We have investigated coarse wind sectors in Busan metropolitan area and simulated detailed wind field using local atmospheric circulation model, RAMS in preceding studies (Part I, Part II). In this study, we divided and analyzed local wind sector in Busan according to the preceding results. We found that Busan metropolitan area is divided into 2 or 3 local wind sector in each coarse wind sector. The 9 coarse wind sectors were classified into 20 local wind sectors in total. But three local wind sectors were finally excluded because of these sectors were located on the complex hill area and the sea. Local wind sectors, therefore, in Busan metropolitan area were defined as 17 regimes. We assessed the location of air quality monitoring sites at Busan metropolitan area using the information of these wind sectors. Most of these were located at proper points, but 6 sites were placed at 3 local wind sectors as a couple and no site was set up at 3 other sectors. Hence the location of these sites was in need of rearrange.

We have analysed the observed surface and vertical meteorological data to get atmospheric information over the Busan metropolitan area. For this, we have selected 10 days in all season such as spring, summer I(Jangma season), summer II(hot season), autumn and winter. The result which have performed cluster analysis using atmospheric data represented that these days are included to most frequently appeared synoptic cluster. We have simulated wind field around Busan metropolitan area which is assigned as 1km2 using RAMS. The calculated air temperature and the wind speed was similar to the observed the that, and the trends of daily variation showed good agreement. RMSE and IOA also showed reliable value. These results indicated the RAMS is able to simulate and predict detailed atmospheric phenomenon.

In this study, climate analysis and wind sector division were conducted for a propriety assessment to determine the location of air quality monitoring sites in the Busan metropolitan area. The results based on the meteorological data(2000～2004) indicated hat air temperature is strongly correlated between 9 atmospheric monitoring sites, while wind speed and direction are not. This is because wind is strongly affected by the surrounding terrain and the obstacles such as building and tree. In the next stage, we performed cluster analysis to divide wind sector over the Busan metropolitan area. The cluster analysis showed that the Busan metropolitan area is divided into 6 wind sectors. However 1 downtown and 2 suburbs an area covering significantly broad region in Busan are not divided into independent sectors, because of the absence of atmospheric monitoring site. As such, the Busan metropolitan area is finally divided into 9 sectors.