the 63 rd interdepartmental hurricane conference st petersburg, florida, march 2-5, 2009
DESCRIPTION
Sensitivity of the HWRF model prediction for Hurricane Ophelia (2005) to the choice of the cloud and precipitation scheme Yuqing Wang and Qingqing Li International Pacific Research center University of Hawaii at Manoa , Honolulu, HI 96822. - PowerPoint PPT PresentationTRANSCRIPT
Sensitivity of the HWRF model prediction for Hurricane Ophelia (2005) to the choice
of the cloud and precipitation scheme
Yuqing Wang and Qingqing LiInternational Pacific Research center
University of Hawaii at Manoa, Honolulu, HI 96822
The 63rd Interdepartmental Hurricane ConferenceSt Petersburg, Florida, March 2-5, 2009
Acknowledgments: Naomi Surgi, Steve Lord, HWRF team as NCEP/EMC
• The storm size is generally too large (increase with time);
• Large storms are too strong while small storms are too weak;
• Storms are too energetic and hard to dissipate;• It performs best for storms in weak shear environment; • Problems in mid-upper level structure for storms in
vertical shear environment.
Some systematic biases of HWRF
Liu et al. 2008, originally from Biju Thomas
Objectives
• To identify the model physics that are critical to the structure and intensity changes in the HWRF model;
• To improve the representation of those model physics to achieve improved prediction of hurricane structure and intensity changes by HWRF model.
Working Hypothesis
• 3D distribution of diabatic heating due to phase changes is the key to both the structure and intensity of hurricanes;
• The vertical heating distribution in in eyewall determined the rate of intensity change, while horizontal heating distribution determines the storm size change;
• Realistic representation of 3D diabatic heating due to phase changes is the fundamental to any model to achieve improved prediction for hurricane structure and intensity!
Hurricane Structure and Intensity Change
Three-dimensional distribution ofInternal atmospheric heating
Grid-scale cloud microphysics
Subgrid-scale Cumulus convection
Vertical motionsPDF in grid scale and
updrafts in plumes
Nonlinear Feedbacks
Hydrometeors in updraft plumes
Initiation of clouds(Liquid/ice)
Nonlinear Feedbacks
How sensitive the simulated hurricane size is to heating in the outer spiral rainbands of the hurricane in the nonhydrostatic hurricane model TCM4
Cloud top brightness temperatures (in Celsius) from satellite observation for Hurricane Ophelia (2005) at 18 UTC 12 September 2005.
Model WRF-NMMExperiment name NKF KF NBM BMConvective parameterization
D1: Kain-Fritsch schemeD2: none
D1: Kain-Fritsch schemeD2: Kain-Fritsch scheme
D1: Betts-Miller-Janjic schemeD2: none
D1: Betts-Miller-Janjic schemeD2: Betts-Miller-Janjic scheme
Horizontal resolution
Mesh 1: 0.25° × 0.25° (108 × 180 × 38)Mesh 2: 0.0833° × 0.0833° (172 × 226 × 38)
PBL scheme Mellor-Yamada-Janjic TKE schemePrecipitation scheme
Ferrier microphysics scheme
Radiation Shortwave and longwave radiation schemes of GFDL
Land surface LOAH land surface model
Lateral boundary and initial data
FNL Data
Initial time 00 UTC 09 Sept. 2005Integration 96 hours
Numerical model settings and experimental design
The model domain used in all experiments. The outer domain D1 is 0.25o resolution and the inner domain D2 is 0.08333o resolution
(a) (c)
(b) (d)
Observed (black) and simulated (red) tracks of Hurricane Ophelia (2005) in experiments (a) NKF, (b) KF, (c) NBM, and (d) BM, respectively, with marks at 6-h intervals.
Time (h)
Min
imum
sea
leve
lpre
ssur
e(h
Pa)
Max
imum
susta
ined
win
d(m
/s)
0 12 24 36 48 60 72 84 96955960965970975980985990995100010051010
15
20
25
30
35
40
45
50
Observed minimum sea level pressureObserved maximum sustained windModeled minimum sea level pressureModeled maximum sustained wind
NKFa
Time (h)
Min
imum
sea
leve
lpre
ssur
e(h
Pa)
Max
imum
susta
ined
win
d(m
/s)
0 12 24 36 48 60 72 84 96955960965970975980985990995100010051010
15
20
25
30
35
40
45
50
Observed minimum sea level pressureObserved maximum sustained windModeled minimum sea level pressureModeled maximum sustained wind
NBMc
Hour (h)
Min
imum
sea
leve
lpre
ssur
e(h
Pa)
Max
imum
susta
ined
win
d(m
/s)
0 12 24 36 48 60 72 84 96955960965970975980985990995100010051010
15
20
25
30
35
40
45
50
Observed minimum sea level pressureObserved maximum sustained windModeled minimum sea level pressureModeled maximum sustained wind
KFb
Time (h)
Min
imum
sea
leve
lpre
ssur
e(h
Pa)
Max
imum
susta
ined
win
d(m
/s)
0 12 24 36 48 60 72 84 96955960965970975980985990995100010051010
15
20
25
30
35
40
45
50
Observed minimum sea level pressureObserved maximum sustained windModeled minimum sea level pressureModeled maximum sustained wind
BMd
96-h evolution in the maximum 10-m wind speed (dashed in m s-1) and the central sea level pressure (solid in hPa) of Hurricane Ophelia (2005) from observation (red) and simulations (blue); (a) NKF, (b) KF, (c) NBM, and (d) BM.
Cloud top brightness temperatures (Celsius) simulated in experiments (a) NKF, (b) KF, (c) NBM, and (d) BM at 18 UTC 12 September 2005.
NKF NBM
BMKF
CAPE simulated in experiments (a) NKF, (b) KF, (c) NBM, and (d) BM at 18 UTC 12 September 2005.
Proposed Work• Fast and slow cloud microphysics processes should not be
equally weighted and the sedimentation of cloud ice should not be neglected. – Both would make the cloud microphysics scheme less time-
step/resolution dependent and producing more realistic 3D distribution of diabatic heating due to phase changes.
• The growth and nucleation of liquid and ice clouds depends strongly on grid-scale vertical motion and subgrid-scale turbulence, critical to horizontal extent of diabatic heating. – To take into account the subgrid-scale super-saturation in both
stratiform and convective parameterization schemes is critical to realistic simulation of cloud structure and heating due to phase changes.