Current Research in EEPS Seminar: Dr. Bronwen Konecky – Washington University, St. Louis
Decoding rainfall variability in the Earth’s tropical land areas from the distant past to today
Tropical rainfall variability has cascading impacts on global climate. Yet the complex water cycle underpinning tropical rainfall variability, especially over land, is poorly understood. The fate of rainfall on land depends on thermal and evaporative conditions in distant oceans where moisture originates, and on the complex mixing, condensation, and re-evaporation it undergoes along its path. Changes in global climate in the modern era or in the geologic past can alter tropical rainfall by shifting oceanic moisture source regions; tipping the continental/oceanic moisture balance; speeding up, slowing down, or redirecting atmospheric transport; or desiccating one region in favor of another. These macro-scale dynamics hinge on microphysical underpinnings, but tracking processes like evaporation on spatial scales from molecular to global, and on temporal scales from storms to the decades-to-millennia timeframe of climate change, requires strategic integration of data and models across spatial, temporal, and disciplinary bounds. Here, I will present new research utilizing the stable O and H isotopic composition of modern precipitation, which is a sensitive recorder of these water cycle processes. I will integrate data from several projects spanning daily to interannual timescales, and use this information to better understand late Quaternary wet-to-dry and dry-to-wet transitions recorded in tropical geologic archives.