Title: Interbasin gradients and past and future Central American hydroclimate variability

Abstract: The paleoclimatic record from Mexico and Central America, or Mesoamerica, documents dramatic swings in hydroclimate over the past few millennia. These have often been interpreted as reflecting meridional migrations of the intertropical convergence zone (ITCZ). Here, I propose an alternate view that emphasizes zonal asymmetries in tropical ocean temperatures by synthesizing proxy indicators of hydroclimate and model simulations of past climate. I show that across a range of proxies of past hydroclimate, tast millennium hydroclimate variability was dominated by opposite‐signed moisture anomalies in northern and southern Mesoamerica. This pattern results from changes in moisture convergence driven by Atlantic‐Pacific interbasin temperature gradients. While this pattern is reproduced by several models and multiple experiments with a single model, models appear to disagree about the underlying dynamics of this interbasin gradient. Moreover, disagreement about the interbasin gradient, and associated hydroclimate pattern, dominates spread in 21st century regional hydroclimate projections. I conclude by discussing ways in which paleoclimate can uniquely shed light on the sources of model disagreement about the interbasin gradient and its hydroclimatic consequences.

Speaker Information
Name: 
Tripti Bhattacharya
Title: 
Assistant Professor
Department: 
Earth and Environmental Sciences
Affiliation: 
Syracuse University
Host: 
Kathleen Johnson
Date and Time: 
Tuesday, November 17, 2020 - 1:00pm