Arctic sea ice extent update

The image below shows sea ice extent as calculated by the Polar View team at the University of Bremen, Germany, updated August 25, 2012.

The image below, edited from the National Snow & Ice Data Center (NSIDC), shows the situation according to the NSIDC updated at August 23, 2012. It's clear that Arctic sea ice extent looks set to reach the 2007 record low within days, if it hasn't been reached already now.

For updates, see the daily images produced by the NSIDC. Note that, to calculate extent, both the NSIDC and the Univeristy of Bremen include areas that show at least 15% sea ice. In the image below, from the Danish Meteorological Institute (DMI), areas with ice concentration higher than 30% are included to calculate ice extent.

Sea ice extent update August 14, 2012

The National Snow and Ice Data Center (NSIDC) at the University of Colorado has released an update. Excerpts follow below, for the full post, see A summer storm in the Arctic.

Arctic sea ice extent during the first two weeks of August continued to track below 2007 record low daily ice extents. As of August 13, ice extent was already among the four lowest summer minimum extents in the satellite record, with about five weeks still remaining in the melt season.

Arctic sea ice extent as of August 13, 2012. Credit: National Snow and Ice Data Center

The average pace of ice loss since late June has been rapid at just over 100,000 square kilometers (38,000 square miles) per day. However, this pace nearly doubled for a few days in early August during a major Arctic cyclonic storm, discussed below.

Unlike the summer of 2007 when a persistent pattern of high pressure was present over the central Arctic Ocean and a pattern of low pressure was over the northern Eurasian coast, the summer of 2012 has been characterized by variable conditions. Air tempertures at the 925 hPa level (about 3000 feet above the ocean surface) of 1 to 3 degrees Celsius (1.8 to 5.4 degrees Fahrenheit) above the 1981 to 2012 average have been the rule from central Greenland, northern Canada, and Alaska northward into the central Arctic Ocean. 

Cooler than average conditions (1 to 2 degrees Celsius or 1.8 to 3.6 degrees Fahrenheit) were observed in a small region of eastern Siberia extending into the East Siberian Sea, helping explain the persistence of low concentration ice in this region through early August.

August 6, 2012, 06:00 GMT surface weather analysis, showing a very strong cyclone over the central Arctic Ocean north of Alaska. The isobars (lines of equal pressure) are very tightly packed around the low pressure system, indicating strong winds. Greenland is on the right side of the figure, Canada at the bottom. Credit: Canadian Meteorological Centre

A low pressure system entered the Arctic Ocean from the eastern Siberian coast on August 4 and then strengthened rapidly over the central Arctic Ocean. On August 6 the central pressure of the cyclone reached 964 hPa, an extremely low value for this region. It persisted over the central Arctic Ocean over the next several days, and slowly dissipated. The storm initially brought warm and very windy conditions to the Chukchi and East Siberian seas (August 5), but low temperatures prevailed later.

On three consecutive days (August 7, 8, and 9), sea ice extent dropped by nearly 200,000 square kilometers (77,220 square miles). This could be due to mechanical break up of the ice and increased melting by strong winds and wave action during the storm.

The image below, from the Danish Meteorological Institute (DMI), shows that sea ice extent took a huge dive early August and has consolidated since, as the winds settled down.

Credit: Centre for Ocean and Ice, Danish Meteorological Institute

Note that, to calculate extent, DMI includes areas with ice concentration higher than 30% (NSIDC includes areas that show at least 15% sea ice). 

Arctic waters are heating up

The post Fires are raging again across Russia featured the image below, showing how much sea waters in the Arctic were already warming up on June 15, 2012.

Satellite image June 15, 2012 from DMI - http://ocean.dmi.dk/arctic/satellite/index.uk.php

The animated image below shows warming of Arctic waters for the period June 13 up to July 1, 2012.

Note: This file is a 1.7MB animation that may take some time to fully load. 

Sea water temperatures in the Arctic are likely to warm up even further, as the summer sun warms up the ocean currents and the rivers, and as less sunlight gets reflected by sea ice and is instead warming up ever larger areas of water. The image below shows the extent to which waters did warm up in September 2011.

As described in the post Abrupt Local Warming, sea surface anomalies of over 5 degrees Celsius were recorded in August 2007 (NOAA image right). 

Strong polynya activity caused more summertime open water in the Laptev Sea, in turn causing more vertical mixing of the water column during storms in late 2007, according to one study, and bottom water temperatures on the mid-shelf increased by more than 3 degrees Celsius compared to the long-term mean.

Indeed, the danger is that heat will warm up sediments under the sea, containing methane in hydrates and as free gas, causing large amounts of this methane to escape rather abruptly into the atmosphere. 

The image on the right, from a study by Hovland et al., shows that hydrates can exist at the end of conduits in the sediment, formed when methane did escape from such hydrates in the past. 

Heat can travel down such conduits relatively fast, warming up the hydrates and destabilizing them in the process, which can result in huge abrupt releases of methane.

Since waters can be very shallow in the Arctic, much of the methane can rise up through these waters without getting oxidized. 

As the methane causes further warming in the atmosphere, this will contribute to the danger of even further methane escaping, further accelerating local warming, in a vicious cycle that can lead to catastrophic conditions well beyond the Arctic.

Finally, remember the image that Professor Peter Wadhams added in his supplementary evidence to the EAC. Below is an annotated version, from Arcus.org. 

Figure 6. Composite satellite measurements of sea surface temperature (SST) and real-
color land and sea ice images for the end of the summer 2011 season in the Pacific Arctic.
Note extreme temperature maximums of 5-8 °C and that multiple ice, atmosphere and
ocean processes help reinforce albedo feedbacks (after Wood et al., submitted).