Post from a Scientist: “Swirling Eddies”

My last lecture was on satellite observations of oceanic eddies. Eddies are regions of rotating water, surrounded by non-rotating water. Eddies of different spatial scales evolve into the movement of great amounts of water, and therefore play an important role in the redistribution of pollutants and the delivery of nutrients for phytoplankton.

Eddies off the coast of France and Spain, Image: http://visibleearth.nasa.gov

Eddies off the coast of France and Spain, Image: http://visibleearth.nasa.gov

First we looked through some satellite imagery showing various manifestations of eddies. In thermal imagery, eddies can be seen due to differences in sea surface temperature between the inside and outside of the eddies. In visible imagery, eddies are visualized by suspended particles in the water, which serve as passive tracers of their formation. In radar imagery, it is either surfactant films or enhanced signal backscattering on shear currents which make eddies visible.

 Then, general ideas of eddy generation were discussed. Eddies can appear either due to velocity and density gradients in the water (in the photo I am demonstrating a gradient with my arms) or by applying a direct action. Among the most important physical reasons of eddy formation are friction caused by a coastline, fronts (borders between waters with different characteristics), variations in the coastline and bottom topography, and obstacles (like islands).

mini-IMG_2075_2

Finally I presented some results of my own research. I have studied mesoscale eddies (with a diameter of several tens of kilometers) and submesoscale eddies (up to about 20 km) in the Baltic, Black, Caspian, Red, and Mediterranean seas. Within this study I had to visually analyze about 10,000 images of different types and I manually detected about 20,000 eddies. As a result of this hard job, for the first time the areas of the most frequent eddy observations were defined, and the statistical parameters of eddy spatial scale were retrieved.

 I think that in general the lecture was interesting. Now I can be more relaxed and spend more time enjoying the severe Arctic weather outside.

 - Svetlana Karimova

Eddies in the Gulf of California. Image from http://visibleearth.nasa.gov

Eddies in the Gulf of California. Image from http://visibleearth.nasa.gov

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14 Responses to Post from a Scientist: “Swirling Eddies”

  1. Amanda Robaina says:

    How does the atmosphere interact with your technology?

    • lindsay says:

      Hi Amanda, there are a lot of things going on in the atmosphere – we study and monitor the motion of parts of the atmosphere, the chemical composition, how it interacts with the surface (whether that surface be ice, ocean, or land), the temperature, humidity, and more. And we use different tools and techniques for a lot of those things. It’s amazing to look at the air and imagine so many details in it!

  2. Rachel Muller says:

    How does the field of physics relate to the work that you are doing in the arctic?

    • lindsay says:

      Hi Rachel, physics is everywhere on the ship – from how the ship moves through the ice, to the formation and changes in the ice conditions due to temperatures and motions, and how we lower equipment into the ocean with pulleys and gears, to the acoustic and electronic signals we use to communicate with the instruments. So it’s everywhere, quite literally! :)

  3. Nicolette Hill says:

    Hey Lindsay, I wanted to if you noticed any changes in the arctic since you’ve started your expedition.

    • lindsay says:

      Dear Nicolette, although we have seen different conditions throughout the expedition, in terms of temperature and ice conditions, we cannot say that we have seen “changes” in the climate since we have been here, because by definition, “climate” refers to conditions over huge distance and long time scales (like decades or more). But over the last couple decades, the climate has definitely been changing.

  4. Yohandra Polanco says:

    Hey Lindsay, do you happen to know if swirling eddies have anything to do with how random organisms appear in different parts of the world? I ask this because I read that “swirling eddies play an important role in the redistribution of pollutants and the delivery of nutrients for phytoplankton”.

    • lindsay says:

      Hi Yohandra, yes, anytime you have movement of water, you will also have movement of organisms, nutrients, and pollution. Some species are even “drifters” and drift along with currents

  5. Daniella Guilarte says:

    Dear Lindsay, Due to the ice in the Artic, does the ocean have any warm water? Or parts that have temperature higher than other parts of the ocean?

    • lindsay says:

      Hi Daniella, the water temperatures at the surface don’t vary by much for a given season in the very high Arctic, but the temperature of the water depends on the layer. Sometimes, currents come in from other places, like the Atlantic, which are warmer and sometimes at a different depth.

  6. Zenaida Debesa says:

    Hey lindsay! I was wondering, how does science and math relate to your arctic expedition?

    • lindsay says:

      Dear Zenaida, science and math is everywhere: the formation and movement of the ice, how the atmosphere affects the sea ice, how the equipment works, how to analyze the data, how the ship’s motor and navigation works, how the technology of satellites work to observe conditions (and help me send information for the blog), etc!

  7. Yanelis Garcia says:

    Hi Lindsay, I was wondering if oceanic Eddies and the ocean acidification is putting any animal species in danger?

    • lindsay says:

      Hi Yanelis, actually yes, ocean acidification is already affecting coral reefs in the ocean, which are becoming “bleached” due to acidification. Also, any animals that have shells (generally made of calcium carbonate), are not able to grow shells as thick and strong as they need to be, because of the more acidic waters.

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