Ocean Networks Canada - CODAR

Expedition 2019: Highlights Story Map

duncanlowrie@uvic.ca — Thu, 14 Nov 2019 19:36:10 +0000

Click here for the full screen interactive experience.

Real-time ocean current data for safe navigation

duncanlowrie@uvic.ca — Fri, 25 Oct 2019 19:23:00 +0000

In August ONC hosted an international gathering of scientists to look at the oceanographic applications of high frequency radar. Participants travelled to Race Rocks, a Marine Protected Area at the entrance to the Strait of Juan de Fuca, to visit one of ONC’s recently installed oceanographic radar. Watch the video above.

Oceanographic radars have been installed in high traffic locations near busy ports along the coast of British Columbia. Different from marine radars, these sophisticated, high frequency, land-based oceanographic radars measure and map surface ocean currents in coastal waters, making it possible to measure waves heights and provide indirect estimates of local wind direction.

These radars systems play a key role in making Canada’s west coast safer for shipping navigation, incident response (such as search and rescue and hazard spill), and tsunami detection. A major benefit of oceanographic radars is their ability to operate under any weather conditions, day or night.

ONC’s Oceans 2.0 portal now provides data from ten CODAR including two Fisheries and Oceans Canada CODAR on Haida Gwaii at Bonilla Island and Sandspit. In addition, one WERA high frequency radar system, a state-of-the-art technology, is located in Tofino on Vancouver Island which uses 12 land-based antennas with a range up to 80 kilometres. The WERA radar specializes in over-the-horizon radar technology to monitor ocean surface currents, waves and wind direction and can scan and detect large events such as tsunamis and storm surges.

Check out our real-time ocean data for yourself on our data management system Oceans 2.0.

Read More:
https://www.oceannetworks.ca/real-time-radar-data-spurs-international-gathering

Understanding the Oceans

nnk@uvic.ca — Sun, 21 Sep 2014 20:45:07 +0000

Blog post by Dr. Rich Pawlowicz. Originally published on Wiring the Abyss 2014 Expedition portal.

Understanding how the oceans work is hard, because we almost always don't have enough measurements to even know what the ocean is doing, never mind why. One of the exciting things in the VENUS Observatory expansion plan was the installation of a radar system that was specially designed to provide estimates of surface currents over a large region covering the Fraser plume. What's the Fraser plume?

Fraser River plume edge in the Strait of Georgia

This is a puddle of light water (formed by mixing fresh Fraser water with salt water) that floats on top of the more saline (and more dense) Strait of Georgia water. It is only a few meters thick (whereas the Strait is 100 metres deep or more), but it is the part of the ocean that is important to us because we boat around in the upper few meters of the ocean. We known, in a general way, that this "puddle" moves around because of the tide and winds, but also can break up into swirls and smaller eddies on its own. Exactly how fast it moves under a wind of a particular speed, and how and what causes it to break up are interesting scientific questions.

Combined satellite image and surface current map. The light region denotes the plume, and it corresponds to a region sediment rich, reflective, low salinity water. The red line shows the track of the BC Ferries M/V Queen of Alberni.

But before getting to the science, we first have to know whether this surface radar gives us a good estimate of surface currents. Does it work? So, we have to make other measurements to test out measurements! During this cruise, I am deploying 'surface drifters'. These are small floats, attached to a 'drogue' to make sure they move with the speed of the water. Positions are tracked using GPS and reported back to us using a satellite phone system. During times when the Tully isn't being used for ROV or other ONC operations (and all the ONC people are fast asleep); I deploy these drifters. Later, after they drift away in different directions, they are picked up by our own boat, the Kraken, which can work in the Strait only during daylight hours. This way I can get some longer deployments without taking a large chance of losing these instruments. After a deployment of 10 hours or so, the Kraken finds them and returns them to the Tully, so I can deploy them again the next night.

Dr. Rich Pawlowicz (UBC) holds a drifter used in the CODAR calibration experiment.

The drifter data from this cruise, along with drifter data from other deployments before and after the cruise, will be used by Postdoc Mark Halverson (UBC) to quantify the accuracy of the radar system, and will be used as a test for several numerical models of the Strait being created by other scientists in Vancouver and Halifax.

UBC Research Vessel Kraken was used to collect drifters daily and bring them back to CCGS Tully for re-deployment at night. In the image L-R: Chris Payne (Marine Technician, UBC), Wayne Lutz (writer) and Mark Halverson (Postdoc, UBC).

from CCGS John P. Tully, Dr. Rich Pawlowicz

Ocean Dynamics Lab

Earth and Ocean Sciences

University of British Columbia

Fraser River Plume

rlat@uvic.ca — Tue, 06 Aug 2013 07:00:00 +0000

The Fraser River reaches the ocean near Vancouver, and there the fresh water it carries mixes with ocean water to form a thin plume of buoyant brackish water, which according to one oceanographer is the “showpiece of the Strait of Georgia.”

