자료동화된 HYCOM모형결과를 통한 일본 남부 쿠로시오 Large Meander에 대한 Koshu Seamount의 영향

Abstract

Several mechanisms have been suggested to explain the transition of Kuroshio path from non-large to large meander south of Japan. Recently, a series of studies using satellite altimetry measurements, reanalysis data, and simplified numerical simulations demonstrates an essential role of Koshu Seamount located south of Cape Shiono-misaki, Japan, in generating the Kuroshio large meander. This study confirms the role of Koshu Seamount using data-assimilated HYbrid Coordinate Ocean Model (HYCOM) outputs. Analyses of model outputs reveal the interaction between deep abyssal anticyclonic circulation around Koshu Seamount and the Kuroshio, which amplifies the trigger meander to create the large meander in 2004. The Kuroshio takes offshore non-large meander paths for about a year from fall 2008. During this period deep anticyclone around Koshu Seamount wasnot developed enough to create the Kuroshio large meander since its path doesnt pass over Koshu Seamount. Scatter plot of upper stretching term versus deep one computed in a box surrounding Koshu Seamount shows negatively-correlated tight relationship between them when the large meander happens, suggesting that baroclinic instability is an important process to create the large meander.rical simulations demonstrates an essential role of Koshu Seamount located south of Cape Shiono-misaki, Japan, in generating the Kuroshio large meander. This study confirms the role of Koshu Seamount using data-assimilated HYbrid Coordinate Ocean Model (HYCOM) outputs. Analyses of model outputs reveal the interaction between deep abyssal anticyclonic circulation around Koshu Seamount and the Kuroshio, which amplifies the trigger meander to create the large meander in 2004. The Kuroshio takes offshore non-large meander paths for about a year from fall 2008. During this period deep anticyclone around Koshu Seamount wasnot developed enough to create the Kuroshio large meander since its path doesnt pass ove