This project focuses on the analysis of the water balance in the Western U.S. during Miocene time through the application of an innovative approach that links changes in precipitation patterns to sea surface temperature (SST) variations in the eastern Pacific and Gulf of Mexico. In contrast to the prevailing arid climate of the modern Western U.S., conditions during middle Miocene time were far wetter despite similar atmospheric carbon dioxide levels. This project will determine how SST variations affect the net transfer of water from ocean to land by using existing Ocean Drilling Program sediment cores to reconstruct a SST time series for the middle and late Miocene, by groundtruthing the time series using terrestrial proxies for climate change, and by applying both regional and global climate models to simulate the impact of SST variations on climate conditions in the Western U.S. The project will produce the first well-constrained SST record for Miocene time and will provide modeling results that hindcast Miocene climate conditions and that may also be applied in a predictive sense to determine the potential impact of warming episodes on the future aridity of the Western U.S. Broader impacts of the project include linkages between the water cycle and regional climate change, support for relatively recent PhDs as principal investigators, and training of graduate and undergraduate students.
