Initialization Schemes in the Naval Research Laboratory’s Tropical Cyclone Prediction Model (COAMPS-TC) Eric A. Hendricks 1 Melinda S. Peng 1 Tim Li 2 Xuyang Ge 3 1 Naval Research Laboratory (NRL), Monterey, CA, USA 2 University of Hawaii and IRPC, Honolulu, HI 3 Pennsylvania State University, State College, PA USA Acknowledgements: Jim Doyle (NRL), Rich Hodur (SAIC), COAMPS-TC group CMOS 2012 Congress / AMS 21st NWP and 25th WAF Conferences Montreal, Canada, 29 May-1 June 2012
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Initialization Schemes in the Naval Research Laboratory’s Tropical Cyclone Prediction Model (COAMPS-TC) Eric A. Hendricks 1 Melinda S. Peng 1 Tim Li 2.
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Initialization Schemes in the Naval Research Laboratory’s Tropical Cyclone Prediction Model
(COAMPS-TC)Eric A. Hendricks1 Melinda S. Peng1
Tim Li2
Xuyang Ge3
1Naval Research Laboratory (NRL), Monterey, CA, USA2University of Hawaii and IRPC, Honolulu, HI
3Pennsylvania State University, State College, PA USA
Acknowledgements: Jim Doyle (NRL), Rich Hodur (SAIC), COAMPS-TC group
CMOS 2012 Congress / AMS 21st NWP and 25th WAF ConferencesMontreal, Canada, 29 May-1 June 2012
Introduction• A crucial part of TC intensity predictions is an accurate and
balanced TC vortex initially• 3DVAR data assimilation systems usually lack proper balance
constraints suitable for multi-scale TC; rapid adjustment often occurs after initialization
• A 4D data assimilation system would alleviate the initial imbalance problem to some degree
• Lack of observational data for TC intensity and structure remains
What do we do in the mean time?
Hybrid 3DVAR/Dynamic Initialization Schemes have the possibility of improving the initial balance and storm intensity/structure, while allowing model physics spin-up, potentially leading to improved intensity and track forecasts
Dynamic Initialization Schemes: TCDI, DI, TCDI/DIApplication to TC Prediction Using COAMPS-TC
NOGAPS/NCEP analysis
3DVAR data assimilation Remove TC vortex
Generate vortex from TCDI
(nudge MSLP)Insert vortex
Run forecast model
Warm Start
Cold Start
12-h forward DI
CNTL
DI
TCDITCDI
TCDI
TCD
I/D
ICNTL: Standard 3DVAR Initialization
DI: 3D Dynamic Initialization to analysis momentum ua (12-h relaxation) after 3DVAR
TCDI: Tropical Cyclone Dynamic Initialization (TC component is dynamic) after 3DVAR
TCDI/DI: Run TCDI, then run DI
)
Synthetic TC obs, Liou and Sashegy (2011)
TCDI: Hendricks et al. (2011) WAF, Zhang et al. (2012) WAF
COAMPS-TC OverviewCurrent and Future Capabilities
• Complex Data Quality Control• Relocation of TC in background• Synthetic Observations: TC vortex• NAVDAS 3DVAR: u, v, T, q, TC option• Initialization: Digital Filter Option• TC Balance Step: (underway)
• Navy Coupled Ocean Data Assimilation (NCODA) System
• 2D OI: SST• 3D MVOI, 3DVAR: T, S, SSH, Ice, Currents• Complex Data Quality Control• Initialization: Stability check
Western North Pacific storms: Chaba, Fanapi, Ma-OnCases: 120
Summary
• Three different TC initialization schemes have been developed, tested with COAMPS-TC– TCDI: tropical cyclone vortex spun-up– DI: Full 3D dynamic initialization to analyses winds– TCDI/DI: Run TCDI, then run DI
• TCDI/DI is shown to have superior performance– Average intensity errors reduced by 3-5 hPa and 2-3 kts
over all lead times – Average track errors reduced by 10-30 nm– Better for intense initializations (< 990 hPa)
• The dynamic initialization procedures allow model physics spin-up and “less shock”
• Future work– DI to satellite observed heating profiles