Subtropical Midsummer Droughts

University Of Miami, Coral Gables FL

Investigators

Abstract

This study is focused on a single phenomenon, the subtropical midsummer drought (which is technically not a drought but a minimum in the climatological annual cycle of precipitation during the rainy season in the inter-American seas region). The investigator will approach the problem at three different spatial scales. At the smallest scale, local atmospheric boundary layer and convective cloud processes that ultimately deliver rainfall will be studied to discern why precipitation diminshes. At the regional scale, features such as ocean-land contrasts, upstream effects and feedbacks, and orographic influences on flow and precipitation will be studied. On the largest scale, the PI will examine the role of large-scale general circulation features on the background state of the global atmosphere. Much of the larger-scale work pivots on the hypothesis that the North Atlantic subtropical high is a driving force for the ""drought"". However, the cloud-scale work is where the process-scale investigations will occur, and the regional scale links these effects together. The research will be pursued on three parallel cross-cutting tracks: observational analysis, dynamical diagnosis and modeling. The PI plans to support a separate PhD student, or perhaps a pair of consecutive MS students, to focus on each track. A better understanding of regional climate should result. There also could be positive impacts on weather and climate prediction across subtropical North America and the southern United States including forecasting of Atlantic and eastern Pacific hurricanes as a result of this research.