Long time series analysis of snow water equivalent across the Amu Darya water towers from remote sensing and in-situ records

Study region In high elevation watersheds of Central Asia, snow is the main source of discharge. Spatially and temporally distributed snow water equivalent (SWE) measurements in-situ or remotely sensed have the potential to estimate whether seasons in a given year will be water-abundant or water-scarce. Study focus Here we show the benefits of FLDAS-Central Asia SWE daily simulations retrieved since 2001 in a snow-fed basin of one of the water towers of Amu Darya. FLDAS estimations were compared with winter field measurements of SWE using a Mount Rose sampler. Despite its tendency to overestimate, FLDAS reliably captures the annual variability of SWE and reproduces temporal patterns with a RMSE of 107 mm. FLDAS was used to estimate the significance of nine snow-season metrics spanning accumulation and melt phases, trends with time. New hydrologic insights The eastern plateau experienced a shorter accumulation and melt season accompanied by a drier snowpack and faster melt rates, driven by its more arid climate, enhanced wind-driven snow redistribution, strong radiation, and higher potential for total residual loss. In contrast, glaciated areas in high elevations of the east and north basin exhibited increasing seasonal snow and wetter conditions in these remote areas with complex topography where in-situ data is unavailable. This study highlights the need for continuous ground-based monitoring of SWE, given the strong correlation between snowmelt and discharge; and to reduce estimation uncertainties in this region.