Quasi 4 Day Mode Observed by a Boundary Layer Radar at Serpong (6°S, 107°E), Indonesia

Abstract

A spectral analysis of lower tropospheric winds, observed by the Boundary Layer Radar (BLR) at Serpong (6°S, 107°E) in West Java, Indonesia during 1992/93, 1993/94, and 1994/95 rainy seasons reveals a pronounced spectral peak, at a period near 4 days. Filtered analysis of this quasi 4 day mode (Q4DM) shows almost an in-phase structure in the vertical. The GANAL (Global Objective Analysis by Japan Meteorological Agency) data for 1992/93 rainy seasons shows that in general the meridional wind component, at the altitude 700hPa, has a westward phase propagation.