Snow and glaciers provide water to the densely populated downstream area of the Tarim River Basin, which is an important irrigated agricultural area in China. Cotton is an important cash crop, and meltwater is an important irrigation water source for cotton in this region. In this study, the spatiotemporal dependence of cotton yield on mountain meltwater resources in the subbasins of the Tarim River basin was quantified by the variable infil-tration capacity (VIC) hydrologic model with the degree-day and CROPR models during 1960-2017. The results showed that the changes in meltwater in all subbasins had a significantly increasing trend. Meltwater contri-butions to cotton irrigation and yield varied spatiotemporally. Along the area south of the Tian Shan Mountains, the meltwater contribution to irrigation showed a decreasing trend from west to east, and the highest contri-bution of meltwater to cotton yield occurred in the Weigan River basin, followed by the Aksu River basin and Kaidu River basin. Along the northern Karakoram Mountains, the meltwater contributions to cotton irrigation and yield first decreased and then increased from west to east. In the whole basin, 48.6% of total irrigation withdrawals originated from mountain snow and glacial meltwater and contributed an additional 55.9% to total cotton production during the study period. The results provide important agricultural information for locations where shifts in water availability and demand are projected as a result of socioeconomic growth.

In Tarim River Basin (TRB), the retreat of glacier and snow cover reduction due to climate warming threatens the regional economy of downstream basins that critically depends on meltwater. However, the quantitative evaluation of its impact on multiple sectors of the socioeconomic system is incomplete. Based on compiled regional input-output table of the year 2012, this study developed a method to analyze the relationships between economic activities and related meltwater withdrawal, as well as sectoral transfer. The results show that the direct meltwater withdrawal intensity (DMWI) of agriculture was much higher than other sectors, reaching 2348.02 m(3)/10,000 CNY. Except for A01 (agriculture) and A02 (mining and washing of coal), the embodied meltwater withdrawal (EMW) driven by the final demand of other sectors was greater than direct meltwater withdrawal, and all sectors required inflows of virtual water (72.45 x 10(8) m(3), accounting for 29% of total supply from cryospheric water resources) for their production processes in 2012. For sectors with high DMWI, improving water-use efficiency is an effective way to reduce water withdrawal. To some extent, the unbalanced supply of cryospheric water resources due to geographical segregation can be regulated by virtual water flows from water-saving to water-intensive sectors. Such decisions can affect the balance between socioeconomic development and environment conservation for long-term sustainability.

The Tarim River Basin (TRB) is one of the most important areas in Central Asia, and also the largest inland river basin in China. The runoff largely originates from alpine mountains, mainly supplied by glacier and snow melting. It meets the demand of oasis and more broadly ecosystems while shaping them up. In this study, the spatio-temporal variations of water balance and vegetation (as measured by the normalized difference vegetation index, NDVI) in the TRB during 2003-2014 were investigated on the basis of multiple satellite observations together with an energy balance model. The interactions between hydrological factors were discussed. Considering that hydrological processes affect on terrestrial ecosystem, variations in vegetation were also analyzed correspondingly. The analysis suggest that water budget has changed in the TRB. By looking into all components in the budget, it is found that there is a slight decreasing trend in precipitation, but a significant decreasing trend in ET at a rate of 38.4 mm/10 a. Meanwhile, there are an evident decreasing trend in both GRACE satellite derived terrestrial water storage change (GRACE-TWS change) and Global Land Data Assimilation System simulated soil moisture change (GLDAS-SM change), at rates of -17.8 mm/a and -17.0 mm/a, respectively, while the ground water (GW) was stable. Overall, the water balance in the TRB is negative during the period. However, it shows a significant increasing trend in snow/ice melting that is discharged into the TRB. The interactions among hydrological variables indicated that the ET, GRACE-TWS change and GLDA-SSM change are strongly dependent on the monthly precipitation. However, a time lag of the GLDAS-SM change occurs influenced by precipitation, which is more obvious than one of the GRACE-TWS change. GW change shows a positive correlation with precipitation over 1-month lag and 2-month lag. The results suggest soil moisture in warm seasons (summer and autumn) are mainly affecting vegetation growth in the TRB. The vegetation in the TRB was greening, the areas of low NDVI (0-0.15) decreased by 18.1% during 2003-2014.