Convective Intraseasonal Oscillations beteween Indian-Pacific and Northeasth Brazil Regions: Some Observational and Models Characteristics

Abstract This study investigated with observations and modeling using daily data of Long-Wave Radiation (RLW) the favorable phase to the convective activity associated with the low-frequency intrassazonal atmospheric variability known with Madden-Julian Oscillation (MJO) between the Indian Pacific region (INDI-PAC) and Northeastern Brazil (NEB) from November to May period of 1982 to 2013. The model used was the Global Ocean-Land-Atmosphere Model (OLAMV3.3) and observations were used for data generated by satellites by the Climate Prediction Center / National Ocean Atmospheric Admistration. The objective was to verify the time of the zonal band shift of these convective oscillations from its initial pulse, INDI-PAC region until reaching NEB. The data filtering method known as Lanczos Filter was applied in the band of 20-70 days in order to eliminate high oscillations, synoptic scales) and low frequencies (annual or more). Spectral characteristics using Wavelet analyzes showed that these oscillations between 20-70 days, from November to May, have a maximum energy spectrum in the observed data centered in the period of 8-16 pentads, end of December and beginning of April. The OLAM showed an advance of this maximum energy peak in the INDI-PAC region and an extension on the date of arrival in the NEB, meaning a delay, being that date for the end of April and May of this maximum of energy on the NEB.