1. Characteristics of Extreme Events in Korea: Observations and Projections Won-Tae Kwon Hee-Jeong Baek, Hyo-Shin Lee and Yu-Kyung Hyun National Institute of Meteorological Research Korea Meteorological Administration 11IMSC, 12-16 July 2010, U of Edinburgh

2. Motivations and Objectives  Observed changes (Previous studies)  Temperature: +1.7 ℃ (including u rbanization effect)  Extremely cold day (T<-10 ℃ ): 30 days (1950s)  recently 10 days  Changes in seasonal length [onset and duration]  Precipitation: +19%  Amount ↑, Wet days ↓, intensity ↑, large temporal variability  Heavy rain days (80 mm/day ) ↑  1.6 day/year → 2.3 day/year (1954-2003, 14 stations)  Focused on the changes of mean values  This study  Trend analysis using climate indices  Changes in extreme values  Future Changes in extreme values 211IMSC, 12-16 July 2010, Edinburgh

3. Data and Methodology 11IMSC, 12-16 July 2010, Edinburgh3 Observation Six Stations Daily T & P 1912-2009 Projection SRES A1B MM5 (~27 km) Daily T & P 1971-2100 Trend in climate indices (27) (CCI/WCRP-ETCCDMI) -16 for temp -11 for precip Trend in climate indices (27) (CCI/WCRP-ETCCDMI) -16 for temp -11 for precip Extreme Analysis - GEV -Tmax, Tmin, Precip Extreme Analysis - GEV -Tmax, Tmin, Precip Extreme Analysis - GEV - Tmax, Tmin, Precip Extreme Analysis - GEV - Tmax, Tmin, Precip

4. Example of climate indices: annual precipitation 411IMSC, 12-16 July 2010, Edinburgh

5. Climate Indices: temperature -Growing season length -Summer days -Tropical nights -Ice days -Frost days -Cool days -Cool nights -Cold spell duration -Diurnal temperature range ℃ /decade UNIT: day/decade 511IMSC, 12-16 July 2010, Edinburgh

6. Climate indices: wet days Unit: days/decade Negative trend in total wet days but positive trends in heavy rain days Total precipitation change is mostly due to the increase of very wet day precipitation. Trend 611IMSC, 12-16 July 2010, Edinburgh Very wet day (95 th ): 41.4mm/day Extremely wet day (99 th ): ~91.1mm/day

7. Results: trend/decade TermTrend/decade Summer days+0.830*** Ice days-0.998*** Tropical nights+0.671*** Frost days-3.546*** Growing season length+3.528*** Max Tmax (Tmin)+0.093*** (+0.201***) Min Tmax (Tmin)+0.127*** (+0.281***) Cool(Warm) nights-0.758*** (+0.176) Cool (Warm) days-0.583*** (-0.074) Warm (Cold) spell duration indicator -0.295 (-1.845***) Diurnal temperature range -0.115*** ***: significant at 99% level, **: significant at 95% level, *: significant at 90% level TermTrend/decade Max 1-day (5-day) precipitation amount +2.321*:Aug (+4.994**): Aug Simple daily intensity index +0.228*** Number of 10mm, 20mm, 30mm precipitation days +0.320* +0.268* +0.246** Consecutive dry (wet) days -0032 (-0.011) Extremely (Very) wet day precipitation +9.004** (+17.339)*** Annual total wet-day precipitation 20.478** 711IMSC, 12-16 July 2010, Edinburgh

8. Summary of Climate Change in Korea 8 Temperature + Summer day + T_min + T_max + Ice day - Frost day - Winter season - Summer + Rain Rate + Lightning + Relative Humidity - Visibility + Cloudiness - Early Spring Blossom Early Less Heating Energy Less Late Autumn Leaves Late More Cooling Energy More Tropical night + Sea Surface Temp + Sea Level + ★ significant level is different at different locations highly significant ( α = 0.01) significant ( α = 0.05) trend but not significant ( α > 0.05) Precipitation + ★ Rain Day - ★ Fog - ★ Heavy Rain + ★ Wind speed - ★ 11IMSC, 12-16 July 2010, Edinburgh GSL + DTR - Wet day precip +

9. GEV Analysis: Methods  Data windows  Sliding window (SW)  fixed sample size (30 years)  Cumulative window (CW)  increase in sample size  Parameter estimations  Maximum Likelihood method (ML)  L-Moment method (LM) 911IMSC, 12-16 July 2010, Edinburgh

10. Annual maximum daily precipitation GangneungSeoulIncheon 1011IMSC, 12-16 July 2010, Edinburgh DaeguBusanMokpo

11. Annual daily maximum precipitation Red: ML Black: LM LocationScaleShapeReturn value: 100yr 30-year sliding window Cumulative window 1111IMSC, 12-16 July 2010, Edinburgh

12. Annual maximum of Tmax Red: ML Black: LM LocationScaleShapeReturn value: 100yr 30-year sliding window Cumulative window 1211IMSC, 12-16 July 2010, Edinburgh

13. Cumulative window 30-year sliding window Annual minimum of Tmin Red: ML Black: LM LocationScaleShapeReturn value: 100yr 1311IMSC, 12-16 July 2010, Edinburgh

14. Regional Climate Change Projection 14  Based on A1B Scenario  Model: MM5  Spatial Resolution~27km  Period: 1971~2100  Data size: 5TB (52 variables)

15. 1511IMSC, 12-16 July 2010, Edinburgh 20yr-return value 20 yr-return value for precipitation (OBS) present (1979-2007) future (2077-2099) difference Min Temperature present (1979-2007) future (2077-2099) difference Max Temperature

16. Summary  Observation  Trends in climate indices show major characteristics of regional climate change.  Recent increase of extreme temperature/precipitation events have been recognized well in GEV analysis.  Precipitation and most of min/max Temperature  increasing of mean and variance in extreme  higher probability of occurrence of extreme events  Annual maximum of Tmax  Decrease of mean and return values but increase in variances  L-moment method show stable performance for parameter estimation  Future Projection (SRES A1B)  At the end of 21 st century: -20-50% of precipitation and 2.5-4.5 degrees of temperature increase over the Korean Peninsula  Precipitation: extreme events are increasing but with large regional variation  Temperature: the increasing trend in daily minimum temperature is highest  Plan for further analysis when CORDEX data become available. 1611IMSC, 12-16 July 2010, Edinburgh

17. 1711IMSC, 12-16 July 2010, Edinburgh