分层的大型海洋响应气压的影响.pdfVIP

FEBRUARY 2007 P O N T E A N D V I N O G R A D O V 245 Effects of Stratification on the Large-Scale Ocean Response to Barometric Pressure RUI M. PONTE AND SERGEY V. VINOGRADOV Atmospheric and Environmental Research, Inc., Lexington, Massachusetts (Manuscript received 29 July 2005, in final form 22 May 2006) ABSTRACT Single-layer (barotropic) models have been commonly used in studies of the inverted barometer effect and the oceanic response to atmospheric pressure loading. The potential effects of stratification on this response are explored here using a general circulation model in a near-global domain with realistic coasts and bathymetry. Periodic forcing by the diurnal and semidiurnal atmospheric tides and 6-hourly stochastic forcing from weather center analyses are both examined. A global dynamic response (i.e., departures from inverted barometer behavior) is clear in the response to atmospheric tides; for stochastic forcing, the largest dynamic signals occur in shallow and semienclosed regions and at mid- and high latitudes. The influence of stratification in the dynamics is assessed by comparing surface and bottom pressure signals. Baroclinic effects are generally weak, particularly in the response to the large-scale atmospheric tides. Under stochastic forcing, largest differences between surface and bottom pressure signals reach 10%–20% of the surface signals and tend to occur in regions of enhanced topographic gradients. Bottom-intensified, localized