Rainfall Variability and Changes in Southern Africa during the 20th Century in the Global Warming Context

摘要: Rainfall variability and changes in Southern Africa over the 20th century areexamined their potential links to global warming discussed. After a shortreview of main conclusions various experiments with Global AtmosphericModels (GCM) forced by increased concentrations greenhouse gases for SouthernAfrica, study datasets documents observed rainfall featuresat both daily seasonal time steps through last century. Investigations dailyrainfall parameters are so far limited South Africa. They show that some regionshave experienced shift toward more extreme events recent decades.Investigations cumulative anomalies summer season do notshow any trend drier or moister conditions during However, closeexamination reveals has experiencedsignificant modifications, especially decades. Interannual variabilityhas since late 1960s. In particular, droughts became intense andwidespread. More significantly, teleconnection patterns associated SouthernAfrican changed from regional before 70s near after,and an statistical association El Nino – Oscillation (ENSO) phenomenon is observed. Numerical French GCM indicate these teleconnections could be related long-term variations Sea-Surface-Temperature background, which part signal.