Open AccessInfluence of Precipitation Assimilation on a Regional Climate Model’s Surface Water and Energy Budgets
Author(s) -
Ana M. B. Nunes,
John O. Roads
Publication year - 2007
Publication title -
journal of hydrometeorology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.733
H-Index - 123
eISSN - 1525-755X
pISSN - 1525-7541
DOI - 10.1175/jhm615.1
Subject(s) - environmental science , precipitation , climatology , shortwave radiation , data assimilation , shortwave , initialization , longwave , climate model , surface runoff , energy budget , assimilation (phonology) , water cycle , meteorology , humidity , atmospheric sciences , climate change , radiative transfer , radiation , geology , geography , ecology , linguistics , oceanography , physics , philosophy , computer science , biology , programming language , thermodynamics , quantum mechanics
Initialization of the moisture profiles has been used to overcome the imbalance between analysis schemes and prediction models that generates the so-called spinup problem seen in the hydrological fields. Here precipitation assimilation through moisture adjustment has been proposed as a technique to reduce this problem in regional climate simulations by adjusting the specific humidity according to 3-hourly North American Regional Reanalysis rain rates during two simulated years: 1988 and 1993. A control regional simulation provided the initial condition fields for both simulations. The precipitation assimilation simulation was then compared to the control regional climate simulation, reanalyses, and observations to determine whether assimilation of precipitation had a positive influence on modeled surface water and energy budget terms. In general, rainfall assimilation improved the regional model surface water and energy budget terms over the conterminous United States. Precipitation and runoff correlated better than the control and the global reanalysis fields to the regional reanalysis and available observations. Upward shortwave and downward short- and longwave radiation fluxes had regional seasonal cycles closer to the observed values than the control, and the near-surface temperature anomalies were also improved.