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