The Impact of Mesoscale Resolution on the Simulation of Warm Season Precipitation over the Continental US

Tuesday, May 13, 2014 - 07:00
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We have performed both AMIP and coupled climate simulations using a global high resolution version of the NCAR Community Atmosphere Model version 5.3. These simulations utilize the Spectral Element Dynamical Core (CAM-SE) and have an approximately uniform 25 kilometers resolution in horizontal. A particular benefit of modeling at this horizontal resolution is the nascent capability of the climate model to resolve, and somewhat realistically simulate, atmospheric mesoscale circulations, such as tropical cyclones and warm season orogenic propagating continental precipitation. In this presentation, we focus on the the orogenic variability, which maximizes in late spring in the model simulations as opposed to the summer season in nature. We examine the impact of this variability on the mean precipitation and hydrologic cycle over the continental US and examine the mechanisms acting in both nature and the climate simulations to ascertain the reasons and mechanisms responsible for the improper phasing of the variability maximum.