Arctic sea ice

There is a lot of talk about sea ice areas and extents without much in the way of good information being provided. I’ve spent some time over the past year or two creating my own versions of the data. The data is often poor.

One finding was there is no material difference between extent and area data. (ask if you want to know more)

I prefer working with best data, the least preprocessed by other people and in this case I have managed to create a daily Arctic extent dataset.

Two datasets are used.

  • NASA Stereo which starts end 1978, data is every other day at first, then daily. It is of reasonable goodness, suffering from the usual multiple satellite problem, inconsistent data. The published data ceases end Dec 2007 and asking for newer data brought a curt response. Seems the authors do not want to update it. Noting where it ends and the general politics, go figure.
  • IJIS/JAXA which seems the only currently published daily data. Unfortunately this originates from a different satellite, the geometry differs, hey ho the earth has two different figures for ice extent and only Arctic extent.

Previous work showed it was probably feasible to map one dataset to the other and that is what I have done, mapped the older dataset to the new, result new data can be added to the end of the dataset.

I also want to know deviation, the annual cycle is a nuisance, this is easy enough to do.

Here is one result. This took a lot of work and is the best I can do at the moment. Improvement are of course always possible.

You will need to open it full size.

The plot is low resolution, without proper data decimation, etc., it would be thousands of pixels wide otherwise. (quick math, >10,000)

NASA data bent to the same law as IJIS data

IJIS/JAXA data

The overlap period is marked and so is the reference period.

Finally the deviation.

As of May 2010 the ice situation continues to be increasingly ambiguous and I have no idea what is happening. Seems most likely we are going through a time of change, happens from time to time, 1970s was one.

Fundamentally not a lot is going on with the ice, to me a little amusing given many people are screaming.

Anyone wanting more detail, here is current at higher resolution, click on the image as usual for full size.

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