| Abstract [eng] |
The aim of this study is to analyse the dependence of the fluctuation of pollen concentration on atmosphere circulation, rainfall and wind speed in Šiauliai city, in 2003 – 2005. In order to implement the aim of the study several tasks were set. The first is to identify backward air mass trajectories and compute the rainfall in the trajectories during 2003–2005. The second is to evaluate the dependence of airborne pollen concentration on the atmosphere circulation. The third is to prove existing long-range transport of pollen by using phenological data. The fourth is to analyse the dependence of pollen concentration on the rainfall and wind speed in Šiauliai city. The data about the amount of pollen were obtained from Šiauliai aerobiological station. Backward air mass trajectories were calculated according to HYSPLIT 4 model, which is provided by Air Resources Laboratory of National Oceanic and Atmospheric Administration. In order to evaluate plants pollination period in neighbouring European countries and pollen long-range transport the data referring to the European Aeroallergen Network database were used. The meteorological data for Šiauliai city was provided by Šiauliai meteorological station, the Hydrometeorological Service of Lithuania under the Ministry of Environment. The analysis of backward air masses trajectories has shown that in 2003–2005 during the blooming period of plants, western and north-western air transport dominated. These air masses moved from 1 European region. It has been estimated, that in 2003 pollen concentrations of Apiaceae Lindl., Artemisia L., Asteraceae Dumost., Betula L., Cupressaceae Rich. ex Bartl., Pinus L., Rumex L. exceeded the average value of the year, when air mass moved from 1 region and pollen concentrations of Chenopodiaceae Vent., Plantago L., Poaceae (R. Br.) Bernhart, Urticaceae Juss., when air mass arrived from 4 region. It has been investigated, that in 2004 pollen concentrations of Apiaceae Lindl., Asteraceae Dumost., Chenopodiaceae Vent., Corylus L., Cupressaceae Rich. ex Bartl., Pinus L., Poaceae (R. Br.) Bernhart, Populus L., Quercus L. and Rumex L. exceeded the average value of the year, when air mass moved from 1 region, Plantago L., Urticaceae Juss. – from 2 region, Acer L. – from 3 region, Artemisia L., Betula L., Fraxinus L. and Salix L. – from 4 region. In 2005 pollen concentrations of Alnus Mill., Chenopodiaceae Vent., Betula L., Acer L., Pinus L. and Apiaceae Lindl. exceeded the average value of the year, when air mass moved from 1 region, Qercus L., Artemisia L., Rumex L. – from 2 region, Urticaceae Juss., Salix L., Ulmus L., Cupressaceae Rich. ex Bartl., Tilia L. and Poaceae (R. Br.) Bernhart – from 4 region. The analysis of the data of European Aeroallergen Network database and backward air mass trajectories allowed to presume that the pollen of Betula L. recorded in Šiauliai aerobiological station in 2003 after blooming was transported from the territory of Russia, the pollen of Cupressaceae Rich. ex Bartl. – from the territories of Sweden and Finland, the pollen of Pinus L. – from the territories of Germany and Austria. The pollen of Alnus Mill. recorded in 2004 before blooming was transported from Poland and Germany, the pollen of Betula L. – from Germany, the pollen of Corylus L. – from United Kingdom and Denmark. Investigated tendencies of erratic variation in daily pollen amount, when rainfall acts, allow presuming that pollen morphology characteristics, rain intensity, duration and rain repartition during a day determine pollen dispersion in the atmosphere. The ambiguous effect of wind speed on the dispersion of pollen in the atmosphere allows supposing that the distribution of the amounts of pollen may be influenced by the morphology of pollen, the uneven distance of plants from the place of measurement and the atmospheric turbulence in the boundary layer. |
