A Method of Estimating Cloud Transmission in the UV Spectral Range using Data from Different Satellite Measurements and Reanalysis

We propose a method for cloud UV transmission evaluating on the base of TOMS/OMI LER (Lambertian Equivalent Reflectivity) dataset, which provides more accurate retrievals of UV levels at ground in conditions with high surface albedo. For the improvement of cloud UV transmission estimates, in addition to TOMS/OMI LER data we used two datasets: low layer cloud amount data from ECMWF ERA Interim reanalysis, and surface albedo retrievals according to the method proposed in [1]. The obtained results were tested against experimental data of the Meteorological Observatory of Moscow State University (MSU MO, 55.7N, 37.5E), which included long-term measurements of erythemally weighed radiation, and UV radiation in the spectral range 300-380 nm. The comparisons were made with the cloud UV transmission estimates, obtained by the standard TOMS LER approach [2]. We showed that the cloud UV transmission estimates from the proposed method gave a better agreement with the experimental data compared with the results obtained from the standard TOMS LER approach for winter conditions with high surface albedo. During warm period the retrievals obtained from different methods are in a satisfactory agreement.