GRACE observes the natural and irrigation-induced regional redistribution of water storage in Central Asia

Central Asia region, where snow and glacier covered Tian Shan and Pamir mountains serve as “Water Tower” to supply populated areas downstream with essential freshwater resources, predominantly for agricultural production in summer and for energy production in winter. To identify the impact of irrigation practices on large-scale water storage by analyzing the spatial dynamics of water storage in Central Asia from sink to source using satellite-based Terrestrial Water Storage (TWS) variations from six GRACE(-FO) solutions and snow cover from MODIS. Snow Cover Index (SCI), a new proxy index for snow accumulation shows that GRACE-based TWS dynamics agree very well with snow accumulation and melt for seasonal and inter-annual variations. The spatial patterns of seasonal TWS variations show water re-distribution from the mountain region to the downstream parts, where agricultural fields are irrigated. In these areas, the maximum storage in summer observed with the majority of GRACE solutions can be attributed to the diversion of water inflow from the mountain ranges into vast areas of agricultural land. The ability of GRACE to observe both natural and human-induced water re-distribution in Central Asia indicates its potential for regional-scale monitoring applications in water resources management. A graphical abstract is mandatory for this journal. It should summarize the contents of the article in a concise, pictorial form designed to capture the attention of a wide readership online. Authors must provide images that clearly represent the work described in the article. Graphical abstracts should be submitted as a separate file in the online submission system. Image size: please provide an image with a minimum of 531 × 1328 pixels (h × w) or proportionally more. The image should be readable at a size of 5 × 13 cm using a regular screen resolution of 96 dpi. Preferred file types: TIFF, EPS, PDF or MS Office files. You can view Example Graphical Abstracts on our information site. • GRACE observes re-distribution of the water from the high-mountain region to the lowland regions with high irrigation activity. • SCI, a new proxy for seasonal snow accumulation, explains more that 70 % of terrestrial water storage in winter in Amudayray and Naryn basins.