Preliminary evaluation of the ENSO´s impacts in hydric conditions of the pampean area through the Surface Temperature and the Enhanced Vegetation Index

HOLZMAN, M. E.; RIVAS, R

Foz do Iguazzu

Encuentro; The Meeting of the Americas; 2010

In South America, the climatic variability could be associated to “El Niño-Southern Oscillation” (ENSO). ENSO is a climatic phenomenon from the equatorial Pacific Ocean related to the “warm tongue” location and it could be interpreted as a seesaw of the atmospheric pressure between the east and the west of this region. The objective of this work is the evaluation of the response from the hydric conditions in the pampean area of Argentina to ENSO´s events through the Ts (Surface Temperature) – EVI (Enhanced Vegetation Index) relation with MODIS (Moderate Resolution Imaging Spectroradiometer) sensor images. This relation was analyzed for natural areas of Uruguay,  La Pampa and Buenos Aires provinces (Argentina) to spring and summer 2005-2006 (neutral period), 2007-2008 (La Niña event) and 2009-2010 (El Niño event). These periods were defined considering the NIÑO 3.4 temperature anomalies (figure 1). The figure 1 also shows the analyzed areas. The results showed that in the forest ecosystems of La Pampa province the Ts/EVI and the NIÑO 3.4 temperature anomalies relation is not direct. On the other hand, Buenos Aires and Uruguay grasslands would be more sensitive to the ENSO´s event.As a conclusion, the Ts/EVI relation could be an indicator of ENSO´s teleconnection in the pampean area, without the need to posses the field data. Nevertheless there would be necessary a more detailed study from previous situations to an ENSO´s event.