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 2006-2009. The IJIS graph is favoured by almost everyone, probably because it looks so nice compared to other graphs (like the one by Arctic ROOS, the University of Bremen and the Danish Meteorological Institute). All the years have a nice colour of their own which makes it easy to eyeball the differences between trends. Most of the betting on minimum SIE is based on the IJIS data. NSIDC has a nice explanation of what sea ice extent is in their FAQ.
July 29th 2010
We are near the end of the month of July and weather conditions have improved somewhat, but still no century breaks in sight. Although the ice looks particularly grey and fragile on satellite images, it is apparent that the losses in extent are partly compensated by a spreading out of the ice in the Beaufort, Chukchi and East Siberian Seas. According to the last SEARCH outlook some of this ice is supposed to be pretty thick, having been transported a long way from home during last winter's extreme negative Arctic Oscillation.
The big question now is: will this sea ice be spread out long enough to keep extent deceptively high until things start refreezing? And that is counting on weather conditions to stay the way have been since the start of July. What happens if weather conditions reverse and stay that way till the end of the season (instead of the to and fro we are witnessing the past weeks), like they did in 2008? Either way, whether ice melts in situ due to air and sea surface temperatures - which will become more difficult by the day - or the ice gets pushed towards the Pole and compacted, extent melt rates will have to seriously start to pick up for 2010 to stay in the race.
Since the last SIE update I was really expecting a century break to be reported, what with high sea level pressure areas developing in the right spots, sea ice area trends decreasing uniformly and large PIPS ice displacement arrows pointing towards Fram Strait. Clearly, the Arctic decided otherwise. And so all we've seen reported by IJIS were decreases that were slightly above the month's average rate, which is of course pretty low itself: 69,531 square km for the 25th, 73,594 square km for the 26th, 68,437 square km for the 27th. And today's reported melt was especially low again with 37,032 square km.
This means that 2009 has taken over 2nd place, although 2010 might clinch it back as 2009 will start to level off soon. 2008 is about to start its final sprint though, with four century breaks next week, just like 2007, which is strolling further and further out of sight.
The current difference between 2010 and the other years is as follows:
2006: -208K (70,025)
2007: +604K (98,609)
2008: -344K (81,069)
- 2009: +30K (92,127)
The average daily melt for the month of July is between brackets. 2010's average daily melt for July is currently 61,808 square km per day.
And here's the IJIS sea ice extent graph:
Compare this to the IJIS sea ice area graph:
Remember, when analysing satellite images a grid cell representing a surface area of 25kmx25km is added to total extent when at least 15% of the grid cell contains ice (and is then counted as 100% ice). With area the actual ice percentages of all grid cells are added up.
From the graph it is obvious that the spreading out of the ice is not having an effect on the steady decrease in area since the start of July. This is also reflected in the Cryosphere Today sea ice area graph that dropped from an anomaly of almost 2 million square km (compared to the 1979-2008 mean) to 1.150 million square km, but has crept back to 1.418 million square km:
Most of this is due to melt on the Siberian side of the Arctic, but the trend of the Arctic Basin sea ice area has also been dropping for a few days in a row now:
This short animation of the PIPS ice displacement forecast of the last 10 days shows things are still very erratic, but at least the arrows are big. No Beaufort Gyre as of yet, but some ice transport towards Fram Strait seems to be happening:
According to weather reports and forecast models like ECMWF we won't be seeing any stabilisation of sea level pressure areas for the coming week or so, but the Arctic Oscillation is slowly shifting from positive from neutral, which indicates that high pressure areas are creeping closer towards the Pole:
TIPS - Other interesting blog posts and news
concerning the Arctic
and its ice:
It's about Arctic explorer Robert McClure whose ship HMS Investigator has been found. I reported in the last SIE update that the search was under way, but these guys seem to be fast. Don't be surprised if they find Franklin's Eurebus and Terror next week. ;-)
Robert Grumbine has a short piece on AGW predictions in the past for Antarctic sea ice cover.
From the San Francisco Chronicle: A new study has found that
the quickest, best way to slow the rapid melting of Arctic sea ice is to reduce
soot emissions from the burning of fossil fuel, wood and dung.
Ousland and Thorleifsson, the two Norwegian adventurers who are trying to circumnavigate the Arctic in one season, have just left Murmansk. In 10 days or so they will reach the islands of Severnaya Zemlya. Hopefully the ice that is still blocking the Northern Sea Route over there, will have subsided.