Jian-Wen Bao (ESRL/PSD)

S. G. Gopalakrishnan (AOML/HRD)

Sara A. Michelson (ESRL/PSD)

NOAA/OAR

in collaboration with Frank Marks of AMOL/HRD,

and Vijay Tallapragada of NCEP/EMC

Sensitivity of the WRF-NMM Model to Physics Parameterizations at Various Vertical and

Horizontal Resolutions

Presented atThe 64th Interdepartmental Hurricane Conference

Savannah, GA, 1-4 March 2010

Outline

1. Motivation and methodology

2. Model initialization and physics options tested so far

3. Highlighted results

4. Summary

Motivation

Methodology

• To explore the flexibility of running HWRF with various physics options in the WRF-NMM modeling framework.

• To benchmark the response of the WRF-NMM dynamic core to various permutations of physics options.

• Idealized case setup to complement real-event investigation

• Evaluation with observation composites and theoretical understanding

Model Initialization

• f plane located at 12.5ºN

• A prescribed axisymmetric vortex:

— maximum sfc tangential wind: 15 m/s

— radius of sfc maximum wind: 90 km

• Quiescent environment thermally corresponding to the Jordan sounding with a constant sea surface temperature of 29ºC

• Initial mass and wind fields derived by solving the nonlinear balance equation for the prescribed vortex (Wang 1995, MWR)

Physics Options Tested So Far

SL/ABL Physics Options

MYJ (NMM Default) GFS (HWRF Default)

Microphysics Options

Option # = 4, WSM 5-class scheme= 5, Ferrier (new Eta) = 6, WSM 6-class graupel scheme

= 8, Thompson scheme

Subgrid Convection Options

SAS (HWRF default)BMJ (Betts-Miller, NMM default)

Radiation Options

Option # = 1, Dudhia SW and RRTM LWOption # = 99, GFDL SW and LW (NMM default)

EXPERIMENT#

Boundary Layer Scheme

Convective parameterization scheme

(D1/D2)

Radiation Scheme

Microphysics scheme

1 MYJ SAS/SAS 1 5

2 GFS SAS/SAS 1 5

3 GFS SAS/SAS 99 5

4 GFS SAS/SAS 99 4

5 GFS SAS/SAS 99 6

6 GFS SAS/SAS 99 8

7 GFS SAS/None 99 5

8 MYJ BMJ/BMJ 1 5

9 GFS BMJ/BMJ 99 5

Physics Permutations

Model grid spacing:dx = 0.06, 0.02 (~9 km, ~ 3 km)dy = 0.06, 0.02 (~9 km, ~ 3 km)kx = 43 (NMM sigma-p levels)

Boundary Layer

Scheme

Convective parameterization

scheme (9km/3km)

Radiation Scheme

Microphysics scheme

Black MYJ SAS/SAS 1 5

Red GFS SAS/SAS 1 5

Gray MYJ BMJ/BMJ 1 5

Yellow GFS BMJ/BMJ 99 5

Sensitivity to SL/ABL and Radiation

Max Surface Wind Speed Min Sea-Level Pressure

36-48 h

Boundary Layer

Scheme

Convective parameterizatio

n scheme (9km/3km)

Radiation Scheme

Microphysics scheme

Green GFS SAS/SAS 99 5

Blue GFS SAS/SAS 99 4

Magenta GFS SAS/SAS 99 6

Orange GFS SAS/SAS 99 8

Purple GFS SAS/None 99 5

Sensitivity to microphysics and Sub-Grid ConvectionMax Surface Wind Speed Min Sea-Level Pressure

36-48 h

Exp. 1 Exp. 2 Exp. 3

Exp. 4 Exp. 5 Exp. 6

Exp. 7 Exp. 8 Exp. 9

36-48 h average Color shades: vertical motion Contours: radial winds Arrows: circ. vectors

MYJ PBL

MYJ PBL

Exp. 1MYJ PBL

Exp. 2GFS PBL

z

wr

v

ru

tdt

dr

Color Shades: Tan. Acc. Averaged over hours 36-48Contours: Tangential windsArrows: Circulation vectors

vDfu

r

vup

rdt

dvr

r

+ 1

UST: 36 - 48 hour averageEXP

#Bound. Layer

Scheme

Convective parameteriz-ation scheme

(D1/D2)

Radia-tion

Scheme

Microphy-sics

scheme

Black (1) MYJ SAS/SAS 1 5

Red (2) GFS SAS/SAS 1 5

Green (3) GFS SAS/SAS 99 5

Blue (4) GFS SAS/SAS 99 4

Magenta (5)

GFS SAS/SAS 99 6

Orange (6)

GFS SAS/SAS 99 8

Purple (7)

GFS SAS/None 99 5

Gray (8) MYJ BM/BM 1 5

Yellow 9) GFS BM/BM 99 5

EXP#

Bound. Layer

Scheme

Convective parameteriza-tion scheme

(D1/D2)

Radia-tion

Scheme

Microphy-sics

scheme

Black (1) MYJ SAS/SAS 1 5

Red (2) GFS SAS/SAS 1 5

Green (3) GFS SAS/SAS 99 5

Blue (4) GFS SAS/SAS 99 4

Magenta (5)

GFS SAS/SAS 99 6

Orange (6)

GFS SAS/SAS 99 8

Purple (7)

GFS SAS/None 99 5

Gray (8) MYJ BM/BM 1 5

Yellow(9) GFS BM/BM 99 5

Sensible Heat Flux: 36-48 hour average

Latent Heat Flux: 36-48 hour averageEXP

#Bound. Layer

Scheme

Convective parameteriza-tion scheme

(D1/D2)

Radia-tion

Scheme

Microphy-sics

scheme

Black (1) MYJ SAS/SAS 1 5

Red (2) GFS SAS/SAS 1 5

Green (3) GFS SAS/SAS 99 5

Blue (4) GFS SAS/SAS 99 4

Magenta (5)

GFS SAS/SAS 99 6

Orange (6)

GFS SAS/SAS 99 8

Purple (7)

GFS SAS/None 99 5

Gray (8) MYJ BM/BM 1 5

Yellow(9) GFS BM/BM 99 5

Summary

(1)   It is useful to set up idealized benchmark cases for the evaluation and understanding of ongoing improvements of WRF-NMM/HWRF.

(2)  The intensification, as realized by the WRF-NMM model, is sensitive to both the SL/ABL physics options, the cloud physics options and the radiation options.

(3)   Different permutations of the SL/ABL and the cloud physics lead to various dynamical properties of the vortex in terms of du/dt and dv/dt .

(4)   Future work will be focused on using observational analysis and theoretical understanding to help determine an “improved”, operational physics configuration.