Correlation between Urbanization Rate in Local Scale and Extreme Climate Indices

Abstract

: This study examines the relationship between urbanization rate and extreme climate indices in South Korea for the period 1981-2010. In the analysis five extreme climate indices related to air temperature and four types urbanization rates are used. In particular, this paper adopts frequency of warm nights(TN90p), intra-annual extreme temperature range(ATR), growing season length(GSL), number of frost days(FD) and heat warm spell duration indicator(HWDI) as extreme climate indices. As a measure of urbanization rate, four kinds of urbanization rate are used: (1) three urbanization rates within a radius of 1km, 5km or 10km of weather station and (2) a urbanization rate of sub-watershed where weather station is located. The trend of extreme climate indices is calculated based on Mann-Kendall trend analysis and Sen's slope, and this trend is contrasted with urbanization rates in eleven climatic regions. The results show that TN90p, GSL, and FD have a relatively high correlation with urbanization rate. This study also shows that a urbanization rate within a radius of 1km of weather station affects GSL and FD. while a urbanization rate within 5km buffer zone of weather station affects TN90p. It is Daegwallyeong, Inje, Yangpyeong, and Hongcheon where extreme climate indices responded sensitively despite the low urbanization rates of these areas. Continual attention is needed to these areas because they are relatively sensitive to climate changes of synoptic scale.