Remote sensing of total precipitable water vapor in the near-IR over ocean glint

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Abstract

A method for remote sensing of total precipitable water vapor using water vapor absorption band at 0.94 µm was previously developed for continental regions. Here we apply a similar technique for ocean areas over the glint region. The glint, or oceanic specular reflection, has a high value of surface reflectance and thus, can work as well as or better than applications over land regions. The method is applied for glint regions measured by the Moderate Resolution Imaging Spectro-radiometer (MODIS) simulator, an imager flown on the NASA ER-2 research aircraft and simulating the expected measurements from the MODIS instrument on board the Earth Observing System (EOS)-Terra satellite. The measurements are made for the Atlantic coast of the United States during the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX). The remote sensing technique is compared with measurements of water vapor column by the Lidar Atmospheric Sensing Experiment (LASE) Differential Infrared Absorption Lidar (DIAL) lidar system also on board the ER-2. Water vapor was derived with an error of ±5 mm PW (precipitable water vapor). Most of the errors are associated with the limitations of an experiment that was not originally designed for this purpose. Much better performance is expected from the actual MODIS instrument.

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