Title: WRF/LSM Implementation and Verification Fei Chen, Mukul Tewari, and Wei Wang (NCAR) John Smart (NOAA/FSL) Collaborators: Ken Mitchell, Mike Ek (NCEP), George Gayno, Jerry Wegiel (AFWA), JinWon Kim (UCLA), QingYun Duan (OH) Sponsored by AFWA and NSF
1WRF/LSM Implementation and Verification Fei
Chen, Mukul Tewari, and Wei Wang (NCAR)John
Smart (NOAA/FSL)Collaborators Ken Mitchell,
Mike Ek (NCEP), George Gayno, Jerry Wegiel
(AFWA), JinWon Kim (UCLA), QingYun Duan
(OH)Sponsored by AFWA and NSF
- Current Status of WRF/LSM implementation
- Verification Framework
- Issues and Future work
2Unique and complex aspects of implementation of
land surface models in WRF
- Selection of land surface models (NOAH/OSU LSM,
CLM, RUC LSM, ) - Background surface fields (landuse, soil texture)
- Initialization of soil state (soil moisture,
sea-ice) - Initialization of vegetation state (fractional
coverage, leaf area index, albedo) - Requirements from other physics routine
- Coupling strategy and verification
- Need coordination among several working groups
3Tasks Completed
- Introduce background fields (SI) 1) 30-second
global USGS 24-category landuse map 2) 30-second
global hybrid (30-sec for CONUS and 5-min
elsewhere) top and bottom soil texture 3) 1-deg
annual mean air temperature as lower boundary
temperature 4) NESDIS 0.144-deg monthly 5-year
climatology green vegetation fraction 5)NESDIS
0.144-deg monthly 5-year climatology albedo - Initialize soil moisture, temperature, snow, and
sea-ice from AVN and Eta (SI, mass and height
version) - Implementation of OSULSM (Physics, WRF release
1.2 Beta) - Inclusion of OSULSM for idealized WRF cases (now
available for mass version)
4Work in Progress
- Implement the FSL LSM (by Tanay Smirnova, FSL)
- Implement the Common Land Surface Model (by
XinZhong Liang, U. Illinois) - Pre-release of the unified NOAH/OSU LSM (UNO?) by
NCEP in Feb. 2002 for internal test at NCEP,
NCAR, AFWA, and UCLA - A new version of the unified LSM is expected to
be released soon
5Work in Progress (Con.)
- Upgrade the unified NOAH/OSULSM to F90 (the
current WRF/OSULSM coupler is in F90) - Include a four-layer sea-ice model
- Introduce a few new variables ( total and liquid
soil water content, fractional snow coverage) - A few changes in the interface
- Expect to implement the unified LSM by September
2002
6LSMs verification framework
- Idealized case (completed)
- theoretical partition of net radiation into
latent, sensible, and ground heat fluxes, phase
of soil temperature, etc. - land-surface/atmospheric interactions (e.g.,
simple 2-D simulations of sea-breeze like
circulations) - Document and provide data for LSMs test
- Uncoupled test (long-term PILPS type data)
- Coupled test (LSM and PBL classic cases
- Select cases (CASES97 and IHOP02)
- model set up provide initial soil and veg
conditions, complete verification data - Long-term statistics from real-time and
retrospective tests - Get this in standard WRF verification data set
7An example CASES97 verification
- Three golden cases
- 29 April homogeneously dry soil, heterogeneous
landuse (green Winter Wheat vs dormant grass) in
the Walnut watershed, KS,70x74 km2 - 10 May heterogeneous soil, both WW and grass
green - 20 May homogeneously wet soil, green WW and
grass - CASES97 Data
- 9 surface stations (near surface weather, surface
heat and radiation fluxes) located over different
landuse - enhanced sounding at 3 sites every 90 minute,
Beaumont site grass Oxford and White Water
sites wheat - Aircraft sounding and heat fluxes along flight
legs - WRF 10km, 244x214x35, MRF PBL, OSULSM, Dudhia
shortwave, RRTM longwave, new Kain-Fritcsh
cumulus, initialized by EDAS 40-km output
800Z 29 Apr 00Z 30 Apr 1997averaged over 4
grass sites red model, green obs
Longwave downward
shortwave downward
?
