Process-Oriented Diagnostics of Dynamical Coupling Between the Troposphere and Stratosphere in Earth System Models

Stratosphere-troposphere coupling has a significant influence on climate variability and extremes across a range of timescales. However, many modern climate models (including comprehensive Earth system models) still struggle to realistically represent such interactions between the troposphere and stratosphere. As a result, these models can have further related deficiencies in representing important aspects of the climate system, such as ENSO teleconnections and the positions of the jet streams, which can undermine their utility for projections of weather and climate extremes. Based on prior work in the field, we have developed a series of “process-oriented diagnostics” (PODs) that can be used to help assess the fidelity of key dynamical stratosphere-troposphere coupling processes in climate models. We have implemented these PODs into the open-source Model Diagnostics Task Force Framework. Furthermore, we are using these PODs to systematically benchmark and evaluate the impact of different model characteristics and configurations on the representation of stratosphere-troposphere coupling in CMIP6 models.