A potential vorticity analysis of the Madden-Julian Oscillation and extratropical cyclogenesis

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Thursday, 8 January 2015: 9:00 AM
121BC (Phoenix Convention Center - West and North Buildings)
Charles Jones, Univ. of California, Santa Barbara, CA

The Madden–Julian Oscillation (MJO) has a significant role in weather and climate variability. The MJO significantly influences the occurrence of heavy precipitation around the globe. Since the MJO involves intense tropical convective heating anomalies, tropical–extratropical interactions are significant during its life cycle. Consequently, the MJO interacts with the large-scale circulation in the extratropics of both hemispheres. This study uses NCEP CFSR reanalysis from 1979-2013 and a tracking algorithm to detect the formation of extratropical cyclones. Events of MJO are identified with filtered outgoing longwave radiation (OLR) and zonal winds at 850-hPa and 200-hPa anomalies. The presentation will discuss the statistics of extratropical cyclones during the life cycle of the MJO. An isentropic potential vorticity analysis is performed to elucidate the dynamical mechanisms associate with the MJO and its influence on extratropical cyclogenesis.