Premium
Role of vegetation dynamics in enhancing the low‐frequency variability of the Sahel rainfall
Author(s) -
Wang Guiling,
Eltahir Elfatih A. B.
Publication year - 2000
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/1999wr900361
Subject(s) - climatology , vegetation (pathology) , forcing (mathematics) , environmental science , climate change , biosphere , climate model , climatic variability , atmosphere (unit) , sea surface temperature , atmospheric sciences , geography , geology , oceanography , ecology , meteorology , medicine , pathology , biology
Rainfall observations in the Sahel region of West Africa show significant variability at the timescale of decades. Here we explore the mechanisms of this low‐frequency variability using a coupled biosphere‐atmosphere model which includes explicit representation of vegetation dynamics. By forcing the model with the observed sea surface temperature (SST) of the tropical Atlantic Ocean during the period 1898–1997, numerical experiments on the climate variability of West Africa have been carried out. The results of these experiments suggest that vegetation dynamics is a significant process in shaping the natural variability of the Sahel rainfall. The response of the regional climate system to large‐scale forcings is significantly regulated by vegetation dynamics. The relatively slow response of vegetation to changes in the atmosphere acts to enhance the low‐frequency rainfall variability. The regional climate system over West Africa has several climate regimes coexisting under the current precessional forcing. Climate transitions between different regimes act as another mechanism contributing to the low‐frequency rainfall variability. Climate persistence at one regime and climate transition toward another collectively compose a distinct type of multidecadal variability.