Abstract: Based on the data of 460 automatic weather stations in the year of 2006, after quality control and data organization, meteorological field of the whole year was calculated by Calmet model. On the basis of hourly wind field and 72-hour trajectory, the diffusion state of Pearl River Delta (PRD) area was divided into three types (systematic wind field, local atmospheric circulation and feeblish systematic wind field). Based on this classification and further classification of atmospheric transmission trajectories, the characteristics of atmospheric diffusion, and atmospheric transmission trajectories and reach in PRD area were analyzed. Specifically, the characteristics of atmospheric transmission and diffusion of the PRD region obviously change with seasons and are highly influenced by sea-land breeze. The best diffusion condition is in winter while worst in Autumn. Additionally the transmission trajectories are markedly distinct between different types and seasons.

Key words: monsoon climate, wind field diagnosis, urban agglomeration, the Pearl River Delta, atmospheric transmission and diffusion

摘要： 为了深入研究珠江三角洲区域大气扩散和输送特征, 利用2006年珠江三角洲地区460个地面自动气象站的全年逐时气象数据和探空资料, 对自动气象站资料进行质量控制并整理, 使用Calmet模式诊断出逐时气象场。利用逐时风场和72小时轨迹, 对该地区的扩散类型进行分类(系统大风型、弱背景影响型和局地环流型), 并依此对该地区的流动状况进行分析。还根据季节和分类结果对扩散路径进行简单的分类, 并依此研究珠江三角洲地区的大气输送路径以及影响范围。分析结果表明: 珠江三角洲地区大气输送特征具有明显的季风性以及海陆风特征; 该地区春季和冬季的大气输送和扩散能力较好, 夏季次之, 秋季最差; 大气输送轨迹随季节变化明显, 并且在不同的扩散类型之间有显著的差异。

关键词: 季风气候, 风场诊断, 城市群, 珠江三角洲, 大气扩散和输送