Sensitivity of Radiation Absorbed in the Ocean to Atmospheric and Oceanic Parameters in the Short Wavelength Region

[摘要] To develop a monitoring technique estimating the shortwave radiation absorbed in the ocean(Iwabs) from space, sensitivities of Iwabs, and the upward irradiance at the top of the atmosphere(It↑) to atmospheric and oceanic parameters are investigated in a model atmosphere-ocean system.These irradiances are computed using the doubling-adding method in the wavelength region ranging from 0.285μm to 5.0μm for the atmosphere-ocean model in the mid-latitude summer.Under no cloudiness, oceanic type aerosols are considered with their size distribution represented by the log-normal distribution.The ocean surface is simulated by many facets whose slopes are changed according to an isotropic Gaussian distribution with respect to the surface wind speed.The effect of whitecaps is also included in the model.Two types of hydrosols are considered: the one engages in of pure scattering and the other includes partial absorption.The present simulation tells us that (1) the atmospheric aerosols mostly affect Iwabs, and It↑;(2) water vapor and ozone in the atmosphere moderately affect Iwabs, but their effects might be evaluated using their spectroscopic absorption characteristics;(3) Purely scattering hydrosols affect Iwabs and It↑, especially in the case of the turbid condition;(4) The surface state of the ocean shows little effect on Iwabs, and It↑ if the solar zenith angle is less than about 60°.These results may be used for development of space techniques upon deriving Iwabs, with the aid of the model atmosphere-ocean system.Finally, to validate Iwabs, by ship, a sensitivity of radiation just above the ocean surface to atmospheric and oceanic parameters is also discussed.

[学科分类] 大气科学