Open AccessEvaluation of the diurnal cycle of precipitation, surface thermodynamics, and surface fluxes in the ECMWF model using LBA data
Author(s) -
Betts Alan K.,
Jakob Christian
Publication year - 2002
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2001jd000427
Subject(s) - diurnal cycle , precipitation , atmospheric sciences , sunrise , environmental science , convective boundary layer , convection , morning , climatology , water cycle , atmosphere (unit) , boundary layer , planetary boundary layer , meteorology , thermodynamics , geology , physics , ecology , astronomy , biology
The mean diurnal cycle of precipitation, near‐surface thermodynamics and surface fluxes from short‐term forecasts of the ECMWF model are compared with corresponding observations from the Large‐Scale Biosphere‐Atmosphere Experiment in the Amazonia wet season campaign in 1999 in Rondônia. Precipitation starts about 2 hours after sunrise in the model, several hours earlier than observed, because the model does not simulate well the morning growth of the nonprecipitating convective boundary layer. However, the mean daily precipitation during the wet season compares well with observed rainfall. On most days, maximum early afternoon temperature and cloud base height are lower in the model than observed. Maximum equivalent potential temperature is close to that observed. The model surface evaporative fraction is higher than observed and rises to near unity in the late afternoon. Work is in progress to evaluate and integrate the parameterizations for shallow and deep convection.