Open AccessImpact of different initial soil moisture fields on Eta model weather forecasts for South America
Author(s) -
de Goncalves L. Gustavo Goncalves,
Shuttleworth William James,
Chou Sin Chan,
Xue Yongkang,
Houser Paul R.,
Toll David L.,
Marengo José,
Rodell Matthew
Publication year - 2006
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 - 10.1029/2005jd006309
Subject(s) - environmental science , water content , climatology , data assimilation , initialization , geopotential height , precipitation , biosphere , biosphere model , extratropical cyclone , moisture , numerical weather prediction , atmospheric sciences , meteorology , geology , geography , ecology , geotechnical engineering , computer science , biology , programming language
Two 7‐day weather simulations were made for South America in July 2003 and January 2004 (in the Southern Hemisphere summer and winter) to investigate the impacts of using different soil moisture initialization fields in the Eta model coupled to the Simplified Simple Biosphere (SSiB) land surface model. The alternative initial soil moisture fields were (1) the soil moisture climatology used operationally by the Centro de Previsão do Tempo e Estudos Climáticos in Brazil and (2) the soil moisture fields generated by a South American Land Data Assimilation System (SALDAS) based on SSiB. When the SALDAS soil moisture fields were used, there was an increase in the model performance relative to climatology in the equitable threat score calculated with respect to observed surface precipitation fields and a decrease (up to 53%) in the root‐mean‐square error relative to the NCEP analysis of the modeled geopotential height at 500 hPa and mean sea level pressure. However, there was small change in the model skill in positioning the primary South American weather systems because of a change in the upper troposphere circulation caused by SALDAS initialization, most noticeably in the South Atlantic Convergence Zone.