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Effects of spatial resolution in the simulation of daily and subdaily precipitation in the southwestern US
Author(s) -
Tripathi Om P.,
Dominguez Francina
Publication year - 2013
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/jgrd.50590
Subject(s) - precipitation , weather research and forecasting model , climatology , environmental science , climate model , horizontal resolution , meteorology , atmospheric sciences , climate change , geology , geography , oceanography
We evaluate the effects of spatial resolution on the ability of a regional climate model to reproduce observed extreme precipitation for a region in the Southwestern United States. A total of 73 National Climate Data Center observational sites spread throughout Arizona and New Mexico are compared with regional climate simulations at the spatial resolutions of 50 km and 10 km for a 31 year period from 1980 to 2010. We analyze mean, 3‐hourly and 24‐hourly extreme precipitation events using WRF regional model simulations driven by NCEP‐2 reanalysis. The mean climatological spatial structure of precipitation in the Southwest is well represented by the 10 km resolution but missing in the coarse (50 km resolution) simulation. However, the fine grid has a larger positive bias in mean summer precipitation than the coarse‐resolution grid. The large overestimation in the simulation is in part due to scale‐dependent deficiencies in the Kain‐Fritsch convective parameterization scheme that generate excessive precipitation and induce a slow eastward propagation of the moist convective summer systems in the high‐resolution simulation. Despite this overestimation in the mean, the 10 km simulation captures individual extreme summer precipitation events better than the 50 km simulation. In winter, however, the two simulations appear to perform equally in simulating extremes.