MYSTERY

Another beautifully sunny day, entirely worthless for albedo measurements. We stopped by our Tent Island study site anyway, just to say hello to the seals and make sure the local street gangs (groups of young, disaffected Adelies, mostly, looking to rumble tourists for pebbles) hadn’t vandalized it.

You may recall that we spent quite a while last week, on the 4th, doing janitorial duty on the ice, clearing off the crust of salty snow that was clinging tenuously to the surface. We came back a few days later on the 7th and the surface was still perfectly clean.



Our beautiful clean ice.

We came back today to find this:



VANDALS





The top photo shows the old crust, which we originally assumed had been there for months. The bottom photo shows the new crust--the bumps are slightly smaller and it's softer, but otherwise strikingly similar.

This is intriguing, because, as I mentioned before, we originally figured that the peculiar snowy crust on the ice must be composed of old frost flowers. However, frost flowers only form on new sea ice. This sea ice is several feet thick and months old. And this new snow crust isn’t just composed of snow fallen from the sky, because that would be fresh; this is salty.

There have been a couple of warm days since the 7th, and a minor storm (seen here out the front of the pisten bully as I attempt to drive home through it):



Fortunately there is nothing to actually run into out here.

But, frankly, we’re pretty stumped as to what could have regenerated the snow crust like this.

After visiting the study site and scratching our heads over unusual snow phenomena, we headed up to Cape Evans to visit Cape Evans Hut, used by both Scott and Shackleton during various Antarctic expeditions.



Cryogenically preserved ketchup



More picturesque than our lab, if rather smaller.

Oh, and here’s our second mystery of the day: we discovered, on examining the high-resolution pictures, that a century-old British paper from the hut has a front-page story about an injury that occurred in the small town of Saranac Lake, New York. Saranac Lake, New York also happens to be the town that Rich calls home. Bizarre coincidence, or prophetic attempt to communicate across a vast span of time and space?

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6 Responses to “MYSTERY”

  1. vida morkunas Says:

    what is the thickness of the ice in the area that you drive through? sure you won’t bump into anything, but is there any danger of driving over thin ice?

    • psychroteuthis Says:

      This late in the season, most of the sea ice is upwards of 1.5 meters thick–they land planes on it, quite large ones. I posted about how we test sea ice for safety, but we haven’t really had to do that very often.

  2. Teri Carns Says:

    So you’re archeologists and anthropologists as well as albedo experts.

    We need to hear more about the Adelies –did I miss something?

  3. Lucas Says:

    Does anybody else you know at McMurdo have any ideas about the salty snow? If not, this might be an interesting opportunity to document an interesting phenomenon. My (very tentative and minimally informed) hypothesis would be that the top layer of the sea ice is subliming and resolidifying as snow. The salt won’t sublime, of course, but it’s conceivable that you’d get pure water subliming and solidifying as snow, with the salt still trapped in microscopic crystals within the matrix.

    If you’re bored and have the facilities to do so, my suggestions would be the following:

    – Scrape some sea ice clear and measure its depth (to as high a precision as possible) and salt content.
    – Set up some equipment to keep a continuous record of temperature and barometric pressure at the site.
    – After the snow forms, scrape it off and either analyze on site or store cold and take it back. Also re-measure the depth of the ice, assuming you can do so precisely enough (I’d expect millimeters of ice to become centimeters of snow, so maybe not).
    – Measure salinity of snow, and examine under a microscope to look for different crystal morphologies. If you see two distinct phases, that’s interesting in itself, and you may be able to correlate with known crystal morphologies of pure water and salt water. If the crystals are big enough, you may be able to isolate enough of them to get salinity measurements of both, but that might just be a huge pain.

    • psychroteuthis Says:

      Excellent points.

      Alas, I don’t think it’s possible to measure sea ice depth to that level of precision. The bottom of the sea ice is made up of large, flat platelets of ice that form when supercooled water comes up from underneath the ice shelf (this is what the Kiwis are studying, and it’s a whole interesting post in itself.) But that means that there’s no readily definable “bottom”, just a transition from platelety ice to more solid ice.

      The other interesting thing that we just found out, on looking at the high-res pictures, is that the crystals in the new snow are very rounded. If they were the result of ice subliming and re-crystallizing, they should be faceted. On the other hand, if the ice sublimed and re-crystallized and then got some salt on it, maybe wicked up from the surface of the sea ice, then melting might round off the edges.

      Hadn’t thought of looking at barometric pressure. I may suggest we add that to the data logger we’re setting up. Whee!

  4. Audited by Emperors « Squid on the Ice Says:

    […] by Emperors By psychroteuthis I made a comment in a previous post about gangs of ne’er-do-well Adelie penguins vandalizing our site. That was, of course, a […]

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