Transcript Operational Use of the Rapid Update Cycle

RUC Land Surface Model
implementation in WRF
Tanya Smirnova, WRFLSM Workshop, 18 June 2003
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Part 1: Current and Future
Initialization of WRF
Land States at FSL
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Goal for use of WRF in the Rapid Update
Cycle
• 2006 - Use WRF model in Rapid Update Cycle
(or Rapid Refresh) application at NCEP
• First step – test WRF model against current
RUC hydrostatic model using common RUC initial
conditions
WRFRUC – WRF initialized with RUC-20 initial
conditions, full-resolution native q/s coordinate
data, including 3-d hydrometeor, land-sfc data
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WRFRUC model configuration
• NCAR mass-coordinate dynamic core - v.1.2.1
• 35 vertical sigma-p levels
• Initial conditions including land states for WRFRUC
- native coordinate data from FSL RUC20 cycle
including assimilation of observations not yet used in
NCEP operational RUC20 – Coupled Data Assimilation
System (CDAS) – available for outside users from
the FSL ftp site in GRIB format
• Lateral boundary conditions from the same FSL
RUC20 48h forecast
• RUC post-processing adapted to WRF output to
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produce RUC look-alike GRIB output
RUC CDAS - four-dimensional system (funded by GAPP)
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•
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Uses a forward full-physics model
Cycles surface/soil fields depending on the RUC atmospheric
forcing
Cycles 5 hydrometor species : cloud, ice, rain, snow and
graupel. Cloud clearing/building based on GOES data
New compared to RUC operational –
1. Forecast length (48-hour forecasts with hourly outputs)
2. Assimilation of:
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•
•
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NEXRAD Radar reflectivity observations
GPS precipitable water
Boundary-layer profilers
Mesonet observations collected at FS
Main Goal: to improve 1-h precipitation forcing and the land
surface model climate
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RUC Control
Stage IV Rainfall
24-hour precipitation accumulation
ending at 1200 UTC 6 May 2003
RUC CDAS
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RUC Control
Spatial Correlation fields of 24-h
Accumulated Precipitation ending
at 1200 UTC 6 May 2003
RUC CDAS
(Dongsoo Kim)
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Diurnal cycle of biases from RUC control and RUC CDAS
averaged for the period 1 December – 1 March 2003
2-m dew point
Western US
2-m temperature
Western US
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Two WRFRUC systems run at FSL in
real time:
1. WRFRUC with 10-km horizontal resolution for
the TAQ (Temperature and Air Quality) project
- 48-hour forecasts twice a day (00 and 12
UTC, runs on JET since June 2002)
2. WRFRUC with 20-km horizontal resolution on
CONUS domain
- 24-hour forecasts twice a day (00 and 12
UTC, runs on JET since February 2003)
http://ruc.fsl.noaa.gov - real-time fields
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Physics options used in WRFRUC at FSL:
- NCEP 5-class microphysics scheme (option 4)
- RRTM longwave radiation (option 1)
- Dudhia shortwave radiation (option 1)
- Mellor-Yamada-Janjic Monin-Obukhov surface
layer (option 2)
- RUC land-surface model (option 3)
- Mellor-Yamada-Janjic TKE scheme (option 2)
- Kain-Fritsch (for CONUS) and Betts-Miller Janjic (for TAQ) cumulus parameterization
(option 1, 2) as of May 2003
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Schematic presentation of processes included into RUC-LSM
6 levels in soil – 0, 5, 20, 40, 160, 300 cm
State variables -
volumetric soil moisture, soil temperature, snow
cover/depth/temperature - cycled in RUC 1h cycle since 1997.
