Open AccessMesoscale Atmospheric Modeling Using a High Horizontal Grid Resolution over a Complex Coastal Terrain and a Wine Region of South Africa
Author(s) -
Valérie Bonnardot,
S. Cautenet
Publication year - 2009
Publication title -
journal of applied meteorology and climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.079
H-Index - 134
eISSN - 1558-8432
pISSN - 1558-8424
DOI - 10.1175/2008jamc1710.1
Subject(s) - mesoscale meteorology , terrain , meteorology , nested set model , sea breeze , horizontal resolution , environmental science , grid , climatology , atmospheric model , weather research and forecasting model , precipitation , geology , geography , geodesy , cartography , database , relational database , computer science
The Regional Atmospheric Modeling System (RAMS) was used to assess local air circulation patterns over the wine-producing Stellenbosch region of South Africa. Numerical simulations using four nested grids (25, 5, and 1 km, and 200 m of horizontal resolution) were performed for each day of February 2000 (during the grape-ripening period) over southern Western Cape Province. Modeled hourly data were extracted from the analysis files and used to produce mean hourly fields (temperature, relative humidity, wind speed, and radiation). Three runs with increasing horizontal resolutions for the finer grid were performed (run 1 with two nested grids of 25 and 5 km; run 2 with three nested grids of 25, 5, and 1 km; run 3 with four nested grids of 25, 5, and 1 km, and 200 m). For each event, the simulations of 1-km and 200-m resolution were superior to the 5-km-resolution simulation, especially in reproducing the local air circulations (sea and slopes breezes) because of a better representation of the local terrain (topography and vegetation cover). The use of a high-resolution grid (200 m) may be of greater value in the identification of potential terrain for viticulture.