Ultraviolet radiation (UVR) suppresses many aspects of cell-mediated immunity but it is uncertain whether solar UV exposure alters resistance to human infectious diseases. Varicella-zoster virus (VZV) causes varicella (chickenpox) and can reactivate from latency to cause zoster (shingles). The monthly incidence of chickenpox and zoster in a defined Polish population over 2 years was recorded and ground level solar UV was measured daily. There was a significant seasonality of UVR. Evidence of seasonal variation was found for all zoster cases and for zoster in males, with the lowest number of cases in the winter. The number of zoster cases with lesions occurring on exposed body sites (the face) demonstrated highly significant seasonality with a peak in July/August. Seasonal models for UVR and zoster cases showed similar temporal patterns. By contrast, for varicella, the maximum number of cases was found in March and the minimum in August/September, probably explained by the respiratory spread of VZV. It is tempting to speculate that the increase in solar UVR in the summer could induce suppression of cellular immunity, thus contributing to the corresponding rise in the incidence of zoster.

Abstract. Recent analysis of the total ozone observations indicate a negative trend of about 4%/decade in the Northern Hemisphere midlatitudes during the last two decades [WMO, 1999]. The effect of this decline on surface UV levels is of interest to a variety of applications. In this work the long-term variation of UV radiation at three stations located in northern Europe (Belsk, Norrk6ping, and Jokioinen) has been studied using data from (1) ground-based observations, (2) surface UV doses determined using TOMS satellite measurements, and (3) reconstructed UV doses using observations of global radiation, total ozone, and radiative transfer modeling. For each station the estimates of daily UV doses from various sources have been intercompared, and a trend analysis has been performed to reveal long-term changes in the UV radiation. Data sets, which start in the late 1970s or early 1980s, show a general positive trend in annual doses of UV radiation. Some of these upward trends are statistically significant. For Belsk the increases are in the range of 5-15% per decade during spring and summer. The largest increases, about 20%/ decade, has been observed in Norrk6ping during spring. At Jokioinen there has been a slight upward trend in UV throughout the year. The analysis of reconstructed Belsk data from 1966 onward shows that the positive trend since late 1970s was preceeded by a negative trend. The reason for such changes is probably not only related to the changes in the total ozone but also to changes in aerosol content and cloudiness. The agreement of the UV series based on different data sources is good. This was studied using a subset of data in which it was required that data from all possible sources were available. The different trend estimates were in very close agreement with each other. However, there were often differences in absolute values, which is probably related to problems in calibration and limitations of the models. IntroductionThe springtime depletion of ozone in Antarctica is a regular phenomenon in the present atmosphere. As a consequence, the levels of ultraviolet (UV) radiation have been increasing focuses on the past changes in UV radiation in Northern Europe using data from various sources. The determination of UV radiation at ground level is probably done with most accuracy using in situ measurements with well-calibrated spectroradiometers. However, these instruments are expensive and laborious to maintain and the spatial and temporal coverage of the measurements is limited. The procurement of broadband UV meters is much cheaper, but maintenance with high-quality control is also expensive [WMO, 1996]. Because of the high costs of maintaining in situ measurement systems it is questionable if a global network with high regional coverage will ever be established. Consequently, there is lack of data over large parts of the Earth, such as oceans and many continental areas, and the knowledge of the long-term changes in UV radiation reaching the ground is limited. However, the UV radiation aff...

Abstract. An analysis of the ultraviolet radiation measurements taken at Belsk by Robertson-Berger meter and Brewer spectrophotometer over the period 1976-1997 is performed. In the Robertson-Berger data series, a mean level shift that can be attributed to change in calibration procedure was detected. In the examination of the series, a wavelet analysis was used. To determine the magnitude of the shift, a relationship between UV radiation and total ozone for a clear sky was applied. The results showed that for the Robertson-Berger data, over the period 1984-1992, the correction factor of 1.14 should be applied. The trend in the whole observational period was 6.1+2.9% per decade. In the estimation of the trend uncertainty, the autocorrelation in the noise and shift of the level in the data was taken into account. The UV-B trend depends mainly on the trend of ozone, and the response of UV-B to ozone changes is most evident for the variations of the ozone content at a large timescale.

Abstract. The total ozone data over Europe are available for only few ground-based stations in the pre-satellite era disallowing examination of the spatial trend variability over the whole continent. A need of having gridded ozone data for a trend analysis and input to radiative transfer models stimulated a reconstruction of the daily ozone values since January 1950. Description of the reconstruction model and its validation were a subject of our previous paper. The data base used was built within the objectives of the COST action 726 "Long-term changes and climatology of UV radiation over Europe". Here we focus on trend analyses. The long-term variability of total ozone is discussed using results of a flexible trend model applied to the reconstructed total ozone data for the period 1950-2004. The trend pattern, which comprises both anthropogenic and "natural" component, is not a priori assumed but it comes from a smooth curve fit to the zonal monthly means and monthly grid values. The ozone long-term changes are calculated separately for cold (October-next year April) and warm (May-September) seasons. The confidence intervals for the estimated ozone changes are derived by the block bootstrapping. The statistically significant negative trends are found almost over the whole Europe only in the period 1985-1994. Negative trends up to −3% per decade appeared over small areas in earlier periods when the anthropogenic forcing on the ozone layer was weak . The statistically positive trends are found only during warm seasons 1995-2004 over Svalbard archipelago. The reduction of ozone level in 2004 relative to that before the satellite era is not dramatic, i.e., up to ∼−5% and ∼−3.5% in the cold and warm subperiod, respectively. Present ozone level is still depleted over many popular resorts in southern Europe and northern Africa. For high latitude regions the trend overturning could be inferred in last decade