MODTRAN CLOUD AND MULTIPLE-SCATTERING UPGRADES WITH APPLICATION TO AVIRIS

Recent upgrades to the MODTRAN atmospheric radiation code improve the accuracy of its radiance predictions, especially in the presence of cl ouds and thick aerosols, and for multiple scattering in regions of str ong molecular line absorption. The current public-released version of MODTRAN (MODTRAN3.7) features a generalized specification of cloud pro perties, while the current research version of MODTRAN (MODTRAN4) impl ements a correlated-k (CK) approach for more accurate calculation of m ultiply scattered radiance. Comparisons to cloud measurements demonstr ate the viability of the CK approach. The impact of these upgrades on predictions for AVIRIS viewing scenarios is discussed for both clear a nd clouded skies; the CK approach provides refined predictions for AVI RIS nadir and near-nadir viewing. (C) Elsevier Science Inc., 1998