VENUS Phase II

In April 2013, the AUV (“Bluefin”) successfully ran a test science mission in Saanich Inlet. Operated by engineers from the UVic’s Ocean Technology Lab, led by Dr. Colin Bradley, the AUV enhances capabilities of VENUS – the coastal ocean observatory of Ocean Networks Canada.

For test deployment in Saanich Inlet the AUV was equipped with key oceanographic sensors, oxygen and temperature, and a multibeam sonar to scan the seafloor. The test mission focused on mapping the Inlet structure to assess both the early spring conditions and whether any mid or deep water intrusions have occurred.

According to Dr. Jody Klymak, an oceanographer from the UVic’s School of Earth and Ocean Science, who helped to organize the science mission, the main objective of the mission was to fully assess capabilities of the mini-sub. “It is an advanced multipurpose tool, and we would like to see it support ongoing research programs at SEOS”. The AUV is capable of powered flight in waters down to 200m depth and can run for up to 8 hours gathering valuable data from the geographically dispersed areas.

Preliminary assessment of the test-mission data from several weeks ago clearly shows that the deep water renewal event in Saanich Inlet has not occurred yet. The event, a long studied natural phenomena, is a harbinger of the spring-coming in Saanich Inlet, when oxygen-rich waters and nutrients finally reach the seasonally hypoxic fjord.

UBC oceanographer Dr. Mark Halverson has been making use of VENUS Coastal Ocean Dynamics Applications Radar (“CODAR”) data from the Strait of Georgia in his research. His analysis revealed an abrupt cutoff in data availability to the south of the coverage area, rather than the gradual fall-off with distance from the two antennae one would expect from purely physical considerations.

Subsequent investigation revealed an overly-restrictive software setting that has since been modified. All ocean-current data going back to the commissioning of the VENUS CODAR array in August 2012 has been reprocessed, extending the coverage of the array southward by about 3 km.

This animated figure shows the coverage area before and after the reprocessing. Thanks go to Dr. Halverson for pointing out this anomaly, allowing us to improve our product. Our users are not mere customers, but active collaborators in the VENUS mission to provide data to the oceanographic community.

Learn more about the VENUS CODAR array at our About the Data page and view the latest CODAR ocean-current data on the VENUS website.

The VENUS BPS winch system test on the OTTB Buoy is progressing. Soon after installation in December 2012, the system underwent a site acceptance test with the manufacturer. Following on from this, the Data Management group has now developed a real time linkage between the system and the database. The next stage is to develop the software infrastructure to command and control the system.

The picture shows the instrument cage (centre) being lowered into position under the winch (centre left). An engineer from MacArtney A/S (next to winch in blue) was on site at this time to conduct the site acceptance test. VENUS engineer Paul Macoun (in red) is spooling in winch cable to take up slack as the OTTB crane is lowered.

We anticipate that the software development will be complete by the end of February 2013, at which time the system will come off the OTTB buoy. The next step will be integration with the custom-built buoy at the Marine Technology Centre.

See Buoy Profiling System (BPS) on the map of the VENUS Saanich Inlet array.

Stacked in the image are 48 plots generated from 16 sensors of the VENUS Ferry System installed on a BC Ferries M/V Queen of Alberni. The comprehensive system monitors oceanographic and atmospheric conditions while the ferry transits between Nanaimo (Duke Point) and Vancouver (Tsawwassen).

Oceanographic parameters collected by the system include seawater temperature, salinity, density, dissolved oxygen, turbidity, and the relative concentration of chlorophyll.

Meteorological measurements focus on marine atmospheric boundary layer conditions and include air temperature, humidity, pressure, wind speed and direction, incoming solar radiation, and out-going irradiance.

The image shows a day of data collected on Jan 5th, 2013. For each parameter, data are plotted in a number of distinct ways to show alternate characteristics of the geospatial and temporal nature of the variations.

The data collected by the ferry system are retrieved daily through a series of communications over the cellular network between the ferry and VENUS shore station. Check out the latest ferry data plots at the BC Ferry plots page.

View full-resolution image (right-click link to download) to see the full-sized plots.

The Ocean Technology Lab’s (UVic) Bluefin AUV has been retrofitted with a suite of instruments to support science experiments in Saanich Inlet (and beyond).

