The Canadian Airport Nowcasting Project (CAN-Now): Vision for future

and preliminary results

George A. Isaac1 and Faisal S. Boudala1

Monika Bailey1, Brian Clark1, Stewart Cober1,, Norman Donaldson1, Norbert Driedger1, Sylvie Gravel1, Ismail Gultepe1,

David Hudak1, Paul Joe1, Stephen Kerr2, Alister Ling3, Janti Reid1, Gilles Simard2and Zlatko Vukovic1

1Science and Technology Branch, Environment Canada, Toronto, Ontario, M3H 5T4, Canada

2 Canadian Meteorological Aviation Centre East, Montreal, Quebec, Canada3 Canadian Meteorological Aviation Centre West, Edmonton, Alberta, Canada

Acknowledgements

Funds from • Transport Canada • Search and Rescue New Initiatives Fund • NAV CANADA• Environment Canada

Also operations and research colleagues in Montreal

Theoretical Limit

NWP Models

Nowcasting

From Golding (1998) Meteorol. Appl., 5, 1-16

The main idea behind Nowcasting is that extrapolation of observations, by simple or sophisticated means, shows better skill than numerical forecast models in the short term. For precipitation, Nowcasting techniques are usually better for 6 hours or more.

Nowcasting/Forecasting High Impact Weather at a HUB Airport

Canadian Airport Nowcasting (CAN-Now)

• To improve short term forecasts (0-6 hour) or Nowcasts of airport severe weather.

• Develop a forecast system which will include routinely gathered information (radar, satellite, surface based data, pilot reports), numerical weather prediction model outputs, and a limited suite of specialized sensors placed at the airport.

• Forecast/Nowcast products will be issued with 1-15 min resolution for most variables.

• Test this system, and its associated information delivery system, within an operational airport environment (e.g. Toronto International Airport - Pearson).

Variables for Airport System

• Snow and rain events• Freezing precipitation and ice pellets• Frost• Blowing snow• Icing aloft• High winds/gusts• Wind shifts/shear• Turbulence• Lightning• Low ceilings• Low visibility and fog• Convective cells

Main equipment at Pearson at the old Test and Evaluation site near the existing Met compound

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•21 instrument bases with power and data feeds.•10m apart; rows 15m apart

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GTAAanemometer

NAV Canada anemometer

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MeteorologicalObservation Building

1. FD12P Viz meter2. Stevenson screen (humidity,

dew point, temperature)3. Old Viz meter# Power distribution box4. Old Viz meter5. Spinning arm, liquid/total

water content probe6. Radiometer7. POSS8. Rosemount icing detector9. Belfort precip gauge,

ultrasonic snow depth10. Hotplate (Yankee)11-13 Empty14. Tower, 2D wind sensor15. Ceilometer16. Empty17. Hotplate (Yankee)18. Geonor precip gauge19, 20 Empty21. Tower, wind speed/ direction, temp, humidity, pressure

Main Site: Instruments

Web Site

• A Web site has been created at: http://www.canadian-airport-nowcasting.org/

• The data on this site is accessible only with a user name and password. The site is currently active.

Click on airport to get products, including TAFS and current weather, as well as specialized products.

Interaction with Users

• Terminal Weather Forecast Working Group (includes NAV CANADA, EC, airline dispatch, GTAA, etc)

• GTAA, Vancouver Airport Authority

• CMAC Workshops

• NAV CANADA

• Transport Canada

Indicators of category level, airport capacity, airport arrival rates, etc

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Prototype Display for CAN-Now

Click for larger map

Prototype Display Contains• Bar chart at 15 min resolution for first two hours, then one

hour resolution for next 4-5 h.• Bar changes colour to attention (yellow) to red (alert) status.

Remains green if everything OK. Bars main contain some text (e.g. T, RH, Visibility, Ceiling, Precipitation Type, etc).

• If chart changes colour, you can click and obtain more information as to why. Either graphs or text from forecaster.

• Display will have configurable radar, satellite or map type display depending on weather situation.

• It will contain recent METARS and TAFS.• A text message from the forecaster outlining significant

features will be included and updated as required.• Besides significant weather variables, the ability to include

AAR, Runway Friction, etc, will be considered. • An area chart showing all the YYZ alternates will be prepared.

The airports will be colour coded to indicate all OK (green), possible problems (yellow) and red (below limits).

Algorithm Development• Visibility/Fog (Gultepe and others)• Ceiling • Blowing Snow (PIEKTUKD, Li & Pomeroy 1997)• Turbulence (TKE, EDR, momentum flux, CAT)• Winds/Gusts/Shear (Goyette et al. and Brassur )• Icing• Precipitation Type (BOURGOUIN (1992) )• Precipitation Intensity• Lightning/Convective Storm• Real Time Verification

YYZ Feb 6, 2008 VISIBILITY and CEILING

YYZ Oct 07-2007 FOG and RAIN

Questions?

YVR Fog Event: Nov. 18-24, 2005