Sensible heat
Latent heat
9Profile of Potential T from 1000-600 mb 30 April
1997 at Beaumont (grass) model oobs
1530Z
0030Z
2030Z
1835Z
10Profile of Mixing Ratio from 1000-600 mb 30
April 1997 at Beaumont (grass)
1530Z
0030Z
2030Z
1835Z
1100Z 29 Apr 00Z 30 Apr 1997averaged over 3
wheat sites
12Profile of Potential T from 1000-600 mb 30 April
1997 at Oxford (wheat)
1530Z
0030Z
2030Z
1835Z
13Profile of Mixing Ratio from 1000-600 mb 30
April 1997 at Oxford (wheat)
1530Z
0030Z
2030Z
1835Z
14IHOP02 Case 12Z 15 12 Z 16 June 2002
Stage IV Radargauge
WRF
IHOP NCAR Surface stations
15Obs 18Z 48 hour WRF 12Z, 36 hour
St. 3
Green sfc pressure (mb) Purple mxing ratio
(g/kg) Red rain rate (mm/hr)
St. 2
St. 1
16Central leg 3 stations southwest to Wichita
St. 4
Green sfc pressure (mb) Purple mxing ratio
(g/kg) Red rain rate (mm/hr)
St. 5
St. 6
17Eastern Leg 2 Stations southeast to Wichita
Green sfc pressure (mb) Purple mxing ratio
(g/kg) Red rain rate (mm/hr)
St. 7
St. 8
18Initialization of Soil State
- Ultimate solution combine LSM, data assimilation
techniques, and remote sensing data - AFWA AGRMET System
- Use observed rainfall, solar radiation, and
analyzed wind, T, and Q - Same background field as WRF
- Simulate long-term evolution of soil and
vegetation state at global scale (40 km, upgrade
to 20 km) - NCEP plans to unify the background fields in
NLDAS - High-Resolution Land Data Assimilation System
(HRLDAS) running at the same grid of WRF, using
HR analysis of surface weather variables,
landuse, etc.
194-month (1998) HRLDAS soil moisture vs Oklahoma
Mesonet observation
5-cm
25-cm
20Summary and Future work
- Good news
- Tight surface-PBL link valuable for verifying and
adjusting LSM and PBL schemes - When underlying surface conditions are correctly
specified, the temperature profile is well
simulated - Temporal and spatial distribution of WRF
rainfall, surface pressure, low-level T and Q are
reasonable (compared to 8 stations for two IHOP02
cases) - Not so good news
- The mixing layer structure for moisture is not
well captured (MRF seems too efficient) - Cannot take everything off the shelf for case
study (soil condition, vegetation condition,
etc.) - Urgent need for WRF realtime runs
- Use AGRMET, or NLDAS, or HRLDAS to initialize
soil state - Use weekly quasi-realtime green vegetation
fraction
21Future work
- Complete LSM/PBL verification data sets
- SI tasks
- Initialize from ARGMET or EDAS or HRLDAS
- global fixed max albedo over deep snow, annual
minimum greenness, realtime weekly greenness,
surface slope index, annual maximum greenness,
frozen soil empirical derivation - Interface issues
- A LANDRIVER separated from current PBLDRIVER to
treat land and inland water body (lake) possibly
on different grid configuration - Albedo and roughness length need to pass into
radiation and PBL schemes - Need precipitation type, convective and
non-convective rainfall rate
22Future Plan
- Real data tests (case studies, Using IHOP data,
etc.) - NCAR, NCEP, AFWA work on unified NOAH/OSU LSM
- Release of WRF/Unified LSM by August 2002
23Combining two NCEP rainfall analysis Utilizing
0.25 gauge-only daily rainfall as primary product
and use hourly Stage IV rainfall to partition the
former into hourly timestep as input to LSM
24-hr rainfall accumulated from 4-km hourly
NCEP Stage IV product
0.25 degree NCEP gauge-only daily rainfall
2424-h rainfall ending 12Z 20 June 1998
MM5 Control
Stage-II Obs
Eta Forecast
MM5 Wet soil
25 Surface layer (top 10 cm soil)
volumetric soil moisture 180
x 180 km2
Initial time From coarse resolution of Eta
field
46 days later Heterogeneity was developed in
the 3-km domain
26OSU LSM in the PSU/NCAR MM5 and WRF(Pan and
Mahrt, 1987 Ek and Mahrt, 1991 Chen and Dudhia,
2001)
Canopy Water Evaporation
Transpiration
Turbulent Heat Flux to/from Snowpack/Soil/Plant
Canopy
Precipitation
Condensation
on vegetation
Deposition/ Sublimation to/from snowpack
Direct Soil Evaporation
Evaporation from Open Water
on bare soil
Runoff
Snowmelt
D Z 10 cm
Soil Heat Flux
Soil Moisture Flux
D Z 30 cm
Internal Soil Moisture Flux
Internal Soil Heat Flux
D Z 60 cm
Interflow
D Z 100 cm
Gravitational Flow