摘要： This study is conducted to identify the synoptic weather patterns that are prone to cause high carbon monoxide (CO) concentrations observed at a mountain site, Lulin atmospheric background station (LABS), in Taiwan due to the biomass-burning activity in Southeast (SE) Asia. LABS is recognized as a clean background station. The study period targets the biomass-burning season (February to May) from 2007 to 2010. The synoptic weather patterns were classified using a two-stage clustering method with inputs from the Weather Research and Forecasting (WRF) meteorological model simulation result in a 27-km spatial grid. A 9-km resolution WRF modeling was performed additionally for 13 to 26 March 2007, when a high CO concentration reaching 500 ppb was observed at LABS. The simulation result indicates that not only the existence of the thermal forcing induced low pressure system formed in Indochina, but also the presence of the high terrain located in the northern part of SE Asia that further forced the uplift of the biomass-burning emissions. On the other hand, when the northeasterly monsoonal flow is strong enough and intruding into Indochina, this would hinder the development of the thermal low and weaken the upward movements, in turn preventing the transport of biomass-burning emissions from Indochina to the area of Taiwan. The simulation results also demonstrate that the location of the SE Asia high pressure system has a moderate effect on the particle dispersion path in the upper level. •WRF simulations were performed during Southeast Asia biomass burning season.•Cluster analysis was performed with WRF output to classify synoptic weather types.•Using a mountain site in Taiwan to assess long-range transported CO from Indochina.•A different long-range transport mechanism of CO from Indochina is identified. 出版者： Elsevier Ltd 出版日期： 2013-10 出處： Atmospheric environment (1994), 2013-10, Vol.78, p.277-290 資源來源： Elsevier ScienceDirect Journals Complete 版權： 2013 Elsevier Ltd 識別號： ISSN: 1352-2310 識別號： EISSN: 1873-2844 識別號： DOI: 10.1016/j.atmosenv.2013.03.020
