During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good explanation of what sea ice extent is in their FAQ. I also look at other things like sea ice area, concentration, volume, temperature and weather forecasts, anything that can be of particular interest. Check out the Arctic sea ice graph webpage for daily updated graphs, maps and live webcam images.
April 1st 2011
The month of maximums, March, is behind us. There has been some very careful speculation on whether we would see a triple top, in other words an even later maximum than last year. I don't believe we will, but what we definitely are seeing resembles last year in that atmospheric patterns have slowed down the start of the melting season, making extent and area numbers hover around the same figures ever since the last update. More on that at the end of this update.
Edit: In the comments Lodger linked to a cool animation from NASA, covering the ice growth from September 16th 2010 till March 16th 2011:
Due to the stalling decrease of SIE numbers the trend line for this year on the IJIS graph has stopped following the pack of low extent years (2005, 2006 and 2007) and is moving towards the pack of high extent years (2008, 2009 and 2010):
The current difference between 2011 and the other years is as follows:
- 2005: +210K(-13,332)
- 2006: +497K (-11,704)
- 2007: +294K (-9,894)
- 2008: -370K (-10,761)
- 2009: -212K (-10,746)
- 2010: -654K (+13,402)
Between brackets is the average daily extent rate for the month of March. The daily average for March 2011 has finished at +2,964 km2, which is considerably higher than most other years, except of course for the highly anomalous 2010. March ended at a total of 13,753,438 km2 which is still 135K below the maximum reached 3 weeks earlier. If the current weather patterns persist there is a very small chance that we see a new SIE maximum, but I sincerely doubt it as the window for melting is starting to open up and SST and insolation start doing their work.
The same goes for the Cryosphere Today sea ice area (SIA) numbers. Although the decrease has stalled there as well, the ice pack would somehow have to gain over 230K at the edges to threaten the maximum, which is a lot at this time of year. What we do see however, is that the anomaly trend has seriously jumped over the 1 million mark and is currently at 0.93 million square km below the 1979-2008 mean. The trend is still flatlining, but a few more days of slow decreases and we could still see the trend line go up a bit before the recent annual anomaly dip towards 2 million km2.
If we look at individual CT regions, it's obvious that the Barentsz Sea is still anomalously low, although there has been a steep rise since last week. The Kara Sea SIA is also on the rise, after a very early dip at the end of this month (the same goes for the Laptev Sea, albeit at a lesser degree). The Bering Sea
has also improved somewhat and even looks a bit better on MODIS images since my post on it. It looks like the ice reduction action has moved to the Baffin/Newfoundland Sea where SIA has dropped precipitously in the last week. Something to keep an eye on.
The downturn in sea ice extent/area decrease was also reflected in one of the handiest tools for short-term prediction, the PIPS ice displacement maps. When arrows are small, I'm guessing the ice isn't moving very fast which gives the water a chance to freeze up, and this shows up in the extent/area numbers. Take for example the forecast for tomorrow:
The reason for a lack of ice movement has all to do with the winds of course. And the winds have to do with atmospheric pressure. The Arctic is currently dominated by low pressure areas, cyclones, but apparently these aren't the monsters that are more common in the middle of winter. Nevertheless, the Arctic Oscillation index is highly positive at the moment:
And it might even get more positive if the forecasts are to be believed:
All in all the end of the winter season is looking very interesting and instructive. As always in the Arctic. Will we see a new maximum?
TIPS - Other blog posts and news articles concerning the Arctic and its ice: