S191 The Madden-Julian Oscillation (MJO) and its Teleconnections

Sunday, 7 January 2018
Exhibit Hall 5 (ACC) (Austin, Texas)
Marybeth Arcodia, Univ. of Miami/RSMAS, Miami, FL

This study will aim to answer two questions: 1) How does the Madden-Julian Oscillation (MJO) produce an effect on the Pacific-North American (PNA) pattern? 2) What is the potential to predict this MJO-PNA teleconnection? The former question will be answered looking at daily OLR, rainfall, and zonal wind vectors at 850mb and 200mb obtained from the NCAR-NCEP Reanalysis data set. The latter question will be addressed by comparing the multi-model forecasts from the North American Multi-Model Ensemble (NMME) with observational estimates. It is recognized that the forecast skill for the MJO in the NMME system is limited to about 14-21 days, and we show how well the NMME models capture the teleconnection during this period of relative skill. There is also an ongoing multi-model sub-seasonal prediction effort (with retrospective forecast data available as of July 2017) and this will also be examined for the teleconnection. A teleconnection associated with the tropical rainfall of the MJO will be determined if a response is seen in regions of subsidence (mid-latitudes). A signal in the mid-latitudes infers that the tropical-mid-latitude coupling has an influence on the PNA teleconnection via Rossby wave forcing. Model and observational data will be compared to determine the interval of time with the highest prediction skill based on the strongest correlation between the two. A comparison will also be done to analyze how closely related the strongest MJO signal is in each. The results of this study will lend to further understand the tropical-extratropical connection in the Pacific as well as confidence in MJO prediction.
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