Assimilate NOAA P3 Tail Doppler Radar Data for Hurricane Initialization at NCEP
Mingjing Tong1
Collaborators: David Perish2, Daryl Kleist3, Russ Treadon2, John Derber2
Xuyang Ge1, Fuqing Zhang4
John Gamache5
NCEP/EMC HWRF team
1UCAR (NCEP/EMC), 2NOAA/NWS/NCEP/EMC, 3IMSG (NCEP/EMC), 4PSU, 5NOAA/AOML/HRD
Jorgensen et al., 1983, J. Climate Appl. Meteor, 22, 744-757
200 km
P-3 regular
400 km
P-3 weak stormP-3 weak storm
global forecast environment
first guess
126 hr forecast
HWRF 6 hr forecast
HWRF vortex initialization
HWRF modified vortex
Relocation, size correction, intensity
correction, adjust mass fields
GDAS forecast analysis
GSI
Data assimilation
observation
Global hybrid EnKF-3DVAR ensemble forecast member 1
global forecast vortex
HWRF environment
Data thinning, quality control
Iterative minimization
Global hybrid EnKF-3DVAR ensemble forecast member 2
Global hybrid EnKF-3DVAR ensemble forecast member N
HWRF Initialization
TC initialization with TDR data assimilation• HWRF model * Non-hydrostatic coupled atmosphere-ocean model, WRF-NMM dynamic core,
rotated E-grid, two way interactive nesting
* Resolution: Parent (Outer) domain 0.18˚ (27 km), inner domain 0.06˚ (9 km), 42 vertical levels
• Data assimilated * Quality controlled tail Doppler radar radial velocity data within [-3 hr, 3 hr] are
assimilated
* Rawinsonde, pibal, class sounding, profiler, dropsonde, AIRCFT, AIRCAR, GPSIPW, surface data (marine/land/splash-level/mesonet), satellite wind
* satellite radiance data: HIRS, AMSU-A, AMSU-B, MHS, sounding
• GSI * Analysis variables: streamfunction, unbalanced part of velocity potential,
unbalanced part of temperature, unbalanced part of surface pressure, normalized relative humidity, satellite bias correction coefficients
* flow-dependent anisotropic background error covariance [Riishøjgaard (1998), Purser 2003b, 2005].
* Background error statistics are estimated in grid space with the NMC method (3DVAR).
* Hybrid DA option
Four HWRF domains (Fig 4.1 of HWRF USERS’ GUIDE)
http://www.dtcenter.org/HurrWRF/users/docs/users_guide/HWRF_V3.3a_UG.pdf
conventional obs ps, t, q, uv, TDR vr
ghost domain
Satellite radiance obs
2011.08.24 00 UTC
outer domain ghost domain
experiment TDRP TDRA TDRB TDRC NTDR
Assimiate TDR Vr data
yes yes yes yes no
background Full HWRF vortex
initialization
Relocate vortex only
Full HWRF vortex
initialization
Relocate vortex only
Full HWRF vortex
initialization
GSIFGAT
no yes no yes no
Post balance
yes yes no no no
2011 TDR DA Real Time Parallel
Real time 3DVAR TDR DA experiments
Real time 3DVAR TDR DA experiments
Hybrid Ensemble-3DVAR System for HWRF
• Current hybrid ensemble-3DAV system is one way coupled system
• Ensemble perturbations come from global EnKF-3DVAR system ensemble forecast interpolated to HWRF analysis domains
• Ensemble covariance is incorporated as part of the background error covariance though extended control variable method (Lorenc 2003; Buehner 2005; Wang et al. 2007)
• May not help much with vortex initialization, hopefully can improve storm environment
Pseudo-ensemble hybrid for HWRF • Poterjoy and Zhang (2011): Wavenumber 0 storm structures have the largest influence on forecast uncertainty for TCs with category 1 or higher intensity.
• Back ground error covariance is dominated by wavenumber 0 component.
• Flow-dependent forecast covariance can be approximated from a sample of near-axisymmetric TC vortices
• TC vortices are created by running idealized 3 km resolution HWRF simulations and grouped by intensity (Xuyang Ge)
• TC library vortices are mapped to the background vortex region (300 km from background TC center) in ghost domain and perturbations are calculated
• Replace global ensemble perturbations with TC vortex library perturbations within 150 km from background TC center
• TC library perturbations are gradually blended with global ensemble perturbations from 150 km to 300 km from background TC center
Analysis increment from single obs testu obs at 0.5 degree north of storm center at 850 level
PEDA
HYBB
PEDA – hybrid DA with pseudo-ensemble HYBB – hybrid DA with pure global ensembleWeight given to ensemble B is 0.8
Analysis increment from single obs testu obs at 0.5 degree north of storm center at 850 level
PEDA – hybrid DA with pseudo-ensemble HYBB – hybrid DA with pure global ensemble
PEDA
HYBB
PEDA
PEDA
HYBB
HYBB
analysis
PEDA
PEDA
HYBB
HYBB
12 hour forecast
First TDR DA cycle of Hurricane Earl
Hybrid TDR test with Hurricane EARL
Hybrid TDR test with Hurricane EARL
Hybrid TDR test with Hurricane EARL
Issues and Discussion
• Over/under estimate storm intensity
* poor background
* DA configuration
• Short term forecast spin up/down * Mass-wind balance
* storm structure
• May need more comprehensive verifications
Plans Model: move on to higher resolution (27km-9km-3km) HWRF.
Assimilation method * Intensive hybrid (1 way coupled) test will be done using ensemble data from the new global EnKF-3DVAR hybrid parallel (prd12q3k).
* Further investigate the performance of PEDA. Improve TC library, e.g. including the size variability.
* Move on to 2 way coupled hybrid system by collaborating with Jeff Whitaker and AOML/HRD
* Analyze cloud variables
DATA * Investigate the impact of assimilating ground based radar data.
* The impact of satellite radiance data in regional model * Cloudy radiance data