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Title, Author, Date, Page 1
WRF for winter roads
Hugo Hartmann, Jelle Wisse, Daniël van Dijke
Presentation 7B.5 – 14th Annual WRF User’s Workshop, 24-28 June 2013
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Winter roads…
Page 2
Winter is beautiful...but that is not the topic of this presentation…
Winter is also very dangerous for public safety!
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• A weather forecasting service of MeteoGroup
RoadCast
Page 3
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• MeteoGroup‘s RoadCast
• WRF case definition
• Results
• Conclusions & Outlook
Outline
Page 4
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Weather forecast…
RoadCast
Page 5
Route based forecast
Local measurements
Database with for all routes: sky and solar view factor
RoadCast core
“Land-surface model”
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Forecast of road surface temperature
Ede
Otterlo
Arnhem
RoadCast sensitivity to temperature variations
Page 6
• Observed temperature variations are more extreme (land-use, topography)
EXPENSIVE! WRF??
17 Feb 2011(clear-sky night)
Observed road surface temperature
Ede
Otterlo
Arnhem
• Solution: use measured air temperature profile as input to the model (thermal map)
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Weather forecast…
RoadCast
Page 7
Route based forecast
Thermal map, TT measurement / simulation
Local measurements
Database with for all routes: sky and solar view factor
RoadCast core
“Land-surface model”
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• Project aim: Investigate whether WRF is able to simulate realistic local air temperature variations during clear and calm nights
• Domain of interest:
Wales, complex terrain
WRF case definition
Page 8
valley
valleyridgeridge
0 km10 km
16 km 22 km
28 km
35 km
Google Earth
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Synoptic situations (clear-sky)
WRF case definition
Page 9
March 26-27, 2012
CASE ‘EAST’ – EASTERLY WIND
March 28-29, 2012
CASE ‘NORTH’ – NORTHERLY WIND
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WRF 3.3.1 (7.5 km – 1.5 km – 0.5 km)• ECMWF 00z input (0.125° 15 km)• One-way nested• Simulation time: 2 days (1 day spin-up)• 39 eta levels (first level 10 m)• 148 x 148 gridpoints (0.5 km)
WRF case definition
Page 10
7.5 km
1.5 km
0.5 km
Google EarthWRF 7.5 kmWRF 1.5 kmWRF 0.5 km
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0 10 m/s
0 20°C0 20°C
Results (0.5 km) – 15 UTC
Page 11
NEAST NORTH
0 10 m/s
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0 20°C0 20°C
0 10 m/s
Results (0.5 km) – 5 UTC
Page 13Page 13
NEAST NORTH
0 10 m/s
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Results – 5 UTC
EAST NORTH
Page 14
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Results – Ridge
EAST NORTH
Page 15
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Results – Valley
EAST NORTH
Page 16
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• More cases needed– Thermal map strongly depends on wind speed/direction, stability
atmosphere)
• 1.5 km / 0.5 km comparable results, but steep peaks/valleys still not resolved satisfactory– Explore potential of improved wind parameterization scheme (Jimenez
and Dudhia, 2011)
• Explore other PBL schemes
• Nearest neighbour procedure not the best option for generating the thermal map– develop alternative methodology(ies) for representative gridpoints
Conclusions & Outlook
Page 17
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Thank you
Title, Author, Date, Page 18