1 Automated Snow Sensor Experiment Overview In 2003, Nolan Doesken (Colorado State Climatologist) was granted funding from Headquarters, to perform testing of snow sensors. Also in 2003, the Grand Rapids Weather Forecast Office and a few other NWS field offices purchased automated snow sensors, due to the need for improvement of snowfall readings. In 2004, a partnership developed between NWS field offices and Colorado State University, with respect to an increase in the number of offices performing testing. NATIONAL WEATHER SERVICE WFO GRAND RAPIDS MI

2 National Test Sites…

3 1)Two snow fences surround the sensor: -first fence is 10' radius from sensor -second fence is 20' radius from sensor 2) Digital sensor output brought into a Linux Box 3)Depth and Temperature readings are parsed and stored in a MYSQL database every 5-minutes using an algorithm to minimize outliers 4) HTML PHP pages have been written to query database and allow visual access to data or graphical output NATIONAL WEATHER SERVICE WFO GRAND RAPIDS MI Inner Ring 10' from sensor Outer Ring 20' from sensor Automated Snow Sensor Experiment

4 Ultrasonic Depth Sensor with temperature probe An integrated temperature probe with solar radiation shield, provides an air temperature measurement for properly compensating the distance measured. An embedded microcontroller calculates a temperature compensated distance and performs an error checking routine. The Judd Communications ultrasonic depth sensor is an inexpensive solution for remotely measuring snow depth. The sensor works by measuring the time required for an ultrasonic pulse to travel to and from a target surface.

5 Side View of Sensor…

6 - Use in storm verification - Provides snowfall data in remote locations - Provides snowfall data around the clock (24-hrs) - Allows for the analysis of melting and compaction rates - Provides snowfall rates for Short Term Forecasting (NOW’s) - Provides enhanced service to customers Benefits of automated Snow Sensor...

7 Example of a 7-day graphical output Freezing Line

8 January 7, 2004 event... Looking north from east side...Looking north from west side... Soil temperature sensor Frost depth gauge Snow Sensor

9 Automated Snow Sensor Data... January 7, 2004 Time (UTC) – Date Temp (°C) Temp (°F) Depth (Inch) False Reports 12: /07/ : /07/ : /07/ : /07/ : /07/ : /07/ : /07/ : /07/ : /07/ ?

10 January 28, 2004 Blizzard Event… Looking north from east side...Looking north from west side... Uniform distribution of snow inside inner circle...

11 Automated Snow Sensor Data... January , 2004 Light snow collapsing... Time (UTC) – Date Temp (°C) Temp (°F) Depth (Inch) 23: /27/ : /27/ : /27/ : /27/ : /27/ : /27/ : /27/ : /27/

12 Internal Software Capabilities Forecaster User Interface

13 Internal Software Capabilities This manual snowfall report form is merged with the snow sensor database to allow direct comparison between manual and automated sensor readings. Manual snow observation entry

14 Internal Software Capabilities Archive Retrieval GUI

15 Internal Software Capabilities Archived Database

16 Future Enhancements... 1) Improve algorithms to handle false reports and snow collapses during events 2) Introduce additional snow sensors to enhance sensitivity : -Lake Effect Snow -Low Water Equivalent Snow 3) Increase outer fence for drifting pattern : -this would decrease likelihood of turbulent eddies in atmosphere over snow sensor 4) Introduce Wind Sensors to study eddy patterns over wind fence

17 Automated Snow Sensor Experiment For additional information check out our website at : or contact: David Beachler MIT WFO GRR