Abstract ATM-9732673 Hastenrath, Stefan University of Wisconsin, Madison Title: Variability of Tropical Circulation and Climate The study purposes to continue the research aimed at understanding by empirical diagnostics the circulation mechanisms that are operative in annual cycle, interannual variability, and decadal- scale evolutions. This work aims at the development of data sets as OLR and CODS data sets and the 40 years NCEP/NCAR reanalysis data. The results from this research will provide valuable climate prediction capabilities which will be of great use for many countries critically dependent on climate.