Studies on the Interaction between North Pacific Intermediate Water and the Kuroshio

北太平洋中层水与黑潮相互作用研究

• 批准号: 13440139
• 负责人: YASUDA Ichiro
• 金额: $ 8.64万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13440139/
• 关键词: Kuroshio; Kuroshio Extension; Oyashio; ocean current; water mass; physical oceanography; oceanography; air-sea interaction

We here hypothesize that variation of the cross-gyre transport from the subarctic to subtropical gyres producing NPIW induces long-term variations in the Kuroshio/Kuroshio Extension current system. In order to validate this hypothesis and detect the actually occurring formation processes of NPIW, we conducted data-analysis, numerical experiments and field observations; we successfully obtained extraordinary results. (1) Based on four surveys of water masses and ocean currents using CTD/LADCP observation, we revealed about 10Sv of cross-gyre Oyashio transport through the following two processes : direct cross-gyre transport along the western boundary and cross-subarctic front (SAF) process occurring along the offshore SAF due to isopycnal mixing. (2) The intrusion of western boundary currents across the wind-driven gyre boundary and related cross-gyre transport are realistically reproduced with a eddy-permitting three layer numerical models with realistic topography and annual mean wind … More stress, with special emphasis on the Oyashio southward intrusion and North Pacific intermediate Water (NPIW) formation. About 3Sv of the model diapycnal upwelling occurring due to strong tidal mixing along the Kurii islands induces a meridional-diapycnal overturning circulation. These results explain the observed features that about 4Sv of the cross-gyre Oyashio transport along the western boundary participate in the formation of NPIW. (3) High-resolution intensive observation using CTD/towed-CTD (MVP : Moving Vessel Profiler) and LADCP/ADCP were performed around the Kuroshio Extension. These observations revealed that intermediate-depth frontal waves with the wavelength of about 200km propagate in the downstream direction with the phase speed of 0.2m/s, amplifying the amplitude. The waves break down and mix the two water masses very efficiently in the downstream regions until 150E. A linear stability analysis reveals that the observed frontal waves are possibly the baroclinically unstable waves due to the coupling between the surface and intermediate-depth vorticity anomalies. The Oyashio water thus enhances intensive mixing and NPIW formation by entering into the Kuroshio Extension. Less

我们在这里假设，从副北极到副热带环流产生NPIW的跨环流运输的变化引起黑潮/黑潮延伸流系统的长期变化。为了验证这一假设，并检测实际发生的NPIW的形成过程，我们进行了数据分析，数值实验和现场观测，我们成功地获得了非凡的结果。(1)基于CTD/LADCP观测的4次水团和海流调查，揭示了近10 Sv的跨环流Oyashio输送通过以下两个过程：沿着西部边界的直接跨环流输送和由于等密混合而沿沿着近海SAF发生的跨亚北极锋（SAF）过程。(2)使用具有真实地形和年平均风的涡流允许的三层数值模型，真实地再现了西部边界流穿过风驱动环流边界的入侵和相关的交叉环流输送 ...更多信息 应力，特别强调Oyashio南入侵和北太平洋中层水（NPIW）的形成。约3Sv的模式diapycnal上升流发生由于强烈的潮汐混合沿着千岛群岛诱导的对流层-diapycnal翻转环流。这些结果解释了观测到的沿西边界沿着的4Sv左右的交叉环流Oyashio输送参与NPIW形成的特征。(3)利用CTD/towed-CTD（MVP：Moving Vessel Profiler）和LADCP/ADCP对黑潮延伸区进行了高分辨率的密集观测。这些观测结果表明，波长约为200公里的中深度锋面波以0.2米/秒的相速度向下游方向传播，使振幅放大。波浪破碎，并在下游区域非常有效地混合两个水团，直到150 E。线性稳定性分析表明，观测到的锋面波可能是由于地面涡度异常与中深涡度异常耦合而产生的斜压不稳定波。因此，亲潮水进入黑潮延伸区，加强了强烈的混合和NPIW的形成。少

项目成果

M.Masujima, I.Yasuda et al.: "Transport of Oyashio water across the Subarctic Front into the Mixed Water Region and formation of NPIW"J.Oceanogr.. 59. 855-869 (2003)

M.Masujima、I.Yasuda 等人：“亲潮水穿过亚北极锋进入混合水区并形成 NPIW”J.Oceanogr.. 59. 855-869 (2003)

M.Masujima, I.Yasuda: "Transport of Oyashio water across the Subarctic Front into the Mixed Water Region and formation of NPIW"J.Oceanogr. 59. 855-869 (2003)

M.Masujima、I.Yasuda：“亲潮水穿过亚北极锋进入混合水区并形成 NPIW”J.Oceanogr。

I.Yasuda, 他2名: "Distribution and circulation of the coastal Oyashio intrusion"J. Phys. Oceanogr.. 31(6). 1561-1578 (2001)

I. Yasuda 等 2 人：“沿海 Oyashio 入侵的分布和循环”J. Phys. 1561-1578 (2001)。

安田一郎: "2.4節:黒潮予測と水産資源の変動.「海と環境-海から見た地球環境」"講談社. 104-110 (2001)

安田一郎：“第 2.4 节：黑潮预测和渔业资源的变化。‘海洋与环境 - 从海上看全球环境’”讲谈社 104-110 (2001)。

I.Yasuda: "North Pacific Intermediate Water : Progress in SAGE and related projects"J.Oceanogr. 60(2). 385-396 (2004)

I.Yasuda：“北太平洋中层水：SAGE 及相关项目的进展”J.Oceanogr。