1. Overview of 2012/2013 winter over South Korea
E-hyung Park, Doo-hee Ryu, and Hyun-kyung Kim
Climate Prediction Division
Korea Meteorological Administration

2. Contents 1. Temp. & Precip. over East Asia
2. Temp. & Precip. over Korea
3. Notable Events & Season Monitoring
4. Summary

3. Temperature & Precipitation over EA
November
December
January
February

4. Temperature over South Korea
Daily Mean Temperature anomaly (℃)
Anomaly: -1.6℃
-3.2℃
-1.1℃
-0.4℃
Mean (-1.0℃)
Above Normal
Below Normal
December
January
February
normal
above
below

5. Precipitation over South Korea
Daily averaged amount of precipitation(㎜)
Ratio to normal: 162%
261%
103%
149%
Total (139.3mm)
December
January
February
normal
above
below

6. Notable Events
&
Season Monitoring

7. Schematic illustration of Ural blocking
DJF 1950~2000
Blocking Frequency
Atmospheric blocking made frequently in Pacific and Atlantic Ocean.
A quasi-stationary blocking high over the North Pacific, which may exert an influence on the East Asian trough and indirectly affect the cold surge pathways in East Asia (Cheung et al., 2012).
The region around the Ural Mountains is the third preferred region for blocking occurrence
A strong positive height anomaly over the Urals in winter is related to a colder surface temperature in East Asia (Li, 2004).
The circulation pattern over the Uarls is one of the critical factors in winter seasonal prediction for East Asia (Li, 2004).
Schematic illustration of Ural blocking

8. Long-lasting cold episode and cold surge
500hPa GPH anomaly (21 Nov. to 10 Dec.)
Daily mean temperature anomaly (℃)
November
3rd
December
January
1st
-1.4℃
(-4.4℃)
-0.3℃
(-1.6℃)
-3.3℃
(-3.7℃)
-5.8℃
(-5.1℃)
11/ / / / / /16 12/ / / /6
SAT anomaly (21 Nov. to 10 Dec.)
From late November to early December, an blocking high occurred over the Bering Sea  Block the west to east progression of the upper level airflow  A cold upper level trough passed through over East Asia

9. Long-lasting cold episode and cold surge
500hPa GPH anomaly (11 Dec. to 10 Jan.)
Daily mean temperature anomaly (℃)
November
3rd
December
January
1st
-1.4℃
(-4.4℃)
-0.3℃
(-1.6℃)
-3.3℃
(-3.7℃)
-5.8℃
(-5.1℃)
11/ / / / / /16 12/ / / /6
From mid to late December, the blocking high occurred over the Ural Mountains  The enhanced northerly cold advection increases mass convergence in the upper troposphere over Siberia  The Siberian High was significantly developed  Cold air outbreak in East Asia
In December, the monthly mean temperature anomaly over South Korea was -3.2°C. It was the coldest since 1973.
The record-breaking minimum temperatures were recorded in 3 to 4 January 2013 over South Korea since record began.

10. Long-lasting cold episode and cold surge
December
January
February
NCEP Climatology
2012/2013
Daily variations of maximum pressure of SH (hPa)
80~120°E, 40~60°N
MSLP anomaly (11 Dec. to 10 Jan.)
SAT anomaly (11 Dec. to 10 Jan.)

11. Frequent snow and rain in winter
Daily averaged amount of Precipitation(㎜)
Siberian High
December
January
February
261%
103%
149%
In December, the monthly total precipitation over South Korea was 60.4㎜. It was the 2nd wettest since The rainy days (days with more than 0.1㎜) was 11.2 days (6.6 days), which was ranked 1st since 1973.
In early-February, the total precipitation was 45.0㎜. It was the 1st since The rainy days was 5.4 days (1.9 days), which was ranked 1st since 1973.
The number of rainy days during in the wintertime was 25.5 days (19.8 days), which was ranked the 3rd largest since 1973.
Warm & Humid
Air
Upper level
Cold Air

12. Stratospheric Sudden Warming
Mean (1991~2004)
2012/2013
Max & Min (1991~2004)

13. Summary
1. Wintertime(2012/2013) climate over Korea - Temperature: below normal (-1.6℃) - Precipitation: above normal (162%) - Rainy days: 25.5 days (3rd largest since 1973)
2. The long-lasting cold episode and cold surge is strongly associated with the blocking high over the North Pacific and Ural Mountains. Especially, the Ural blocking intensifies the Siberian high and triggers a cold air outbreak in East Asia.
3. Continuously warm and humid southwesterly flow collided frequently with cold and dry continental upper air over the Korean Peninsula which induced severe atmospheric instability.

14. ____ ___ ___ ____ _________

15. Siberian High & SAT Daily mean temperature anomaly (℃) December
January
February
NCEP Climatology
2012/2013
-3.2℃
-1.1℃
Above Normal
Below Normal
-0.4℃
Daily variations of maximum pressure of SH (hPa)
80~120°E, 40~60°N

16. SAT anomaly
2009/2010 DJF
2010/2011 DJF
2011/2012 DJF
2012/2013 DJF

17. Regression map & Anomalous pattern
Korea Precip. (DJF) & OLR(DJF): 1979/80~2011/12
OLR 2012D/13J Anomalous pattern (Clim: DJF)

18. Velocity Potential and SST Anomaly
December
SST monthly Anomaly