Welcome, everyone, to the first video in our second lecture for Mesmetodo Infernikoden.
This is also the second lecture in the first block, looking at in-situ measurement methods and measurement strategies.
So last time we looked at all the different scales of ocean processes,
and now we want to get a bit more into how these scales affect our choice of a measurement platform and a measurement strategy.
By basically going through more examples of measurement platforms,
and what kind of ocean processes, what kind of scales they can capture.
And so the problem, of course, is that we cannot capture all ocean scales at the same time.
We need to be selective.
And so we have to optimize our measurement strategy and our choice of instruments and measurement platforms based on the questions we want to answer.
And there are a lot of trade-offs that go with this.
For example, do we need in-situ measurements or can we use remote sensing products?
Does our platform need to be mobile or can it be stationary?
Or is it better if it's stationary versus mobile?
What kind of information do we lose or gain by choosing one or the other?
Do we have to be connected to the instrument during the measurements or can it be autonomous?
Can it go out and record a bunch of measurements and then we collect the instrument at the end or the platform and download the data?
Or can it send it remotely via satellite so we can collect the data as it goes but not be connected to it directly?
And of course, there's a cost issue.
So do we have enough funding to have a ship for a month or do we need a cheaper option to try and answer the question that we're interested in?
And throughout this, we have to consider that we're looking at four dimensions of information.
So we have the horizontal and x and y, the vertical and the z, and the time, and time as the fourth dimension.
Can we capture all of these dimensions with our measurements or do we have to settle for a selection?
Do we have to focus only on the vertical or only on the horizontal?
And can we capture a temporal aspect or do we have to just look at snapshots and not consider how this variability really changes in time?
So measurement platforms aren't just for research, although this will be focusing on really here.
But we have to remember that they're also used in different situations for long-term monitoring, for example, or for predicting or forecasting ocean weather.
So basically, looking at wave conditions or current conditions that might be useful for ships that are transport ships or cruise ships or what have you, also for tourism.
So what are the wave conditions along the coast might be useful for people who are using the beaches or for maybe even more relevant surfers.
And of course, collection information, the military also uses many similar tactics for collecting information.
And a lot of the research or the instruments and the research that's been done for oceanography has come through different militaries.
And it continues to be an important factor, for example, in the US and many military ships are used for ocean research,
even if it's not directly with the military. And in Canada, for example, the Coast Guard ships are the main research vessels.
So if a cruise is planned to a particular area where a coastal ship needs to do its normal monitoring, researchers come along and the ship's route is based on the research.
But if something comes up, an emergency comes up where the Coast Guard are needed, then the research is put to the side and the first priority is then for coastal protection or emergency services.
There are many different research platforms available.
And if we kind of go from top to bottom, we start with satellites, which I don't show a picture of here, I won't talk too much about, you'll learn a lot more of that in the second blocks, the second and third block of this lecture of this course.
In between the satellite and land or sea stations, we could also include aerial images, aerial photography from planes.
Small light planes can be used to focus in on a particular feature that we want an overview, we want an overhead image of that maybe the satellite doesn't capture at a high enough resolution.
For example, eddies on the scale of kilometers, maybe are below the range of most satellites, or at least in the past, near satellites might start to capture these, but in any case, these aerial use of light planes can give us a lot more detailed information of a particular feature or region.
Then we get to the ocean surface, or first we get to the land and underwater stations, which are kind of jumping ahead, but if we start at land stations, they might monitor sea level along coasts and are more permanent fixtures.
Underwater stations can be perhaps permanent, but are probably more likely less permanent. Here are a few examples of underwater stations.
Generally small platforms where we can mount a bunch of different instruments. They may be standalone, we may just lower them down and have their own power, their own hard drives to record data,
and then we bring them back up after a certain period, after our measurements are done, and then collect the data.
But they may also be connected to land as shown here with these via cables generally, of course, and then these cables are then run along the seafloor until they can get to a point where we can collect the data generally on land, although perhaps a floating mooring or a pile in shallow waters could be another point that we could connect them to.
And then at the ocean surface we have, of course, ships, one of the major measurement platforms, and one that's used often at the Institute of Oceanography here. This is a picture of the Meteor, the German research vessel.
Also at the ocean surface we have a variety of drifters. They can be buoys, they can be drifters, they can be floats, and here are a couple examples on the right here.
So this is a drifter. So you can see this, the top is basically a buoy that floats at the surface.
It has a long rope, usually about 15 meters, that goes down to a sail, it's called a sail. And the sail is actually what drives the buoy along. So there'll be some wind and wave influence at the surface, but by adding the sail that's the currents at this depth, so let's say 15 meters, that really pulls along the buoy.
And so when we put a GPS tracker in the surface buoy, we can track its position and see how the currents at 15 meters move this buoy along and then track these currents.
On the right is a float, an Argo float, which follows a similar principle, but it's a bit more complex. So it can change its buoyancy and move through the water column in making vertical profiles.
And every time it reaches the surface, it can connect to satellites and send back its data. And here you can see some of the instruments here positioned near the surface or near the top of the instrument.
And so it can record initially temperature, salinity, or conductivity and pressure, but more and more instruments are being added to these Argo floats and they're expanding as more and more added, we get more and more data from all the different regions of the oceans, which will
look at in more detail later on.
Then sort of with similar to these Argo floats are gliders, which is shown below, and they kind of fall into this remotely operated or autonomous vehicles.
And so you can guess a float is also sort of somewhere between falls between these these two characterizations.
And so these gliders can also sort of, so to say, fly through the ocean by changing their buoyancy. But because they have wings, they can also cover distance, not just vertically, but also horizontally and collect data as they go.
Now, if you can also have essentially a glider with a motor, which would then be considered more like an REOV, which may or may not be connected directly to the ship, but may be guided by a program to tell it to go to a certain location and then resurface, or attach the ship so that you can guide it as it moves through the water.
And there are many platforms that are somewhere in between that kind of fall in between these different characterizations.
And then the sort of the deepest option, which is similar to an underwater station is an anchoring. This is just a bit simpler than an underwater station, essentially a weight at the bottom with a buoy at some point, either at the surface or below the surface.
And between the buoy and the weight, you have the option to attach many different instruments and you can just lower it into the water and leave it there until your measurements are completed and then pick it up again.
So this concludes video one of lecture two in Mesmetoto and Vanekruten.