Sofiev M, Siljamo P, Ranta H, Rantio-Lehtimäki A
Air Quality Research Department, Finnish Meteorological Institute, Helsinki, Finland.
Int J Biometeorol. 2006 Jul;50(6):392-402. doi: 10.1007/s00484-006-0027-x. Epub 2006 Apr 5.
This paper considers the feasibility of numerical simulation of large-scale atmospheric transport of allergenic pollen. It is shown that at least small grains, such as birch pollen, can stay in the air for a few days, which leads to a characteristic scale for their transport of approximately 10(3) km. The analytical consideration confirmed the applicability of existing dispersion models to the pollen transport task and provided some reference parameterizations of the key processes, including dry and wet deposition. The results were applied to the Finnish Emergency Dispersion Modelling System (SILAM), which was then used to analyze pollen transport to Finland during spring time in 2002-2004. Solutions of the inverse problems (source apportionment) showed that the main source areas, from which the birch flowering can affect Finnish territory, are the Baltic States, Russia, Germany, Poland, and Sweden-depending on the particular meteorological situation. Actual forecasting of pollen dispersion required a birch forest map of Europe and a unified European model for birch flowering, both of which were nonexistent before this study. A map was compiled from the national forest inventories of Western Europe and satellite images of broadleaf forests. The flowering model was based on the mean climatological dates for the onset of birch forests rather than conditions of any specific year. Utilization of probability forecasting somewhat alleviated the problem, but the development of a European-wide flowering model remains the main obstacle for real-time forecasting of large-scale pollen distribution.
本文探讨了对致敏花粉进行大规模大气传输数值模拟的可行性。研究表明，至少像桦树花粉这样的小颗粒能够在空气中停留数天，这导致其传输的特征尺度约为10³千米。分析考量证实了现有扩散模型适用于花粉传输任务，并给出了包括干湿沉降在内的关键过程的一些参考参数化方法。研究结果应用于芬兰应急扩散建模系统（SILAM），该系统随后被用于分析2002 - 2004年春季期间花粉向芬兰的传输情况。反问题（源解析）的结果表明，取决于具体气象形势，能影响芬兰领土的桦树开花主要源区为波罗的海国家、俄罗斯、德国、波兰和瑞典。实际的花粉扩散预报需要欧洲的桦树林地图以及统一的欧洲桦树开花模型，而在本研究之前这两者均不存在。根据西欧国家森林资源清查数据和阔叶林卫星图像编制了一幅地图。开花模型基于桦树林开始生长的平均气候日期，而非任何特定年份的情况。概率预报的应用在一定程度上缓解了问题，但开发全欧洲范围的开花模型仍是大规模花粉分布实时预报的主要障碍。
