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.

The heavy snowfall event over the eastern part of Seoul, Korea on Mar. 04, 2008 has been abruptly occurred after the frontal system with the heavy snowfall event had been past over the Korean peninsula on Mar. 03, 2008. Therefore, this heavy snowfall event couldn't be predicted well by any means of theoretical knowledges and models. After the cold front passed by, the cold air mass was flown over the peninsula immediately and became clear expectedly except the eastern part and southwestern part of peninsula with some large amount of snowfall. Even though the wide and intense massive cold anticyclone was expanded and enhanced by the lowest tropospheric baroclinicity over the Yellow Sea, but the intrusion and eastward movement of cold air to Seoul was too slow than normally predicted. Using the data of numerical model, satellite and radar images, three dimensional analysis products(KLAPS : Korea Local Analysis and Prediction System) of the environmental conditions of this event such as temperature, equivalent potential temperature, wind, vertical circulation, divergence, moisture flux divergence and relative vorticity could be analyzed precisely. Through the analysis of this event, the formation and westward advection of lower cyclonic circulation with continuously horizontal movement of air into the eastern part of Seoul by the analyses of KLAPS fields have been affected by occurring the heavy snowfall event. As the predictability of abrupt snowfall event was very hard and dependent on not only the synoptic atmospheric circulation but also for mesoscale atmospheric circulation, the forecaster can be predicted well this event which may be occurred and developed within the very short time period using sequential satellite images and KLAPS products.

Intraseasonal variability of the tropical convection over the Indian/western Pacific is studied using the Geostationary Meteorological Satellite high cloud amount. This study is directed to find the tropical-extratropical interaction in the frequency range of intraseasonal and interannual variabilities of the summer monsoon occured over the domain of 90E-171W and 49S-50N. Especially, in order to investigate the intraseasonal interaction of East Asia summer monsoon associated with the tropical convections in the high cloud amounts, the spatial and time structure of the intraseasonal oscillation for the movement and the evolution of the large-scale convections are studied. To describe the spatial and the time evolution, the extended empirical orthogonal function analysis is applied. The first mode may be considered to a normal structure, indicating that the strong convection band over 90E-120E is extended to eastward, but this mode was detected as a variable mode near Korea and Japan. The second, third and fourth modes were amplified with the intraseasonal variability during summer monsoon. It is found that the dominant intraseasonal mode of the tropical convection consists of the spatial changes over a broad period range centered around 40∼50days.