Column atmospheric water vapor and vegetation liquid water retrievals from Airborne Imaging Spectrometer data

作者：Bo‐Cai Gao, Alexander F. H. Goetz · 发表于：Journal of Geophysical Research Atmospheres · 年份：1990 · DOI：10.1029/jd095id04p03549 · 被引用次数：439 · 研究领域：Atmospheric and Environmental Gas Dynamics、Calibration and Measurement Techniques、Atmospheric Ozone and Climate

High spatial resolution column atmospheric water vapor amounts were derived from spectral data collected by the airborne visible‐infrared imaging spectrometer (AVIRIS), which covers the spectral region from 0.4 to 2.5 μm in 10‐nm bands and has a ground instantaneous field of view of 20×20 m from an altitude of 20 km. The quantitative derivation is made by curve fitting observed spectra with calculated spectra in the 1.14‐μm and 0.94‐μm water vapor band absorption regions using an atmospheric model, a narrowband spectral model, and a nonlinear least squares fitting technique. The derivation makes use of the facts that (1) the reflectances of many ground targets vary approximately linearly with wavelength in the 0.94‐ and 1.14‐μm water vapor band absorption regions, (2) the scattered radiation near 1 μm is small compared with the directly reflected radiation when the atmospheric aerosol concentrations are low, and (3) the scattered radiation in the lower part of the atmosphere is subjected to the water vapor absorption. The technique is directly applicable for retrieving column water vapor amounts from AVIRIS spectra measured on clear days with visibilities 20 km or greater. The precision of the retrieved column water vapor amounts from several data sets is 5% or better. Based on the analyses of an AVIRIS data set that was acquired within an hour of radiosonde launch, it appears that the accuracy approaches the precision. The derived column water vapor amounts are independent o...