NCEP/EMC Operational Hurricane Weather Research and Forecast

(HWRF) Modeling System

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Vijay TallapragadaJCSDA-HFIP Workshop on Satellite Data Assimilation

for Hurricane Forecasting

December 02, 2010

Outline

• Current operational HWRF system• Evolution of HWRF• FY2011 ongoing developments• Collaborative efforts• Future developments

Operational HWRF Modeling System• Current operational HWRF

– Regional-Scale Ocean-Atmosphere Coupled Modeling System specially designed to advance hurricane track and intensity forecasts.

– Non-Hydrostatic system of equations formulated on a rotated latitude-longitude, Arakawa E-grid and a vertical, pressure hybrid (sigma-P) coordinate.

– Based on WRF NMM V2.0 framework with movable, vortex following high-resolution nested grid

– 27 km outer domain, 9 km inner domain, 42 vertical levels• Advanced vortex initialization and GSI/3DVAR data assimilation

– Advanced vortex initialization and GSI/3DVAR data assimilation consisting of Vortex relocation, Storm size and intensity correction based on tcvitals, and combination of bogus (synthetic) vortex and six-hour cycling

– Assimilation of satellite radiance datasets in the hurricane environment• Coupled to Princeton Ocean Model (POM) in the Atlantic

– Feature based initialization of cold wake, loop current, warm and cold core eddies

• Physical parameterizations designed for tropical environment– GFS/GFDL SAS Convection and PBL– GFDL Surface Physics, Radiation, Ferrier Microphysics

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Evolution of HWRF• Initial implementation in 2007 hurricane season

– Model design and development of movable nested grid started in 2002– Initial HWRF workshop at NSF in 2004– 28 different configurations tested individually (each with about 200 simulations)

before initial implementation– Extensive 3-season (2004-2006) pre-implementation testing of HWRF for all

storms in the Atlantic and Eastern Pacific basins• Vortex initialization upgrades in 2008

– Address intensity bias for weaker systems, modifications to storm balance

• Infrastructure upgrade and transition to P6 in 2009– Capability enhancements to allow coupling to HyCOM and Wave Watch-III– Script enhancements (identical scripts for NCO operations and EMC parallels)

• Physics and initialization upgrades in 2010 to improve the forecast skill.

– New baseline version with several bug fixes– Modified surface physics formulation and use of Gravity Wave Drag

parameterization– Addition of satellite radiance data assimilation in the hurricane environment– Focus on reducing intensity bias

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HWRF Atlantic Track Forecast Errors HWRF Atlantic Intensity Forecast Errors (less skillful at all times)

Negative bias for HWRF Atlantic Intensity Forecasts

Performance of the Operational HWRF for 2010 ATL hurricane season

Rapid growth of intensity errors

HWRF E-Pac Track Forecast Errors HWRF E-Pac Intensity Forecast Errors (less skillful at all times)

Negative bias for HWRF E-Pac Intensity Forecasts

Performance of the Operational HWRF for 2010 EPAC hurricane season

Rapid growth of intensity errors

Current HWRF activities/developments• Major upgrade to the HWRF modeling system for 2011:

– Establish a community repository of the operational HWRF and upgrade HWRF infrastructure to V3.2+ (collaboration with DTC)

– Couple to HYCOM ocean model in the Atlantic– Improve vortex initialization for more realistic storm size and intensity corrections– Physics upgrades include testing of new GFS convection, modified PBL and

modifications to treatment of horizontal diffusion– Simplified operational system with added flexibility and multi-platform

compatibility• Subversion based code management

– HWRF-POM and HWRF-HYCOM baseline configurations for T&E– Synchronization of EMC and DTC repositories

• Product development– Generating simulated GOES WV and IR imagery and simulated radar reflectivity

products starting in 2010– Additional simulated microwave products in 2011/2012– High-frequency output and additional derived variables for diagnostics – Enhancements to GrADS based HPLOT diagnostics and visualization software– New enhanced HWRF website for product display and navigation

WRF V3.2

WRF V3.1.1

WRF V3.1

WRF V3.0

WRF V2.2

WRF V2.1

WRF V205/2004

07/2009

04/2010

08/2005

12/2006

04/2008

04/2009

FY2011 Operational HWRF Configuration

HWRF operational configuration (2011)

Extensive Testing (pre implementation)

WRF Repository (hosted by DTC)

HWRF2007

HWRF2008

HWRF2009

HWRF2010

WRF V3.2+02/2011

upgrades2011

•Modified vortex initialization (storm size correction and balanced vortex)•Coupling to HYCOM in the Atlantic•New GFS Deep/Shallow Convection•Modified PBL, Radiation, Microphysics•Modified horizontal diffusion

Extensive Testing (individual upgrades)

Regional Hurricane Model Development at EMC9

HWRF produces too few strong storms

Vortex Initialization Issues/Challenges

Positive bias for weaker storms, negative for stronger storms (spinup/spindown)

Broad initial vertical structure

Insufficient vortex size correction

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0 50 100 150 200 250 300 350 400

