The 23rd Conference on Hurricanes and Tropical Meteorology

12B.4
EMPIRICAL DETERMINATION OF BASIC CLOUD REGIMES

Chichung Lin, UCLA, Los Angeles, CA

With the objective of developing an empirical cumulus para- meterization scheme in mind, basic vertical profiles of cumulus heating and drying are empirically determined by applying the Rotated Principal Component Analysis (RPCA) to observational data, including ECMWF Re-Analysis and GATE dataset. The basic profiles obtained are analogous to the cumulus effects associated with different cloud types in the Arakawa-Schubert cumulus parameterization. It is found that, although the cumulus heating and drying patterns are apparently distinct for different regions, roughly 85% of the variance can be explained by linear combinations of two basic profiles determined through the RPCA as far as active convective regimes are concern. Moreover, the two basic profiles are similar for a variety of regions selected for analysis. It indicates that the basic cloud regimes are quasi-universal when the presence of each basic profile is interpreted as the realization of a convective cloud regime

The 23rd Conference on Hurricanes and Tropical Meteorology