Two of the regional climate models used in NARCCAP have had changes
made to their configurations since the beginning of the program. In
both cases, the changes were made after an initial run using NCEP
boundary conditions was completed and data from that run published.
Rather than rescinding the data from the original model runs and
replacing it, the updated models used to complete the NARCCAP suite of
simulations have been given a new 4-letter designation to distinguish
them from the original model. Data from the original NCEP-driven runs
will remain available.
WRFP has been superseded by WRFG.
ECPC has been superseded by ECP2.
Note that updates to the NARCCAP website to reflect this change are
not yet complete.
ECPC vs ECP2
Data from the Regional Spectral Model was originally designated
ECPC, for the Experimental Climate Prediction Center at Scripps
Institute of Oceanography, where this model was run. Data from the
updated model has been designated ECP2.
The main difference between ECPC and ECP2 concerns how spectral
nudging was employed. Spectral nudging forces the regional model
solution to follow closely its driven global model for scales usually
close to and above the synoptic scale. The ECPC-RSM's standard version
of spectral nudging combines a spectral damping of horizontal wind
tendency and areal average correction of temperature, moisture, and
surface pressure. In ECP2, the moisture correction component of the
spectral nudging was not used, resulting in better simulation of
precipitation. ECP2 also has a larger domain than ECPC, more closely
matching the region modeled by the other RCMs.
WRFP vs WRFG
Data from the Weather Research & Forecasting model was originally
designated WRFP, the P standing for PNNL (Pacific Northwest National
Lab), the home of the modeling group running this model. Data from
the updated model has been designated WRFG.
In the WRFP run, the model used the Kain-Fritsch convective
parameterization scheme. The updated model uses the Grell scheme
instead, which improves the reproduction of temperature and
precipitation. The G in WRFG stands for Grell.
Kain, J. S., 2004: "The Kain-Fritsch convective
parameterization: An update." J. Appl. Meteor., 43,
Grell, G.A. and D. Devenyi, 2002: "A generalized
approach to parameterizing convection combining ensemble and data
assimilation techniques." Geophys. Res. Lett., 29, 1693-1697.