bluewave

It would probably take an extraordinary circumstance to ever see a September minimum extent above 6 million sq km after the damage that was done to the ice during the 2007-2012 era.

Tough to beat the 2012 extent record with such a strong summer polar vortex pattern since then. But 2007 will probably go down in history as the year that the Arctic permanently shifted to this warmer state with reduced sea ice. Even recent numerous more favorable summers haven't allowed the sea ice recover to pre 2007 levels. Our best year now is still lower than anything that came before 2005-2007.

Coming up on the 7th anniversary. Just turn down those speakers.

It will be great to get the rainfall and wind measurements which have been lacking for the Bronx.

New rooftop mesonet site for the Bronx. It's 189 feet up so the temps will be different than the surface. http://www.nysmesonet.org/mesonow#?stid=BRON

I got a chance to watch the new jetty building operation the other day when I was down in Long Beach. Pretty impressive job at beaches like Neptune where all the boulders are piled up on the beach by a stream of trucks. The beaches especially on the east sides of the new jetties have really gotten longer. It's becoming more of a walk from the boardwalk to the ocean than it used to be as the longshore current piles up the sand against the new jetties.

Typical post 2012 summer with stronger polar vortex conditions preventing a challenge to the 2012 record minimum extent. This summer was right down the middle between 2013-2014 and 2015-2016.

Update from NSIDC: https://nsidc.org/arcticseaicenews/ Ice retreat from August 1 to August 21 averaged 73,000 square kilometers (28,000 square miles) per day. This was faster than the 1981 to 2010 average rates of ice loss of 57,300 square kilometers (22,000 square miles) per day, but slower than in 2012, which exhibited the fastest rate of ice loss compared to any other August in the passive microwave satellite data record. Normally the rate of ice retreat slows in August as the sun starts to dip lower in the sky. The rate of ice loss was more rapid at the beginning of August, slowing down considerably starting on August 17. Air temperatures the first two weeks of August were 1 to 3 degrees Celsius (2 to 5 degrees Fahrenheit) cooler than the 1981 to 2010 average throughout the Arctic Ocean and over Greenland and the North Atlantic. The lowest air temperatures relative to the long-term average were found in coastal regions of the Kara and Barents Seas, continuing the pattern seen throughout much of this summer. Cooler than average conditions within the Central Arctic were a result of persistent cold-core cyclones. These cyclones have not been as large or as strong as the Great Arctic Cyclones of 2012 and 2016, despite the central pressure of one of these systems dropping down to 974 hPa on August 10. In addition, these cyclones are located closer towards the pole within the consolidated ice pack, where they are less likely to cause significant ice loss, as did the 2012 Great Arctic Cyclone in the Chukchi Sea. While air temperatures start to drop in August, ice melt continues through the month as heat gained in the ocean mixed layer during summer continues to melt the ice from below and from the sides. Sea surface temperatures have been up to 5 degrees Celsius (9 degrees Fahrenheit) above average near the coastal regions, but generally near average or slightly below average along the ice edge in the Beaufort and Chukchi Seas

No problem. We may be able to further decline the anomaly if we can avoid the historic warmth that we saw last Oct-Dec. That may set the volume up to come into next summer a little better than we saw this year. The state of the sea ice next summer will then come down whether the less hostile 2013-2017 stronger polar vortex pattern can prevail another year. Or the 2007-2012 dipole pattern makes a return. Be interesting to see how many more years the 2012 can hold on. The reversal of the summer pattern in 2013 turned out to be a surprise that people didn't think was possible during the fall of 2012. But some studies came out in early 2013 that mentioned this possibility. Long term sea ice decline with increases or decreases in the short term rate.

One of the greatest early August anomaly decreases on the PIOMAS with the cool and stormy pattern in the Arctic. Also among the strongest polar vortex patterns for the first half of August.

