The PI will investigate the dynamical nature of the impact of downward wave coupling (DWC) on the tropospheric circulation and climate in reanalysis data and its representation in a state-of-the-art seasonal forecast and climate model. The goal is to assess the potential impact for seasonal forecasts and climate prediction in the troposphere. The research will focus on the Northern Hemisphere where the stratospheric variability allows for a clear separation of months with DWC and downward zonal mean coupling. The analysis will shed insights into the dynamical cause and evolution of individual wave reflection events and composite events to understand (i) the direct impacts of planetary wave reflection from the stratosphere on the phase and amplitude structure of the tropospheric wave pattern and (ii) the subsequent impacts of DWC on the tropospheric circulation both in the mid troposphere and the surface and how they compare to the impacts of downward zonal mean coupling. Increased understanding of the dynamical processes by which the stratosphere can influence the troposphere has the potential to lead to improved seasonal forecasting and climate prediction, thus leading to significant societal impacts.
