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Prediction of seasonal rainfall in the sahel region using empirical and dynamical methods
Author(s) -
Folland Chris,
Owen John,
Ward M. Neil,
Colman Andrew
Publication year - 1991
Publication title -
journal of forecasting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.543
H-Index - 59
eISSN - 1099-131X
pISSN - 0277-6693
DOI - 10.1002/for.3980100104
Subject(s) - climatology , sea surface temperature , environmental science , range (aeronautics) , tropics , atmospheric dynamics , meteorology , atmosphere (unit) , geography , geology , ecology , materials science , composite material , biology
Long‐range weather forecasting is a notoriously difficult area of environmental science. However, recent improved understanding of atmospheric dynamics and better observations indicate that useful progress, rooted in scientifically sound ideas, may be possible with long‐range forecasting in the tropics. We describe recent research into the mechanisms and prediction of rainfall in the sub‐Sahara during the main summer rainfall season, concentrating on the Sahel region. We use a complex physical model of the atmosphere (a ‘general circulation’ model) and two relatively simple statistical models to show that large‐scale variations in sea surface temperature (SST) can strongly influence seasonal Sahel rainfall. Persistence of patterns of SST anomalies (deviations from long‐term average) is sufficient to allow useful forecasting techniques to be based on fields of SST anomalies observed in the preceding spring. However, persistence of the SST anomalies may not always be sufficient to provide a skilful forecast.