Estimating fractional sky cover from spectral measurements

作者：Min Qilong^*; Wang Tianhe; Long Charles N; Duan Minzheng

来源：Journal of Geophysical Research, 2008, 113(D20): D20208.

DOI：10.1029/2008JD010278

A method for estimating fractional sky cover from spectral measurements has been developed. The spectral characteristics of clouds and clear-sky aerosols are utilized to partition sky fraction. As illustrated in our sensitivity study and demonstrated in real measurements, the transmittance ratio at selected wavelengths in insensitive to solar zenith angle and major atmospheric gaseous absorption. With a localized baseline procedure, retrievals of this ratio method are independent of absolute calibration and weakly sensitive to changes in cloud and aerosol optical properties. Therefore this method substantially reduces the retrieval uncertainty. The uncertainty of this method, estimated through the sensitivity study and intercomparison, is less than 10%. With globally deployed narrowband radiometers, this simple ratio method can substantially enhance the current capability for monitoring fractional sky cover.

• 出版日期2008-10-31
• 单位中国科学院大气物理研究所