NAM Configuration Testing


The NOAA Earth Modeling System (NEMS) with the Nonhydrostatic Multiscale Model on the B-grid (NMMB) core (Janjic and Gall 2012) is currently utilized in operational forecasting applications at the National Centers for Environmental Prediction (NCEP). Recently, a new microphysics option, the Thompson microphysics scheme (Thompson et al. 2008), was introduced into NEMS/NMMB. The Developmental Testbed Center (DTC) conducted a test and evaluation activity to assess the forecast performance of two microphysical schemes in NEMS/NMMB. The first configuration was based on the operational physics suite at the NCEP for the North American Mesoscale (NAM) model, while the second configuration substituted the Thompson microphysics for the current operational Ferrier-hires microphysics scheme.

The runs for this test and evaluation activity were initialized every 36 hours for one month in each season and run out to 48 hours. A 12-km North American parent domain with a 3-km one-way CONUS and Alaska nest (nest_mode=1-way) was used.