought. In addition, more time was needed for a meteorological drought to transition into a lake hydrological drought after a changing environment.

为深入贯彻落实党的十九大提出的乡村振兴战略,水利部、财政部于2019年部署开展水系连通及水美乡村建设试点工作.本文结合目前三批共127个水美乡村建设试点,尤其是针对已完成终期评估的第一批55个试点县,介绍了试点建设情况和成效.根据不同试点县水资源条件、区域特点和经济社会发展状况等因素,分析总结了建设试点中存在的问题、原因以及试点工作经验,提出了推进水美乡村建设的技术指导、组织实施等方面的建议.

揭示长江经济带水资源空间均衡特征可为水资源利用效率和区域经济发展水平的提升提供理论依据.以长江经济带11个省级行政区为研究单元,构建水资源-土地资源、水资源-人口、水资源-经济共3对匹配关系,在此基础上,提出水资源负载指数对长江经济带11个省级行政区水资源的开发利用程度进行评价,进而揭示长江经济带水资源的空间不均衡特征和时空变化规律.研究结果表明:①长江经济带局部地区水资源与土地资源空间分布存在错位,其中四川-重庆、安徽、湖北地区基尼系数超过了联合国规定的警戒线0.4;②长江经济带整体平均匹配差异表现为水资源-经济基尼系数>水资源-土地资源匹配基尼系数>水资源-人口匹配基尼系数,长江经济带水资源空间分布与生产力布局不协调;③长江经济带水资源负载指数整体水资源开发利用程度呈现东高西低的特征,2010—2019年长江经济带整体水资源负载指数呈上升趋势.

The Tibetan Plateau (TP) is an important water source in Asia, and precipitation and evaporation patterns at different geographical and temporal scales play a significant role in managing water resource distribution. Based on quality control data from 87 meteorological stations, this study analyzed the spatial and temporal evolution patterns of precipitation and pan evaporation (Epan) on the TP in 1966–2016 using the Mann–Kendall test, the moving t-test, wavelet analysis, Sen’s slope method, and correlation analysis. The results revealed that the average mean temperature in the TP area increased by about 2.1 °C during the study period, and precipitation steadily increased at an average rate of 8.2 mm/10a, with summer and autumn precipitation making up about 80% of the year. In contrast, Epan showed an overall decreasing trend at a decline rate of 20.8 mm/10a, with spring and summer Epan values making up about 67% of the year. The time series of the precipitation and Epan within the TP region clearly exhibit nonstationary features. Precipitation is more concentrated in the southeast than in the northwest, while Epan is mostly concentrated in the southwest and northeast of the plateau around the Qaidam Basin. The “evaporation paradox” phenomenon was common in the TP region for about 40 years (1960s–1990s) and gradually faded in the 21st century. In addition, we introduced a standardized precipitation evaporation index (SPEI) to investigate the differences and relationships between precipitation and Epan time series over the past 50 years. The findings indicate that the southern Qinghai was dominated by an arid trend, while the central and southeast TP remained wet. Droughts and floods coexist in the eastern Qinghai and southern Tibet areas with high population concentrations, and the risk of both is rising as the inhomogeneity of precipitation distribution in the TP region will increase in the future. This study can be used as a reference for managing water resources and predicting regional drought and flood risk.

Due to their special geographical locations and environments, plateau lakes play a key role in maintaining regional water balance, but lake water storage changes are upsetting this balance. Based on data from lakes on the Tibetan Plateau (TP), this study used the Spatial Processes in Hydrology (SPHY) model to simulate the runoff process in the Siling Co basin from 2000 to 2016 and estimated the changes in water storage of Siling Co and the contribution of each component of runoff into the lake. The results showed that the water storage capacity of Siling Co has increased by 1.2 billion m3/yr, and the lake area continues to expand; declines in precipitation have significantly reduced baseflow (BF), rainfall runoff (RR), and snow runoff (SR), while temperature increases have raised glacier runoff (GR). The simulated average runoff showed that BF, GF, RR, and SR contribute 24%, 22%, 16%, and 38%, respectively, of the flow into Siling Co. Based on hypothetical climate change scenarios and two Shared Socioeconomic Pathways (SSP1-2.6 and SSP3-7.0) from the MRI-ESM2-0 GCMs, this study estimated that a 10% increase in precipitation could lead to a 28% increase in total runoff, while a 1 °C increase in temperature could lead to a 10% decrease in runoff. The average runoff depth of the basin is expected to increase by 30–39 mm, since the temperature and precipitation may increase significantly from 2020 to 2050. The intensification of glacial melting caused by the increase in temperature continues, posing a greater challenge to many water resources management problems caused by the expansion of lakes.

