Characteristics of Mesoscale Eddies in the Kuroshio-Oyashio Extension Region Detected from the Distribution of the Sea Surface Height Anomaly
Characteristics of Mesoscale Eddies in the Kuroshio-Oyashio Extension Region Detected from the Distribution of the Sea Surface Height Anomaly
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DOI：
10.1175/2009jpo4265.1
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发表时间：
2010-05-01
影响因子：
3.5
通讯作者：
Yasuda, Ichiro
中科院分区：
文献类型：
--
作者：
Itoh, Sachihiko;Yasuda, Ichiro
本研究调查的海平面高度异常（SSHA）的分布，旨在量化的中尺度涡旋的特征，在黑潮-Oyashio延伸区（KOER），强烈的中尺度涡旋是常见的水文调查。密集分布的反气旋性涡旋（AE）和气旋性涡旋（CE）的KOER首次检测到足够的时间和空间覆盖范围，使用Okubo-Weiss参数没有平滑。它们对总SSHA方差的贡献估计约为50%。最高振幅的区域位于黑潮延伸区（KE）的轴的北部和南部的AE和CE，这分别代表暖心和冷心环，该地区向极沿着日本和千岛-堪察加海沟，特别是AE。沿沿着亚北极锋（SAF）还发现了两种极性和中等振幅的涡旋。KE以北和以南地区的涡旋通常向西传播，平均速率为1-5 cm s（-1）;那些沿着北纬46度以南的海沟和沿着SAF的涡旋分别以1-2和0.5-1 cm s（-1）的平均速率向极地传播。由于KE南北两侧AE和CE的不对称分布，以及它们沿日本海沟和千岛-堪察加海沟沿着的不对称振幅，这些地区存在显著的涡度、热量和盐度的涡动通量。
This study investigates the distribution of the sea surface height anomaly (SSHA) with the aim of quantifying the characteristics of mesoscale eddies in the Kuroshio-Oyashio extension region (KOER), where intense mesoscale eddies are commonly observed during hydrographic surveys. Dense distributions of both anticyclonic eddies (AEs) and cyclonic eddies (CEs) are detected for the first time in KOER with sufficient temporal and spatial coverage, using the Okubo-Weiss parameter without smoothing. Their contribution to the total SSHA variance is estimated to be about 50%. The zones of highest amplitudes are located north and south of the axis of the Kuroshio Extension (KE) for AEs and CEs, which represent warm-core and cold-core rings, respectively; the areas extend poleward along the Japan and Kuril-Kamchatka Trenches, especially for AEs. Eddies of both polarities and with moderate amplitudes are also recognized along the Subarctic Front (SAF). Eddies in areas north and south of the KE generally propagate westward, at a mean rate of 1-5 cm s(-1); those along the trenches south of 46 degrees N and along the SAF propagate poleward at mean rates of 1-2 and 0.5-1 cm s(-1), respectively. Because of the asymmetric distribution of the AEs and CEs in the areas north and south of the KE, and the asymmetric amplitude of them along the Japan and Kuril-Kamchatka Trenches, there exist significant eddy fluxes of vorticity, heat, and salinity in these areas.