OBSERVATIONS OF DUST-STORMS IN CHINA,MONGOLIA AND ASSOCIATED DUST FALLS IN KOREA IN SPRING 2003

摘要

A joint monitoring of dust-storms that occurred in East Asia from March until May 2003 has been carried.Our discussions include dust-storm observations in the source areas of China and Mongolia,and measurements with satellites and ground monitors in central Korea.Differences were found in the definition and measurement of dust-storms.Over the source area of Mongolia there were 6 dusty days in March,18 days in April,and 10 dusty days in May.In Inner Mongolia of northern China there were 4 dust-storms with 14 dusty days observed over the three months.In central Korea,a sink area,there were 4 cases of weak dust-storm and 17 dusty days in the spring of 2003.The highest PM10 value was 607 mugm~(-3) and PM 2.3 was 149 mugm~(-3),respectively.These observations identify the growing need for further universal observation practices and dust-storm reporting in future. Observations indicated that snow covered the central part of the Gobi Desert,near the boundary of China and Mongolia,from December until mid-March.This is in contrast to other years when the Gobi was relatively wet,producing unfavourable conditions for the formation of intense dust-storms.In addition,the very strong winds associated with intense cyclones and anticyclones were not apparent and the systems shifted northward during the spring.As a result,the frequency and intensity of observed dust-storms in 2003 in this region were very low.This confirms that there is variability in the frequency of dust-storm formation due to the current process of desertification and climate change.