Climate Change Scenarios over the South American Region:

CARRIL A. F., C. G. MENÉNDEZ AND M. N. NUÑEZ

INTERNATIONAL JOURNAL OF CLIMATOLOGY

RMetS

Año: 1997 vol. 17 p. 1613 - 1633

0899-8418

Results of four different coupled atmosphere-ocean general circulation modelruns for South America and surroundings oceans are examined. The mean responseof the simulated climate system to a gradual increase of greenhousegases is presented. The transient coupled experiment data provided for theIntergovernmental Panel on Climate Change (IPCC) were the most recent availableto us at the time of this study from the following research centers in Europeand USA: The United Kingdom Meteorological Office (UKMO), the Max-PlanckInstitute for Meteorology (MPI), the Geophysical Fluid Dynamic Laboratory(GFDL) and the National Center for Atmospheric Research (NCAR).The regional performance of the control simulations (with fixed CO2 concentration)is determined comparing sea level pressure, near surface zonal wind, precipitationand surface air temperature from the models, against climatologicalobserved fields. The response of the climate system to the enhanced emissionscenarios is established comparing the control experiments with the respectivetransient experiments around the time of doubling CO2. To assist in estimatinglikely future climate change in the South American region, only the results ofthose model experiments with the best control simulation of current climate inthe region are considered: the UKMO and MPI models. A maximum warmingover the continent and a minimum warming in the extratropical oceans, a slightintensification and southward migration of the subtropical ridge, a deepening ofthe subantarctic trough, an intensification of the westerly winds, and increasingprecipitation in the tropics and in the mid-latitude oceans are the most importantpotential changes simulated by both models for the increased CO2 scenarios.