The influence of atmospheric circulation conditions on pollen concentrations of two taxons (Betula and Alnus) in Wroclaw, Poland, for the years 2005–2014 was analysed. Pollen concentration was analysed separately for twenty circulation types that were determined using objective classification. The results indicate the atmospheric circulation conditions favourable for both low and high pollen concentrations over Central Europe. Pollen concentrations vary significantly according to circulation types. The highest pollen concentrations for both taxons are typical for warm, sunny, and dry anticyclonic circulation types with anticyclone in the lower and upper troposphere, especially for types with advection from the SW. The lowest pollen concentrations are observed for cold, wet, and cloudy cyclonic types with advection from the northern sectors. There is also a positive and statistically significant trend in the frequency of circulation types favourable for high concentrations of Betula and Alnus.

中文翻译：

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大气环流条件对波兰弗罗茨瓦夫桦木和赤杨花粉浓度的影响

分析了 2005 年至 2014 年大气环流条件对波兰弗罗茨瓦夫两种分类群（桦属和赤杨属）花粉浓度的影响。针对使用客观分类确定的 20 种循环类型分别分析了花粉浓度。结果表明大气环流条件有利于中欧的低花粉浓度和高花粉浓度。花粉浓度因循环类型而异。两个分类群的最高花粉浓度在温暖、阳光充足和干燥的反气旋环流类型中是典型的，对流层下层和上层有反气旋，特别是对于来自西南对流的类型。在寒冷、潮湿和多云的气旋类型中观察到最低的花粉浓度，并伴有来自北部地区的平流。