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Oceanic responses to H urricane I gor over the G rand B anks: A modeling study
Author(s) -
Ma Zhimin,
Han Guoqi,
Young Brad
Publication year - 2015
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2014jc010322
Subject(s) - baroclinity , storm surge , upwelling , surge , barotropic fluid , oceanography , geology , storm , seiche , turbulence , climatology , meteorology , atmospheric sciences , physics , geomorphology
A three‐dimensional (3‐D) baroclinic finite‐volume ocean model (FVCOM) was developed to examine the oceanic response to Hurricane Igor over the Grand Banks of Newfoundland. Hurricane Igor generated a storm surge of almost 1 m at St. John's and about 0.8 m at three nearby coastal tide gauge stations (Bonavista, Argentia and St. Lawrence). The surge magnitude from the 3‐D baroclinic model agrees approximately with tide‐gauge observations at all four stations, slightly better than that from an alternative 3‐D barotropic case. The sudden drop of sea surface temperature caused by the storm, approximately6 o C as observed by buoys, is well simulated by the baroclinic model with a k‐ε turbulence closure. A sensitivity simulation with the Mellor‐Yamada turbulence closure significantly underestimates sea surface cooling. It is shown that the sea surface cooling is mainly associated with turbulent mixing, and to a lesser degree with Ekman upwelling. The model solution shows that the largest surge occurred between Bonavista and St. John's. Further analysis suggests the generation of a free continental shelf wave after the storm made landfall, with the peak surge propagating from St. John's to St. Lawrence.