Warm Season Precipitation Estimation and Analysis in the Colorado East River Basin during SPLASH and SAIL field experiments

In high-altitude complex terrain regions, observing precipitation and understanding atmospheric physical processes and land-atmosphere interactions pose challenges that curtail our ability to forecast water supply accurately. Even in snow-driven water supply regions such as the East River Watershed in the Upper Colorado River Basin, warm season precipitation that comes as a result of the summer monsoon can provide critical moisture. Studying these processes in this hydrologically critical region is key to improving water forecasts. The NOAA-led Study of Precipitation, the Lower Atmosphere and Surface for Hydrometeorology (SPLASH), and the DOE-led Surface Atmospheric Integrated Field Laboratory (SAIL) field campaigns were motivated by the gaps that exist in precipitation and land surface observations and associated water forecast challenges that exist in this region. SPLASH and SAIL together include a comprehensive, state-of-the-art observing network with the goal of advancing weather and water prediction capabilities.

In this study, a combination of X-Band scanning radar, vertically pointing profiler radars, precipitation gauges, and disdrometers are used to characterize warm season precipitation in the East River Watershed. A methodology for estimating surface rainfall from dual-polarization radar observations (i.e, quantitative precipitation estimation - QPE) will be used to evaluate the NOAA High-Resolution Rapid Refresh (HRRR) quantitative precipitation forecasts (QPF). In addition, we will compare the X-band radar QPE and HRRR estimates with operational data products such as the Multi-Radar/Multi-Sensor System (MRMS) as well as surface observations to better understand the uncertainty of precipitation across time and spatial scales.