A short demo …. VejVejr is an internetbased surveillance and forecasting system, developed by DMI and Vejdirektoratet. VejVejr provides any tools needed.

a short demo ….

VejVejr is an internetbased surveillance and forecasting system, developed by DMI and Vejdirektoratet.

VejVejr provides any tools needed to secure proper decisionmaking with regards to preventing slippery roads.

Contacts:

Pernille Arnsfelt Hansen DMI – pah@dmi.dk

Søren Brodersen DMI – sb@dmi.dk

Slippery roads when: • Road-temperature < 0• Rime - dewpoint is higher than road-temperature• Ice – moisty or wet roads• Precipitation

We need to know:

• Road-temperature – actual and forecasted• Humidity – dewpoint• Precipitation• Cloudcover• Road condition – wet, moisty, salinity, freezingpoint etc.

Actual time or historic mode

Road T > + 2

Road T < + 2 but above 0

Road T < 0

Road T < 0 and dewpoint higher(riming)

Worst status next 5 hours

Choose your local area…

Forecasts for each roadweatherstation

doubleclick!

Alarm status

Observations

T 2m

Road T

dewpoint

Forecast

Road T < 0 from 02.50 hoursDewpoint is higher – this means riming (hoar frost)

Road resistance – how wet is the road ?

Dry

Moist

Wet

Salty

Forecast of precipitation – time/type/intensityForecast of cloudcoverForecast of wind – direction/speed

To 24 hour forecast

24 hour forecast

Forecasted precipitation:SnowSnow and rain mixedRain

Area-forecast

Comments from meteorologist

Online radar data – 10 min intervals

Precipitationtype and intensity:RainRain and snow mixedSnow (or freezing rain)

Animation

Online satellitedata from MSG2 – 15 min interval

Cloudtype color-code:Dense clouds – Weak radiation, weak road-cooling.Scattered clouds – Periodic radiation, some road cooling.Cirrus – Thin clouds, some radiation, some road cooling.

Animation

Allows you to follow changes in cloudcover – to spot areas with either clear weather (and cooling/radiation) as well as clouds that provide little or no heat-insulation.

Help - explanation

Online help to all screen-images

Online Web-cams

Regional text-forecast

7 days text-forecast

Observations from roadweatherstations - graphics

Roadtemperature

Roadcondition

Precipitation

Salinity

Freezingpoint

Roadweather observations for your chosen area - text

Observations from specific roadweatherstation - text

Animation - your own choise of observed parameters

This function allows you to follow any weather development, for instance roads cooling or precipitation spreading.

All observations can be animated and color-coded as you like it…

Graphics – your own choise of visualisation

Wind forecast (for bridges mainly)

How does it work …?

INPUT: •Observations, from roadweatherstation.

•Meteorological stations

•Satellite data (clouds)

•Atmosphere condition from HIRLAM weather model.

…compute

OUTPUT:

Future road condition.

Numeric ROAD Numeric ROAD CONDITION modelCONDITION model

Model area and road weather station network

Exclusive forecast available for each road-station.

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Prognoselænge

Cel

siu

s

Verification 2006-2007 :

Mean ABSOLUTE error. Mean ABSOLUTE error.

0

10

20

30

40

50

60

70

80

90

100

< 1 1 - 2 > 2

Celsius

%

2005 / 2006

2006 / 2007

(Situations with road temperature between -3 and +3)

Distribution of the 3-Distribution of the 3-hour forecast error.hour forecast error.

Error in degrees Celcius

Thank you for your attention.Thank you for your attention.

If you have questions or things you would like further explained, please contact us anytime.

Pernille Arnsfelt Hansen, meteorologist, pah@dmi.dk

Søren Brodersen, senior meteorologist, sb@dmi.dk