ISEE 2007 CONFERENCE ABSTRACTS SUPPLEMENT: Abstracts
*Department of Climatology and Landscape Ecology, University of Szeged, Hungary; and †István Bocskai Secondary and Technical School, Szerencs, Hungary.
Southern part of the Great Hungarian Plain (including Szeged city) is the mostly endangered region with ragweed pollen concerning not only the Carpathian Basin but also whole Europe. The aim of the study was to analyze the role of the long-distance transport of ragweed pollen in its concentrations over Szeged.
Material and Methods:
Three days (June 21, 1993; July 3, 2000; and July 6, 2003) were selected from the 15-year period of 1989 to 2003, for which ragweed pollen was detected, despite the fact that local pollen dispersion had not been started. Ragweed pollen of transported and local origin was separated so that ragweed pollen detected before flowering of local ragweed was considered as of transported origin. Then, backward trajectories belonging to the days of peak concentrations of this period (ie, those trajectories belonging to the 3 days selected) were examined for 3 and 7 days, respectively. For the 3 days selected, archive meteorological database was used and the HYSPLIT model was applied to calculate trajectories of ragweed pollen grains as well as to detect their source regions.
It was detected that on the days with the highest ragweed pollen levels during each year of the 15-year period examined, air currents arrive over Szeged partly from northwest (namely, from the region between Rivers of the Danube and Tisza) and partly from southern-southwestern direction (namely, form the regions of Southern France, Northern Italy, and Croatia). Over the latter mentioned regions the flowering period of ragweed starts earlier than in Southern Hungary.
According to the backward trajectories received, ragweed pollen can only come from abroad, arriving over Szeged region either from northwest or from southern-southwestern direction. In both cases ragweed pollen originates from south-southwest of Hungary, namely from regions where climate is warmer and drier.