Process-oriented Diagnosis and Metrics Development for the Madden-Julian Oscillation Based on Climate Simulations

“The Madden-Julian Oscillation (MJO) exerts significant influences on global climate and weather including in North America, and serves as a critical basis of the “Seamless Prediction” concept by bridging the forecasting gap between medium- to long-range weather forecasts and short-term climate prediction. The MJO, however, remains poorly represented in state-of-the-art general circulation models (GCMs) as well as NWP models, which leaves us greatly disadvantaged in undertaking climate change studies, particularly in projecting future changes in extreme events that are significantly modulated by the MJO.

In this proposed study, built upon both the PI’s (Jiang, co-organizer of the MJOTF/GASS MJO Project) and Co-PI’s (Maloney, co-chair of the WGNE MJO Task Force and NOAA MAPP CMIP5 Task Force) extensive experiences in studies on process-oriented metrics for the MJO, as well as the co-I’s (Zhao) and collaborator’s (Lin) expertises in GFDL model development, we propose to further explore key physical processes for realistic MJO simulations in GCMs by diagnosing observations and multi-model simulations including the 27 model datasets collected from the MJO Task Force/GASS MJO project and GFDL GCM simulations. In particular, we plan to comprehensively evaluate several processes previously considered to be important for the MJO, including feedbacks between environmental moisture and convection, convection and its induced circulation, and cloud-induced radiative heating and convection. Findings from this project will be developed into effective process-oriented metrics to assess reasons for MJO fidelity and particularly provide insight into key GCM deficiencies in MJO simulations, which further will provide valuable guidance for model development. These metrics will be built into standard software packages as part of collective efforts coordinated by the Type-1 project, and be installed at GFDL and other modeling centers. This proposed work will significantly contribute to GFDL’s model development efforts related to CMIP6 and IPCC AR6, particularly regarding representation of the MJO.

This proposal is strongly relevant to one of the NOAA NGSP’s long-term goal, “toward an improved scientific understanding of the changing climate system”, by advancing core capabilities in “understanding and modeling” and “predictions and projections”, as well as societal challenges in “climate impacts on water resources” and “changes in extremes of weather and climate”. In particular, this proposal directly addresses MAPP Program’s FY15 goal for “Process oriented evaluation of climate and Earth system models and derived projections”, particularly in the Area A: “Metrics for climate and Earth system model development”, as a type-2 subproject with the specific focus on the MJO.”