Influence of Dust Storm Frequency in Northern China on Fluctuations of Asian Dust Frequency Observed in Japan

Abstract

Relationship between Asian dust frequency observed in Japan (ADF) and dust storm frequency (DSF) in northern China was examined with up-to-date long-term observational data. Possible climatic conditions associated with variations of ADF were also explored. It was found that DSF at stations in Inner Mongolia and its vicinity (IMV) and ADF behaved nearly parallel to each other from the mid 1970s. Significant positive correlation between DSF in IMV and ADF suggests that IMV has a stronger influence on ADF than other dust source regions in northern China. Composite maps of Sea Level Pressure and 700 hPa wind fields for extreme ADF years exhibited a spatial pattern with cyclonic anomalies over the area from Northeast China to north Japan and anticyclonic anomalies around the Gobi desert in high ADF years. This situation corresponds to enhanced cyclonic activities in Northeast China and intensified cold air outbreaks in IMV, which are favorable for formation of dust storms in IMV.