92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Sunday, 22 January 2012
The Large-Scale Influences on the Intensity and Position of the Amundsen / Bellingshausen Seas Low
Hall E (New Orleans Convention Center )
Kyle R. Clem, Ohio University, Athens, OH; and R. L. Fogt

The Amundsen-Bellingshausen Seas Low (ABSL), a semi-permanent low pressure system in the South Pacific, may be related to the regional warming across West Antarctica and the Antarctic Peninsula. As a means to understanding this connection, much more knowledge is needed on the variations of the ABSL, especially since this system resides in one of the poorest meteorologically sampled regions globally. This research examines large-scale climate influences on the position (latitude, longitude) and the magnitude (central pressure) of the ABSL.

Using data from three global atmospheric reanalyses, we find strong seasonal relationships between tropical sea surface temperatures (SST) and the location and intensity of the ABSL. Interestingly, the relationship varies by season and with the location of SST anomalies; a non-uniform impact is found across the tropical Pacific Ocean. For example, only regions along the dateline in the equatorial Pacific show impacts on the longitude of the ABSL, most marked when SSTs are above average. A relationship with the latitude of the ABSL was observed with SST anomalies just east of the dateline, during both warm and cold SST anomalies. In contrast, SST anomalies in the far eastern tropical Pacific (along the coast of South America) show a strong influence on the magnitude of the central pressures of the ABSL. Somewhat surprisingly, the connections of the ABSL position are more strongly tied to remote influences stemming from the tropical Pacific Ocean, rather than from hemispheric wide pressure fluctuations manifested in the Southern Annular Mode.

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