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Erythemal UV observations at Belsk, Poland, in the period 1976–2008: Data homogenization, climatology, and trends

Krzyścin J., Sobolewski P.S., Jarosławski J., Podgórski J., Rajewska-Więch B.

Acta Geophysica

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2011

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Vol. 59, no. 1

155-182

EN

Measurements of erythemal irradiance have been carried out continuously at Belsk since May 1975. We present a homogenization procedure of the UV time series for the period of 1976-2008. Long-term oscillations discovered in the homogenized data set agree with those extracted from the reconstructed UV data for all-sky and clear-sky conditions. The UV climatology was established and the UV variability was determined. Positive UV trends were found for the period of 1976-2008 in the annual mean (5.6±0.9% per decade), in the seasonal mean for the warm subperiod of the year (April-October, 5.5±1.0% per decade), and in monthly means (˜2-9% per decade). A satisfactory agreement between the trend extracted from the homogenized ground-based data and that found in satellite UV data for Belsk (1979-2008) supports the reliability of satellite trend analyses over wider areas during snowless periods.

2

Zmiany całkowitej zawartości ozonu w atmosferze nad Belskiem na tle zmian ozonu nad Europą w latach 1963-2008

Rajewska-Więch B., Krzyścin J.

Przegląd Geofizyczny

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2010

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Z. 1-2

49-59

PL

W pracy przedstawiono zmiany w całkowitej zawartości ozonu w Belsku i Europie na tle średnich wieloletnich (1963-2008). Od 2002 r. obserwujemy w Europie (i w Belsku) powrót do spadkowej tendencji całkowitej zawartości ozonu, zwłaszcza w sezonie zimowym. W sezonie letnim i jesiennym tendencja spadkowa istnieje w serii czasowej od lat 70., ale tempo spadku osłabło od połowy lat 90. ubiegłego wieku. Taki nieoczekiwany kierunek zmian w warstwie ozonowej może być wynikiem specyficznych fluktuacji w dynamice atmosfery. Dominującym czynnikiem spodziewanej regeneracji ozonu i powrotu jego zawartości do stanu sprzed lat 1980. jest spadek zawartości niszczących ozon substancji. O tym, kiedy i w jakim stopniu ten powrót nastąpi w różnych rejonach Ziemi, będą współdecydować zmiany klimatu. Najczęściej szacuje się, że powrót ozonu do stanu sprzed lat 1980. w obszarze 60oS-60oN nastąpi około połowy XXI wieku.

EN

The results of measurements of column amount of ozone (total ozone) at Central Geophysical Observatory, Institute of Geophysics, Polish Academy of Sciences, at Belsk the long-term ozone changes in the period (1963-2008) are discussed and compared with those in the midlatitudinal and Central Europe. Since 2002 rather unexpected declining tendency appear over Belsk and Europe. It is especially pronounced in winters and the whole year data. Such decline appear after the period (since ~1995) when first signs of the ozone recovery were seen, i.e., slowing down rate of ozone decrease and a kind of the ozone trend overturning in winter months. The ozone depleting substances content in the stratosphere has been decreasing since mid 1990s as a result of restriction in production of such substances introduced by the Montreal Protocol (1988). Thus, there were expectations of a continuation of the ozone recovery in recent years. The chemical forcing related to decreasing concentration of ozone depleting substances has induced upward tendency in ozone since 1995. Appearance of a negative tendency in winter data and yearly data seem to be related with specific atmospheric circulation in recent years. Now it is difficult to estimate how persistent will be the present total ozone decline due to dynamical forcing. The interplay of ozone changes with the climate may induce unexpected regional changes in the ozone layer. The retrospective examination of the past ozone variability suggests that the long-term dynamical forcing on the ozone layer will be soon acting in opposite direction over Europe, i.e., the ozone amount in the atmosphere will be increasing in next few years.

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O niedoborach ozonu w atmosferze w latach 1963-1998 na podstawie pomiarów w Belsku

Degórska M., Rajewska-Więch B., Krzyścin J.

Przegląd Geofizyczny

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1999

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Z. 4

257-268

EN

In the past two decades significant decreases in the ozone layer have been observed. The greatest ozone losses have occurred at the high and middle latitudes during the winter and spring seasons. The global average ozone decline in 1979-1997 was estimated as about 506% during the winter and spring about 3% during the summer and autumn at extratropical regions of the northern hemisphere and about 5% over the southern hemisphere. An acceleration of the rate of ozone decline has been observed during the last decade not only in winter-spring but also during the summer months. Under cloudless skies, the UV solar radiation is much more intense in the summer months than during other seasons. Thus, the increasing ozone losses are then of special importance because of the potentially excessive solar UV radiation flux. Confirming evidences of ozone changes were provided by analysis of systematic ground-based and satellite measurements at the stations of the World Meteorological Organization (WMO) Global Ozone Observing System (GO3OS). The measurements of total amount of ozone and its vertical distribution have been performed by means of the Dobson spectrophotometer at Belsk Observatory (Poland) since 1963. Total (columnar) ozone is an important quantity controlling the strength of UV solar radiation which reaches the earth surface; it is measured as a thickness of ozone atmospheric layer at standard pressure and temperature. Ozone deficiencies at northern midlatitudes were considered basing on the data from the Belsk station. The total ozone values for the period 19963-1997 were analysed with a special attention paid to the summer seasonal means. It was, for example, shown that differences between winter-spring mean ozone value and those of summer season distinctly decreased in the period 1964-1997 (about 3% per decade). The record low daily ozone value on 1 January 1998 over Belsk, associated with the passage of an ozone 'mini-hole' across Europe from 30 December 1997 through 2 January 1998, was demonstrated. The total ozone trends at Belsk during 1970-1997 were compared with those in 1980-1997. As for other stations of northern midlatitudes, at Belsk an acceleration of the season), especially in the winter-spring season. The ozone vertical profile trends, derived from the Belsk measurements obtained by means of Umkehr method, were established using the multiple regression model for the period 1980-1997. The trends were negative (and statistically significant at the 1 level) at all altitudes; the downward trend was largest (about - 6% per decade) between 0-28 km in spring. (...) There are serious implications of the depleted atmospheric ozone layer. Increasing penetration of ultraviolet solar radiation to the Earth's surface poses a potential threat to the global ecosystem.