The spatio-temporal pattern of the global water resource has significantly changed with climate change and intensified human activities. The regional economy and ecological environment are highly affected by terrestrial water storage (TWS), especially in arid areas. To investigate the variation of TWS and its influencing factors under changing environments, the response relationships between TWS and changing environments (climate change and human activities) in Central Asia have been analyzed based on the Gravity Recovery and Climate Experiment (GRACE) data, Climatic Research Unit (CRU) climate data and Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing data products (MOD16A2, MOD13A3 and MCD12Q1) from 2003 to 2013. The slope and Pearson correlation analysis methods were used. Results indicate that: (1) TWS in about 77 % of the study area has decreased from 2003 to 2013. The total change volume of TWS is about 2915.6 × 10⁸ m³. The areas of decreased TWS are mainly distributed in the middle of Central Asia, while the areas of increased TWS are concentrated in the middle-altitude regions of the Kazakhstan hills and Tarim Basin. (2) TWS in about 5.91% of areas, mainly distributed in the mountain and piedmont zones, is significantly positively correlated with precipitation, while only 3.78% of areas show significant correlation between TWS and temperature. If the response time was delayed by three months, there would be a very good correlation between temperature and TWS. (3) There is a significantly positive relationship between TWS and Normalized Difference Vegetation Index (NDVI) in 13.35% of the study area. (4) The area of significantly positive correlation between TWS and evapotranspiration is about 31.87%, mainly situated in mountainous areas and northwestern Kazakhstan. The reduction of regional TWS is related to precipitation more than evaporation. Increasing farmland area may explain why some areas show increasing precipitation and decreasing evapotranspiration. (5) The influences of land use on TWS are still not very clear. This study could provide scientific data useful for the estimation of changes in TWS with climate change and human activities.

受气候变化影响,近20 a来长江源区径流条件发生了较大变化。以沱沱河为研究区域,采用沱沱河1960—2019年实测水文气象资料,分析了长江源区沱沱河季节性径流变化规律,以及季节性降水、气温的变化规律,采用交叉小波变换分析季节性径流与降水、气温之间的时频变化规律及其相关关系。研究结果表明:沱沱河春、夏、秋季径流均呈现出显著增加的趋势,其中春、夏、秋季径流突变点均集中在2006—2008年附近;各季节性降水增加的趋势并不显著,但季节性气温显著上升并延续至今;夏季径流与夏季降水之间的相关程度最为明显,其次为秋季和春季;气温对径流的影响是正相关的,但在不同时间尺度上存在不同的表征,其中以夏季气温和秋季气温对径流的影响最为显著。研究结果对揭示气候变化条件下长江源区季节性径流演变规律及其水文响应提供了参考。

Climate change has greatly impacted the runoff conditions in the source region of the Yangtze River in the past two decades. We analyzed the seasonal runoff variation, seasonal precipitation, and temperature variation based on measured hydro-meteorological data from the Tuotuo River hydrological station and meteorological station from 1960 to 2019. The cross wavelet transform is applied to examine the time-frequency variation and correlation among runoff, precipitation, and air temperature. Results reveal that the runoff of Tuotuo River in spring, summer, and autumn exhibited a significant increasing trend, with abrupt change points concentrated around 2006-2008. The increasing trend of seasonal precipitation was not significant, but the seasonal temperature displayed a marked rise that continues to the present. The correlation between summer runoff and precipitation was the most apparent, followed by autumn and spring. Temperature had a positive correlation with runoff, but it manifested differently on various time scales. Summer and autumn temperatures had the most significant effect on runoff. These findings provide important insights into the evolution law of seasonal runoff and hydrological response in the source region of the Yangtze River under the impacts of climate change.