Future Changes in MJO Teleconnections and its Impacts on Precipitation Extremes

Abstract:

Future changes of boreal winter MJO teleconnections over the Pacific/North America region are quantitatively examined in the newly released multi-ensemble Coupled Model Intercomparison Project phase 6 (CMIP6) ScenarioMIP runs using the teleconnection diagnostics proposed in our recent study (Wang et al. 2019). The results suggest a robust eastward shift and shorter persistence of MJO teleconnections in the future, while changes in the amplitude and pattern consistency are more uncertain. Possible causes of MJO teleconnection changes are investigated from the impacts of the MJO and basic state on the anomalous Rossby wave source. Various MJO and basic state metrics which characterize the changing MJO propagation, amplitude, and jet position will be used to discover their relationships with the changing MJO teleconnections.

Impacts of MJO teleconnections on precipitation extremes over North America in the future are also examined. Changes in characteristics of precipitation extremes related to active MJO events will be discussed including the absolute frequency of precipitation extremes, the preference of precipitation extremes to occur in a specific MJO phase, the precipitation intensity, and duration.

Wang, J., H. Kim, D. Kim, S. A. Henderson, C. Stan, and E. D. Maloney (2019): MJO teleconnections over the PNA region in climate models. Part I: Performance- and process-based skill metrics, J. Climate, 33, 1051-1067. doi: 10.1175/JCLI-D-19-0253.1.