Direct turbulence observation around Kuril Straits and studies on the impact of the tidal mixing on the North Pacific

北太平洋海洋生态系统，包括金枪鱼和小型中上层鱼类，如沙丁鱼和凤尾鱼，已知与年代际海洋气候变化有关。然而，多年代际时间尺度的海洋气候变率和机制仍然不清楚，因此无法预测。目前研究发现了由月球轨道变化引起的18.6年周期的潮汐周期与西北亚北极太平洋水团的双年代际变化以及北太平洋冬季NPI（北太平洋指数）、PDO（太平洋年代际振荡指数）和MOI（东亚季风指数）等北太平洋气候指数之间的关系。俄罗斯“赫罗莫夫”号船的直接湍流观测证明了千岛海峡周围强烈的潮汐混合；垂直扩散系数达到1000 cm2/s以上，大约是普通开放海洋中等深度值（0.1 cm^<2>/s）的10000倍。这种强烈的潮汐混合变化与18.6年周期的潮汐循环有关，可能会改变鄂霍次克海的表面盐度，然后改变西北陆架地区的中间水形成（下沉）速率。这解释了鄂霍次克海和洋潮中间水域的双年代际变化。千岛海峡周边及北海道和东北东岸等尺度深度变化以海岸困波形式传播，可能改变黑潮强度和热输运。这种沿海变化可能到达赤道，并可能影响ENSO。海洋的这些变化可能通过大气遥相关导致阿留申低压的变化。本研究将天文上可预测的18.6年周期潮汐周期与小尺度海洋混合现象联系起来，并解释了北太平洋亚北极地区表层到中深度水质量的双年代际变化。该研究还提出了与海洋环流和北太平洋气候变率的联系。这开启了多年代际尺度海洋-气候-生态系统变化的可预测性。由于潮汐混合在时间和空间上都有较大的变化，因此需要对混合热点的湍流进行进一步的观测，以明确强混合机制并量化混合。营养物的垂直输送及其对海洋生态系统长期变异的影响和水的纵向输送及其对海洋环流和气候的影响的研究正在进行。少

North Pacific marine ecosystem including tuna and small pelagic fish as sardine and anchovy is known to be related with inter-decadal ocean-climate variability. However, multi-decadal time-scale ocean-climate variability and mechanism remain unclear and thus unpredictable. Present studies discovered the relationship between the 18.6-year period nodal tidal cycle caused by lunar orbital variation and the bi-decadal variability of water-masses in the northwestern subarctic Pacific and of the North Pacific climate indices as winter NPI (North Pacific Index), PDO (Pacific Decadal Oscillation Index) and MOI (east-Asian Monsoon Index). Direct turbulence observations by the Russian Vessel Khromov evidenced the strong tidal mixing around the Kuril Straits; the vertical diffusivity reached over 1000 cm2/s, which is roughly 10,000 times the value (0.1 cm^<2>/s) in ordinary open ocean intermediate depths. Changes in this strong tidal mixing associated with the 18.6-year period tidal cycle probabl … More y change the surface salinity in the Okhotsk Sea and then intermediate water formation (sinking) rate in the northwestern shelf region. This explains the observed bidecadal variations in the intermediate waters in the Okhotsk Sea and Oyashio. The isopycnal depth changes observed around the Kuril Straits and along the east coast of Hokkaido and Tohoku propagate as coastally trapped wave and may change the Kuroshio intensity and heat transport. This coastal change may reach the equator and may influence the ENSO. These changes in the ocean could lead to the changes in the Aleutian Low Pressure, through atmospheric teleconnection. The present study linked the astronomically predictable 18.6-year period tidal cycle and with small-scale ocean mixing phenomena, and explained the surface to intermediate depths water-mass bi-decadal variability in the North Pacific subarctic regions. This study also proposed the link with the oceanic circulation and North Pacific climate variability. These open the predictability of multi-decadal scale ocean-climate-ecosystem variability. Since the tidal mixing considerably changes temporally and spatially, we need further observation of turbulence in mixing hot spots to make clear the strong mixing mechanism and to quantify the mixing. Studies are going on about the vertical transport of nutrients and influence on long-term marine ecosystem variability and diapycnal water transport and influence on the ocean circulation and climate. Less