The goal of this project is to improve understanding of how tropical convective systems influence high latitude Southern Hemisphere (SH) climate anomalies on seasonal, El Nino Southern Oscillation (ENSO), and anthropogenic change time scales. Sensitivity of SH atmospheric structures to tropical forcing will be examined through observational analysis and a new modeling strategy. The following hypothesis will be tested: SH atmospheric structures are sensitive to the location and timing of outflow from deep convection in the upper troposphere and lower stratosphere (UTLS), and this modulation depends on season, phase of ENSO, and longer-term trends. A novel technique that avoids the complexity of modeling tropical convection by representing tropical convective anomalies with meridional outflow perturbations in the SH subtropical UTLS will be utilized in the study. Monthly mean and ENSO mean basic states for the present (from global analyses) and for 2100 AD (from climate model forecasts) will be used as boundary conditions for ensembles of simulations with the University of Wisconsin Nonhydrostatic Modeling System (UWNMS).
An important component of this work is to integrate what is known about coupling between the tropics and Antarctica for dissemination to the public via images and text on a dedicated website. This outreach activity will help educate the public regarding how the tropics and Antarctica are coupled on seasonal, ENSO, and anthropogenic global change time scales. This work will also help reduce uncertainty in seasonal ENSO forecasts for Antarctica and future climate simulations.
This work has the potential to improve seasonal forecasting of the influence of ENSO on Antarctica, via a careful analysis of ENSO and Antarctic surface data and high resolution UWNMS simulations. This work will also improve our understanding of teleconnections and provide climatological descriptions of the relationship among subtropical UTLS anticyclones, synoptic Rossby wave breaking, and extratropical planetary waves.
