Effects of the Speed and Direction of Surface Winds on the Radiation in the Atmosphere–Ocean System

Abstract

Effects of the surface wind speed and direction on the radiation field in the model atmosphere–ocean system is theoretically investigated for the wavelength of 865 nm. The wind direction is considered for 0°, 45°, 90°, 135°, and 180° from the solar direction, where the wind speed is assumed to be 5 m/s and 11 m/s. The computational scheme is the doubling-adding method where polarization effect is included. Computational results show that the effect of the wind direction on the radiance at the top of the atmosphere is generally smaller than the effect of a change in wind speed from 5 m/s to 11 m/s. However, the opposite trend is shown at some viewing angles when wind speed is 11 m/s. For small optical thickness of aerosol (0.052), the effect of the wind direction on the radiance at the top of the atmosphere becomes larger than 20% even if the wind speed is 5 m/s. It is also shown that the degree of polarization is generally less sensitive to the wind speed and direction than the radiance. Therefore, measurements of the polarization from satellites may provide useful additional information for retrieval of the optical characteristics of the atmospheric aerosol.