Thermodynamic Changes in the Atmosphere Associated with Pre-monsoon Thunderstorms Over Eastern and North-Eastern India

Abstract

AbstractDuring the pre-monsoon season (March–May), eastern and north-eastern India receives frequent thunderstorms. These thunderstorm events are responsible for sudden wind gusts, high rainfall and associated lightning, which destroy property, the environment and human habitats. As thunderstorms are short span events with high vertical cloud development, they make noticeable changes in the thermodynamics of the atmosphere. Identifying these thermodynamical changes may enhance the understanding genesis of these convective events and their propagation and would improve forecasting of these events more accurately. The present work reviews the atmospheric thermodynamical changes due to pre-monsoon thunderstorms over eastern and north-eastern India. The review found that the study region experiences frequent multi-cell clusters or squall line thunderstorms. The existence of small hills and plateaus in the area acts as triggering agents for thunderstorm initiation (e.g. Chota Nagpur Plateau and Hazaribagh Plateau in eastern India), and the Bay of Bengal is the source of moisture supply. The convective instability indices work well over eastern India but fail to differentiate the thunderstorms over north-eastern India. Various studies reveal that the frequency and intensity of these thunderstorms are changing over the region due to global warming. The pre-monsoon thunderstorms over eastern and north-eastern India inspired researchers to formulate new thermodynamic indices listed in the present review. The study also discusses the use of re-analysis data to calculate thermodynamic indices and their closeness to calculations based on in-situ data over the region.KeywordsThunderstormsThermodynamic indicesRadiosondeRe-analysis dataClimate changeNor’westersKalbaishakhiEastern and North-Eastern India