MDSS Welcome Presentation Oct 05

1
Vehicles as Mobile Meteorological
Platforms Introductory Research
Clarus ICC Meeting 4 Falls Church, VA 9 August,
2006 Andrew Stern Consulting Meteorologist
(Mitretek Systems)
Road Weather Management
2
Ponder for a moment

• What if vehicles could be used as mobile weather
  observing platforms?
• How would thousands (if not millions) of new
  observations change the way that weather is
  analyzed in the lower atmosphere (PBL)?
• Are mobile observations from passenger vehicles
  of sufficient quality to be useful for the
  weather or other communities?

3
Mitretek Research Objectives

• Recognize potential benefits of VII extend beyond
  traffic
• Create foundational research on the use of
  vehicles as weather probes
• Begin a discussion about the quality of weather
  data from vehicles
• Provide an initial estimate of temperature bias
  from vehicle sensors during free flow conditions

4
Mobile Wireless Laboratory (MoWL)
MoWL Tours today during the PM break!
5
Sensor Placement MoWL
GPS Receiver
Control Products 999J Ambient IR
Temperature Sensor _at_ Front Bumper
OBD2 Intake Air Temperature (IAT)
Watchport USB Ambient Temperature Sensor _at_ Air
Intake
Watchport USB Ambient Temperature Sensor _at_ Front
Bumper
Watchport USB Ambient Temperature Sensor _at_ Rear
Bumper
6
Sensor Placement Crown Victorias
GPS Receiver
OBD2 Intake Air Temperature (IAT)
Watchport USB Ambient Temperature Sensor _at_ Air
Intake
Watchport USB Ambient Temperature Sensor _at_ Front
Bumper
Watchport USB Ambient Temperature Sensor _at_ Rear
Bumper
7
Test Domain Dulles Toll Road (DTR)
8
Data Collection Segments on the DTR
9
Single Point Data Samples
Fixed Observations IAD ASOS _at_ 1552 Air
Temp18.9C (66F) DTR Plaza ESS _at_ 160813
Air Temp 19.3 C (66.7 F) Road Temp 23.3
C (73.9 F)
Mobile Lab Date 02/16/06
Time 160826 Location 38 56 47.25N, 77
17 39.52W Speed 55 mph Ambient
Temperature - OBD2 (IAT) 70 F - Air
Intake 69.56 F - Rear Bumper 77.62 F -
Front Bumper 68.75 F - Front Bumper (999J
GT) 68.6 F Road Surface Temperature -
Front Bumper (999J) 68.8 F
Dulles Toll Road
Car 1 Date 02/16/06 Time
160826 Location 38 56 47.05N, 77 17
39.40W Speed 55 mph Ambient Temperature -
OBD2 (IAT) 68 F - Air Intake 69.12 F
- Rear Bumper 86.75 F - Front Bumper 68.62
F
Car 2 Date 02/16/06 Time
160826 Location 38 56 46.96N, 77 17
38.32W Speed 54 mph Ambient Temperature -
OBD2 (IAT) 70 F - Air Intake 69.31 F -
Rear Bumper 82.25 F - Front Bumper 69.18 F
10
Data Run History
11
Research Questions

• The balance of this presentation will focus on
  five questions that were formulated at the
  beginning of this project
• Data accuracy
• Temperature vs. vehicle speed
• Sensor placement
• Temperature profiles of like vehicles
• External weather effects

12
Q1 Data Accuracy

• Would mobile-sensed temperature data provide a
  set of observations that accurately represent the
  state of the atmosphere (e.g., free of
  contaminant heat from vehicles or radiated from
  the road surface)?

13
Q1 Data Accuracy
1.3 or less mean error (warm bias) compared
to in situ observations
999J In Situ Sensor
14
Q2 Temperature vs. Vehicle Speed

• How do mobile air temperatures vary under
  different travel speeds?

15
What Happens in Heavy Traffic?
Blue Car 12/22/06
Video Snapshot Time
16
Congestion Modifying Road Temps
Snap Shot
100F
90F
80F
17
Q3 Sensor Placement

• Does the position of air temperature sensors in
  the vehicle play an important part in obtaining
  representative ambient values?

18
Q3 Sensor Placement
19
Q4 Temp Profiles of Like Vehicles

• Do vehicles of like make, model and year have
  identical thermal profiles?

Light Blue
Silver
20
Q4 Temp Profiles of Like Vehicles

• Comparing data only when all sensors provided
  samples
• In every case, there was a significant difference
  between the readings on the silver and blue Crown
  Victoria cars

21
Q5 External Weather Effects

• Do external weather phenomena, such as strong
  winds, cloud cover or precipitation,
  significantly modify air temperature readings
  obtained from vehicles?

22
External Effects

• Winds
• Windy if Dulles ASOS wind speeds of gt10 kts or
  gusts gt15 kts
• Almost no change seen in front or rear bumpers
• Slight cooling in the engine compartment
• Cloud Cover
• Based on driver estimate of total sky cover
• Most sensors exhibited slight cooling with more
  clouds
• Magnitude of the bias was very small

23
Precipitation
24
Precipitation
25
Summary

• In free flow, mobile air temperatures only had a
  1 degree warm bias
• Vehicles of like year, make and model can have
  very different thermal profiles
• Traffic congestion can cause significant changes
  to both air and pavement temperatures
• External factors such as sun angle and
  precipitation can modify mobile air temperature
  readings

26
Challenges

• Are mobile observations feasible for weather?
• Can statistics be used to remove biases
  associated with
• individual vehicle thermal profiles?
• traffic/congestion?
• environmental factors (precipitation)?
• How do you aggregate the observations?
• individual points?
• average along a length of roadway?
• grid points?

27
Next Steps

• Collection of data during summer/high sun angle.
  Obtain information on
• Heat buildup on road surfaces and how that may
  translate to vehicles
• Heat dissipation rates in vehicles in free flow
  and congestion
• Effects of thunderstorms on air and pavement
  temperatures
• Data collection period 1 July- 15 Sept

28
Is a WDT needed?
29
Additional Information

• For questions on mobile weather research
• Andy Stern, Mitretek Systems
• astern_at_mitretek.org, 703-610-1754
• FHWA Road Weather Management
• Paul Pisano
• Paul.Pisano_at_dot.gov, 202-366-1301