• Journal of the Korean Geographical Society
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• v.37 no.4
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• pp.385-402
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• 2002

This study examined temporal and spatial patterns of bioclimatic perceived sultriness in South Korea by analyzing the climatology of heat index calculated from ambient temperature and relative humidity for the period of 26 years (1973-1998). As results, spatially, bioclimatic sultriness above all thresholds frequently occurred mainly in the central western inner area, the southwestern inner area, and the southeastern inner area of South Korea. Especially, Miryang in the southeastern inner area of South Korea was proved to be, bioclimatically, the sultriest area in South Korea that has recorded frequent high heat index. Temporally, frequency of sultriness in the contiguous South Korea significantly increased in the 1990s. Specifically, In 1994, frequencies of heat index exceeding each threshold was the highest all over South Korea. Normally, the sultriness with high heat index exceeding 40.6$^{circ}C$ occurred mainly for the period of between the end of July generally after Summer Changma and the beginning of August before another small rainy season of years. These temporal-spatial distributions of bioclimatic sultriness in South Korea showed various patterns regionally, affected by physical and anthropogenic climatic factors such as topography, latitude, altitude, water bodies or aforestration, urbanization, and industrialization as well as movements of large-scale air masses.

• Journal of the Korean Geographical Society
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• v.41 no.5 s.116
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• pp.527-544
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• 2006

This study provides a definition of heat waves, which indicate the conditions of strong sultriness in summer, appropriate to Korea and intends to clarify long term(1973-2006) averaged spatial and temporal patterns of annual frequency of heat waves with respect to their intensity. Based on examination of the Korean mortality rate changes due to increase of apparent temperature under hot and humid summer conditions, three consecutive days with at least $32.5^{\circ}C,\;35.5^{\circ}C,\;38.5^{\circ}C,\;and\;41.5^{\circ}C$ of daily maximum Heat Index are defined as the Hot Spell(HS), the Heat Wave(HW), the Strong Heat Wave(SHW), and the Extreme Heat Wave(EHW), respectively. The annual frequency of all categories of heat waves is relatively low in high-elevated regions or on islands adjacent to seas. In contrast, the maximum annual frequency of heat waves during the study period as well as annual average frequency are highest in interior, low-elevated regions along major rivers in South Korea, particularly during the Changma Break period(between late July and mid-August). There is no obvious increasing or decreasing trend in the annual total frequency of all categories of heat waves for the study period However, the maximum annual frequencies of HS days at each weather station were recorded mainly in the 1970s, while most of maximum frequency records of both the HW and the SHW at individual weather stations were observed in the 1990s. It is also revealed that when heat waves occur in South Korea high humidity as well as high temperature contributes to increasing the heat wave intensity by $4.3-9.5^{\circ}C$. These results provide a useful basis to help develop a heat wave warning system appropriate to Korea.