A LAYMAN’S OBSERVATIONS CONCERNING ARCTIC SEA ICE VOLUME

VIEW LAST YEAR ON AUGUST 5

NP last year Aug 5 npeo_cam1_20120805201206

VIEW THIS YEAR ON AUGUST 5

NP Aug 5 npeo_cam2_20130805065710

One thing I notice while comparing the pictures of this year and last year is, (beside the obvious fact this year is colder and this year’s picture has no melt-water,) is that this year’s picture has more pressure ridges.  I  assume this suggests that the same area of ice has a greater volume, because it is thicker at those pressure ridges.

Much of what I notice cannot be called “scientific,” because I’m just using my eyes, but  I don’t feel my lack of science should cause me to be discredited.  After all, who would you rather have playing in the outfield in a baseball game: A non-scientific guy who just uses his eyes, and sprints to where the ball flies, and catches it, or a scientist who uses a slide-rule or computer keyboard, and is so busy calculating that the ball bounces off his head? However it would be nice to have a few numbers at my finger-tips, just so I could look a little bit scientific, even if I’m not.

One thing I’ve been paying attention to is the drift of the ice.  It is generally south towards Fram Strait, but this year it keeps pausing and backing up.  Try this on the south-bound lane of a freeway, and I bet you’ll gather scientific evidence of a pile up.  That is what a pressure ridge is, in my eyes.  A pile up.

Recently the ice sped up and for six hours and was moving along at a 0.2 miles per hour.  How did I figure that out?

In my youth I sailed, and they measured things in miles, and also a degree of latitude was devided into sixty “minutes,” and, because a degree of latitude is sixty miles, each “minute” was a mile.  Nice and simple, but then they went all decimal on me.  Now you need to know a tenth of a degree is six miles and a hundredth of a degree is six tenth of a mile. (You figure out the kilometers, if that is your cup of tea.)

By looking at the data at  http://psc.apl.washington.edu/northpole/PAWS819920_atmos_recent.html I can see that between 1200z on August 4 and 300z on August 5 the camera was moving south at a hundreth of a degee latitude every three hours.  If you devide that 0.6 by three, you get 0.2 miles per hour.  However then it slowed, and the last available data (yesterday’s) shows it is only moving three thousandth of a degree every three hours, or a thousandth of a degree per hour, or 0.06 miles per hour.

Ice chunks tend to tailgate on the ice highway, and because they do not allow for a proper braking distance, when one brakes then up the highway there has to be some sort of pile up.

Longitude is a real pain, especially up near the pole.  For example, if you are standing a stride from the pole, a single stride to the side will cover 90 degrees longitude, but if you are standing two strides from the pole, the exact same stride will cover only 30 degrees.  Therefore I’m not even going to try to give longitudinal measurements in miles.  However I feel it is noteworthy that yesterday the ice at Camera Two was moving west, came to a screaming halt, and now is heading east.  This business of changing lanes without the proper use of turn-signals has got to cause pile ups to either side, on the Ice Highway to Fram Strait.

Besides the figures we have for Camera Two, we have another Buoy located roughly 79 miles to the north northeast, called “PAWS Buoy ID 975420.”  Located on a separate plate of ice, it represents another vehicle on the ice highway, and it is interesting to compare its smashing and crashing with the smashing and crashing of Camera Two.

Ignoring the sideways lane-changing of longitude for the moment, it can be seen that both slammed on the brakes and went in reverse between 600z on August 1 and 1200z on August 2.  However Camera Two backed up .052 degrees of latitude, while the northern bouy only backed up .039 degrees.  In terms of latitude alone, the distance between the two narrowed by .013 degrees.  I make that to be .78 miles.

Now, if we were dealing with latitude alone, you would have a situation where, on the ice highway, PAWS Buoy ID 975420 blared his horn, swore like a Boston driver, there was a tremendous crash, and he had a really ugly rumple in the hood of his car.  You take .78 miles of ice and crunch it into a pressure ridge, and that is one heck of a pressure ridge.

Of course we need to add in the sideways motion of longitude.  PAWS Buoy ID 975420 likely changed lanes like a Boston driver.  However there was likely some serious bumping going on, and some pressure ridges were built, (as well as gaps and leads opened up.)

I will leave it to those more scientifically inclined to figure out the distances involved in longitudinal motions.  My point is that, as I pointed out in an earlier post, not all plates of ice are created equal.  Some plates are “baby ice,” nice and flat, and between three and nine feet thick.  But other plates include pressure ridges, and can be as much as a hundred feet thick where those pressure ridges are located.  If you simply look at a picture from outer space, and use some sort of standard area-based equation to determine the volume of the collected plates, chips and crumbs of ice you can see, you are ignoring the fact that different plates have different histories.  If you bang about “baby ice” long enough it starts to include pressure ridges, and is no baby any more, and perhaps deserves a new name, perhaps “Boston driver ice.”

I am aware we have maps that portray the thickness of arctic ice, such as the Navy map at, http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictnowcast.gif however the problem with such maps is that a pressure ridge is too thin to show up.  It would be thinner than a hair on such a map.  In fact it would be as thin as the flagellum of a bacteria, and the map would require one heck of a zoom feature to even see the darn thing.

Therefore I just use my eyes, and notice the pressure ridges seen from Camera 2, that were not so common last year.

Before I close, I would like to gloat about something just a bit.  You see, last spring I faced some friendly derision for predicting the sea ice extent would only get down to six million square kilometers.  I claim to have used no science, and only to have used my eyes.  Now, (perhaps only for a brief time,) there seems to be a small chance I could actually be right.

If, against all odds, I turn out to be right, I will be like the outfielder who caught the ball.  Some scientists, far better at math than I, will be rubbing their heads because they didn’t use their eyes.

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