Topocaustics

L. Y. Oey, Y. L. Chang, Z. B. Sun, X. H. Lin

研究成果: 雜誌貢獻期刊論文同行評審

10 引文 斯高帕斯(Scopus)

摘要

Deep (∼2000 m) observations near the Sigsbee escarpment in the Gulf of Mexico show short-period (approximately 5-12 days) energetic currents due to topographic Rossby waves (TRW's). We suggest that the phenomenon is due to the focusing and accumulation of TRW energy by the slopes coupled with a bend in isobaths, in a topographic caustic (topocaustic). The idea draws on a simple mathematical equivalence between the propagation of internal waves and of TRW's. Topocaustics occur near regions of maximum NT = N|∇h| (N = Brunt-Väisälä frequency; h = water depth). Because of the one-sided propagation property of TRW's, energy also tends to accumulate at the "western" end of closed contours of NT. The process is demonstrated here using a nonlinear primitive-equation numerical model with idealized bathymetry and forcing. A Gulf of Mexico simulation initialized with a data-assimilated analysis covering the period of the Sigsbee observation is then conducted. The mooring is near a localized maximum NT, and Intrinsic Mode Functions confirm the existence of energetic bursts of short-period deep-current events. The strong currents are locally forced from above, either by an extended Loop Current or a warm ring.

原文英語
頁(從 - 到)277-286
頁數10
期刊Ocean Modelling
29
發行號4
DOIs
出版狀態已發佈 - 2009

ASJC Scopus subject areas

  • Computer Science (miscellaneous)
  • Oceanography
  • Geotechnical Engineering and Engineering Geology
  • Atmospheric Science

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