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This paper investigates regional sources and transport routes of Asian dust observed in Korea over the past 40 years, that is from 1965 to 2004. These long-term changes were studied in relation to climatic changes and causes. About 87% of dust events in Korea occur in the spring and have been increasing steadily since the 1980s. These trends can be attributed to regional changes in dust sources to windward and the resultant transport pathways of dust storms. This study establishes that dust events have greatly increased during the 3 years from 2000 to 2002. It may be the result of not only an eastward shift in the regional source of dust but also changes in upper-level synoptic transport patterns. Intensified atmospheric circulation and an associated increase in wind speed as well as changes in snow cover, surface wetness and potential evaporation rates throughout Inner Mongolia and Manchuria are likely to be the main causes of the steadily increasing number of dusty days in Korea. [Copyright &y& Elsevier]

This study compares the impacts of El Niño Modoki and El Niño on precipitation over Korea during the boreal winters from 1954 to 2009. Precipitation in Korea tends to be equal to or greater than the normal level during an El Niño Modoki winter, whereas there is no significant change during an El Niño winter. Greater than normal precipitation during El Niño Modoki was also found over the lower reaches of the Yangtze River, China and much of southern Japan. The latitudes of these regions are 5-10° further north than in southern China, where precipitation increases during El Niño. The following two anomalous atmospheric circulations were found to be causes that led to different precipitation distributions over East Asia. First, an atmospheric wave train in the lower troposphere, which propagated from the central tropical Pacific (cyclonic) through the southern Philippine Sea (anticyclonic) to East Asia (cyclonic), reached the southern China and northern Philippine Sea during El Niño, whereas it reached Korea and southern Japan during El Niño Modoki. Second, an anomalous local meridional circulation, which consists of air sinking in the tropics, flowing poleward in the lower troposphere, and rising in the subtropics, developed between the southern Philippine Sea and northern Philippine Sea during El Niño. During El Niño Modoki, however, this circulation expanded further to the north and was formed between the southern Philippine Sea and regions of Korea and southern Japan. [ABSTRACT FROM AUTHOR]