Wang, Y, Lu, D, Huo, J (2007). Determination of the optical thickness and effective particle radius of clouds from transmitted solar radiation measurements. PROGRESS IN NATURAL SCIENCE, 17(10), 1199-1207.
A method is presented for determining the optical thickness (tau(c)) and effective particle radius ( r(e)) of stratiform cloud layers from transmitted solar radiation measurements. A detailed study shows that the cloud optical thickness and effective particle radius of water clouds can be determined from transmission function measurements at 0.75 and 2.13 mu m, provided that the scaled optical thickness tau'(0.75)> 1 and r(e) > 5 mu m. The wavelengths adopted by our study are similar to the channels of the moderate resolution imaging spectrometer (MODIS). The proposed method is invalid for optically thin clouds since transmission at 2.13 pm is less sensitive to r(e). The retrieval errors of tau'(0..75) and re monotonically decrease with increasing tau(c). For clouds having tau'(0.75) >= 2, the retrieval errors of tau'(0.75) and r(e) are below 10% and 20%, respectively. Transmissions at 0.75 and 1.65 mu m can also be used to retrieve tau(c) and r(e).