Systems and methods are provided that involve obtaining emissivity and reflectivity by the ratio of the radiance temperature versus the sea level temperature as observed by a satellite, and may further calculate two reflectivity values observed or simulated by the vertical or horizontal polarized channels of microwave, and then estimate a surface roughness. Further, illustrative implementations may involve obtaining the regression relation expression between the surface roughness and the wind strength and then detecting the sea-surface wind, using the information observed by the satellite again. As such, the sea-surface wind information can be obtained through satellite observation, and the information can be utilized for preventive activities against disaster including typhoon, the energy industry including wind power and the fishery in quasi-real time.