An intercomparison of observed and simulated extreme rainfall and temperature events during the last half of the twentieth century: part 2: historical trends

JOSE A. MARENGO · MATILDE RUSTICUCCI · OLGA PENALBA · MADELEINE RENOM

CLIMATIC CHANGE

SPRINGER

Año: 2010 vol. 98 p. 509 - 529

0165-0009

We analyze historical simulations of variability in temperature and rainfallextremes in the twentieth century, as derived from various global models runinforming the Fourth Assessment Report of the Intergovernmental Panel on ClimateChange (IPCC-AR4). On the basis of three indices of climate extremes, wecompare observed and modeled trends in time and space, including the directionand significance of the changes at the scale of South America south of 10◦ S. Theclimate extremes described warm nights, heavy rainfall amounts and dry spells. Thereliability of the GCM simulations is suggested by similarity between observationsand simulations in the case of warm nights and extreme rainfall in some regions. Forany specific extreme temperature index, minor differences appear in the spatial distributionof the changes across models in some regions, while substantial differencesappear in regions in the interior of tropical and subtropical South America. Thedifferences are in the relative magnitude of the trends. Consensus and significanceare less strong when regional patterns are considered, with the exception of the La Plata Basin, where observed and simulated trends in warm nights and extremerainfall are evident.