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Abstract:
Simulations have shown, that in the case of a Known particle shape measurements of solar radiation in the spectral ranges around 1.05 and 1.6 mu m contain enough information to estimate cloud optical depth and effective particle size. The results of an EoF analysis give rise to the hope, that this estimation is also possible for the case of an unknown particle shape. Therefore some additional spectral regions in the near-infrared have to be considered.
During the aircraft campaign EUCREX 94 different missions with the multispectral sensor OVID were flown inside frontal ice cloud systems. This study present estimated effective radii and cloud optical depths from measurements around 1.05 and 1.6 mu m under the assumption of different particle shapes. The best agreement with independent measurements of other instruments result from the assumption of an irregular polycrystal.
An additional consideration of spatial features allows the distinction of cloud layers in different altitudes in the atmosphere. This study shows as an example a comparison of spectral measurements above multiple layer clouds with simulations of an atmosphere with two cloud layers. The measurements can be well described by simulations with a realistic choice of cloud parameters. (C) 1999 Elsevier Science ltd. All rights reserved.
