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The westerly jet (WJ) is an important component of atmospheric circulation, which is characterized by prominent seasonal variations in intensity and position. However, the response of the WJ over Asia during the Last Glacial Maximum (LGM) is still not clear. Using general circulation model experiments, the seasonal behaviors of the WJ over central Asia and Japan are analyzed in this paper. The results show that, compared to the present day (PD), the WJ presents a complicated response during the LGM, both in intensity and position. Over central Asia, it becomes weaker in both summer and winter. But over Japan, it is enhanced in summer but becomes diminished in winter. In terms of position, the WJ over central Asia shifts southward in both summer and winter, whereas the WJ over Japan moves southward in summer but does not change obviously relative to PD in winter. Such WJ changes are well explained by meridional temperature gradients in high troposphere, which is closely linked to seasonal thermal anomalies over the Tibetan Plateau (TP). Despite cooler LGM conditions, the anomalous warming center over the TP becomes stronger in summer. Derived from the heat budget equation, the stronger heating center is mainly caused by the weaker adiabatic cooling generated from ascending motion over the area south of the TP. In winter, the cooling over the TP is also strengthened, mostly owing to the subsidence-induced weaker adiabatic heating. Due to the importance of the WJ, the potential role of TP thermal effects should be a focus when explaining the East Asian climate change during the LGM. [ABSTRACT FROM AUTHOR]

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]