Oceanographers have been studying the Fraser River plume since at least the 1960s, but more recently, Ocean Networks Canada has installed a radar system to measure the surface currents in this region. Furthermore, Ocean Networks Canada has also installed the Seakeeper seawater monitoring system on the BC Ferries MV Queen of Alberni to collect detailed information of water properties along the Duke Point – Tsawwassen ferry route which cuts through the plume eight times per day. These new observations, coupled with satellite imagery, are being used by UBC researchers Dr. Mark Halverson and Prof. Rich Pawlowicz to reveal the nature of the Fraser plume. The research is being carried out as part of the Marine Environmental Observation Prediction and Response Network (MEOPAR), which is tasked with improving Canada’s ability to respond to marine hazards.

In the early summer when the Fraser River carries high sediment loads, the plume is easy to distinguish from ocean water by its distinct light brown colour (above). It can be highly reflective and opaque to sunlight, and because it is a mixture of river and ocean water, it can be quite “fresh.” A comparison of the measured surface currents to both surface water salinity and satellite imagery shows that a jet of swiftly flowing water can form near low tide.

A sharp change in the currents occurs where the ocean colour and salinity change rapidly, signifying the edge of the plume. As the plume waters move away from the river mouth, it appears that the wind ultimately determines its fate. During northwesterly winds, the plume is driven to the south, while during southeasterly winds, it is driven to the northwest. However, the relative importance of the wind might change when the river flow is much higher. Ultimately, researchers hope that a better understanding of the surface currents in this area will be useful to emergency response operations by providing a way to anticipate the trajectory of, for example, spilled oil or other contaminants.

Article by Mark Halverson (University of British Columbia)

Animated Surface Currents Data Product

rlat@uvic.ca — Tue, 13 Nov 2012 08:00:00 +0000

Another animated data product has been added to the VENUS 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.

VENUS CODAR Array Delivers Total Current Vectors

rlat@uvic.ca — Wed, 10 Oct 2012 07:00:00 +0000

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.

Calibrating Second CODAR Antenna

rlat@uvic.ca — Wed, 08 Aug 2012 07:00:00 +0000

A 4-member team from Ocean Networks Canada 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 the VENUS data plots for more information about CODAR and other types of data provided by Ocean Networks Canada.

Setting Up Second Coastal Radar Antenna on VENUS

rlat@uvic.ca — Tue, 17 Jul 2012 07:00:00 +0000

Paul Macoun (Ocean Networks Canada Engineering team) prepares the second CODAR antenna for installation at our shore station near Vancouver airport. Following the final testing, the antenna will be collecting radial velocity data from the surface waves in the Strait of Georgia.

The first CODAR antenna, installed at the West Shore Terminal, Delta, BC, has been operating since fall 2011. The combined data streams from both antennae will provide measurements of surface waves and currents.

Animated Radial Current Vectors

rlat@uvic.ca — Mon, 13 Feb 2012 08:00:00 +0000

The CODAR station at the Westshore Terminal in Tsawwassen measures surface ocean currents using radio signals reflected off waves in the Strait of Georgia.

A second station, near Vancouver Airport, will be installed in the next month or so, after which it will be possible to resolve north-south and east-west components of the currents. In the meantime, with only a single station operating, it is possible to measure only radial current velocities–that is to say, only the components of ocean currents that are directly towards or directly away from the receiving antenna can be detected.

Interpreting the physical meaning of plots of radial velocities is challenging. An extremely small current-velocity arrow pointing due west, for example, may be evidence of an extremely weak westward current, but it could also correspond to an extremely strong northward current with a very small westward component.

Nevertheless, this animated sequence of radial current vectors from February 1, 2012 gives some tantalizing hints of the current patterns that will be fully resolvable once the second station is up and running.

A plot of estimated tidal heights and current speeds lies below the mapped currents.

Current speeds are shown in red, with positive values denoting incoming tide (flowing south to north) and negative values denoting an outgoing tide.

Tide heights are shown in blue.

At the time of peak incoming tidal flow, at 04:00 UTC, one would expect to see currents moving northwest, along the Strait. Looking at those CODAR arrows that lie parallel to the strait’s direction, this is in fact what is seen at 04:00. Similarly, at 22:00, at peak outgoing tidal flow, the CODAR arrows (again, those that are parallel to the strait’s direction) indicate a flow to the southwest, as one would expect.

Strait of Georgia Surface Current Monitoring Station Online

rlat@uvic.ca — Mon, 28 Nov 2011 08:00:00 +0000

The first of two High Frequency (HF) coastal radar Stations was successfully installed on Nov. 24th at the Westshore Coal Terminal in Delta, BC. The station is now monitoring radial surface currents within a 20 km range in the Strait of Georgia. The installation timeline happened to overlap with the onset of a strong winter storm. The engineering team managed to erect the antenna in strong winds, but were able to escape the worst of the storm by 2 hours.

Monitoring surface currents in real-time using this technology will bring multiple benefits to a number of organizations, helping them to make important operational decisions. The second station will be installed 20 km to the north in early 2012. Once operational, the radial data from both sites will be combined to generate vector maps of surface currents in a 20 km X 20 km grid between the stations.

Ocean Networks Canada - CODAR

Expedition 2019: Highlights Story Map

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Real-time ocean current data for safe navigation

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Understanding the Oceans

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Fraser River Plume

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Animated Surface Currents Data Product

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VENUS CODAR Array Delivers Total Current Vectors

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Calibrating Second CODAR Antenna

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Setting Up Second Coastal Radar Antenna on VENUS

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Animated Radial Current Vectors

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Strait of Georgia Surface Current Monitoring Station Online

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