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Multi-model Coupled Air-Sea Forecasts of Typhoons during ITOP. Brandon Kerns*, Shuyi S. Chen, Chiaying Lee, and Falko Judt RSMAS/University of Miami. *[email protected]. I nterdepartmental H urricane C onference Miami, Florida 28 February – 3 March 2011 . Outline. - PowerPoint PPT Presentation
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MULTI-MODEL COUPLED AIR-SEA FORECASTS OF TYPHOONS
DURING ITOPBrandon Kerns*, Shuyi S.
Chen, Chiaying Lee, and Falko Judt
RSMAS/University of Miami
Interdepartmental Hurricane Conference Miami, Florida 28 February – 3 March 2011 *[email protected]
Outline UM/RSMAS Realtime coupled modeling
system
Coupled Model Forecast verification Track and intensity Combined track & Intensity: Cross-
Along Track Intensity Error (CATIE) Beyond track and intensity: structure
(e.g., size, asymmetry, etc.)
U.Miami Real Time Coupled Multi-Model System
Atmosphere Ocean Waves Initlal/Boundary ConditionsUMCM MM5 3DPWP* WW3
GFS, NOGAPS, JMA, ECMWFCWRF WRF-ARW 3DPWP*
*Price et al. (1986)
12 km
4 km
1.3 km
0Z 5-day Forecast Cycle: UMCM-gfs~ 06 Z
Model and analysis begin
~ 14 Z
Forecast/analysis finished
~ 21 Z
ITOP Forecast Briefing
12 km
1.3 km
4 km
Atmosphere Ocean
Waves
Verification: ITOP Cases
These were CHALENGING cases!
Storm Dates Number of Forecasts*
Lupit (2009) 15-18 Oct. 2009 4Fanapi (2010)
15-18 Sept. 2010
4
Megi (2010) 13-18 Oct. 2010 6
TOTAL: 14
S-curve S-curve A record-breaking Cat-5 super typhoon
*Once per day while storm isin area of interest.
Track Intensity
• High-resolution (1.3 km) coupled models (UMCM and CWRF) improve intensity forecast significantly• GFDN and COAMPS-TC have smaller intensity error, but larger track error compared to that of global models
Track and Intensity
GFDN great intensity forecast
GFDN big track error
OPERATIONAL High-res UMCM & CWRFIN
TEN
SIT
Y
TR
AC
K
Megi Megi
MegiMegi
Cross/Along Track Intensity Error “CATIE”
GFDN CWRF-gfs
Cross Track Error Cross Track Error
Alo
ng T
rack
Err
or
Alo
ng T
rack
Err
or
24 hr48 hr
72 hr
120hr
96 hr
Cross/Along Track Intensity Error “CATIE”
GFDN CWRF-gfs
Comparison of dropsondes and model wind swath.
TC Structure: Size and Asymmetry
UMCM-gfs CWRF-gfsFanapi Fanapi
Verification of Structure: Size
•Hurricane wind radii are near the best track estimates, but not gale radii.•Details of the wind field can affect ocean response.
UMCM-gfs
UMCM-gfs
BEST
9/16 9/17 9/18 9/19 9/20 9/21
Fanapi
Rad
ius
(nm
)
100
200
Verification: (Cold Wake)UMCM-gfs CWRF-gfs
Satellite SST SATSST
Summary High-resolution coupled atmosphere-ocean-wave model
forecasts were made in real-time in support of the ITOP field campaign.
Track and intensity errors of the high-res coupled models for the 3 typhoons compare favorably with the operational models and the official JTWC forecast.
The “CATIE” diagram is used to visualize/verify track and intensity errors concurrently.
ITOP provides a unique, coupled data set for evaluation and verification of the high-res coupled model forecasts of TC structure, air-sea fluxes, and upper ocean properties.
