Collaborative Research: Space-Time Variability of Rainfall and its Effects on Rainfall Estimation

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0002019Wurman This work is a collaborative research effort between Princeton University, the University of Washington, and the University of Oklahoma, supported by collaboration with the USDA/ARS National Sedimentation Laboratory. The central theme of the proposed research is on the characterization of the variability of rainfall in space and time, how that depends on the storm environment, and how this space-time variability affects our capability to estimate surface rainfall and rainfall kinetic energy. Radar observations at very high spatial (tens of meters) and temporal (tens of seconds) resolution will be made over the dense rain gauge network of the Goodwin Creek research watershed in northern Mississippi. These detailed observations are embedded with the larger-scale NEXRAD WSR-88D radar observations, and measurement of the storm environment.This work entails detailed Lagrangian, radar-based analyses of storm cells, their evolution and motion, and how that results in the observed spatial rainfall distribution.. These space-time analyses of rainfall at the regional scale will be linked to physical properties of the storm environment. At the Goodwin Creek watershed scale, key error sources of the different approaches (i.e., rain gauge, radar, and radar-gauge combined) to estimate rainfall rate and kinetic energy flux in space and time will be investigated. In particular, we seek to determine how much of the variance of radar-estimated versus rain gauge-accumuluated rainfall amount can be explained by the sampling volume difference in combination with the subgrid-scale rainfall variability, which is linked to physical parameters that characterize the atmospheric storm environment. We anticipate that our results will lead to a better understanding of how data obtained at different resolutions in space and time can be compared and merged.