Estimation of the Overland PM 2.5 Distribution Using GOSAT CAI

Abstract

In recent years, people have become concerned about the health impacts of PM 2.5 through cross-border pollution. Although measurement stations for PM 2.5 in Japan are insufficient, it is very difficult to increase observation stations because of budget constraints. The objective of this study was therefore to estimate the overland PM 2.5 distribution using GOSAT CAI data (Level 1 B data product) for free, high spatial / quantization resolutions (500 m/12 bits), and quick repeat cycle (3 days). A significant correlation was observed between the monthly average reflectance after the cloud screening and topographical correction at CAI Band 1 (380 nm) and the monthly average PM 2.5 (PM 2.5_ave). Finally, the characteristics of PM 2.5_ave distribution in the Chugoku-Shikoku and Kita-Kyushu regions of Japan are discussed using the proposed method. Relatively high PM 2.5 distribution in spring and summer within the limits of Japanese environmental standards was demonstrated in these study areas. GOSAT CAI data is an effective tool for monitoring monthly average PM 2.5 distribution.