The 23rd Conference on Hurricanes and Tropical Meteorology

10B.13
MODULATION OF INTRASEASONAL (25-70 DAY) PROCESSES BY THE SUPERIMPOSED ENSO CYCLE ACROSS THE PACIFIC BASIN

Jon M. Schrage, Purdue University, West Lafayette, IN; and D. G. Vincent, A. Fink, and C. A. Clayson

Using the 15-year ECMWF Reanalysis (ERA) data set and the Outgoing Longwave Radiation archive, a description of the effects of interannual variability on intraseasonal convection along the equator is presented. The El Niņo-Southern Oscillation (ENSO) phenomenon produces a significantly different environment over the central Pacific, which is a critical region in the life cycle of the Madden-Julian Oscillation (MJO). During the El Niņo years, the MJO is found to propagate farther eastward across the tropical Pacific, whereas it tends to become quasi-stationary over the western Pacific Warm Pool region in other years. Changes in the MJO's upper-level outflow and the associated low-level westerly wind bursts during El Niņo are examined. These interannual changes in intraseasonal processes result in changes in the downstream teleconnection patterns in both hemispheres

The 23rd Conference on Hurricanes and Tropical Meteorology