珠穆朗玛峰北坡桤木属大气花粉传输路径与来源

Transport Pathways and Source Areas of Airborne Alnus Pollen on the Northern Slope of the Mt.Qomolangma Region

认识区域大气花粉组成及其形成条件有利于明确不同类型花粉组合的气候与环境意义。利用布卡大气花粉采样器在珠穆朗玛峰北坡开展了连续2年(2012—2013年)的大气花粉观测研究。基于后向轨迹和潜在来源区域模型,探讨了秋季主要组分桤木属花粉的传输路径与潜在来源区域,分析了桤木属花粉与其植物分布和大气环流的关系及气候指示意义。结果显示:(1)桤木属花粉季气团传输路径主要来自于采样点西南方向;(2)桤木属花粉潜在来源区域与其气团传输路径基本一致,主要是喜马拉雅山脉中段,包括尼泊尔中部和东部以及西藏南部等地区;(3)桤木属花粉数量、传输路径和来源区域的年际变化与大气环流有关,受高空西风影响的西南气团对桤木属花粉影响更大。研究结果可以为认识珠穆朗玛峰北坡外来花粉的气候意义提供科学依据。

Understanding the composition and formation conditions of regional airborne pollen is essential for elucidating the environmental significance of different pollen assemblages.A Burkard pollen trap was utilized to monitor airborne pollen on the northern slope of Mount Qomolangma over two consecutive years(2012 and 2013).Utilizing backward air mass trajectory analysis and source receptor models,this study delved into the pathways and potential sources of Alnus pollen,the predominant component during autumn.The analysis also explored the relationships between Alnus pollen,plant distribution,atmospheric circulation,and its environmental implications.The study yielded three main findings:Firstly,the predominant air mass transport pathway during the Alnus pollen season originated predominantly from the southwest of the sampling site.Secondly,the potential source area of Alnus pollen was primarily situated in the middle Himalayan region,encompassing central,eastern,and southern Nepal Tibet,largely aligning with the principal air mass transport pathway.Thirdly,interannual variations in Alnus pollen quantity,transport pathways,and potential source areas may be linked to atmospheric circulation patterns.Specifically,the southwest air mass,influenced by the upper westerlies,exhibited a more pronounced impact on Alnus pollen dispersion.These findings offer foundational insights into the climatic significance of exotic pollen on the northern slope of Mount Qomolangma.