Late spring ultraviolet levels over the United Kingdom and the link to ozone

J. Austin (1) , C. M. H. Driscoll (2) , S. F. G. Farmer (1) , M. J. Molyneux (1)

1 Meteorological Office
2 NRPB - National Radiological Protection Board

Erythemally-weighted ultraviolet (UV_ery) levels measured over southern England, during anticyclonic weather between 30 April and 2 May, 1997, were almost 50 higher than normally expected for clear skies and were similar to mid-summer values for the first time since measurements began in 1990. Investigation of this episode suggests that a combination of both meteorological and chemical effects were responsible for generating record low ozone amounts for the time of year. Further, comparisons between the A band ultraviolet (315 to 400 nm wavelength) amounts, and radiative calculations confirm that the high UV_ery was primarily due to the reduction in total ozone. These results are contrasted with a similar period for 1998, in which near climatological ozone amounts were measured. The prospects for enhanced UV_ery levels in future years are briefly reviewed in the light of expected increases in stratospheric halogen levels and greenhouse gases.

Domaines: Océan, Atmosphère; Sciences de la Terre

J. Austin, C. M. H. Driscoll, S. F. G. Farmer, M. J. Molyneux. Late spring ultraviolet levels over the United Kingdom and the link to ozone. Annales Geophysicae, 1999, 17 (9), pp.1199-1209. ⟨hal-00316664⟩