珠江三角洲（Pearl River Delta，PRD）位於華南沿岸，為中國大陸重要的經濟發展地區之一，現今已有超過五千萬的人口居住在此地區。近二十年來，由於經濟、工業與基礎建設的快速發展相當，因此當地的空氣品質與氣候的改變也倍受觀注。許多學者的研究中指出，秋、冬兩季，在PRD地區經常發生高濃度的空氣污染物事件。澳門屬於珠三角沿海城市之一，位於珠江入海口西側，人口密度位居世界城市排名之首。本研究使用WRF（Weather Research and Forecasting）中尺度氣象模式模擬2007年10月24日至26日期間高臭氧濃度事件日之氣象環境，並使用MODIS（Moderate Resolution Imaging Spectroradiometer）2007年之土地利用型態資料，以更新及改善現有WRF氣象模式所提供之下邊界環境。由觀測資料顯示，事件日期間綜觀系統相對較弱，風場有明顯的日變化。透過更新土地利用型態後，模擬結果之風場和溫度場在澳門地區均有明顯地改善。針對風場的分析結果顯示，珠江口有複雜的風場分佈特性，海風先於中午12點開始發展，並在午後開始增強，而珠江口東側之海風較西側強。東測主要為香港、深圳等地區，其都市分佈範圍較西側之澳門特區廣，因此珠江口附近之海灣風主要為吹向香港特區方向之西風，並隨著時間轉至西南風，夜間轉吹南至東南風。同時模擬期間之背景盛行風場為東北風，午後海風的進入導致風場在珠江口區域行成一低風速區。由後推軌跡與粒子排放的分析結果顯示，污染物有可能來自深圳、東莞等之大型工業區，並且伴隨的午後低風帶傳送至澳門與香港西側沿岸地區。Pearl River Delta (PRD) is located in southern China near the coastline. It is one the most populated regions in China with more than 50 million people living in this area. Through the last two decades, PRD region has experienced the unprecedented land-use and land-cover changes as a result of rapid economic development and urban expansion. Its possible impact on regional air quality and climate change is a major concern of the national government as well as the global community.In this study, Weather Research and Forecasting (WRF) meteorological model is performed using the updated land use data for a high ozone event (October 24 to 26, 2007). In addition, the land use data is re-classified and updated using the 500-m resolution Moderate Resolution Imaging Spectroradiometer (MODIS) satellite products.The simulation using the updated land use data improves the wind speed, temperature and wind direction. Analysis of the wind field simulation result demonstrated that the see-breeze flow direction is opposite to the prevailing wind (1300 to 1800 LST) that forms a stagnant wind condition near the Macao and Pearl River Estuary region. The sustained sunlight combined with stagnant wind condition favors the accumulation of the air pollutants. The trajectory analysis showed that the ozone concentration is transported from Shen-Zhen and Dong-Guan industrial area in the Guang-Dong province.
