A gradually increasing number of damage phenomena of natural disasters occur all around the world, nowadays, due to climate changes, in the aspect of damage’s volume and frequency. Helped by this trend, a great deal of research on the prediction of climate changes is actively made in each nation. In particular, a research on the changing hydrologic environments occurring due to climate changes is perceived as one of important research methods to prevent and minimize physical and human damages inflicted by natural disasters whose main culprit is abnormal changes of weather. Such researches on the prediction of climate changes predict the changing hydrologic environments, based on the outcomes of an analysis using GCM(General Circulation Model) as a physical model grounded on a scenario of CO2 emission. But, some specific data on rainfalls based on the outcomes of such analysis using GCM tend to measure rainfalls per month or day. Thus, such data are not used in the hydrologic field, and are used to a limit extent, if any. In general, not a few researches on an analysis of the changing rainfalls are being conducted using factors in relation to total quantity of the maximum rainfalls per constant time, month and year. Actually, such analysis of total quantity-based rainfalls can be made in the quantitative terms, but such analysis has some limits in measuring the structural changes of rainfalls.
in this study, the temporal structure of extreme rainfall events was characterized using the Neyman-Scott Rectangular Pulse Model(NSRPM) for more detail analysis. The Neyman-Scott Rectangular Pulse Model (NSRPM) was used to enlarge the understanding of the structural characteristics of the rainfall events since the NSRPM is able to reflect the underlying physical phenomena of cluster characteristics of rainfall events such as intensity, duration, location, number of rain cells.
hourly precipitation data of 14 weather stations in Han river basin (Seoul, Incheon, Wonju etc.) during summer season between 1973 and 2010 were used. the analyzing window was increased by adding years from the first 20 years (1973~1992). The number of rain cells, μ increased. The intensity of rain cells, ξ, increased. The duration of rain cells, η-1, decreased. The interval between rain cells, β-1, decreased. It inferred that the final summer rainfall quantity increase was caused by the increase of intensity and number of rain cells. The intensity of rain cells is about three times bigger than that of final rainfall intensity. The decrease of the cell duration may cause more concentrated heavy rainfall.