Surface water and energy budgets for the Mississippi catchment area from global reanalysis and a regional climate model

Abstract

Characteristics of the Mississippi catchment surface water and energy budgets in the National Centers for Environmental Prediction (NCEP) regional spectral model (RSM) and the driving NCEP/NCAR global reanalysis (NCEPR) are compared. The RSM is similar to the Global Spectral Model (GSM) used in the reanalyses, in that it was originally derived from the global model. However, the RSM does not have an artificial water source to maintain the surface moisture (unlike the NCEPR) and the RSM surface water dries. Although the much larger wintertime surface water difference has only a small effect on the evaporation differences and other components of the wintertime water and energy cycles, summertime effects are greater. The RSM develops consistent summertime hydroclimatological differences of decreased surface water, precipitation, evaporation, increased sensible heating, outgoing longwave radiation, incoming solar radiation and temperature. The RSM Mississippi River basin also has larger interannual surface water (and other water and energy) variations than might be discerned from the NCEPR.