Interannual variability of cyclone trajectories in South America using probabilistic clustering techniques

DECHAT D.; M. PULIDO; M. M. LUCINI

Foz Iguazu (Brazil)

Conferencia; The Meeting of the Americas, AGU; 2010

American Geophysical Union

Techniques for the statistical classification of cyclone trajectories and cyclone genesis are developed and applied in the Ocean Pacific of the Southern Hemisphere. The cyclone trajectories are the result of an automatic technique for the detection and tracking of features in observed fields which are applied to the geopotential and the mean sea level pressure fields from ERA 40 reanalysis data and NCEP analysis. The trajectories are optimally classified using mixture of polynomial curves, the method determines the common spatio-temporal characteristics of the trajectories classifying them in clusters. The genesis points are clustered using bidimensional Gaussian mixtures. The interannual variability of the cyclone trajectories and genesis is examined. The sensitivity of the trajectories and the genesis points to the tropical SST forcing is evaluated for different years which are selected in different groups depending on ENSO index. The aim of this analysis is to show if it is possible to verify the processes suggested by Orlanski (2005) on the cyclone trajectory sensitivity to the tropical SSTs. The results show that the mean curves representing the trajectory clusters do not show a statistically significant sensitivity to large-scale forcings.