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Effects of tropical convection on the predictability of the Sahel summer rainfall interannual variability
Author(s) -
Thiaw Wassila M.,
Kumar Vadlamani
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2001gl013139
Subject(s) - predictability , climatology , environmental science , forecast skill , sea surface temperature , convection , canonical correlation , meteorology , geography , geology , mathematics , statistics
Tropical convection as inferred from OLR, and global SST, are used as predictor fields in separate canonical correlation analysis (CCA) experiments. The experiments are based on 43‐year (1955‐98) observed SST data and 20‐year (1979‐98) OLR record. The aim is to study the role of tropical convection in improving the predictions of the interannual variability of the Sahel summer rainfall. Forecast skills for OLR and SST predictor fields are estimated using a cross‐validation scheme. Average region‐wide correlation skill for OLR is 0.368, which is slightly higher than skill for SST based on a 43‐year record (0.308). However, much of the skill in the latter is associated with long term trends. Skill for OLR outperforms significantly that of SST based on a 20‐year historical record. Hindcasts for the Jul‐Sep Sahel rainfall in 1997 and 1999 show an improvement over SST in the predictions of the interannual variability where OLR is used as predictor field.