Oscar Schofield, Professor of Bio-Optical Oceanography at the Rutgers University COOL lab (Coastal Ocean Observation Lab) uses state-of-the-art oceanographic tools such as satellites, models, radar, AUVs, and gliders. “I used to go to sea for 6 months at a time as a grad student, but now with technology I’m at sea every single day”.
Photo: Rutgers University
Oscar Schofield has called the ocean a “harsh and unexplored realm.” He works with his team to understand the physical and biological components of ocean phenomena, such as biological hotspots, plankton blooms, and the movement of ice shelves. He has advised dozens of graduate and undergraduate students, has published hundreds of peer-reviewed articles, and is very well respected in the field of oceanography.
We’re passionate with Oscar’s idea of “going to sea every day” with the help of technology. This is the problem what we are solving here at Marinexplore, to make it possible for everyone to go to sea every day.
Oscar talked with Marinexplore about the trials and tribulations of integrating different data platforms, the progress his field has made over recent years, and the remaining mysteries of oceanography.
Erica: You’ve mentioned that historically, one of the biggest problems in marine physics & biology is how to track and follow a piece of water. Today, are we able to overcome this challenge, and if so, how?
Oscar: We are able to overcome it for surface water because we can use radar that gives us surface current velocities, and you can combine that with satellites. So we can track a water mass at the surface, but doesn’t mean that water is going the same direction underneath the surface. We also have gliders, AUVs, and a lot of robots, but we don’t have enough coverage to be absolutely sure. So to solve that problem, we need to put a lot of resources into one location and then turn on models, and then feed the data into the models to keep the models on track. But it’s still a difficult problem.
Erica: Could you tell us a bit more about the sensors you use to collect your data?
Oscar: We use three main platforms. First, we have satellites – they give us synoptic maps of the physics, like temperature, sea surface height, ocean color, etc. Then we combine that surface map with a surface map from the second platform we use, which is radar. The radar we use is called CODAR which is a shore-based system that sends out a radio pulse, and uses a Doppler shift to determine how fast the waves are moving towards you or away from you. Any place where the two systems overlap you can derive a current vector – with speed and direction. The third platform is robotic systems; we use gliders which can be out for a month to a year, depending on the sensors it’s carrying, and it will travel about 20-30 km a day. Then we have propeller AUVs, which are used for much shorter durations, but provide much higher resolution. So to look for example at a coastal river plume, you’d nest the high-resolution AUV map within the less-resolved glider data.
A fourth platform that we used a lot in the past, but not so much now, are electro-optic cables. One of the first ones was called Leo, it’s an electro-fiberoptic cable that goes from land out into the sea, basically like a giant extension cord. So you can put sensors on it and collect very high-resolution data out in the deep sea. With these cables you don’t have good resolution in space, but you have resolution in time.
Legendary picture of Scott Glenn, Josh Kohut and Oscar Schofield from Rutgers Coastal Ocean Observation Lab. Oscar, his head in the water, is doing here “underwater monitoring” in the old-fashioned way.
Erica: Can you be more specific about the resolution of these different platforms?
Oscar: For the satellites, we download about 16 passes a day, which brings us to terabytes of data over short periods of time. The resolution depends on the satellite – usually anywhere from 1-10km, but some satellites can get you down to 30m or even 5m resolution. The CODAR system sends out a series of radials firing out in all directions, and you create a series of bins. The size of the bin varies with the frequency of the radar that you’re using. For shelf data we use about 5-6 km resolution, which goes about 200 km offshore. There’s a medium-frequency that we use for offshore wind development, about 3 km, then we have a 1.5 km resolution system for right at the mouth of major shipping ports.
Erica: How do you handle the processing of your data?
Oscar: It’s all automated at this point, all of the data streams are processed and posted to the web right away, so they’re publically available. Then we hook up with our modelers so they can pull it into data assimilation efforts. The ROMS model developers are right here at Rutgers, in fact it the ROMS model system was developed at the same time when we were developing our observing network. We work a lot with the Navy and NOAA, so when we are flying gliders out in the deep sea, they can use our data too.
