Teleconnections between tropical-extratropical oceans and the daily intensitiy of extreme rainfall over Argentina.

ROBLEDO, FA, PENALBA, OC AND BETTOLLI, ML

Foz de Iguazu

Congreso; The Meeting of the Americas. AGU 2010; 2010

AGU

We have explored the covariability between sea surface temperature(SST) for all the oceans from 17.5 N to 90 S and the daily intensity of extremerainfall in Argentina.The main goal of this work is to identify the other ENSO likeregions of the oceans related with the extreme rainfall in Argentina. The tropicaland subtropical Atlantic Ocean and the Indonesian Sea, in addition to areas ofthe Indian Ocean have influence on Argentina’s extreme rainfall. This analysiswas performed using a Singular Values Decomposition (SVD) for three australseasons (spring, summer and autumn) in the period 1962 to 2005. The wavelettransform was applied to the SVD time series of the SST to analyze thedominant cycles and their period of occurrence. Two data sets were used:monthly SST from the Kaplan SST V2 from the NCEP/NCAR and high qualitydaily rainfall for 35 surface stations from the National Weather Service ofArgentina distributed throughout the country. The monthly mean of dailyintensity of extreme rainfall index (DIER) is the quotient between the monthlyaccumulated extreme rainfall (AE) and the number of days with extremeprecipitation events per month (PE). We consider extreme daily precipitationwhen rainfall is greater than the mean 75th daily percentile for the period 1961to 2000. Equation 1 represents the DIER index and was performed for each ofthe 35 meteorological stations................