I think people were really inspired by the “Met Tower” I wrote about a few days ago, because a lot of people have asked lots of questions about it. So I spoke with Irina Repina, the lead scientist on the expedition for this work, and I wanted to give everyone a little more information about it. As a reminder, or for readers new to the blog, the Met Tower (“met” is short for “meteorological”) is meant to help us understand the interactions between the sea ice and the atmosphere. It measures temperature as well as wind speed and direction, using a sonic anemometer that measures wind speed in 3 dimensions. The idea is to measure the “turbulent flux” – in other words, the exchange of heat and momentum – at the boundary between the ice/ocean and the atmosphere. These measurements are very sensitive, and need to be very accurate, so you can imagine why it is more difficult to take these measurements on the ship. I can tell you firsthand that the ship is its own source heat, movement, and turbulence! So when there is a chance to get out on the ice, it is a special opportunity to use the Met Tower!
The reason why this is so important to understand is that the interaction at this boundary not only has local effects, but global effects as well, due to the global circulation of the atmosphere and oceans. In the Arctic, there are lots of different kinds of surfaces: open water (calm or stormy), solid ice (of different thicknesses and ages), melting ice, ice combined with open-water “leads,” etc. This makes for a really complex set of circumstances when trying to figure out how energy is exchanged between the atmosphere and the ocean. On one hand, the presence of sea ice impedes the heat exchange at the atmosphere-ocean boundary. On the other hand, the very presence of ice is determined by the intensity of that heat exchange. So the goal of the Met Tower is to get direct measurements of these turbulent fluxes which affect the entire atmosphere-ocean-ice system. So next time you look at one of those beautiful pictures of the Arctic that seems so calm and serene, think about all of this turbulence and complexity. Even though we can’t see it ourselves, the Met Tower helps us figure it out.
Try This!
A lot of the phenomena we see in the atmosphere have analogies in the ocean – because liquids and gases are both fluids. Winds and ocean currents are generated by heat differences across distance, and both have the effect of distributing heat. Try gently lowering a small container of hot, colored water (use food coloring) into a larger container of cold water. What happens? What do you think causes this effect?
What happens when the water flows into the ice , does it become denser do to the cold?
Hi Marcos, yes, as the water flows into regions with sea ice, it sinks under the less dense water. In the Arctic, these surface waters will be also very cold, but less salty, so they are less dense than the incoming water.
Hi am student from ms.gilbret class how do the satellites collect data for your expendiction?
Hi Kenya, that’s a really good question, and we have had about 4 presentations on the expedition about that! 🙂 Satellites are really important to our expedition, and also important to how we know about what’s going on in the Arctic. By orbiting the Earth, satellites can continually monitor and take images of the Earth. This is how we know that sea ice levels have been decreasing over the last few decades. Satellites also give us information about the ice conditions, which help us plan our navigation through the best possible route!
Hi am student from ms.guilbret how does artic water impact with other oceans
Hi Kenya, actually a lot of scientists here are working on that exact idea. If you look at a map, the Arctic is connected to the other oceans in a couple places, but the widest and deepest pathway is between the Arctic and the Atlantic Oceans and is called the Fram Strait, alongside Greenland. Currents pass through the strait in both directions, and since water from each ocean has unique characteristics, changes in one ocean can affect the other. For example, the Gulf Stream in the Atlantic becomes the North Atlantic current, which then moves into the Arctic. Each mass of water has different temperatures, salinities, etc, so scientists can actually track water from one place to another.
Hello, Lindsay. I was just wondering, given how many scientific instruments you guys use, is there anything that directly measures the rate at which arctic sea ice is melting or forming to help predict the rate of rising sea levels?
Hi Jennifer, the way that we measure the amount of Arctic sea ice and observe how it is changing over time is not with equipment onboard, but with what’s in the air. Satellites have shown that the extent of Arctic sea ice has decreased over the years, and scientists use that data to predict future levels based on previous trends.
Why is gas a fluid in your experiment?!?!?!?!?!?!?!
Hi Xander, actually gases are always considered “fluid” because they have no fixed size or boundary, and can flow, almost like liquids (molecules in gases are just not bound together as tightly as in liquids).