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Probability distribution of surface wave slope derived from spaceborne remote sensing data

星载遥感数据面波斜率概率分布

基本信息

批准号：
11640424
负责人：
EBUCHI Naoto
金额：
$ 2.18万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640424/
关键词：
remote sensing surface wave wind wave wave slope microwave scatterometer visible radiometer GMS 可視赤外放射計リモート・センシング可視・赤外放射計

项目摘要

The probability distribution of the sea surface slope has been estimated using sun glitter images derived from the visible wavelength radiometer on the Geostationary Meteorological Satellite (GMS) and surface vector winds observed by spaceborne scatterometers. The brightness of the visible images is converted to the probability of wave surfaces which reflect the sunlight toward GMS in grids of 0.25° x 0.25° (latitude x longitude). The slope and azimuth angle required for the reflection of the sun's rays toward GMS are calculated for each grid from the geometry of GMS observation and location of the sun. The GMS images are then collocated with surface wind data observed by three scatterometers. Using the collocated data set of about 30 million points obtained in a period of 4 years from 1995 to 1999, the probability distribution function of the surface slope is estimated as a function of wind speed and azimuth angle relative to the wind direction. The results are compared with those of Cox and Munk (1954). The surface slope estimated by the present method shows a narrower distribution and much less directivity relative to the wind direction than that reported by Cox and Munk. It is expected that their data were obtained under conditions of growing wind waves. In general, wind waves are not always developing, and the slope distribution might differ from the results of Cox and Munk. Most of our data are obtained in the subtropical seas under clear-sky conditions. This difference in the conditions may be the reason for the difference of slope distribution.

使用从地球静止气象卫星（GMS）上的可见波长辐射计获得的太阳闪烁图像和星载散射仪观测到的表面矢量风来估计海面坡度的概率分布。可见图像的亮度被转换为以 0.25° x 0.25°（纬度 x 经度）网格将太阳光反射到 GMS 的波面的概率。根据 GMS 观测的几何形状和太阳的位置，计算每个网格将太阳光线反射到 GMS 所需的斜率和方位角。然后将 GMS 图像与三个散射仪观测到的表面风数据进行搭配。利用1995年至1999年4年间获得的约3000万个点的并置数据集，估计了表面坡度的概率分布函数，作为风速和相对于风向的方位角的函数。结果与 Cox 和 Munk (1954) 的结果进行了比较。与 Cox 和 Munk 报道的相比，本方法估计的表面坡度显示出更窄的分布和相对于风向的方向性要小得多。预计他们的数据是在风浪不断增强的条件下获得的。一般来说，风浪并不总是发展，坡度分布可能与 Cox 和 Munk 的结果不同。我们的大部分数据都是在晴空条件下在副热带海洋中获得的。这种条件的差异可能是坡度分布差异的原因。