연구보고서
- 저자
- 오지현 박사
- 작성일
- 2019.06.12
- 조회
- 209
- 요약
- 목차
This study aims to develop a method of defining extreme events in order to apply for subseasonal forecast. The subseasonal forecast targeting 15-60 days in advance has received much attention to bridge the gap between short-range forecast and long-range forecast. Furthermore, it is vital to monitor and predict extreme events occurring globally and more frequently than before, so that we can promptly cope with disaster caused by extreme events such as heatwaves, cold surges, and floods.
After conducting various sensitivity tests on percentile-based criteria, periods of climatology, we developed Extreme Index which can be used for subseasonal forecast of extreme events. The Index takes frequency, magnitude, and extent of extreme events into account for easy application regardless of area and climate feature of domain of interest. We showed that the increase in warm extreme and decrease in cold extreme over the globe are well represented by the Extreme Index. Also, the recent increase in heavy rainfall over the East Asia is well detected by the Extreme Index.
On the basis of Extreme Index, in particular, the cold extreme from week 1 through week 6 over the Central Asia tends to increase despite the global warming trend. We investigated extreme events such as heatwaves, cold surges, heavy rainfall related to Typhoon and Changma in South Korea by using Extreme Event. We further examined subseasonal prediction skill of European Centre for Medium-Range Weather Forecasts (ECMWF) for 2016 heatwave case in South Korea based on Extreme Index.
Since the Extreme Index is designed to focus on extreme events regarding subseasonal time range, it has some limitations in representing day-to-day change of the extreme events. However, the extreme events which persist for several days can be identified and predicted by the Extreme Index.