PESSACG Natalia Liz
congresos y reuniones científicas
Impacts of land use changes in southern South America climate for extreme climatic periods
Conferencia; 10th ICSHMO: International Conference on Southern Hemisphere Meteorology and Oceanography; 2012
Institución organizadora:
American Meteorological Society (AMS), in collaboration with the Institut de recherche pour le développement (IRD) and Météo-France.
This study examines the effects of land use/land cover changes (LULCC) over the climate in two important agricultural regions over southern South America, La Plata Basin and the Argentinean Pampas. In the last decade these regions have been suffered a replacement of the natural cover, mainly by the expansion of the agricultural activity, associated with an increase in the soy production. In this context and with the objective of analyze the impacts of LULCC in the southern South America climate, a series of sensitivity experiment were performed with the MM5 regional model, in which the natural cover was replaced by crop during different years related with extreme phases of the El Niño-Southern Oscillation (ENSO). The main impacts of LULCC over the climate in southern South America are a cooling and wetting over the north and central Argentina, Paraguay and part of Bolivia during the austral spring and summer seasons. Besides that, simulations allow us to determine the effect over the regional climate of the local and remote forcing together, and show that the interannual variability is important when assessing the strength of the impact. The cooling due to LULCC signal during El Niño year over north Argentina and Paraguay tends to weaken the strength of the interannual variability during the austral spring, which is characterized by a warm anomaly over this area. During summer, El Niño signal over this region is weaker than during the spring and is playing in the opposite way, cooling the atmosphere near to the surface, in the same way as the LULCC. Over the central and east of Argentina and Uruguay the interannual variability during summer presents a cold anomaly and the LULCC signal tend to enhance this effect and during La Niña there is a warming that is enhanced by the LULC signal.