Comparison of surface UV irradiance in mountainous regions derived from satellite observations and model calculations with ground-based measurements

Autor: Jochen E. Wagner, Federico Angelini, Antti Arola, Mario Blumthaler, Michael Fitzka, Gian Gobbi, Richard Paolo Kift, Axel Kreuter, Harald E. Rieder, Stana Simic, Ann Webb, Philipp Weihs
Jazyk: angličtina
Rok vydání: 2010
Předmět:
Zdroj: Meteorologische Zeitschrift, Vol 19, Iss 5, Pp 481-490 (2010)
Druh dokumentu: article
ISSN: 0941-2948
DOI: 10.1127/0941-2948/2010/0347
Popis: Several UV data products derived from satellite measurements, 1-D and 3-D radiative transfer modeling are compared with high-quality ground-based measurements. Data products include the UV index, erythemally weighted daily dose and spectrally resolved UV irradiances at 305, 310, 324 and 380 nm. The study focuses on the UV radiation climate in mountainous terrain under cloud-free conditions. The results show, that overall the 3-D- and the 1-D-model agree best with the measurements (average ratio 1.10 and 1.13, range 0.88-1.6). It is also found that snow and local topography have a rather minor impact on ground UV-irradiance, while altitude plays a significant role >5 %). Satellite-retrieved values significantly underestimate irradiance for most of our stations due to erroneous cloud correction (average ratio 0.89, range 0.6-1.35). However, if one compares the uncorrected (cloud-free) satellite-retrieved values to the measurements, the ratios are only slightly larger (average ratio 1.14, range 0.8 - 1.6) than for the 1-D- and 3-D-model. The main deficiencies arise in determining the correct surface height and albedo within the satellite-retrieval algorithm.
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