The Effect of Irrigation on Premonsoon Season Precipitation over South West Bengal, India

Abstract

The present work is on the modification of climatic variables, such as rainfall, as a result of change in land use during the premonsoon period over the southern part of West Bengal, India. Data analysis supports a decreasing tendency in rainfall during the recent years. As a possible factor behind such change, a significant increase in agricultural activity during recent years in coastal and inland regions has been stressed. The increase in soil moisture as a result of irrigation hinders the development and intensity of the sea-breeze circulation. The low-level moisture supply also decreases, which is an essential criterion for the formation of premonsoon thunderstorms, that is, northwesters. So, the increased vegetation or soil moisture is not always likely to increase rainfall activity; rather, mesoscale effects may be more important in some specific areas.