A quantitative analysis of the enhanced-V feature

Enhanced longwave InfraRed (IR) satellite imagery of deep convection sometimes display a cloud-top V-shaped feature, where a relatively warm equivalent blackbody temperature (BT) region of the storm top is enclosed by a V-shaped region of colder BT (Negri 1982; McCann 1983; Heymsfield et al. 1983a, 1983b; Fujita 1982). This feature is known as the enhanced-V. Enhanced-V features and severe weather are related. The presence of these V-features signifies strong tropospheric shear and intense updrafts, both of which are also essential for severe thunderstorms (Heymsfield and Blackmer 1988).

Early enhanced-V studies (McCann 1983) used eight-kilometer spatial resolution and 30-minute temporal resolution Geostationary Operational Environmental Satellite (GOES) IR imagery. In contrast, the spatial resolution of current satellite imagery is one-kilometer for Polar Orbiting Environmental Satellite (POES) IR imagery. This improved spatial resolution is used in this study to detect and investigate quantitative parameters of the enhanced-V feature. This study describes and analyzes quantitative parameters of the enhanced-V feature and discusses geographic and daytime versus nighttime satellite overpass distributions with the enhanced-V feature.