LCDR DesaRae Janszen Chief, Sector SF Waterways Management

Visibility Sensors
Briefing for San Francisco Harbor Safety Committee
Navigation and PORTS Workgroups
LCDR DesaRae Janszen
Chief, Sector SF Waterways Management Division
Mr. Richard Lopez
Vessel Traffic Specialist, VTS San Francisco
Background
• Current HSC Best Practices state vessels >1600
Gross tons will not transit through Critical
Maneuvering Areas (CMAs) when visibility is less
than .5 mile.
• VTS has been enforcing this Best Practice, although
it is not law
• Visibility is currently what mariners on scene report.
To have a law, we need to remove the variability of
a human observer by providing consistent results.
Background
• Coast Guard would like to codify the .5 mile
restrictions in the CFR
• Need a reliable, sustainable, and continuously
operating visibility data collection platform that
helps mariners and VTS make informed
decisions in foggy or low visibility situations.
Needed Outcome of Meeting
• Agreement that Visibility Sensors are
needed and should be funded (Funding
source TBD)
• Agreement on the number needed and
general location of the Visibility Sensors
• Agreement on PORTS maintaining Visibility
Sensors
Signpost
• The Visibility Sensors NOAA recommends
• How they work
• How much they cost
• The 9 Critical Maneuvering Areas
PORTS Visibility
• NOAA/CO-OPS has conducted many tests of
different visibility sensors in different locations.
• The sensor chosen has been successfully
integrated into NOAA’s PORTS program.
• New tool for the suite of PORTS sensors to aid in
the safe and efficient use of the nations
waterways.
Sensor selection testing
•
•
•
•
•
Since 1999, tested 8 sensors (4 different technologies) at 5 separate locations
None met NWS standards
Partnered with FAA to test latest technology, culminating in selection of FS11
FS11 best sensor for marine applications
2008: Joint field test with USCG (USACE facility, Duck, NC): data comparison and
testing for optimal maintenance schedules (www.frf.usace.army.mil/airvis/av.shtml)
Sensor Testing Sites
• Sterling Test
Center, Sterling
VA, 2001
• Kitty Hawk, NC,
2004
• Volpe Test
Center, Cape
Cod, MA, 2004
• USACE/FRF,
Duck, NC, 2008
Continuing Testing
• USACE/FRF, Duck,
NC 2008 – present
o Long term
evaluation of
sensor
performance
• Continued
collaboration with the
FAA on sensor
development
The Winner!
Vaisala
FS11
Visibility
Sensor
How it works
•
Transmitter
Receiver
•
•
•
Measures scattering of beam by
aerosols in a small volume of air
between the transmitter and
receiver
CO-OPS only releasing data up to
10 km (5.4 nm)
Accuracy: ±10%
“Smart” sensor:
Internal quality control system
Data adjusted for any lens
contamination
Vaisala FS11 Visibility Sensor
This sensor does NOT measure visibility by looking out onto the horizon!
Measures at the source.
Vaisala FS11 On Scene
Air temp /
Relative
humidity
sensor
Visibility data dissemination turned on in January, 2010
Air temperature/RH dissemination turned on July, 2010
Example of Visibility Sensor data:
Mobile Bay PORTS®
Front page: Station map
Mobile Bay PORTS ® page:
tidesandcurrents.noaa.gov/ports
Data Access:
®
PORTS
Data Access: PORTS®
Data Access: PORTS®
Text-based PORTS® Screen
Data Access: PORTS®
3 Days Water Level/Met
Plot
Visibility plot
Visibility Observations
View Data option
Visibility Observations
Units can be
changed to nm.
Visibility =
radius of circle
Photo taken at the trade center in downtown
Mobile, looking south down the ship channel:
3/24/10 ~8:30am CDT
Episode: 00:00 to 10:30 CDT
3/23 21:30 – 3/24 15:30 CDT
Comparison to Airport data
Not just fog…
Rain event – Aug 29, 2010
Middle Bay Port, AL
Mobile Downtown airport data:
Rain between 5:00 and 10:00
CDT.
