Possible Near-IR Channels for Remote Sensing Precipitable Water Vapor from Geostationary Satellite Platforms

Abstract

Abstract Remote sensing of tropospheric water vapor profiles from current geostationary weather satellites is made using a few broadband infrared (IR) channels in the 6–13-µm region. Uncertainties greater than 20% exist in derived water vapor values just above the surface from the IR emission measurements. In this paper, we propose three near-IR channels, one within the 0.94-µm water vapor hand absorption region, and the other two in nearby atmospheric windows, for remote sensing of precipitable water vapor over land areas, excluding lakes and rivers, during daytime from future geostationary satellite platforms. The physical principles are as follows. The reflectance of most surface targets varies approximately linearly with wavelength near 1 µm. The solar radiation on the sun-surface-sensor ray path is attenuated by atmospheric water vapor. The ratio of the radiance from the absorption channel with the radiances from the two window channels removes the surface reflectance effects and yields approximately...