Role of catchment morphometrics in addressing the spatial resolution of GRACE-derived total water storage changes

The spatial resolution of the total water storage changes from GRACE data is a conundrum, but also the most sought after quantity. The availability of various solutions exacerbates the situation -- unconstrained spherical harmonics, constrained spherical harmonics, mascons and different data processing centers. Some attempts have been made previously to arrive at an answer, and some numbers have been proposed. Notably, in the context of hydrologic applications, the spatial resolution morphs into a question of the catchment sizes and shapes, thereby rendering some of these numbers deficient. This study uses ideas from leakage analysis to arrive at answers for the spatial resolution issue. Care is taken to incorporate the morphometric characteristics of catchments in the answers being arrived at.