采用青海省1965—2018年50个气象站月降水资料和同时段太阳黑子相对数资料,将青海省划分为长江和澜沧江源区、黄河源区、东部低海拔区和柴达木盆地区,运用集中度和集中期、线性倾向估计、M-K检验法和Morlet小波分析法对青海省时空降水变化特征进行分析.结果表明:青海省降水量在空间分布上呈现由西北向东南增加的特征,在年际变化上,青海省和4个分区年降水量都具有上升趋势,其中青海省平均上升0.81 mm/a;青海省降水年内分配不均,降水集中度具有逐渐趋向均匀的趋势;青海省出现微弱的降水突变信号,青海省主体和东部低海拔区突变始于2006年前后,长江和澜沧江源区突变始于2003年前后,柴达木盆地区突变于2001年前后,而黄河源区存在4个可能突变点;柴达木盆地降水变化具有22～23 a的主周期,青海省和其他3个分区都具有28～30 a的主周期,在28 a尺度上青海省和4个分区降水量与太阳黑子相对数的小波系数都分别达到了0.95、0.86、0.91、0.93和0.75的正相关性,且显著性水平均为0.01.

拉萨河流域处青藏高原中南部,因其独特的地理位置是对气候变化较为敏感的区域之一,同时也是青藏高原人口和耕地较为密集区域.在建立SWAT模型对拉萨河流域水循环过程进行模拟的基础上,通过设置不同气候情景与土地利用状况,分析近30 a来拉萨河流域径流变化的成因,并研究径流对气候因子变化的敏感性.结果表明:①气候变化与土地利用对径流影响占比分别约为82.95％和17.05％,主要原因在于近30 a拉萨河流域土地利用情况变化不大,而气温、降水则呈显著增加趋势;②降水每增加10％,流域径流约增加11.8％,且径流对降水变化敏感性的空间差异性较小;③气温每增加1℃,流域总径流约增加2.5％,但径流随气温变化的空间差异性较大,其中,中上游地区径流减小0.7％,下游地区径流约增加3.6％.

The Yarlung Zangbo River is the largest river on the Tibetan Plateau and a major international river in South Asia. Changes in the blue and green water resources in its basin are of great importance to the surrounding local and Asian regions in the context of global warming. This research used the Soil and Water Assessment Tool model to estimate blue and green flows (BWF and GWF) and analyze the spatial-temporal distribution characteristics under different hypothetical climate change scenarios. The results show that (1) the multi-year average BWF in the middle and upper reaches of the Yarlung Zangbo River Basin is 176.2 mm, the GWF is 213.1 mm, and the difference between precipitation and total water resources is only 5.4 mm; (2) both BWF and GWF in this basin showed a slightly increasing trend from 1980 to 2010, but the distribution of subbasins from upstream to downstream is decreasing; and (3) GWF has a positive correlation with both precipitation and temperature, but BWF only increases with precipitation and decreases with increasing temperature. Moreover, the change in blue and green water resources is more sensitive to the changes in precipitation than to changes in the temperature.

Monitoring runoff is critical for water resources management. Remote sensing can be an effective technique to investigate changes in runoff on data-scarce regions. This study used Calibrated Passive Microwave Daily EASE-Grid 2.0 Brightness Temperature Earth System Data Record (CETB) and M/C signal method to simulate runoff in Lhasa River Basin. This satellite-derived runoff was compared with gauge observations and Soil and Water Assessment Tool (SWAT) model simulations. The results show that (1) the well-correlated satellite-derived M/C signals are able to detect the runoff process in the selected river channels. For most gauges, the runoff generated by M/C signals fit well with observation, giving a Pearson correlation coefficient greater than 0.9, Nash-Sutcliffe efficiency coefficient greater than 0.8, and relative error less than 15%; (2) When compared to the SWAT model, the M/C signal method has advantages in flood season runoff simulation. These two simulation methods are nearly equal for the entire runoff process; (3) For runoff simulation influenced by the underlying surface and the shape of the river channel, the M/C signal method is better suited in areas with a low fraction vegetation cover and channels with a typical inverted trapezoid shape. Overall, we conclude that M/C signal method simulation is a valuable source of surface water information and could be used for runoff monitoring in data-scarce areas.

