Geographical distribution of extreme deep and intense convective storms on Earth

Abstract

Vigorous convective storms can not only produce severe destructive weather events and lead to huge damages, but also play a vital role in stratosphere–troposphere exchange (STE). Based on 16-yr Tropical Rainfall Measuring Mission (TRMM) observational data, global geographical distribution of extremely deep and intense convective storms has been investigated. The results show that convective storms are mainly distributed in the tropics, with the largest storm event density located in tropical Africa, tropical Americas and the Maritime Continent. However, compared to convective storms, the most intense and deepest convective storms present a distinctly different geographical distribution pattern, which is true even if the same convective storm samples are used. Overall, tropical Africa is the only region in the world where the distributions of deep and intense convective storms overlap. Other than that, convective storms in the Maritime Continent region are characterized by large convective depth but weak convective intensity, while the opposite is true in subtropical land regions. The top 1% deep convective storms occur most frequently in boreal winter (48%) and spring (36%), and are mainly distributed in the Maritime Continent and tropical Africa. Those most intense convective storms show a weak seasonal variation in quantity while their distributions are significantly different from season to season. Further analysis reveals that convective properties of storms in different regions are distinctly different, and even different in the same region such as tropical Africa but in different seasons. This result suggests that although the formation of convective storm requires sufficient water vapor supply and instable atmospheric conditions, deep convection needs more water vapor supply to develop compared to intense storms. • The geographic distributions of deep and intense convective storms exhibit distinctly different patterns. • Convective storms are strong in convective depth in maritime continent, but strong in convective intensity in subtropical continent. • Deep convection is more likely to occur in a more humid environment than intense storms.