Sara Sanchez is a Chancellor's Postdoctoral Fellow in the Department of Atmospheric and Oceanic Sciences at the University of Colorado, 麻豆官网. Her research interests span tropical climate variability, climate change, paleoclimate dynamics, and isotope geochemistry. Her current work involves investigating low frequency climate variability in the data-sparse tropical oceans by fusing information from climate models with high resolution paleoclimate proxies. Prior to coming to CU-麻豆官网, Sara was a JISAO Postdoctoral Fellow at the University of Washington and received听her Ph.D. from Scripps Institution of Oceanography.听
Abstract
High resolution paleoclimate archives and听historical changes in the tropical hydrological cycle
Climate models suggest that the global hydrological cycle will feature some of the most robust responses to climate change, yet many regional responses remain uncertain. Forced trends in precipitation and evaporation may already be observable, but are difficult to discern due to the sparse network of precipitation and sea surface salinity observations, particularly over the tropical oceans. However, high resolution paleoclimate archives can help. Coral skeletal 未18O and, in particular, paired analysis of coral skeletal 未18O and Sr/Ca can offer insight into historical changes in historical hydroclimate variability through the reconstruction of 未18O of seawater at monthly to annual resolution. Seawater 未18O is primarily controlled by variations in precipitation, evaporation, and ocean circulation and is highly correlated with sea surface salinity. Here, I merge coral records of 未18O and Sr/Ca with the dynamics, spatial teleconnections, and intervariable relationships of isotope enabled global climate model simulations using the Last Millennium Reanalysis (LMR) offline data assimilation framework (Hakim et al. 2016, Tardif et al. 2019) to examine historical changes in the tropical hydrological cycle. In particular, I use this novel approach to examine the 20th century trends of precipitation and temperature, and the precipitation response to extreme phases of the El Nino Southern Oscillation. Finally, I explore the strengths, challenges, and significant opportunities ahead.