The precision of satellite-based net irrigation quantification in the Indus and Ganges basins

Abstract. Even though irrigation is the largest direct anthropogenic interference in natural terrestrial water cycle, limited knowledge of amount applied for exists. Quantification via evapotranspiration (ET) or soil moisture residuals between remote-sensing models and hydrological models, with latter acting as baselines without influence irrigation, have successfully been various regions. Here, we implement a novel ensemble methodology to estimate precision ET-based net quantification by combining different ET precipitation products Indus Ganges basins. A multi-model calibration 15 independently calibrated simulate rainfed was conducted before quantification. Based on average, 2003–2013 amounts 233 mm yr−1 (74 km3 yr−1) 101 (67 basins, respectively. Net Basin evenly split dry wet periods, whereas 70 % occurs during period Basin. We found that, although annual from varied 91.5 yr−1, within 25 per season entire study area, which emphasizes robustness approach. variance decrease uncertainty decreased, related climatic conditions, i.e., high under arid conditions. decomposition analysis showed that accounted 73 overall seasonally dependent, an increase monsoon season. The results underline framework support large-scale sustainable resource management irrigated land.