HAFS Physics Priorities
Chunxi Zhang
1, Weiguo Wang
1, Zhan Zhang
2, Avichal
Mehra
2, Bin Liu
1, Jili Dong
1, Lin Zhu
1, Qingfu Liu
2,
Junghoon Shin
1, Hyun-Sook Kim
1, Ligia Bernardet
2, Man
Zhang
3, Dominikus Heinzeller
3, Grant Firl
4 1IMSG,
2NOAA,
3CIRES,
4NCAR
1
Physics Schemes Physics Schemes Physics Schemes
Path to A Successful Physics Suite
2
Testing
(track, intensity, size …)
Physics
Suites SchemesPhysics
Better understanding
Tuning & developing
A physics suite that is best for HAFS
(
either an existing suite with the modified schemes orCumulus (SH, DP, MID) (1-m, 2-m, 3-m)Microphysics Radiation (LW, SW) PBL (Stable, Unstable) Surface
(land, water, ice)
Cloud Detrainment Cloud Effects Surface Fluxes Convective Rain Non-Convective Rain Convective Cloud Fraction PBL Cloud Fraction Downward SW/LW Upward SW/LW OGWD NOGWD Closure Closure
Interactions among physics schemes
Selected Physics Suites in HAFS
4
GFSv15
(HAFS.v0A) GFSv16 GFSv17 HWRF RAP (HRRR)
Cumulus (CP) sa-SAS1 sa-SAS sa-SAS sa-SAS* sa-GF
Microphysics (MP) GFDL GFDL Thompson SWSA-FA Thompson
Radiation RRTMG RRTMG RRTMGp RRTMG* RRTMG
OGWD GFS GFS uGWPv1 GFS* (off v0A) modified-GFS
NOGWD off uGWPv0 uGWPv1 off off
LSM NOAH NOAH NOAH MP NOAH* RUC
Surface Layer GFS2 GFS GFS GFDL MYNN
PBL HEDMF3 sa-TKE-EDMF
(TEDMF) sa-TKE-EDMF(TEDMF) modified-HEDMF MYNN-EDMF
Known Issues for GFSv16 in GFS forecasts:
Increased right-of-track bias at longer lead times for North Atlantic TCs Larger TC False Alarm Rate in the western North Atlantic
Tendency to strengthen all TCs in the long range 1. HAFS.V0A turned CP off
2. HAFS.v0A used a modified GFS surface layer scheme
5
Selected Physics Schemes in HAFS
PBLName HEDMF TKE-EDMF YSU EEPS MYNN-EDMF
Done (Y/N/C) C Y Y N N
Results (+/-/M) -
-GWD
Name GFS GFS_PARA NO_GWD UGWP
Done (Y/N/C) C Y Y N
Results (+/-/M) +
-MP
Name GFDL Thompson SWSA-FA
Done (Y/N/C) C Y N
Results (+/-/M) ++
CP
Name NO_CP sa-SAS sa-GF sa-nTiedtke
Time period: Aug 30 – Oct 12, 2018
(9 storms)
7
Relative to the control run (HEDMF); positive is better
8
PBL
Relative to the control run (HEDMF)
9
10
11
GWD
Relative to the control run (GWD)
12
MP & CP
13
MP & CP
14
15
On the 34 kt Radii Bias
the Tracking Algorithm
16 I II III IV 500 km 1050 km Each quadrant
(start with the radius 500 km)
Calculate wind speed and distance to center for each grid
Sort all grid cells based on wind speed
Find the grid with the wind speed just
Total Condensate Advection Separate Water Species Advection
Stronger cells
HWRF
the FA MP scheme
Overshootings
Convective cells
Hurricane Florence
The E-epsilon (EEPS) PBL scheme
(Zhang et al. 2020, MWR)
A few iterations with
smaller time steps
are necessary for
numerical stability when
time step is very large
Kv is the vertical mixing coefficient with the subscript v substituted by m for momentum (Km)
h for heat and moisture (Kh)
Detering and Etling (1985) Langland and Liou (1996)
Duynkerke and Driedonks (1987)
21
Relative to the control run (HEDMF)
22
track intensity size
MP H H H PBL M H H CP H M H GWD1 M L L Surface Layer2 H H H Land1 L L L Radiation1 L L L
The potentials to further improve TC forecasts
High (
H
) – Medium (
M
) – Low (
L
)
1. We will follow the UFS weather model
Physics Priorities
The schemes that can improve the
track forecast
through the
improvement of large-scale circulation forecast and storm
structure.
The schemes that can improve the
intensity forecast
through the
improvement of air-sea interaction and better representation of
convective cells and clouds.
The schemes parameterize moist convection (
MP, PBL and CP
)
have high priorities.
The surface layer scheme coupled with the ocean and wave
models has high priority
The schemes have less room and will be improved in the UFS
weather model have low priorities (e.g., GWD, land surface and
radiation).
The “suite integration” is always considered!
Thanks!
