1. G.-H. Ryu1, B. J. Sohn2, M.-L. Ou1, H.-J. Song2,
6th International Precipitation Working Group Workshop-São José dos Campos- October 15~19, 2012
The Rainfall System Classification over the Korean Peninsula Using TRMM TMI and Ground Measurement Data
G.-H. Ryu1, B. J. Sohn2, M.-L. Ou1, H.-J. Song2,
M.-J. Kim1, and C. D. Kummerow3
1National Institute of Meteorological Research, South Korea
2Seoul National University, South Korea
3Colorado State University, U.S.A.

2. TB85V vs. GPROF-V6 rain rate
TMI TB85V vs. Gauge Rain Rate (over Korea)
TB85V vs. GPROF-V6 rain rate
TB85V vs. AWS rain rate
[Ryu et al. 2012, JAMC]

3. CFADs: Contoured frequency by altitude diagrams
CFADs of PR Reflectivity Classified by Rain Rate
0 < RRPR < 10
10 < RRPR < 20
20 < RRPR < 40
RRPR > 40
Korea US
CFADs: Contoured frequency by altitude diagrams

4. PDF Classified by PR Rain Rate
Storm height (TRMM PR )
TB85V (TRMMTMI)

5. Ground Validation over the Korea (V7)
Ground measurements
- S-band radar reflectivity, rain rate
- Gauge : rain rate from TRMM-GSP algorithm
TRMM measurements
- TRMM/PR reflectivity, rain rate
- TRMM/TMI rain rate
Period:
- Aug ~ Aug. 2010
Pusan
Gosan
Seongsan
Jindo
# of matchup
(day) V6 V7
same event day
Jindo
300
286
Pusan
221
211
Gosan
212
202
Seongsan
214
201
100km

6. Ground Validation over the Korea (V7)
Radar PR
TMI
AWS PR
TMI
PR vs TMI GR

7. Comparison with Ground Measurements (Convective)
Radar PR
TMI
AWS GR

8. Rain System Characteristics over the Korean Peninsula
- Lower/warm clouds can also cause heavy rainfall over the Korean peninsula
- Heavy precipitation over East Asia is more like a tropical ocean pattern, differentiated from the land-type precipitation, whose typical clouds are high and ice-abundant.
- Little ice cloud during the summer time (rare hail or lightening occurrence)
- Convective instability may not be the main mechanism of inducing the heavy rainfall.
Therefore, surroundings also seems to be an important element of inducing heavy rainfall over the Korean peninsula or East Asia.

9. Classification using K-means clustering (I)
Cloud Regime Classification over the Korean Peninsular
- MODIS COT vs. CTP
- JJA, 2007~2010
- Synoptic fields using ERA-Interim reanalysis data
Deep
convective
Anvil
Congestus
Thin
cirrus
Shallow Cu
Marine Sc
[Rossow et al. 2005, GRL]

10. Cumulus convection Deep convection Low cloud Anvil 1 Cirrus Anvil 2
Statistics for clusters
Cumulus convection
Deep convection
Low cloud
US= 28%
Korea= 34%
US (TMPA): 3.2 mm/day
Korea (TMPA): 8.7 mm/day
Korea (AWS): 8.9 mm/day
US= 8%
Korea= 20%
US (TMPA): 9.7 mm/day
Korea (TMPA): mm/day
Korea (AWS): 25.8 mm/day
US: 32%
Korea: 18%
US (TMPA): 0.1 mm/day
Korea (TMPA): : 0.4 mm/day
Korea (AWS): 1.3 mm/day
Anvil 1
Cirrus
Anvil 2
US: 10%
Korea: 17%
US (TMPA): 1.9 mm/day
Korea (TMPA): 3.2 mm/day
Korea (AWS): 2.4 mm/day
US: 11%
Korea: 5%
US (TMPA): 0.1 mm/day
Korea (TMPA): 0.7 mm/day Korea (AWS): 0.6 mm/day
US: 11%
Korea: 6%
US (TMPA): 0.8 mm/day
Korea (TMPA): 1.2 mm/day
Korea (AWS): 1.5 mm/day

11. Mean Synoptic pattern over East Asia(JJA, 2002~2010)
Jun.
Jul.
Aug.
850hPa
500hPa

12. Cumulus convection Cumulus convection Korea US
Column Water Vapor (Korea vs. US)
Cumulus convection
Cumulus convection
Korea US
Deep convection
Deep convection
Geopotential Height (Solid), Temperature (Dash), Wind (Vector) at 850 hPa

13. Classification using K-means clustering (II)
TB85V-RainRate Classification over the Korean peninsula
- Gauge rain rate vs. TRMM TMI TB85V
- Periods: JJA, 2002~2010
- Synoptic fields using ERA-Interim reanalysis data

14. Statistics for clusters (JJA, 2002~2010)
Stratiform system
Cumulus convection
Light rain system I
Deep convection
Light rain system II

15. Synoptic Pattern of Geopotential Height with Wind at 850 hPa
(JJA, 2002~2010)

16. Summery & Conclusion
Satellite-based rain retrieval algorithm developed for TRMM severely underestimates the rainfall under humid the environment because of less available ice in the cloud over Korean peninsula or East Asia.
Cumulus parameterization scheme working well over US may not always work over Korea (known from various numerical simulation studies, or from diagnostics studies using reanalysis data), same as shown in the rain retrievals.
IR and MW-based classifications show similar clusters including their synoptic patterns showing over 30% .
Convective instability may not be the main mechanism of inducing the heavy rainfall. Large-scale synoptic environment possibly establishing a ‘water vapor river’ that transports much of water vapor into the peninsula and surroundings also seems to be an important element of inducing heavy rainfall over this region.

17. THANK YOU

18. Synoptic Pattern of Geopotential Height with Wind at 500 hPa
(JJA, 2002~2010)