Characteristics of upper-level and boundary layer forcing in Western Pacific cyclones.

Abstract

A study of the characteristics of upper-level and boundary layer forcing in Western Pacific cyclones is conducted. Data for this study consists of twenty seven cyclones identified during the months of February and March 1986 and 1987. The cyclones were stratified into three separate classes of weak, moderate and intense cyclones based on observed deepening rates. Each class of cyclone was examined to determine general characteristics of the upper-level and boundary layer forcing. A representative cyclone from each class was chosen and a detailed examination of the upper-level and boundary layer forcing was conducted. Results indicate that during rapid deepening coupling between the upper-level forcing and forcing in boundary layer occurred only in the moderate and intense cases and was the result of strong baroclinic forcing aloft in these cyclones.