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WRFRUC initialization needed:
•
Changes to WRF SI (Brent Shaw) –
use of native RUC vertical coordinate rather than
isobaric levels to provide initial fields of
atmospheric variables including hydrometeors
(vapor, cloud, ice, rain, snow, graupel)
The most recent official release of WRF SI includes
all these changes
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REAL changes for WRFRUC initialization :
Changes to REAL (Dave Gill)
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accommodate for level structure in RUC soil domain
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pass through hydrometeor fields
Further changes needed to pass through from SI to
WRF model other land-surface related variables
such as:
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2 fields for snow temperature
snow density
water vapor mixing ratio at surface
liquid volumetric soil moisture and others
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WRFRUC LSM uses :
- soil and vegetation parameters, vegetation
fraction and albedo provided by WRF SI
- cycled soil temperature and moisture from RUC20
(RUC and WRFRUC use the same LSM, land-use and soil
classifications, and the same parameter tables)
- cycled snow depth and temperature from RUC20
- ice in soil is initialized in WRF
Atmospheric forcing is provided by WRF. Still need
from WRF modeling framework:
- precipitation type (solid versus liquid)
- option in surface driver for implicit solution of
energy and moisture budgets
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Vegetation types –
both provided by WRF SI
(24 USGS classes)
RUC20
Land-use parameters:
• roughness length
• emissivity
• plant coefficient
WRF10
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Soil types –
both provided by WRF SI
(16 classes)
RUC20
Soil parameters –
look-up table
WRF10
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Soil moisture analysis
Valid 0000 UTC
17 June 2003
RUC20
WRF10
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RUC10
Terrain
Elevation
(dm)
TAQ domain
RUC20
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Surface temperature
0000 UTC, 17 June 2003
RUC20
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Part 2: Evaluation of LSM
performance
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RUC LSM participated in:
 Project for the Intercomparison of Land-Surface
Parameterization Schemes (PILPS) - Phase 2d
 Snow Models Intercomparison Project (SNOWMIP) – Phase 1
RUC LSM is implemented in:
• Operational RUC20 at NCEP
• Real-time RUC20 at FSL (CDAS)
• MM5 chemistry package (Georg Grell) used for
- air quality predictions
- regional climate simulations (FSL, Germany, Israel)
• WRF model
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Improved 1-d (PILPS 2d – Valdai, Russia) total runoff and snow water
equivalent forecasts with improved snow and soil physics in MAPS landsurface model
Total runoff
November 1976 - May 1977
Skin temperature
Snow water equivalent
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Effects of frozen soil physics on the simulation of the melting
seasons, Valdai, Russia (1966-1983)
Dates when snow
ablation starts
Dates when snow pack
is all melted
(Smirnova et al., JGR (2000), 105, 4077-4086)
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SNOWMIP, an intercomparison of snow models: first results
P. Etchevers, E. Martin, R. Brown et al.
ISSW meeting, August 2002
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Cycled field of snow depth
from operational RUC20
at NCEP
Valid at 2100 UTC
8 January 2003
7 January 2003
NESDIS daily snow cover
8 January 2003
8 January 200325
RUC
12-h
forecast
WRF
Valid
1200 UTC
29 January
2003
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18-h forecast of surface temperature from RUC and WRF
against RUC-20 analysis
1800 UTC 29 January 2003
RUC-10
WRF-10
RUC-20
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Station verification
for TAQ project
Hartford, CT
9 June 2003
0000 UTC –
11 June 2003
0000 UTC
http://www.etl.noaa.gov/programs/2002/taq/verification
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Station verification
for TAQ project
Boston, MA
9 June 2003
0000 UTC –
11 June 2003
0000 UTC
http://www.etl.noaa.gov/programs/2002/taq/verification
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Station verification
for TAQ project
Worcester, MA
9 June 2003
0000 UTC –
11 June 2003
0000 UTC
http://www.etl.noaa.gov/programs/2002/taq/verification
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12-h surface forecasts verified vs. METAR obs
11 April – 11 June 2003
RUC-20 vs. WRFRUC-20 – all METARs in domain
Variable
Wind spd – s.d.
Wind spd bias
Temp –s.d.
Temp – bias-00z
Dewpoint – s.d.
Dewpoint – bias
RUC
2.0
0.1
2.7
0.6
3.4
-0.6
WRFRUC
2.8
0.9
2.7
-1.2
3.5
-3.2
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12-h winds
aloft forecasts
– verified
against
rawinsonde
RUC-20 vs.
WRFRUC-20
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WRFRUC-20
(KF cumulus)
21-h forecasts
RUC-20
(GrellDevenyi
cumulus)
Valid 2100 UTC
10 June 2003
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