Temporal Variations of the Net Kuroshio Transport and Its Relation to Atmospheric Variations
Temporal Variations of the Net Kuroshio Transport and Its Relation to Atmospheric Variations
复制标题
DOI：
10.1007/s10872-010-0050-8
复制
发表时间：
2010-10-01
影响因子：
2.3
通讯作者：
Suga, Toshio
中科院分区：
文献类型：
--
作者：
Sugimoto, Shusaku;Hanawa, Kimio;Suga, Toshio
日本气象厅使用从日本南部（北纬 34 度）到新几内亚（南纬 1 度）的东经 137 度经线重复剖面的长期水文数据，对净黑潮输送的时间变化进行了调查。本研究根据海面动态高度分布定义了黑潮和黑潮逆流（KCC）的边界。与KCC相关的西向流和黑潮以北的冷核涡流被从与黑潮相关的东向流中去除，以便严格估计净黑潮输送。黑潮净输运揭示了低频变化：十年（约 10 年）时间尺度上的重要信号。黑潮净输送量的变化主要是由与黑潮南边界周围主密斜深度垂直运动相关的洋流速度场大小的变化引起的：黑潮南边界周围主密斜深度的加深在黑潮区域等重面形成了一个急剧的北上倾斜坡度，最终净黑潮输送量随着黑潮向东输送量的增加而增加。通过使用风驱动的后报模型，发现主要的密斜深度变化是由第一模式斜斜罗斯贝波引起的，可归因于两种类型的阿留申低气压（AL）变化：AL的震级变化和AL的经向运动。
Temporal variations of the net Kuroshio transport are investigated using long-term hydrographic data from repeat section of the 137 degrees E meridian from the south of Japan (34 degrees N) to New Guinea (1 degrees S) conducted by the Japan Meteorological Agency. In this study, boundaries of the Kuroshio and the Kuroshio Counter Current (KCC) are defined based on the sea surface dynamic height distribution. Westward flows associated with the KCC and cold-core eddy north of the Kuroshio are removed from the eastward flow associated with the Kuroshio in order to estimate the net Kuroshio transport strictly. The net Kuroshio transport reveals low-frequency variations: significant signals on a decadal (about 10-year) timescale. The variations of net Kuroshio transport are predominantly caused by changes in the magnitude of oceanic current speed fields associated with a vertical movement of the main pycnocline depth around the southern boundary of the Kuroshio: deepening of the main pycnocline around the southern boundary of the Kuroshio forms a sharp northern upward-tilting slope of the isopycnal surfaces at the Kuroshio region, and eventually the net Kuroshio transport increases together with the Kuroshio eastward transport. By using a wind-driven hindcast model, it is found that the main pycnocline depth variation results from the first-mode baroclinic Rossby waves attributable to two types of Aleutian Low (AL) changes: a change in the magnitude of AL and meridional movement of AL.