Synoptic-scale disturbances near the Equator

Abstract

A spectral analysis of winds analyzed and initialized at the European Centre for Medium-Range Weather Forecasts reveals an abundance of power in the 850mb meridional wind along the equator with periods near four days. The power is mostly in the westward propagating component. The structure of the disturbances bears resemblance to the expected structure of an equatorially trapped mixed Rossby-gravity wave over the central Pacific and Atlantic oceans, although the anomalies, while statistically significant, are extremely small. The outgoing longwave radiation (OLR) pattern is consistent with the flow field, suggesting that the waves are not merely a model artifact. -from Authors