Predictability of Severe Thunderstorms with Fractal Dimension Approach

Thunderstorm is meso-scale weather with space scale varying from a few kilometres to a couple of 100 kilometres and time scale varying from less than an hour to several hours. Severe thunderstorms, however, produce strong surface wind squalls, lightning, heavy rain showers, occasional hail, down-bursts and tornadoes leading to loss of life and property on the ground and aviation hazard aloft. Prediction of severe thunderstorm is a challenging task for the atmospheric scientists around the globe. The rationale of the present study is, thus, to view the relative significance of two important convective energies, convective available potential energy (CAPE) and convective inhibition energy (CIN) in the genesis of severe thunderstorms during the pre-monsoon season (April – May) over Kolkata (22°32'N, 88°20'E). The concept of fractal dimension is applied in this study to observe the degree of selfsimilarity between CAPE and CIN for the prevalence of severe thunderstorms during the pre-monsoon season. Fractal dimension of CAPE and CIN is measured with the help of the level of free convection (LFC). The fractal dimension is considered in this study as the measure of randomness. The result reveals that CIN has more selfsimilarity than CAPE for the genesis of severe thunderstorms over Kolkata.