Retrieval of the optical thickness of inhomogeneous from multispectral satellite measurements 

作成者 Kikuchi, Nobuyuki, Iwabuchi, Hironobu, 早坂, 忠裕
作成者の別表記 Hayasaka, Tadahiro
日本十進分類法 (NDC) 512.75, 451
内容 研究概要:A method is presented for determining the optical thickness of horizontally inhomogeneous clouds from reflected solar radiation measurements. A new parameter of effective gradient is defined as an oblique angle of the plane parallel. Under the assumption that the effective particle radius of clouds is constant in the cloud layer, the optical thickness and effective gradient of clouds in the independent pixels of satellite scene can be determined from reflection function measurements at weak absorbing wavelength (0.86μm) and absorbing wavelength (2.16μm). Applying this method to Landsat TM measurements, we recognize that the effective gradient at 0.86μm is smaller than at 2.16μm and the effective gradient ratio is estimated to be 0.65 for nadir view with oblique sun (θ_0=60°). By applying the effective gradient ratio to the oblique plane parallel model, the analysis provides a good estimate of the optical thickness and effective gradient of cloud. In addition to Landsat TM measurements, an analysis of the forward and backward scattered radiation field of a fractal cloud model is carried out using a Monte Carlo simulations. It is shown that a good agreement between estimates and originals of the optical thickness of cloud can be obtained and the effective gradient ratio is smaller in the backward view and larger in the forward view than in the nadir view.
コンテンツの種類 研究報告書 Research Paper
DCMI資源タイプ text
掲載誌情報 Proceedings of the CEReS international symposium on remote sensing of the atmosphere and validation of satellite data page.101-105 (2001)
言語 英語

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