Observation of the surface mixed layer and its modeling

表面混合层的观测及其建模

• 批准号: 10640421
• 负责人: YAMAZAKI Hidekatsu
• 金额: $ 1.98万
• 依托单位: TOKYO UNIVERSITY OF FISHERIES
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640421/
• 关键词: turbulence; mixing; mixed layer; closure model; Kelvin-Helmholtz instability

We have developed a new microstructure instrument to observe both physical and biological parameters simultaneously. The instrument is equipped with standard turbulence sensors and temperature gradient, as well as bio-optical sensors for measuring in situ chlorophyll and turbidity variations. Simultaneous measurements with this profiler and an acoustic Doppler velocimeter were carried our in a flow tank, and data from both instrument agreed well. Turbulence spectra computed from both instruments agreed with the Kolmogorov inertia subrange hypothesis over more than 1.5 decades in wavenumber space. Data from field tests conducted with the profiler showed that turbulence spectra measure in situ agreed with the empirical Nasmyth spectrum when corrections were made for the shear probe's spatial averaging. Dissipation rates as low as 5x10^<-10> W kg^<-1> were resolved.A new high-resolution bio-optical sensor is developed and calibrated. The probe enables us to perform high-resolution measure … More ments of in-situ chlorophyll and turbidity. The sensitivity and the spatial resolution of the probe are tested in several laboratory experiments. Analysis of the test data shows that this probe is capable of resolving spatial distributions of chlorophyll as small as 0.02 m. Analysis of the spectral characteristics of chlorophyll and turbidity signals recorded in field tests corroborate the laboratory results.From a previously conducted field experimental data we identified a Kelvin-Helmholtz billow from vertical turbulence velocity and instantaneous heat flux signals obtained from airfoil shear probes and thermistors mounted on a research submarine. The vertical turbulence velocity indicates that the horizontal scale of the billow was about 3.5 m. The spectral slope of the vertical turbulence velocity component is close to -2, revealing the flow is two-dimensional. We show a remarkable agreement between the length scales of the observed billow and those computed from direct numerical simulations based on similar conditions.In order to combine the new field measurements with numerical models, we are developing a random walk simulation model for phytoplankton production making use of 2.5 level Mello-Yamada closure model. We have compared this new approach with a simple Ekman layer model. We report a rapid deeping revealed in Mello-Yamada model makes a significant difference in the random walk trajectories, however, the total productions at the end of the simulation show similar results. Less

我们已经开发了一种新的显微结构仪器，同时观察物理和生物参数。该仪器配备了标准的湍流传感器和温度梯度，以及用于测量现场叶绿素和浊度变化的生物光学传感器。同时测量与此轮廓仪和声学多普勒测速仪进行了我们在一个流动的坦克，从这两个仪器的数据一致。湍流谱计算从两个仪器同意Kolmogorov惯性子范围假设超过1.5十年的波数空间。与剖面仪进行的现场试验的数据表明，湍流光谱测量在现场同意的经验Nasmyth频谱时，剪切探头的空间平均进行了修正。研制<-10><-1>了一种新型的高分辨率生物光学传感器，并对该传感器进行了标定。该探头使我们能够进行高分辨率测量 ...更多信息 叶绿素和浊度的原位测量。在几个实验室实验中测试的探头的灵敏度和空间分辨率。试验数据的分析表明，该探头能够分辨小至0.02 m的叶绿素空间分布。叶绿素和浊度信号的光谱特性的分析证实了实验室的结果，从以前进行的现场实验数据，我们确定了开尔文-亥姆霍兹翻腾的垂直湍流速度和瞬时热通量信号从翼型剪切探头和安装在研究潜艇的湍流。垂直湍流速度表明，巨浪的水平尺度约为3.5米。垂直湍流速度分量的谱斜率接近-2，表明流动是二维的。为了将新的现场测量结果与数值模式联合收割机相结合，我们利用2.5层Mello-Yamada闭合模型建立了一个浮游植物生产的随机行走模拟模型。我们比较了这种新的方法与一个简单的埃克曼层模型。我们发现在Mello-Yamada模型中发现的一个快速的加深使得随机行走轨迹有显著的差异，然而，在模拟结束时的总产量显示出类似的结果。少

项目成果

Wolk, F., L.Seuront and H.Yamazaki: "Spatial resolution of a new micro-optical probe for chlorophyll and turbidity"J.Tokyo University of Fisheries. (in press). (2001)

Wolk, F.、L.Seuront 和 H.Yamazaki：“用于叶绿素和浊度的新型微光学探针的空间分辨率”J.东京水产大学。

Wolk,F.,L.Seuront and H.Yamazaki: "Spatial resolution of a new micro-optical probe for chlorophyll and turbidity"J.Tokyo University of Fisheries. (2001)

Wolk，F.，L.Seuront 和 H.Yamazaki：“用于叶绿素和浊度的新型微光学探针的空间分辨率”J.东京水产大学。

Wolk,F.,L.Seuront and H.Yamazaki: "Spatial resolution of a new micro-optical probe for chlorophyll annd turbibity"J.Tokyo University of Fisheries. (2001)

Wolk,F.,L.Seuront 和 H.Yamazaki：“叶绿素和浊度的新型微光学探针的空间分辨率”J.东京水产大学。