Brandon Kerns Shuyi S Chen Chiaying Lee and Falko Judt RSMASUniversity of Miami I nterdepartmental H urricane C onference Miami Florida 28 February 3 March 2011 ID: 796089
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Slide1
Multi-model Coupled Air-Sea Forecasts of Typhoons during ITOP
Brandon Kerns*, Shuyi S. Chen, Chiaying Lee, and Falko JudtRSMAS/University of Miami
Interdepartmental Hurricane Conference Miami, Florida 28 February – 3 March 2011
*bkerns@rsmas.miami.edu
Slide2Outline
UM/RSMAS Realtime coupled modeling system
Coupled Model Forecast verificationTrack and intensityCombined track & Intensity: Cross-Along Track Intensity Error (CATIE)
Beyond track and intensity: structure (e.g., size, asymmetry, etc.)
Slide3U.Miami
Real Time Coupled Multi-Model System
AtmosphereOcean
Waves
Initlal/Boundary Conditions
UMCM
MM5
3DPWP*
WW3
GFS, NOGAPS, JMA, ECMWF
CWRFWRF-ARW3DPWP*
*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 ZForecast/analysis finished~ 21 ZITOP Forecast Briefing
12 km
1.3 km
4 km
Slide4Atmosphere
Ocean
Waves
Slide5Verification: ITOP Cases
These were CHALENGING cases!
StormDatesNumber of Forecasts*Lupit (2009)
15-18 Oct. 20094Fanapi
(2010)15-18 Sept. 2010
4Megi (2010)
13-18
Oct. 2010
6
TOTAL:
14S-curveS-curve
A record-breaking Cat-5 super typhoon
*Once per day
while storm isin area of
interest.
Slide6Track 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
Slide7Track and Intensity
GFDN great intensity forecast
GFDN big track error
OPERATIONAL High-res UMCM & CWRF
INTENSITY TRACK
Megi
Megi
Megi
Megi
Slide8C
ross/
A
long
T
rack
I
ntensity
E
rror “CATIE”
GFDN CWRF-gfs
Cross Track Error
Cross Track Error
Along Track Error
Along Track Error
24 hr
48 hr
72 hr
120hr
96 hr
Slide9C
ross/
A
long
T
rack
I
ntensity
E
rror “CATIE”
GFDN CWRF-gfs
Slide10Comparison of
dropsondes
and model wind swath.
TC Structure: Size and Asymmetry
UMCM-
gfs
CWRF-
gfs
Fanapi
Fanapi
Slide11Verification 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
Radius (nm)
100
200
Slide12Verification: (Cold Wake)
UMCM-
gfs
CWRF-
gfs
Satellite SST
SATSST
Slide13Summary
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.