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An Analysis of the Low-Level Wind Field Over the Ross Ice Shelf, Antarctica. Melissa A. Richards ( Nigro ) John J. Cassano University of Colorado. Agenda. Components of the Low-Level Wind Field Over the Ross Ice Shelf Strong Wind Speeds Near the Dufek Coast & the Prince Olav Mountains
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An Analysis of the Low-Level Wind Field Over the Ross Ice Shelf, Antarctica Melissa A. Richards (Nigro) John J. Cassano University of Colorado
Agenda • Components of the Low-Level Wind Field Over the Ross Ice Shelf • Strong Wind Speeds Near the Dufek Coast & the Prince Olav Mountains • Case Study – September 2009 • Conclusion & Future Work Sabrina AWS Photo Courtesy of Shelley Knuth
Components of the Low-Level Wind Field Synoptic Forcing Katabatic Winds Role of local topography? Figure from Parish and Bromwich (1987) Average Wind Field Barrier Winds Figure from Parish et al. (2006)
Dufek Coast & Prince Olav Mountains Previous studies • Seefeldt and Cassano [2008] • Mountains protrude into low-level jet resulting in a tip jet • Steinhoff et al. [2009] • Flow is primarily around the mountains not over resulting in a “knob” flow • Each study mentions the need for additional analysis of the dynamics in this region to determine the mechanisms responsible for the strong winds in this region
Synoptic Forcing – Over the RIS BEFORE AFTER
Barrier Winds 10 m Winds 700 mb Winds SLP
Synoptic Forcing – Upper Level Ridge SLP 500 mb 300 mb BEFORE AFTER
Conclusion & Future Steps CONCLUSIONS: • The interaction of two or more forcing mechanisms can result in areas of very strong winds • Forcing for barrier wind development not seen at the 10 meter level, but evident at 700 mb where observations do not currently exist • The forcing mechanisms throughout the jet are spatially different FUTURE STEPS: • Understand the dynamics that cause the jet to accelerate in the location of the Sabrina AWS • Determine how often these events occur and if the same forcing mechanisms are present