SPATIAL AND TEMPORAL PERTURBATIONS VARIABILITY IN TROPICAL AND EXTRATROPICAL SYSTEMS IN SOUTH AMERICA

Climate variability at different scales of the atmosphere is a research field that has received a very special interest in recent years. In this work we study the temporal and spatial atmospheric circulation variability, through an analysis of monthly anomalies for the 850 hPa at three South America rawinsonde stations. In particular, we analyze extreme anomalies in the eastern region of tropical and extratropical South America, and its regional behaviour related to climatic change. Also, a latitude-longitude comparison is presented. For this study we use rawinsonde data from Argentina (Córdoba and Ezeiza) and the south of Brazil (Galeão) spanning the period January 1973- October 2005 and covering an area of interest limited by the latitudes 20º S and 40º S. The two former stations represent the extratropical region, while the latter represents the tropics. Geopotential heights obtained from the rawinsondes are the variables used in this analysis. The methodology used consists in the application of basic statistics parameters, Fourier analysis, and a cluster analysis to classify the atmospheric circulation fields