An evaluation of cloud affected UV radiation from polar orbiting and geostationary satellites at high latitudes

Abstract

For the first time two satellite-derived decadal scale climatologies of UV daily doses that are based on independently developed methods have been intercompared and compared to surface measurements. The methods mainly differ in the use of data from different instruments for probing the cloud fields (i.e. the AVHRR instrument aboard the polar orbiting NOAA satellites and the MVIRI instrument aboard the geostationary Meteosat satellite). This study focuses at the high latitudes close to 70°N (Northern Norway), a region initially expected as particularly problematic for geostationary satellites. However, an intercomparison of satellite derived UV-A, UV-B, and CIE daily doses for March, April, May, and July in the period from 1990 to 2001 gives correlation coefficients ranging from 0.91 to 0.97 depending on the area of averaging. A comparison of satellite derived CIE daily doses to surface measurements provides correlation coefficients in the order of 0.93.