Variability of phenological stages of Dactylis glomerata in dependence on meteorological conditions in the Czech Republic

Abstract

pressure (SLP) and 500 hPa geopotential height pattern over Europe on days with high concentration of ragweed pollen in Poznan in years 1996-2010. Methods: Ambrosia pollen data was collected by Hirst-type volumetric spore trap. Pollen grains were counted under the optical microscope (magni cation: 400x) and expressed as P m-3. Daily pollen concentrations were clustered in three intervals: low ( 30 Pm3) levels. For days attributed to these groups, synoptic charts were created on the basis of see level pressure (SLP) records from NCEP/NCAR reanalysis [2]. In addition, maps of 500 hPa geopotential heights were constructed. e method of interpolation was kriging. Results: Overall, 206, 23 and 17 days with low, medium and high concentration of ragweed pollen (respectively) were recorded in Poznan in years 1996-2010. Synoptic charts showed (Fig. 1) that during days with high pollen count of Ambrosia in Poznan the high pressure center was located in the area of northern Belorussia. e lowest pressure center was located over Iceland and the Atlantic Ocean in the south of the Iceland. As the geostrophic wind is parallel to the isobars and approximately determines the air mass transfer, it can be concluded that presented pressure pattern causes the air motion exactly from the Pannonian Plain to Poland, with south-east direction. Conclusions: e mechanism of long-range transport of Ambrosia pollen from Balkans to Poland highlighted by Sikoparija et al. [1] seems to be valid in all days with high concentrations of Ambrosia pollen in Poznan, 1996-2010. Averaged synoptic charts con rm that the air mass transport occurs from southeast to northwest with the strong high pressure center over Belorussia. When that pressure pattern is observed in weather forecast during August or September there is a possibility to record Ambrosia pollen in Poznan.