Much cooler summer regime since 2013 with low pressure dominating instead of high pressure. Likely quite a bit of snow has fallen from this Arctic cyclone... Wish the polar bears could report obs [Map: esrl.noaa.gov/psd/people/amy…]pic.twitter.com/nrL6U5LplZ

Yeah, the record August 2012 storm seemed to be the exception to the rule. http://nsidc.org/arcticseaicenews/2012/08/a-summer-storm-in-the-arctic/ Low pressure systems over the Arctic Ocean tend to cause the ice to diverge or spread out and cover a larger area. These storms often bring cool conditions and even snowfall. In contrast, high pressure systems over the Arctic cause the sea ice to converge. Summers dominated by low pressure systems over the central Arctic Ocean tend to end up with greater ice extent than summers dominated by high pressure systems. However, the effects of an individual strong storm, like that observed in early August, can be complex. While much of the region influenced by the August cyclone experienced a sudden drop in temperature, areas influenced by winds from the south experienced a rise in temperature. Coincident with the storm, a large area of low concentration ice in the East Siberian Sea (concentrations typically below 50%) rapidly melted out. 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. However, it may be simply a coincidence of timing, given that the low concentration ice in the region was already poised to rapidly melt out.

There may also be a higher degree of uncertainty in the PIOMAS data compared to other years. But we saw how the the PIOMAS and NSIDC extent widely diverged in 2013 compared to the 2007 season. Lower PIOMAS in 2013 vs 2007,but the cool 2013 summer resulted in a much higher higher September extent than 2007. http://nsidc.org/arcticseaicenews/2017/03/ It was a very warm autumn and winter. Air temperatures at the 925 hPa level (about 2,500 feet above sea level) over the five months spanning October 2016 through February 2017 were more than 2.5 degrees Celsius (4.5 degrees Fahrenheit) above average over the entire Arctic Ocean, and greater than 5 degrees Celsius (9 degrees Fahrenheit) above average over large parts of the northern Chukchi and Barents Seas. These overall warm conditions were punctuated by a series of extreme heat waves over the Arctic Ocean. Data from the European Space Agency’s CryoSat-2 satellite indicate that this winter’s ice cover may be only slightly thinner than that observed at this time of year for the past four years. However, an ice-ocean model at the University of Washington (PIOMAS) that incorporates observed weather conditions suggests the volume of ice in the Arctic is unusually low.

So far it looks like the Arctic storm has slightly slowed the decline rate as the pack appears to be spreading out a bit. The storm has brought an early freeze for the post 2005 Arctic. Right now the extent is tracking between 2007 and 2016 as 2012 pulls further out of reach.

There has traditionally been a relationship between Arctic sea ice and the AMO as we have seen with the decline in the 20's and 30's. More specifically, the region south of Greenland seems to have the largest influence on September minimum extent. When those SST's were at their warmest from 2005 -2012, there were three new records set in 2005, 2007, and 2012. The reversal to cooler SST's in this region since 2013 has been accompanied by no new September extent records. You can see the 2005-2012 rate of decline was in a class by itself with nothing else coming close. While that area south of Greenland has cooled dramatically in recent years, the AMO has still remained positive.

Recent cooler temps and stronger polar vortex let 2017 fall a little behind 2007 over the last few days.

Early dip near freezing with the strong polar vortex similar to 2014 and 2013.

It could also be related to why the Siberian October snow signal hasn't worked in recent winters with the stronger PV and more +AO/+NAO.

We missed our chance to beat 2012 when the strong dipole pattern of 2007-2012 failed to emerge in June. So the 2012 extent record will remain safe another year. The HadGem model did a great job back in 2012 showing a slower rate of loss vs the extreme 2005-2012 loss rate. I am wondering if the dramatic dipole reversal following the historic 2007-2012 rapid melt seasons is a result of the weaker AMOC? http://nsidc.org/arcticseaicenews/ In the far northern Atlantic, warm water flowing northward from the tropics is cooled by the atmosphere, becomes denser, and eventually sinks to great depths. The descending water is key in driving a sub-surface and surface ocean circulation system called the Atlantic Meridional Overturning Circulation (AMOC), which is part of the global ocean conveyor belt of heat and salinity. Where the Atlantic water sinks has a very important effect on the climate of Northern Europe; the heat that the ocean loses to the atmosphere is what keeps Northern Europe quite warm relative to its latitude. For example, Amsterdam is at the same latitude as Winnipeg, Canada, but experiences much warmer winters. Based on a recent modeling study, Florian Sévellec and colleagues propose that the ongoing loss of Arctic sea ice may disrupt the AMOC. The sea ice loss leads to a freshening of the northern North Atlantic and stronger heat absorption at the surface. This means that waters in the northern North Atlantic are less dense than they used to be, which has the effect of providing a cap, or lid, that may inhibit the northward flow of warm waters at the surface and the eventual sinking of these waters. The authors suggest that the Arctic sea ice decline may help to explain observations suggesting that the AMOC may be slowing down, and why there is a regional minimum in warming (sometimes called the Warming Hole) over the subpolar North Atlantic.

