In order to understand the formation process of the radiance distribution in the sea, it is necessary to determine the radiance distribution in each scattering order analytically. For this purpose, a plane-parallel layer model that computes primary scatterin gradiance was developed for obtaining ananalytical understanding of the radiance distribution in each scattering order. The plane-parallel layer model was developed from the definitional equation of a volume scattering function and by integrating this function over the thickness of the plane-parallel layer. When the thickness of a plane-parallel layer was considered to be infinitesimal, the formula obtained was in agreement with the existing primary scattering model. By expanding this plane-parallel layer model to high-order scattering, a numerical model for radiation transfer can be obtained.

From recent mooring observations carried out along the coast of Tango Peninsula, we found that stormy current, Kyucho, rarely occurred before passage of Typhoon or midlatitude cyclone and damaged set-net around the peninsula. We examined the characteristics and generation mechanism of the Kyucho associated with the case of Typhoon 0514. Mooring current and temperature data obtained at the eastern part of the peninsula showed that the northward strong current (approximately 0.8 ms^－1) accompanied with temperature decrease have developed before passage of the typhoon. The currents distributed with the coast on the left hand were extracted as the first EOF mode and its time variation was found to be crossly correlated with the westward wind at Mt. Taiko (at the center of the peninsula). From a numerical experiment using 3D level model with uniform stratification condition, the northward strong current and temperature decrease at the eastern part of the peninsula was well reproduced by forcing of the wind which was blowing more than two days before passage of Typhoon 0514. We concluded that the Kyucho occurred at eastern part of the peninsula before passage of Typhoon was due mainly to the coastal jet excited by continuously blowing strong westward wind.