Projected precipitation changes in South America: a dynamical downscaling within CLARIS

SÖRENSSON, A.A.; C. MENÉNDEZ; R. RUSCICA; ALEXANDER, P.

METEOROLOGISCHE ZEITSCHRIFT (BERLIN)

E SCHWEIZERBARTSCHE VERLAGS

Año: 2010 vol. 19 p. 347 - 355

0941-2948

Responses of precipitation seasonal means and extremes over South America in a downscaling of a climate change scenario are assessed with the Rossby Centre Regional Atmospheric Model (RCA). The anthropogenic warming under A1B scenario influences more on the likelihood of occurrence of severe extreme events like heavy precipitation and dry spells than on the mean seasonal precipitation. The risk of extreme precipitation increases in the La Plata Basin with a factor of 1.5–2.5 during all seasons and in the northwesternpart of the continent with a factor 1.5–3 in summer, while it decreases in central and northeastern Brazil during winter and spring. The maximum amount of 5-days precipitation increases by up to 50 % in La Plata Basin, indicating risks of flooding. Over central Brazil and the Bolivian lowland, where present 5-days precipitation is higher, the increases are similar in magnitude and could cause less impacts. In southern Amazonia, northeastern Brazil and the Amazon basin, the maximum number of consecutive dry days increases and meanwinter and spring precipitation decreases, indicating a longer dry season. In the La Plata Basin, there is no clear pattern of change for the dry spell duration.