Surface UV from ERS-2/GOME and NOAA/AVHRR data. A case study

A satellite based method for deriving spatial distributions of erythemally weighted UV irradiance at the surface has been developed. The effects of ozone column amount and cloud optical thickness on UV were taken into account by the combined usage of the new European-Space-Ageney's GOME (Global-Ozone-Monitoring-Experiment) sensor onboard the European-Research-Satellite-2 (ERS-2) and the NOAA/AVHRR instrument, respectively. As an example for application, horizontal distributions of surface UV irradiances are derived in a region covering the area of Southern Germany on two days 22. July and 13. August 1996. These two days represent clear and cloudy conditions, respectively. For the cloud free day 22. July 1996 the surface UV measurements at Garmisch-Partenkirchen and Hohenpeissenberg (Southern Germany) were about 4.5 per cent lower than those derived from satellite measurements. In addition, the accuracy of the method in case of the cloudy day is discussed.