Comparisons between ground measurements of UV irradiance 290 to 380nm and TOMS UV estimates over Moscow for 1979-2000

Abstract

We show comparisons between ground-based measurements of UV irradiance less 380 nm and satellite TOMS UV retrievals within the whole period of TOMS measurements (1979-2000) over Moscow. We analyze the scale of temporal averaging of ground-based UV data taken with 1 minute resolution which should be used while comparing with TOMS data measured once per day within a relatively large footprint area (50-100 km2). Another objective is to study interannual variability of UV irradiance obtained by ground-based UV measurements and TOMS UV retrievals for the whole period of observation (1979-2000) over Moscow area. The analysis of interannual variations in satellite UV retrievals and ground-based UV irradiance is given together with examination of different atmospheric parameters, which are available from ground and satellite observations. A special attention is given to the comparisons of UV radiation obtained from ground and satellite measurements in spring season when the maximum ozone loss is observed. This is done together with the analysis of interannual variations in snow characteristics (snow albedo, snow depth, etc) and in cloudiness. We revealed the uncertainties in TOMS UV retrievals at specified atmospheric conditions by using ancillary information. The comparisons between TOMS and ground-based UV radiation in cloudless atmosphere with different aerosol optical properties are of particular concern.