Vertical eddy diffusivity in the subsurface pycnocline across the Pacific
Vertical eddy diffusivity in the subsurface pycnocline across the Pacific
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太平洋地下密斜层的垂直涡流扩散率
DOI：
10.1007/s10872-020-00589-9
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发表时间：
2021
影响因子：
2.3
通讯作者：
Yasuda I.
中科院分区：
文献类型：
--
作者：
Itoh S.;Kaneko H.;Kouketsu S.;Okunishi T.;Tsutsumi E.;Ogawa H.;Yasuda I.
在分层的海洋中，地下斜斜的垂直涡旋扩散率通过将营养物质从较暗/营养丰富的层向上输送，在新的生产中起主要作用。为了评估难以间接估计的地下层的扩散率，我们在夏季在开放太平洋的300米以上进行了直接微观结构测量，从40°S到50°N沿170°W和137°E到120°W横跨副热带北太平洋（21°30′N - 23°N）。中、低纬度地区地表下斜以高盐度的副热带海水为主，呈现出随深度和纬度增加而增加的副热带模态水域。在北太平洋，高纬度地区存在低盐度亚北极水，季节性浅斜。扩散系数的基准面为0.14 ~ 0.47 × 10-5m2s-1，而赤道潜流在次表层形成强切变的地方以及夏威夷脊等内潮能较高的地区，扩散系数的标高高达0.51 ~ 13 × 10-5m2s-1。风对扩散率的影响不太明显，可能是因为夏季风能普遍较低。亚热带北太平洋剪切应变比在纬度上呈圆顶型，自西向东呈增加趋势。本研究提出的扩散系数的地理分布将有助于通过改进物质运输的估计，更好地理解分层上层海洋的生物地球化学循环。
In the stratified ocean, vertical eddy diffusivity in the subsurface pycnocline plays a major role in new production through transporting nutrients upwards from the darker/nutrient-rich layer. In order to evaluate the diffusivity that was less available in the subsurface layers where indirect estimations are difficult, we conducted direct microstructure measurements in the upper 300 m of the open Pacific during summer, from 40°S to 50°N along 170°W and from 137°E to 120°W across the subtropical North Pacific (21°30′N–23°N). The subsurface pycnocline in the mid- and low-latitude regions was occupied primarily by the Subtropical Underwaters characterized by high salinity, and the Subtropical Mode Waters appeared with an increasing depth and latitude. In the North Pacific, low-salinity subarctic water with shallow seasonal pycnocline was observed in the high-latitude region. The base level of the diffusivity was 0.14–0.47 × 10–5m2s–1, while elevations up to 0.51–13 × 10–5m2s–1were observed at the equator where the Equatorial Undercurrents formed the strong shear in the subsurface layer, and in areas high internal tide energy such as the Hawaiian Ridge. The effect of wind on the diffusivity was less clear, probably because the wind energy is generally low during summer. The shear-to-strain ratio showed dome-shaped profiles with respect to latitude and an increasing trend from west to east in the subtropical North Pacific. The geographical distributions of the diffusivity presented in this study will contribute to better understanding biogeochemical cycles in the stratified upper ocean through improving estimations of the material transport.
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北太平洋副热带模式水湍流动能耗散率的直接测量
DOI：
--
发表时间：
2008
期刊：
Geophysical Research Letter 35
影响因子：
--
作者：
Hosokawa;K.;T. Tsugawa;K. Shiokawa;N. Nishitani;Y. Otsuka;T. Ogawa;and M. R. Hairston;Mori Kosuke
通讯作者：
Mori Kosuke
影响因子：
2.3
作者：
H. Kaneko;I. Yasuda;S. Itoh;S. Ito
通讯作者：
H. Kaneko;I. Yasuda;S. Itoh;S. Ito
影响因子：
5.2
作者：
Nagai, Takeyoshi;Tandon, Amit;Doubell, Mark J.
通讯作者：
Doubell, Mark J.
北太平洋扩散系数的空间分布及其对水体变化的影响
DOI：
--
发表时间：
2018
期刊：
Journal of Geophysical Research: Oceans
影响因子：
--
作者：
S. Kouketsu
通讯作者：
S. Kouketsu
影响因子：
2.2
作者：
Fer, Ilker;Peterson, Algot K.;Ullgren, Jenny E.
通讯作者：
Ullgren, Jenny E.