Radar Observations of Precipitation During SPLASH

The Study of Precipitation, the Lower Atmosphere and the Surface for Hydrometeorology (SPLASH) is a two-year field campaign, aimed at applying observations and resulting enhanced process understanding to evaluate and advance NOAA's prediction of weather and water in mountainous regions for improved early warning and to inform preparedness. SPLASH is being conducted in the East River watershed in western Colorado, part of the Colorado River Basin headwaters region.

An X-band, dual-polarimetric scanning radar as well as two vertically-pointing snow-level radars (SLRs) and disdrometers were installed as part of SPLASH to observe precipitation processes in the East River Valley and surrounding terrain. The X-band radar provides information on the spatial variability of precipitation while the SLRs and disdrometers provide detailed information on vertical structure and particle size characteristics. The information from the combined sensors is being used to better understand the microphysical properties of wintertime and summer storms as well as for evaluating quantitative precipitation forecasts in NOAA's High Resolution Rapid Refresh model. In addition, the SPLASH scanning radar observations are being used to fill a gap for the local NWS operational radar (NEXRAD) which is blocked from viewing precipitation in the valley by the surrounding terrain.

The SPLASH radar and SLR observations were conducted in close coordination with an X-band radar system deployed as part of the DOE-led Surface-Atmosphere Integrated field Laboratory (SAIL) campaign.

During SPLASH, a variety of precipitation systems have been sampled, including synoptically-forced winter time storms with locally-induced orographic enhancement and monsoon-driven convective rainfall. In this presentation, an overview of the SPLASH radar program is provided using a sample of observations and information collected from the combination of X-band, SLRs, and disdrometers. Dual polarimetric signatures from the SPLASH radar, together with fallspeed information from the SLRs and particle size information from the disdrometers, are used to diagnose the microphysical characteristics of different types of precipitation for selected events.