Radius (km) before the size correction

Rad

ius

(km

) afte

r the

siz

e co

rrec

tion

Model radius

Current sizecorrectionNew sizecorrection

Size Size correcticorrectionon

IntensitIntensity y correcticorrectionon

25.1

85.075.0

2

1

6h fcst

Modified vortex initialization procedure: Improved mass/wind balance & storm size correction, with a focus on reducing initial spinup/ spindown issues, and improve track/intensity forecast skill in the first 12-24 hrs

Max Wind vs centeral Pressure at 6hr forecastHurricane Alex and Earl

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920 930 940 950 960 970 980 990 1000 1010 1020

Central Pressure (mb)

Max

imum

Win

d Sp

eed

(kts

)

ctl: initctl: +06hrdiff: +06hrno-init:+06hrLinear (ctl: init)Linear (ctl: +06hr)Linear (diff: +06hr)Linear (no-init:+06hr)

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1 10 19 28 37 46 55 64 73 82 91 100 109 118 127 136

Forecast Time (9min)

Max

imum

win

d sp

eed

(kts

)Time series of max. wind speed (Celia: 2010062218)

84kts becomes 55kts around the first 2hours

9kts drop at the first 9min

34kts radii distribution observation (y-axis) vs HWRF forecast (x-axis)

06hr

96hr

48hr24hr

72hr 120hr

Band 3 Loop Simulated Band 3 Loop Real

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Ongoing Model development & collaborative efforts• Further advancements to the HWRF modeling system (EMC & HRD)

– third nest capability, advanced diagnostic capability (diapost), idealized simulations

• Code management and community support at DTC– Setup HWRFV3.2+ and provide support to the community through DTC– Development of R2O/O2R infrastructure and testing facility at DTC

• Data assimilation (EMC, HRD, CIRA)– Real-time test of the P3 TDR data flow from aircraft to NCO/TOC/AOC and

assimilation using advanced GSI.– Ensemble data assimilation (MLEF, CIRA) and hybrid EnKF (HRD).

• HWRF Diagnostics (HFIP, EMC, NHC, FSU, CIRA, HRD, UMBC/UMD)– Identifying forecast errors from different components of model physics and

dynamics– Hurricane model diagnostics, evaluation and verification– Develop a common and comprehensive diagnostics framework and tools to

integrate model output with available observations for verification– Cloudtop datasets for storm scale diagnostics

• HWRF Physics (URI, GFDL, ESRL,HRD)– Surface fluxes, sea spray and wave coupling– Physics for high-resolution (convection, micro physics, PBL, LSM )

Hurricane-Wave-Ocean-Surge-Inundation Coupled Models

High resolution Coastal, Bay & Estuarine hydrodynamic model*

Atmosphere/oceanic Boundary Layer

WAVEWATCH III*Spectral wave model

Land and coastal watersNCEP/Environmental Modeling CenterAtmosphere- Ocean-Wave-Land

runoff

fluxes

wave fluxes

wave spectra

windsair temp. SST

currents

elevations currents3D salinities temperatures

other fluxes

Surge*Inundation*

radiativefluxes

HWRF SYSTEM NMM V2.0 Hurricane atmosphere

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Princeton Ocean Model (POM) for Atlantic Region

GFDL Slab ModelNOAH LSM*

*Future developments

Upgrade to HWRF V3.2+ in FY2011

FY2011 Upgrade to HYCOM Ocean Model

HWRF Prioritized Activities for FY11• Comprehensive testing of HWRFV3.2 • Focus on reducing intensity errors in the first 24 hrs of

forecast• Focus on improving track forecast skill• Focus on improving intensity forecast skill • Comprehensive HWRF model diagnostics • Real-time parallels using high resolution triple nested

HWRF (27/9/3)• Real-time parallels using advanced GSI and hybrid-EnKF

DA methods• Continuous advancements to the HWRF modeling system

Advancing the HWRF System

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2011 2012 2013 2014* 2015*

Resolution/ Infrastructure Triple nested HWRF

(27/9/3 km)

Increased vertical resolution, higher model top, upgrades to WRF infrastructure, NEMS/ESMF/NMM-B, community R2O efforts (HFIP)

Physics Convection, PBL, Horizontal diffusion

Shallow convection, Microphysics, Radiation, Surface Physics, Coupling to Waves and Land Surface, Physics for high-resolution

DA/ Vortex Initialization

Storm size correction, gradient balance

Inner core (Doppler Radar, satellite)

Hybrid-EnKF DA, advanced vortex relocation procedure, improved GSI

Ocean HYCOM Coupling

Improved ocean data assimilation, physics and resolution

Waves One-way Wave Coupling Two-way wave coupling, multi-grid surf zone physics, effects of sea spray

Diagnostics and Product Development

HWRF Ensembles, Coupling to Hydrological/ Surge/ Inundation models, diagnostics, product development

Ongoing WorkPotential 2011 upgrades

Future developments

*Potential Computer upgrade

HWRFV3.2+

Thanks for your attention

Questions?