An Observational Study of Easterly Waves over the Eastern Pacific in the Northern Summer Using FGGE Data

Abstract

Abstract FGGE revel III-b data provided by the European Centre for Medium-Range Weather Forecasts and the outgoing longwave radiation data measured by satellites are used to investigate observationally relationships between deep cloud activity and large-scale meteorological fields during the Northern Hemisphere summer (May–September) of 1979 over the eastern Pacific. Aside from the summer monsoon area over southern and eastern Asia, the eastern Pacific is the area where strong, deep convection frequently develops in the northern summer. This is also one of the tropical ocean areas that have been least explored meteorologically. A power spectral analysis using the Maximum Entropy Method is made for the meridional wind component at 850 mb at various grid points in the analysis domain for each mouth from May through September. The waves with a period of 4–6 days are not only stronger in July and August than those of other months, but active in the regions of 100°–130°W in the eastern Pacific and 130°–160°E i...