Total ozone and surface UV trends in the United Kingdom: 1979-2008

Abstract

In this study we present the UK's total ozone and UV data records, their measurement and preliminary processing, and discuss the observed trends. Notably, we combine the records from the Camborne and Reading sites to obtain a single ozone data series for southern England—a total duration of 30 years. Two-section linear trends and cross-over years are determined for Lerwick and southern England, both annually and seasonally. The observed minimum using this technique in the UK ozone record is found to occur during the year 1993. Significant trends of − 4.8% per decade for southern England and − 5.8% per decade for Lerwick are seen prior to the mid-1990s; the rate of decrease in the UK being at the upper limit of other European stations. No significant ozone trend is seen for the latter period in either location in contrast with Europe as a whole. We, additionally, compare the satellite-derived total ozone trends for both locations. The UV record at Reading showed a significant trend from 1993 to 2008 in the daily maximum UV index record (6.6% per decade), despite no significant recovery in the total ozone data series, suggesting a reduction in cloud cover during the midday period. Filtering data to remove other factors shows the erythemal UV to have an ozone-dependent trend of − 0.11% per year, but this is not statistically significant. We find no correlation between anomalies in the surface UV and total ozone records suggesting that the majority of the inter-annual variability is due to changes in cloud cover and other effects. Copyright © 2011 Royal Meteorological Society