Impact of High Spatial Resolution of LIS Analyses on COAMPS Forecasts

The U.S. Navy Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS^®*) uses the global analyses produced by the Global Air-Land Weather Exploitation Model (GALWEM) and Land Information System (LIS) from the U.S. Air Force 557th Weather Wing (557WW) to initialize the land surface model (LSM) component of COAMPS. The spatial resolutions of the GALWEM-LIS analyses have been increased from 0.25^o (v7.0) to 10 km (v7.2) recently at 557WW. The GALWEM-LISv7.2 analyses with10 km resolution allows the LSM to resolve the land surface features that are not possible with the 0.25^o resolution analyses. In this study, we conduct COAMPS numerical experiments to investigate the impacts of high spatial resolution initial land surface conditions from the GALWEM-LISv7.2 on COAMPS forecasts over three areas that have significant variation of environmental conditions. The three areas used in the study are Hawaii, Arctic, and California Westcoast. The numerical results demonstrate that the high spatial resolution LIS analyses provided a much better representation of the land surface features, such as the detailed features of soil temperature and moisture, in the LSM model. For example, the new LIS analyses can correct previously uniform features of soil temperature and moisture in all Hawaii islands from using the coarse resolution LIS analyses. Consequently, the COAMPS forecasts for Hawaii with an inner grid resolution 1.67 km have shown significant improvements when the 10 km resolution LIS analyses are used to initialize COAMPS LSM. We will discuss the numerical results from all these three areas.