By Rachel Berkowitz
As a physics undergraduate in his native Germany, Andreas Münchow got hooked on the idea of physical oceanography when he went to the UK as part of his studies. The German government offered students a year of funding to study abroad, and Münchow jumped at the opportunity to travel and live away from home.
While Münchow was studying at University College of North Wales, a US professor who was good friends with Münchow's adviser offered Münchow the chance to work with him at the University of Delaware and earn his PhD. Münchow eagerly accepted and is now an associate professor at the university’s Graduate College of Marine Studies. He spends a lot of time at sea studying the interaction between ice sheets and oceans.
PT PT: What research problems are you currently working on?
MÜNCHOW MÜNCHOW: Right now the big problem that I'm trying to tackle is how ice shelves and the ocean interact and how floating glaciers in the Arctic impact local climate. Will some of the warming that we see in the ocean accelerate the discharge of ice from the Greenland and Antarctic ice sheets? That's one of the largest uncertainties in IPCC [Intergovernmental Panel on Climate Change] reports about how warming temperatures are impacting sea-level rise.
Research questions include heat and mass balance and how the ocean actually melts the ice. That brings up mixing and boundary layer questions, dynamical feedback, and where the ocean, ice sheet, and bedrock intersect.
PT PT: What were the main goals of the Nares Strait expedition, in which you sailed along the channel connecting the Arctic Ocean and North Atlantic Ocean to the west of Greenland?
MÜNCHOW MÜNCHOW: The Nares Strait project was a field study to investigate how the relatively fresh seawater and ice in the Arctic Ocean is related to the water in the North Atlantic Ocean. This project was started in 2003 with Oxford University's Helen Johnson and with Humfrey Melling [of the Institute of Ocean Sciences, Fisheries and Oceans Canada].
The Arctic has two major connections to the North Atlantic. To the east of Greenland, the seas were a cold war battleground and have been really well studied over the last 30 to 40 years. But we knew nothing about what was happening to the west of Greenland, and that's what started the Nares Strait project. We wanted to complement the studies on the east side of Greenland and see whether fluxes of heat, salinity, and ice are comparable.
The new data impact how people do numerical modeling of the entire globe, as we previously only had data on one of the two connections from the Arctic to the Atlantic.
PT PT: What is the most challenging thing about Arctic field work?
MÜNCHOW MÜNCHOW: The most challenging thing is getting to the place you want to go. It's very remote and requires gathering resources together. Getting the ship and the funding is the first objective. But then you have to work with the people on the ship to travel to remote places without endangering lives. For example, the Petermann Glacier was spawning ice islands like crazy, and we wanted to get near or into the fjord to take measurements where no ship has entered before because it has never been open water.
PT PT: What does a typical day on an Arctic research trip involve?
MÜNCHOW MÜNCHOW: A typical day involves lots of waiting and being ready for things to happen on a moment's notice. The ship may all of a sudden be at a location that was unexpected, so you're always improvising, but trying to do so in a systematic way.
On a typical day on the 2012 expedition during which we wanted to recover the moorings [instruments stationed on the sea floor], we have to know the ice conditions to gather as much data as possible, including satellite data, prior knowledge, and prediction of tides. Once we have the right location, we get some acoustic instruments that let us ”talk” to instruments moored at the bottom of the ocean. We send them a signal to bring them to the surface. Then we send out a Zodiac [inflatable boat] to tow the instrument to the crane next to the ship, bring it on the ship, clean it, connect it to a computer, and download data. While that's happening, another two to three people prepare to take measurements of the temperature and salinity at that location, while the ship is preparing to move to the next location and the process is repeated.
This can be repeated for up to 18 hours! It becomes routine because you work in tiny groups, including the ship crew and the captain, so it becomes one incredibly skilled team where everyone knows exactly what to do.
PT PT: Did your PhD involve much field work? What questions were you trying to answer?
MÜNCHOW MÜNCHOW: During my PhD, I was trying to learn what happens to freshwater from a river if it discharges into an ocean. The scale at which the Coriolis force becomes important is within 5 to 10 km of the coast, so this flow pattern is basically an effect of the Earth's rotation on the different density of water between river and ocean. I started small scale, but that's the connection to what I'm doing now: Exactly the same physics apply. A reservoir discharging into the North Atlantic Ocean creates a stratified flow and has similar dynamics to river discharge.
PT PT: When did you have your first field work experience, and how did it influence your career?
MÜNCHOW MÜNCHOW: My very first field work was during my studies in Britain, camping by the Conwy River in North Wales to guard the temperature and salinity measurement instruments that I had set up in the Conwy estuary. I was trying to measure salinity intrusions into the estuary, and I found it exciting that I had been given these instruments and been allowed to think the whole project up myself.
PT PT: How has physical oceanography changed over the course of your career?
MÜNCHOW MÜNCHOW: When I started working in the Arctic, there were lots of people who said you can't do that, there's too much ice, so you won't be able to get there. But every year until now, from 1993 when I was first in the Arctic, I can see the difference in ice coverage. The ice is disappearing. I talk to people who went to sea in the 1960s and 1970s, and they say the work we're doing now would have been impossible back then.
The ice is disappearing over the course of a generation. In the 1990s we were running into ice in the Arctic, but now we can sail there [in open water]. It's a sad story because the planet is changing on a short time scale.
PT PT: Where do you see the future of physical oceanography going?
MÜNCHOW MÜNCHOW: This is sad in a way, but I see oceanography going further away from field work because it's very expensive. A lot of field work will be replaced with computer modeling. I like computers, and I work with them all the time, but I fear that the excitement of field work and the reality check of field observations will slowly disappear. Satellite radar doesn't penetrate the surface to give the same detail as sea-based observations.
We'll still be modeling circulation patterns and how flows affect the North Atlantic mode, but computer modeling requires parameterization: How real is it? Models are getting better, but you need a reality check.
PT PT: Have you ever seen a polar bear?
MÜNCHOW MÜNCHOW: Absolutely! And narwhals and walruses. That doesn't happen every day, but when it does, everyone on the ship turns into a tourist.