analyzed large-scale fields. The main goal of this study is to investigate how much the regional model adds smaller scale
precipitation information that the large-scale fields do not resolve. The modeling region for this study covers the
southeastern United States (Florida, Georgia, Alabama, South Carolina, and North Carolina) where the summer climate
is subtropical in nature, with a heavy influence of regional-scale convection. The coarse resolution (2.5deg latitude/longitude)
large-scale atmospheric variables from the National Center for Environmental Prediction (NCEP)/DOE reanalysis (R2) are
downscaled using the NCEP Environmental Climate Prediction Center regional spectral model (RSM) to produce
precipitation at 20 km resolution for 16 summer seasons (19902005). The RSM produces realistic details in the regional
summer precipitation at 20 km resolution. Compared to R2, the RSM-produced monthly precipitation shows better
agreement with observations. There is a reduced wet bias and a more realistic spatial pattern of the precipitation
climatology compared with the interpolated R2 values. The root mean square errors of the monthly R2 precipitation are
reduced over 93 (1,697) of all the grid points in the five states (1,821). The temporal correlation also improves over 92
(1,675) of all grid points such that the domain-averaged correlation increases from 0.38 (R2) to 0.55 (RSM). The RSM
accurately reproduces the first two observed eigenmodes, compared with the R2 product for which the second mode is
not properly reproduced. The spatial patterns for wet versus dry summer years are also successfully simulated in RSM.
For shorter time scales, the RSM resolves heavy rainfall events and their frequency better than R2. Correlation and
categorical classification (above/near/below average) for the monthly frequency of heavy precipitation days is also
significantly improved by the RSM.
Document ID
20140013404
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Date Acquired
November 6, 2014
Publication Date
August 10, 2010
Publication Information
Publication: Climate Dynamics
Volume: 37
Issue: 6-May
Subject Category
Report/Patent Number
Funding Number(s)
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
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