Effect of the Strong Wind and Land Cover in Dust Source Regions on the Asian Dust Event over Japan from 2000 to 2011

The relationship between the strong wind and land cover in dust source regions and the Asian dust event over Japan (ADE) was analyzed using the weather reports and coverage of the Normalized Differential Vegetation Index (NDVI) derived from the MODIS-Terra reflectance products during the spring (March to May) of 2000 to 2011. The target area for the dust source area in northeast Asia was defined as 35 degrees N to 45 degrees N and 100 degrees E to 115 degrees E as with Kimura (2012), with reference to past results (Iwasaka et al. 2009; Lim and Chun 2006; Shao and Dong 2006; Sun et al. 2001). The annual change in the number of ADE agreed well with the Dust Storm Frequency (DSF) in the target area (R-2 = 0.549). Strong wind has significant effect on ADE (R-2 = 0.538), and coverage of NDVI ranging from 0.05 to 0.2 (bare land or bare land with less vegetation) and that of NDVI over 0.2 (vegetation surface reducing dust outbreaks) in April and May are also related to the number of ADE. The coverage of bare land or bare land surface with less vegetation decreased by 4%; in contrast, vegetation surface reducing dust outbreaks increased 4% in the 12 years from 2000 to 2011. Increasing trend of vegetation corresponded to the decreasing trend in ADE (R-2 = 0.359).