Heavy thunderstorms and
heavy rain 6:45 and 8:00 CDT
Note rise in RH with drop in
visibility
The Caveats
• Cannot compare to airport data with
confidence
Sensors installed right next to each other can
deviate from each other
o Fog might not be uniform
o
• Point source measurement. Will not
capture patchy fog.
 Multiple sensors recommended within
operational visibility system
Cost Break Down
(Standard Station Configuration)
• Sutron Data Collection Platform (DCP) $7K, Stand $750
• Visibility Sensor $15K
• Relative Humidity, Air Temperature and Solar Radiation
Sensors $1,150
• Batteries and Chargers $300
• Cables and Supplies $500
• Enclosure $800
• GOES Antenna/mount/$350
• IP modem with antenna $1K
TOTAL $26,850 + site improvement cost
Cost Break Down cont.
• Site improvement costs may include
concrete pad, labor, AC Power, and
other requirements specific to each
site ~$15K
Grand Total $42,000
Labor cost, materials will vary on region of country.
User Feedback
“The new visibility sensors have been very helpful over the
past 2 weeks giving us a better idea of how surface visibilities
were trending over the eastern/northeastern sections of
Mobile Bay. This data helped us with not only bolstering our
confidence in putting fog with visibilities below one nautical
mile in the marine forecast, but also with the aviation forecast
at Brookley Field.”
--Mobile WFO Warning Coordination Meteorologist
The pilots have been using the data to make ship
movement decisions and the data have been great.
They have confidence in the system.
-- Patrick Fink (Office of Coast Survey), via the
Mobile Bar Pilots President
Benefits
• Adding a new capability to the PORTS
program which provides information for safe
and efficient marine navigation (Pilots &
VTS).
• Provide an indication of local visibility
independent of observer bias.
• Help the National Weather Service to provide
better local forecast.
Future Sensor Plans
• Deployment of Visibility sensor in Chesapeake
Bay, and Narragansett Bay PORTS, and a third
sensor has been requested in Mobile Bay.
• PORTS NY-NJ, Columbia River, Tampa Bay, and
Boston along with the Great Lakes have
expressed interest.
• Continued long term testing and collaboration with
the FAA, USACE, and USCG for improving the
sensor.
Critical Maneuvering Areas
Do we need visibility sensors in all 9
CMA’s?
Does any CMA need more than one?
9 CMA’s
1. Redwood Creek
2. San Mateo-Hayward Bridge
3. Oakland Bar Channel*
4. Islais Creek Channel
5. Richmond Inner Harbor
6. Richmond-San Rafael Bridge, East Span
7. Union Pacific Bridge
8. New York Slough, up-bound
9. Rio Vista Lift Bridge
Ideal Placement of Sensors
Neutral backgrounds to the
north of the sensor with
relative flat surroundings
near shorelines due to fog
dynamics
1. Redwood Creek
Redwood Creek – 2 possibilities
2. San Mateo-Hayward Bridge
3. Oakland Bar Channel
Oakland Bar Channel Recommendation
1 of 5
Oakland Bar Channel
Recommendation 2 of 5
Oakland Bar Channel
Recommendation 3 & 4 of 5
• The pier at the USCG Sector SF on the eastern
side of Yerba Buena Island. This elevation and
buildings near shore are a negative hence placing
the sensor on the pier.
• Another location would be on Treasure Island.
There is a short pier about mid way out that
might be suitable or the larger clear area near the
western end of the island.
Oakland Bar Channel
Recommendation 5 of 5
4. Islais Creek Channel
Islais
Creek
Channel
5. Richmond Inner Harbor
Richmond Inner Harbor
Richmond Inner Harbor
6. Richmond-San Rafael Bridge, East Span
Richmond-San Rafael Bridge,
East Span
7. Union Pacific Bridge
Union Pacific Bridge
8. New York Slough, up-bound
New York Slough, up-bound
9. Rio Vista Lift Bridge
Conclusions/Votes
• Agreement that Visibility Sensors are
needed and should be funded
• Agreement on PORTS maintaining Visibility
Sensors
• Agreement on the number needed and
general location of the Visibility Sensors
Questions?