THE AEROSOL LOADING FOR INLAND AND CLOSE-SHORE CITY DERIVES FROM URBAN ATMOSPHERIC MODEL

Visibility degradation has become an environmental topic of community concern in most urban areas because of low visibility range that will lead to the deterioration of air quality. Atmospheric aerosol plays an important indicator of visibility distance range because it will influence the objects that can be seen. Microclimate can be defined as the climate of a small area such as part of a city. Inland city is the city located at interior of a country or region while close-shore city is the city that is surrounded by the sea or located near the sea. Both areas have different microclimate types.The objective of this study is to investigate the relationship of visibility range with atmospheric aerosol that can possibly be used as an indicator of air quality between the inland and close-shore city. The study used atmospheric model for urban aerosol algorithm in ATCOR2 PCI Geomatica to analyse the distribution of aerosols in terms of percent (%) reflectance. Landsat 5 Thematic Mapper images in Penang Island and Kuala Lumpur for the year 1993, 1999 and 2005 have been used to determine the aerosol loading. The atmospheric aerosol loading from the image was retrieved by different visibilities range at the distance of 10 km up to 50 km which are later converted into (%) reflectance. The mean reflectance values of a 3x3 pixel window were derived over urban features for both areas. The pattern of aerosol loading increased when visibility range is in between 10 to 20 km and decreased when visibility range is more than 30 km for both areas. In year 1993, the maximum aerosol loading was 9.7% in Kuala Lumpur and 15.1% in Penang Island. In year 1999, the highest aerosol loading was recorded at 11.3% in Kuala Lumpur and in Penang Island, the reading was 17.9%. The maximum aerosol loading showed in year 2005 was 10.1% in Kuala Lumpur and 20.0% in Penang Island. From the results, it shows that the aerosol loading for different atmospheric climates can be estimated using urban atmospheric model. The distance of the range of visibility can be used as an important parameter to determine the aerosol loading.

کلیدواژه ها:

Aerosols ، reflectance ، visibility ، microclimate and imaging data