In the image, the vehicle is in a test tank at the UVic’s Marine Technology Centre (MTC), undergoing a ballasting exercise and general readiness testing on Dec. 14, 2012. AUV missions in Saanich will begin early in 2013.

A joint team of VENUS and UVic/Ocean Technology Lab engineers tested a winch system on the Ocean Technology Test Bed (OTTB) Buoy in Saanich Inlet. The winch is part of the VENUS Buoy Profiling System (BPS) – a water column instrument platform – destined to become a part of the Saanich Inlet array of VENUS. The core structural component of the BPS, 8-meter wide buoy, has been refurbished and currently is at the Marine Technology Center. The testing of the winch conducted in the last week is a planned step on the way to get the BPS ready for its deployment, preliminary scheduled for late springs/summer 2013.

The VENUS Ferry System is back online, collecting data from a number of surface and meteorological station sensors. After the scheduled maintenance the M/V “Queen of Alberni” (BC Ferries) is back on its route between Nanaimo and Vancouver (Duke Point – Tsawwassen). Browse VENUS data plots gallery or access the data in the archive.

Note: Please note that Ferry data archiving and delivery is a work in progress. If you encounter problems or errors while accessing VENUS Ferry Data in the archive, please send us a note at venus@uvic.ca or via our contact form. Thank you for your collaboration.

The VENUS data team adds another animated data product to its data plots gallery.

This animated image depicts measurements of the surface ocean currents in the Strait of Georgia over a recent 24-hour period.

The currents are measured using a “CODAR” (Coastal Ocean Dynamics Applications Radar) system. The VENUS CODAR system consists of two antennae, one at the Iona Wastewater Treatment plant, near Vancouver Airport, the other at the Westshore Coal Terminal, near the BC Ferries port at Tsawwassen. These are labelled in the image as “VION” and “VCOL”, respectively.

Each image in the sequence shows the current averaged over an hour. The size of the arrows is proportional to the current magnitude. The location of each measurement is at the midpoint of the corresponding arrow.

The depicted measurements span an entire tidal cycle, but the flood and ebb tides seen in the animation are not symmetric: the southward-trending ebb tide is considerably stronger than the northward-trending flood tide. This is most likely due to the prevailing winds over the last few days which have been from the NW, pushing surface currents to the south. The ebb tide reinforces this flow and thus appears very strong, while the flood tide works against the wind driven flow and thus appears weaker.

Links: CODAR Last 24 Hours Daily Animation

This image depicts the surface ocean currents in the Strait of Georgia, measured during a strong ebb tide. The currents, averaged over an hour, were measured using a “CODAR” (Coastal Ocean Dynamics Applications Radar) system. The VENUS CODAR system consists of two antennae, one at the Iona Wastewater Treatment plant, near Vancouver Airport, the other at the Westshore Coal Terminal, near the BC Ferries port at Tsawwassen. These are labelled in the image as “VION” and “VCOL”, respectively.

There is a generally southward trend to the currents, as would be expected during an ebb tide. For the most part, the currents are between about 30 and 60 cm/s, but there is a handful of current arrows indicating westward flows of upwards of 90 cm/s. The direction and position of these currents suggest that they represent outflow from the Fraser river.

A four-member team from VENUS traveled to the Strait of Georgia shore station, located near Vancouver Airport, to calibrate the newly-installed CODAR antenna.

Generally, an antenna pattern measurement (“APM”) is performed using a powerboat to carry the radio transponder, but the shallow mudflats surrounding the Iona shore station made this impossible. Waiting for high tide, the team launched a canoe from the Iona causeway and paddled it through the required arc.

The calibration process entails moving a radio transponder around the CODAR station along an arc of radius 1 kilometre. Ideally, the signal reception would be uniform over this arc, but various objects surrounding the antenna (trees, buildings, etc., but especially metallic objects) introduce distortions in the electromagnetic environment. The CODAR station receives the signal from the transponder, and uses it to map the spatially-varying antenna reception.

After several hours of paddling the VENUS team was on its way back; while technicians at CODAR in San Francisco began processing the APM data collected during the day. After this is complete, it will be possible to combine data from the Iona and Westshore Coal Terminal CODAR stations to generate two-dimensional maps of ocean currents in the Strait of Georgia between the two stations.

Check out VENUS data plots at http://venus.uvic.ca/data/data-plots/.

In the image, Paul Macoun and Richard Dewey, mounting the transponder on the canoe.