기후변화영향평가모형 개발

Abstract

Development of Impact Assessment Model by Climate Change on Water Resources In recent years, global warming has emerged as a popular issue and became more evident and the impact of global warming in various aspects has been investigated by many institutions. Among the various aspects of global warming, the impact on the terrestrial water cycle has been focused as one of the utmost important climate change policy issues because it directly affects the human settlement and ecosystem. This study collected and reviewed the global and regional climate modeling results to assess the impacts of global warming on the water cycle and developed a Soil Water Balance Model (SWBM) This Model was based on soil moisture changes in order to project the impact on water shortage caused by changes in water resources supply capacity under the changed future climate. Also a raster-based SWBM reflect the soil moisture changes by incorporating such techniques as Thornthwaite and Penman-FAO24 potential evapotranspiration methods to estimate the future potential run-off changes of the major river basins in the Korean peninsula. In order to predict the future climate change and water resources impact, this study employed 4 IPCC/SRES scenarios, 12 GCM results (SRES A1,A2,B1 and B2: CCSRNIES, CSIROMK2, A2 and B2: HadCM3, CCCma) supplied by the IPCC Data Distribution Center and RAMS regional climate model of the National Institute for Environmental Studies of Japan and the SWBM (Vorosmarty et al., 1989, 1998; AIM, 1997) was applied to each 0.05° grid cell over the study area, the entire Korean peninsula. Biophysical datasets as input of SWBM at 0.05° (longitude×latitude) spatial scale were produced over the study area. The current monthly mean temperature and precipitation datasets were respectively produced by the krigging spatial interpolation technique with the Korea Meteorological Administration and UNEP’s Global Historical Climatology Network Data incorporating the lapse rate. The watershed and stream network data were produced with the GTOPO30 digital elevation model in a 30-sec mesh grid. Each produced watershed was assigned by the Pfafstetter watershed coding system (Pfafstetter, 1989) to identify the upstream and downstream watersheds. Lastly, the field capacity dataset was produced with the soil property, vegetation rooting depth and Batjes’ PTF (different pedo-transfer functions) rules. The soil texture data and soil depth data were collected from the detailed soil map and the vegetation data was derived from the land cover classification map of the Korean Ministry of Environment. To acquire the field capacity data in North Korea, the FAO’s World Maximum Soil Water Map (1996) at a 5×5 arc minute resolution was employed. The future runoff change of the present years (1981~1990) and that of the future years (2041~2050) were analyzed by employing SWBM on the area between latitude 33°~44° 30’ and longitude 123° 30’~131° 30’ focusing on 10 major watershed basins in both North Korea and South Korea The major findings in this study are as stated below: First, a numerical simulation with RCM predicts that the temperature rises about 3.7℃ in the summer and 3℃ in the winter while the SRES scenarios project the temperature rise within a range of 1~3.5℃ in the summer and 1~3℃ in the winter in South Korea. In North Korea, the RCM predicts that the temperature rise would be about 4.3℃ in the summer and 2.7℃ in the winter while the SRES scenario projected the mean temperature flux range to be 1~5.3℃ in the winter and 1~3.2℃ in the summer. Second, the RCM and SRES scenario resulted different projections in precipitation variability. While RCM projected the future precipitation variability in South Korea to be about 10% in the summer and 65% in the winter, the SRES scenario projected the mean precipitation flux range to be -10~55% in the winter and -20~20% in the summer. In North Korea, the RCM projected the precipitation variability to be about 30% in the summer and 55% in the winter while the SRES scenario predicted -10~40% in the summer and -20~20% in the winter. Third, among the four IPCC/SRES scenarios, the B1 scenario turned out to be the development road map with the minimum impact on runoff. Moreover, a heavier impact on runoff is predicted in South Korea than North Korea. The RCM generated a higher future runoff projection than the SRES scenarios in general, and showed an opposite result to the SRES projections in North Korea. ？ In South Korea, the B1 scenario was predicted to bring the least magnitude of impact on the runoff and precipitation (-5.4%) while the A1 scenario was predicted to bring the most severe impact(16.3%). ？ In North Korea, the B1 scenario turned out to associate the least magnitude of impact (0.6%); however, RAMS regional climate model projected a notable 41.9% variability on runoff. ？ In the projected runoff changes of 10 major watershed basins in the Korean peninsula, RAMS regional climate model predicts a heavy increase of runoff in the Aplock, Chungcheon, Daedong, and Yesung River basins in North Korea, and Han and Geum River basins in South Korea. ？ Under the SRES scenario, in South Korea, the A1 scenario was predicted to lead to serious adverse impacts including floods in the Han River and Geum River basins due to the noticeable increase of rainfall during the rainy season. In North Korea, a decline in the runoff in Tuman River was also predicted.