Hydrol. Earth Syst. Sci., 23, 897–923, 2019 https://doi.org/10.5194/hess-23-897-2019 © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License. Estimating irrigation water use over the contiguous United States by combining satellite and reanalysis soil moisture data Felix Zaussinger1, Wouter Dorigo1, Alexander Gruber1,2, Angelica Tarpanelli3, Paolo Filippucci3, and Luca Brocca3 1CLIMERS – Research Group Climate and Environmental Remote Sensing, Department of Geodesy and Geoinformation, TU Wien, Vienna, Austria 2Department of Earth and Environmental Sciences, KU Leuven, Heverlee, Belgium 3Research Institute for Geo-Hydrological Protection, National Research Council, Perugia, Italy Correspondence: Felix Zaussinger (
[email protected]) and Wouter Dorigo (
[email protected]) Received: 6 August 2018 – Discussion started: 10 August 2018 Revised: 12 December 2018 – Accepted: 5 February 2019 – Published: 18 February 2019 Abstract. Effective agricultural water management requires state-level irrigation water withdrawals (IWW) but system- accurate and timely information on the availability and use of atically underestimate them. We argue that this discrepancy irrigation water. However, most existing information on irri- can be mainly attributed to the coarse spatial resolution of gation water use (IWU) lacks the objectivity and spatiotem- the employed satellite soil moisture retrievals, which fails poral representativeness needed for operational water man- to resolve local irrigation practices. Consequently, higher- agement and meaningful characterization of land–climate in- resolution soil moisture data are needed to further enhance teractions. Although optical remote sensing has been used to the accuracy of IWU mapping. map the area affected by irrigation, it does not physically al- low for the estimation of the actual amount of irrigation wa- ter applied.