Erica: Do you think that models are best used for making predictions or for hindcasting?
Oscar: Well, you have to do both. The hindcasting will always be used for model development, or for science – to understand why something happened, to look at the sensitivities of a process, at forcing from both sides. For example, we have a grad student interested in the big phytoplankton bloom event on our coast, which occurs in the wintertime. It’s a very delicate balance between how strong is the wind, how cloudy it is, and what the mixing is. So she uses the model to look at the sensitivities of the biology to enhanced wind, enhanced river outflow, etc. The idea is to have all the models running all the time, coupled with the observation stream. Then you can ask, which one do you trust and why, why are they different, what’s different about how they’re parameterized, or what assumptions do they have built into them?
Erica: Do you feel that models today are accurate enough to make predictions, or should we use caution with predictions?
Oscar: They’ve gotten a lot better, and especially with assimilation turned on, because it keeps them in check. They’re still a work in progress. But I trust it enough to plan my science, for example to plan my experiments. Would a company want to use it now to make predictions? That’s the big question. For example, do they use the global models and hope that with enough observational data the model will stay on track? Or in a coastal zone, do they need to be using the higher-resolution models? That’s the big question, and that’s where the field is going in the next 5-10 years. But for a lot of processes you’re interested in, models still may not solve the problem because they are simply too coarse in resolution.
Erica: Now let’s talk about your fieldwork. You have spent a lot of time on research vessels. Could you tell us more about it?
Oscar: Well, the fieldwork has really changed – I used to go to sea for 6 months at a time as a grad student, but now with technology I’m at sea every single day, which is great. How we go to sea is changing. Now a lot of technology is doing the mapping for me – so we can go to sea to just do experiments because the maps of the feature we want to look at will be handed to us before we leave the docks.
Erica: Is that appealing to you?
Oscar: Well yes, for one ship time is expensive – an open ocean class vessel might cost $75,000 a day. So if I can get 10 times more experiments done and I know I’m in the right area, that’s great. If you can follow the water, you know you can follow one population over time, so you can look at how the biology is changing the chemistry and how is it feeding back to the physics. This is something we used to guess at but could never really answer, because we could never sample that one parcel of water.
So in that sense how we go to sea has changed, but on the other hand it’s the same, you’re still running around with a CTD, you profile the water, you use your intuition to find what process you’re interested in, then you do your experiment.
Erica: What is the most spectacular part of the ocean you’ve experienced?
Oscar: I still go to sea to the Antarctic every January and February, and that’s just spectacular, it’s an amazingly beautiful place. I’ve been to many parts of the world – from the Gulf of Mexico at night, sampling microbes with a zodiac, to riding out hurricanes, to slashing through the marginal ice zone in Antarctica, that’s the part I know. But now I can be at sea all the time. We have two gliders in the water today. With my morning coffee I can check in and see what’s happening in the North Atlantic today, then go about the rest of my day.
Erica: Have you ever lost any equipment in a storm?
Oscar: You always lose equipment. If you’re afraid of losing equipment you shouldn’t be an oceanographer. We’ve lost 7 gliders – but we’ve gone around the earth several times, and been at sea 2,000 days since we first started. In comparison to the cost of ship day’s it’s nothing. We’ve also lost some gliders to animals – we lost one glider to a shark off the Azores. It was struck from below in the open ocean. It came to the surface so we could download the data and there was nothing we could do, so we just had to watch it sink.
Erica: Have you ever lost equipment because of theft?
Oscar: We’ve had some stolen by boaters, but once it breaks the surface we are able to talk to it. The best story was, we deployed one off the coast of Australia and a recreational fisherman picked it up. He put it in his boat, he drove it down the highway near Perth, and brought it to his back yard. We turned a sensor on so it started to make a chirping sound. His neighbor looked over the fence, and this was during one of the Gulf wars, and it sort of looks like a cruise missile with an American flag on it. So she threatened to call the police, and we saw him bring it back on the freeway and he dumped it behind a warehouse. So we were able to go back, dust it off, and put it back in the water. So in our job there’s a lot of reacting to events as they happen.