The median of the 36 September mean extent forecasts is slightly below last September.

It will be interesting to see if the September 2012 low extent record can remain in place into the early 2020's. Or if the dipole pattern makes a return in 18-19 finally allowing a new record minimum to be set. Not sure many in September 2012 though it would take so long to break the record.

The rate of losses did slow post 2012 relative to the rapid 2005-2012 decline rate. But the long term downward trend will continue. https://theconversation.com/why-arctic-melting-will-be-erratic-in-the-short-term-35969 A new study I co-authored with a team of Canadian and American scientists, published in Nature Climate Change, highlights that the recent slower melt is a temporary, but not unexpected, deceleration. The complex climate models used to make projections of future climate also exhibit similar periods of little change and more rapid change in Arctic sea ice. The recent trends are well within the range of these expectations. We might even see a decade or more with little apparent change in sea ice. The causes of these fluctuations in melt rate are still being explored. Onesuggestion is that slow variations in Atlantic sea surface temperatures are involved. More observations of the Arctic ocean, atmosphere and sea ice would help answer this question. An ice-free future? When will the Arctic be ice-free – or equivalently, when will the ball reach the bottom of the hill? The IPCC concluded it was likely that the Arctic would be reliably ice-free in September by 2050, assuming high future greenhouse gas emissions (where “reliably ice-free” means five consecutive years with less than 1 million km2 of sea ice). We expect the long-term decline in Arctic sea ice to continue as global temperatures rise. There will also be further bounces, both up and down. Individual years will be ice-free sometime in the 2020s, 2030s or 2040s, depending on both future greenhouse gas emissions and these natural fluctuations.

Yeah, the HadGEM1 did a great job. https://www.the-cryosphere.net/7/555/2013/ Mechanisms causing reduced Arctic sea ice loss in a coupled climate model A. E. West, A. B. Keen, and H. T. HewittMet Office Hadley Centre, Exeter, UK Received: 09 May 2012 – Discussion started: 18 Jul 2012 Revised: 04 Feb 2013 – Accepted: 18 Feb 2013 – Published: 26 Mar 2013 Abstract. The fully coupled climate model HadGEM1 produces one of the most accurate simulations of the historical record of Arctic sea ice seen in the IPCC AR4 multi-model ensemble. In this study, we examine projections of sea ice decline out to 2030, produced by two ensembles of HadGEM1 with natural and anthropogenic forcings included. These ensembles project a significant slowing of the rate of ice loss to occur after 2010, with some integrations even simulating a small increase in ice area. We use an energy budget of the Arctic to examine the causes of this slowdown. A negative feedback effect by which rapid reductions in ice thickness north of Greenland reduce ice export is found to play a major role. A slight reduction in ocean-to-ice heat flux in the relevant period, caused by changes in the meridional overturning circulation (MOC) and subpolar gyre in some integrations, as well as freshening of the mixed layer driven by causes other than ice melt, is also found to play a part. Finally, we assess the likelihood of a slowdown occurring in the real world due to these causes.

I think some people are coming into each season thinking that it will be a continuation of the 2007-2012 mega dipole pattern. But outside July 2015, the summer Arctic pattern did a complete reversal following that 2012 record breaking summer. It was like the 2012 extremes of low sea ice extent and Greenland melt flipped a switch over to a new regime. Maybe some type of mini summer Arctic D-O event?

I agree. The coming cooldown across the CAB should keep 2017 behind the 2012 extent over the next the next 10 days. 2012 will probably run away from 2017 in early August when the steep 2012 drop occurred. With the exception of July 2015, a cooler polar vortex has dominated the Arctic summers from 2013-2017.