Under the background of global climate change, drought is causing devastating impacts on the balance of the regional water resources system. Hydrological drought assessment is critical for drought prevention and water resources management. However, in China to assess hydrological drought at national scale is still challenging basically because of the difficulty of obtaining runoff data. In this study, we used the state-of-the-art passive microwave remote sensing techniques in river runoff modelling and thus assessed hydrological drought in Mainland China in 1996–2016. Specifically, 79 typical hydrological stations in 9 major basins were selected to simulate river runoff using the M/C signal method based on a high-resolution passive microwave bright temperature dataset. The standardized runoff index (SRI) was calculated for the spatial and temporal patterns of hydrological drought. Results show that passive microwave remote sensing can provide an effective way for runoff modelling as 92.4% and 59.5% of the selected 79 stations had the Pearson correlation coefficient (R) and the Nash-Sutcliffe efficiency coefficient (NS) scores greater than 0.5. Especially in areas located on Qinghai-Tibet Plateau in the Inland and the Southwest River Basin, the performance of the M/C signal method is quite outstanding. Further analysis indicates that stations with small rivers in the plateau areas with sparse vegetation tend to have better simulated results, which are usually located in drought-prone regions. Hydrological drought assessment shows that 30 out of the 79 stations present significant increasing trends in SRI-3 and 18 indicate significant decreasing trends. The duration and severity of droughts in the non-permanent dry areas of the Hai River Basin, the middle reaches of the Yangtze River Basin and the Southwest of China were found out to be more frequent and severe than other regions. This work can provide guidance for extending the applications of remote sensing data in drought assessment and other hydrological research.

: The Jinsha River Basin (JRB) is the most important tributary of the Changjiang River and the most ecological vulnerable region to climate change. Therefore, to better understand the hydro-meteorology characteristics of JRB and enhance hydrological forecasts, a temporal-spatial analysis of historical hydro-meteorological elements and drought characteristics is required. In this study, 45 meteorological stations and 5 hydrologic stations in JRB for the last 60 years of historical data were utilized for analyze the temporal-spatial distribution and trends of hydro-meteorological elements, while drought characteristics in this basin were assessed using SPI values at six-month scales (SPI-6). The results show that: (1) the three daily temperature types (minimum, mean and maximum) and precipitation of the JRB all show an increase from the upper to lower reaches. (2) the Mann-Kendall test analysis of hydro-meteorological elements’ annual values reveals that the mean temperature of 42 stations is rising, while precipitation is rising at 25 stations. The runoff at all five hydrologic stations is increasing. The temperature and precipitation in the upper reaches are the areas with the greatest increase in the JRB, while the precipitation in the lower reaches is the only one that is on a downward trend. (3) In the drought analysis based on SPI-6, the downstream of JRB, which is located in Sichuan and Yunnan provinces, is the region with the most severe drought. There is no visible trend in drought duration at most stations, and the drought magnitude analysis is dominated by a decreasing trend. However, the drought intensity analysis is dominated by an uptrend, especially in the mid- and lower streams.

开展安徽省江北产业集中区污水处理厂入河排污口设置论证,目的在于合理开发利用与保护水资源,保障水域生活、生产和生态用水安全,为各级水行政主管部门审批入河排污口以及建设单位合理设置入河排污口提供科学依据.经过现场查勘、资料收集整理及补充监测,根据排污口位置所涉及江段的水文水质、水生态、水功能区划成果及取排水状况,分析了废污水排放的受纳水体(长江)水质和水生态环境状况.本文结合水功能区划,采用MIKE21数学模型模拟的方法,对排污口设置后废污水排放进行了模拟预测,论证分析了排污口设置对受纳水体水质和水生态环境的影响,以及对有利害关系的第三者产生的影响,并对排污口设置的可行性和合理性进行了分析.

As an important control station for the mainstream of the lower reaches of the Yangtze River, studing the runoff change characteristics in dry season at Datong Hydrological Stations can provide a comprehensive grasp of the hydrological conditions in the lower reaches of the Yangtze River. This study uses linear trend method, Mann-Kendall method and wavelet analysis method to analyze the dry season runoff change characteristics at Datong Station, and the following conclusions are obtained: the average flow in the dry season at Datong Station has shown a significant increasing trend and a significant change period, while the first main period is 35-year; for the typical dry months, there is no significant increasing trend in December, but the increasing trend is significant in January and February; The dry season runoff at Datong Station accounted for a significant increase in the proportion of the entire year since 2003.