Erica: What happens if the equipment fails?
Oscar: We had one flying in an area that we can’t say where it was, but it froze up during a typhoon. Because it was during a military exercise it could only be picked up by a military ship, but the military ship was far away, so it floated nearly 1500 km through these coastal zones and all we could do was hope it wouldn’t get picked up and start an international incident. So that was a very long summer.
Erica: If you could ride on the back of a glider in any part of the ocean, where would you go?
Oscar: The big area where I want the capability to go to is under ice shelves. Right now the way the glider communicates is when the tail breaks the surface, it gets its position fix and its dive profile. So when it’s under an ice shelf, you can’t talk to it. What we think is happening in the poles is a positive feedback loop – where the deep ocean is melting the ice shelves. What I really want to do is make really extensive maps of the underside of the sea ice that’s melting. We want to build ears for the gliders to set up acoustic underwater beacons to be able to communicate with it.
Erica: Can you tell us about a surprising finding you’ve had from the glider data?
Oscar: Hurricane Irene came up our coast and the weather folks got the trajectory right but the intensity very wrong. On our coast in the summer we have a very stratified shelf, it goes from 28 degrees to 2 degrees in 2 meters. So when you run the hurricane forecast, you use the input from the sea surface temperature. But what the glider saw is that once the hurricane gets close, it has mixed up the water, which decreases the intensity of the storm. What was really interesting is that the injection of cold water to the surface was actually driven by bottom-boundary physics, not surface-boundary physics. So it wasn’t the wind driving it, but instead the movement of the water over an irregular sea floor.
Erica: Do you use the models for weather forecasting at all?
Oscar: We do a little forecasting – one current project is on sea breeze. One of the biggest issues now with power companies here is the presence or absence of sea breeze in the summer time on the Jersey Shore. If there is no sea breeze, everyone turns on their air conditioning. But the way you buy power is you buy it 2-3 days in advance, and it’s cheap, but if you buy it the day of, it’s 10 times more expensive. But if you buy too much, you can’t store it, and you pay a pollution tax. So the power companies want to know the probability of the sea breeze so they know how much to buy. They have been funding one of our weather guys to work on this.
Erica: How did the utility companies hear about your work in the first place?
Oscar: We started posting satellite data to the web in the early nineties. Every year our web hits are increasing, 70% is the general public. In the summer months we might get a quarter of a million web hits a day. Fishermen use glider data to detect ocean fronts, to determine where fish aggregate. Sailors use us to determine routes for long sailing races. A lot of people can use ocean data and see the utility of it.
Erica: Do you think there’s anything that current scientists should be doing to inspire the next generation of scientists?
Oscar: One thing we need to do for the youth is to show them that they can be a scientist today. They can be exploring the ocean before they have a PhD. They just need to get comfortable looking at data.
We were challenged by NOAA to “excite the next generation” – by getting a glider to travel across an ocean basin. We started a class, initially with 6-7 students. We got a glider across the Atlantic and the students just loved being part of the science expeditions. Now the class is 70 students, and about a third are not science majors. It helps those who are just starting out to just get comfortable reading these maps and handling the data.
Erica: How has teamwork contributed to your success in science?
Oscar: There’s no way I could’ve had the career I’ve had without teamwork. When I interviewed here for my faculty job I started talking with Scott Glenn, and we eventually started a lab together and we’ve been working together for 15 years. It’s great; you get to work with your best friends. Some Europeans refer to us as “one of the most productive partnerships of the last decade.” What’s great is, you can take on big projects because you can divvy up the work. Every day we connect and discuss the objectives for the day and then we split it up and get it done. I think all the good questions now are interdisciplinary, so a lot of science is headed that way.