posted Jan 23, 2011, 5:07 PM by Cesar Harada
Via Prof Jennifer Gabrys - Thanks !
On the 23rd September 2001 the eight Volvo Ocean Race yachts left Southampton to circumnavigate the world in one of the worlds toughest professional yacht races. Volvo took over sponsorship of the previously named Whitbread Race which takes place every 4 years. More information about the race can be found on the Volvo Ocean Race web page.
As part of their sponsorship of the race, Volvo launched the Volvo Ocean Adventure. The Volvo Ocean Adventure is a free web based environmental, education programme for young people world-wide, designed to educate, excite, stimulate and motivate them to see how they can have a positive impact on the environment through their own actions.
Part of this involved equipping all the yachts with instrumentation packages, designed by Saturn Solutions, to gather environmental data such as ocean temperature and colour as they made their way around the world. From these, information on phytoplankton distributions, suspended sediment and pollutants can be obtained, as well as temperature profiles.
Example data collected during the race
The Saturn Solutions instrument packages fitted to the yachts primarily consisted of:
- a thermistor chain which was embedded in the rudder or keel, used to measure ocean temperature
- a thermistor unit which collected the data from the thermistor chains
- three optical radiometers positioned above the water line, used to measure ocean colour. Two of these were downward looking (measuring light reflected from the water) and one was upward looking (measuring ambient light)
- the Ocean-i unit which collected and processed data from the thermistor unit and radiometers and sent it on to the communication system.
Ocean-i and the Pilotfish unit mounted
onboard one of the Volvo Ocean Race
On-board the yachts, Ocean-i asked all 3 radiometers and the tilt/roll sensor to acquire data at 10, 20, 30, 40 and 50 minutes past the hour. If at the start of an acquisition cycle, the signal to noise ratio for the upward looking sensor was less than 10, then no data was collected on the basis that it was dark.
The samples collected were stored as raw data on the Flash card and in the memory. Towards the end of each hour, Ocean-i looked at the 5 samples collected in order to choose the best one to send to the communications system. It did this by looking at the ratio of 570/600nm for the downward looking sensors - the sample with the highest ratio was selected. If any of the ratios were greater than 5, Ocean-i used the tilt/ roll data to choose the data from the sensor looking most directly downwards at the water. This meant that during daylight hours, towards the end of the hour, Ocean-i selected the best measurement from the downwards looking sensors. This data was then merged at selected wavelengths into 24 windows (nominally 6 channels wide) as was the corresponding upwards looking measurement.
At 55 minutes past the hour, the thermistor unit collected 16 measurements from each of the thermistors and averaged them. Then, on the hour, thePilotfish Marine Wireless Gateway asked Ocean-i for it's acquisition data for that hour. Ocean-i sent the windowed data from the selected downward and upward looking measurements, the corresponding tilt and roll measurement, the time of the measurement, the sensor ID (from which the measurement was taken), the integration times for the measurements and the temperature. The Pilotfish unit transmitted this data back to Race Office using Sat C along with position information and data from a number of other on-board sensors.
From there, the data was distributed and presented on the web site.
From a long-term scientific stand point the data can be used to validate and calibrate satellite information as well as provide an increasingly global environmental data set.