The Rainfall System Classification over the Korean Peninsula Using TRMM TMI and Ground Measurement Data

Transcription

1 6 th 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. Ryu 1, B. J. Sohn 2, M.-L. Ou 1, H.-J. Song 2, M.-J. Kim 1, and C. D. Kummerow 3 1 National Institute of Meteorological Research, South Korea 2 Seoul National University, South Korea 3 Colorado State University, U.S.A.

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

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 Pusan # of matchup (day) V6 V7 same event day Jindo 100km Jindo Pusan Gosan Seongsan Gosan Seongsan

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

7 Comparison with Ground Measurements (Convective) AWS Radar PR TMI 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~ Synoptic fields using ERA-Interim reanalysis data Deep convective Anvil Congestus Thin cirrus Shallow Cu Marine Sc [Rossow et al. 2005, GRL]

10 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): 27.8 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) 850hPa Jun. Jul. Aug. 500hPa

12 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~ 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.

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