The Effects of Large-Scale Dynamic Flows on Tropical Deep Convective Morphology

Abstract:

This study utilizes a recently developed database of tropical, marine deep convective cloud sizes and shapes observed from CloudSat. New additions to the dataset include measurements of the local environmental characteristics in which each convective cloud is embedded. The database is used to enumerate the sensitivity of cloud morphology to the local environment. Herein, the influence of deep-layer vertical shear of the horizontal wind and mid-level vertical velocity will be examined. It is shown that deep-layer shear acts to influence the length scales of convective anvil widths and depths so as to widen and consequently shallow anvils. Anvil base properties are particularly sensitive to shear. Upward mid-level vertical velocity is shown to raise cloud top heights and widen anvils. It also acts to increase the number of convective cores within a cloud system. The relative influences of these quantities are compared to other environmental factors including convective available potential energy, sea-surface temperature, and aerosol concentration. Shear and mid-level vertical velocity are shown to significantly impact ensemble convective morphology. The implications of these trends are discussed.