1. Jun-Hyeok Son and Kyong-Hwan Seo
Dominant Modes of the East Asian Summer Monsoon Using Equivalent Potential Temperature
Jun-Hyeok Son and Kyong-Hwan Seo
Department of Atmospheric Sciences,
Pusan National University, Korea 1

2. East Asian Summer Monsoon
EPT and dEPT/dy June
EPT and dEPT/dy July
Color : 850-hPa Equivelant potential temperature (EPT)
Contour : Meridional gradient of EPT

3. A method for determining stationary front
Surface water chart
(KMA)
Meridional gradient of
850-hPa equivalent
potential temperature
(EPT)
Climate and Atmospheric Dynamics Lab

4. East Asian Summer Monsoon
서 론
East Asian Summer Monsoon
Precipitation
JJA
June
July
Aug.
Color : precipitation mean
Contour : interannual STD

5. Multi-variables EOF using EPT, u-wind and v-wind in 850-hPa
General characteristics during the Changma period
Multi-variables EOF using EPT, u-wind and v-wind in 850-hPa
June
July
- 850-hPa EPT (color)
- 850-hPa wind (vector)
Okhotsk Sea high is strong in June.
WNPSH is dominant in July.
Climate and Atmospheric Dynamics Lab

6. General characteristics during the Changma period
Wave-train from North Atlantic Ocean (June)
Wave-train from Western North Pacific (July)
Climate and Atmospheric Dynamics Lab

7. General characteristics during the Changma period
June MAM(0)
July MAM(0)
June JJA(0)
July JJA(0)
Correlation of SST (color)
Climate and Atmospheric Dynamics Lab

8. Correlation matrix EOF for EPT
Quick summery
Dominent modes of EASM in July
Correlation matrix EOF for EPT
First three modes of EOF (color) and regressed precipitation (contour)

9. Dominent modes of EASM in July
Quick summery
Dominent modes of EASM in July
SST correlation map
PC1
PC2
PC3
DJF(-1)
MAM
JJA
DJF

10. Dynamical mechanism (mode 1)
Quick summery
Dominent modes of EASM in July
Dynamical mechanism (mode 1)
Low
High
Low
Westerly wind
Color : Precipitation
Vector : 500-hPa wind

11. Dynamical mechanism (mode 2)
Quick summery
Dominent modes of EASM in July
Dynamical mechanism (mode 2)
Low
High
Color : T500, Contour : Z500, Vector : 200-hPa wind

12. Dynamical mechanism (mode 3)
Quick summery
Dominent modes of EASM in July
Dynamical mechanism (mode 3)
Easterly wind anomaly
Low
High
Westerly
Color : Precipitation, Vector : 500-hPa wind

13. Physical-statistical prediction model
Quick summery
Work in progress......
Physical-statistical prediction model
P = A(May) B(Mar. ~ Apr.) C(May – Apr.) D(Apr.)
Domain of PRCP : [ ~ °E, ~ 41.25°N]

14. Development of physical-statistical
Quick summery
Work in progress......
Development of physical-statistical
prediction model
GMSS (0.67)
Forecast
Above
Normal
Below
OBS
2006, 2009, 2012
2003, 2007, 2011
2005, 2010
1995, 1996, 1997, 1998, 2001
1999
1994, 2000, 2002, 2004, 2008
Observation
Forecast
Forecast using previous spring (until May) SST

15. 1 2 3 Summery Interannual variation of East Asian
summer monsoon is dominated by
different mode in June and July.
- June : Okhotsk Sea high (mP)
- July : WNPSH (mT) 1
The CP El-Nino, PDO and Indian Ocean basin wide warming affect to
the East Asian summer monsoon in July.
These boundary forcing make atmospheric waves and significantly
intensify the East Asian summer monsoon front. 2
Based on these analysis, physical-statistical prediction model is built
up for the forecast of the precipitation in July.
(correlation : 0.78, RMSE : 0.75). 3
Climate and Atmospheric Dynamics Lab

16. Thank you.
Climate and Atmospheric Dynamics Lab