bluewave

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.

1 hour ago, dWave said:

I was waiting for the Bronx one. It'll be interesting to compare to. I'm on the other side of the NYBG, just under 2 miles SE of Lehman. 

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

7 hours ago, PhillipS said:

Apologies if I'm splitting hairs, Bluewave, but August didn't see an increase in Arctic SIV, it saw a decrease in the anomaly.  Arctic SIV continued to drop, albeit at a slower rate.  

 

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.  

15 hours ago, chubbs said:

This year has been cool like 2013 so the volume and extent data are not inconsistent.

 

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

1 hour ago, ORH_wxman said:

Yeah it's actually a pretty compact ice pack right now. I think the cyclone perhaps has just slowed the peripheral melting. 

Though bluewave is correct that typically cyclones over the CAB try and disperse the ice. But the concentration hasn't suffered even if it is doing that. 

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.

1 hour ago, chubbs said:

This year's low volume/high NSIDC area status is unusual. Looks like the mild winter is having some impact but is a weaker factor than a slow start to the Arctic Ocean melt season.

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.

12 minutes ago, ORH_wxman said:

The cold pool in the North Atlantic also really expanded and intensified in 2013 which was right after the huge Greenland melt in 2012...so I wonder if that was at least partially related. 

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.

14 hours ago, WidreMann said:

I would trust the dynamical more than the statistical, because we are in uncharted territory here. Even so, it looks like the median of those models would still be above 2012.

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.

1 hour ago, chubbs said:

We are running below the trendline so can't give this prediction a gold star yet..  

 

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.

19 hours ago, ORH_wxman said:

It is definitely weird that we saw an abrupt flip. I wish we knew what caused it. It seems to coincide with the formation of the deep cold pool anomaly in the North Atlantic sometime in spring of 2013 when the deep blocking from early that spring broke down. But I'm not sure what is cause and what is effect and also what is just reinforcing feedback. Probably some combo but interesting nonetheless. 

The hadgem model from Hadley center seemed to predict this on some level after 2012...which is a nice score by that model. 

Yeah, the HadGEM1 did a great job.

https://www.the-cryosphere.net/7/555/2013/

1 hour ago, ORH_wxman said:

Yeah if you read the Arctic sea ice forums, most of them are convinced every season is going to be a record low. There's a select few posters on there that do a good job and are pretty objective about the data but you can ignore the other 90% of them. As skier said, most of them just post anecdotes...pictures of buoy webcams or zoomed-in visible satellite pics that show ice "rubble" and then claim that means it has to melt out this year. 

There's no doubt that this year started off really bad coming out of winter...likely worst on record...but it's clear now that we didn't carry that momentum into spring and summer. It will still be a pretty low ice year because of how bad we started, but I don't think we will get near any records. Maybe volume can still be close if we get some hostile weather in August. 

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?

17 hours ago, ORH_wxman said:

PIOMAS had a mid-month update....2017 is still lower than 2012 by a very slim margin. It is 150 km^3 lower than 2012...it was 180 km^3 lower on July 1st update so basically no change. However, the difference in the CAB has shrunk to almost zero...compared to July 1st which had quite a bit more CAB volume in 2012 versus 2017. So I think it is only a matter of time before 2012 runs away from this year...but we will see. Until the total number diverges, it is still a race.

This seems to be supported by the area numbers too (NSIDC area as measured by SSMI/S)...after starting off the month with some big drops as noted earlier in this thread....we've come to a screeching halt in area loss. We are sitting at 5.62 million sq km for area right now which is more than 800,000 sq km above 2012 at this point (with the big August cyclone still looming in 2012). We are actually ahead of 2013 and 2014 right now as well, but I do not believe we will stay there because both of those years went into big pauses later this month.

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.

20 minutes ago, ORH_wxman said:

Yeah I'm not sure what he is seeing that indicates we will go lower than 2012...there's still an outside chance we go lower on volume only because the very thick ice near Greenland and the CAA is quite a bit thinner than 2012...but the rest of the pack is in superior shape than 2012 was at this point, so it is hard to see how the area and extent get anywhere near it. Volume will be a task...it will require probably very hostile weather from here on out. We entered July nearly tied with 2012 for volume and so far this July has been significantly colder than 2012. We had a decent chance to beat 2012 on extent/area coming into May, but the weather since then has all but eliminated that chance now...never say never, but I'd put the odds probably below 10%. Maybe if we get a 2007-esque pattern later this month and right through all of August, we will make up ground.

 

Yeah, and how much colder this summer is in Greenland compared to 2012.

http://polarportal.dk/en/nyheder/arkiv/nyheder/bringing-harmonie-to-the-greenland-ice-sheet/

Martin Stendel, Polar Portal leader, agrees. “This year has been extremely unusual, with a snowy winter and then a cool period at the start of this month. It’s extremely important we get the surface mass balance right.”

The period from the 27^th June to the 5^th July saw days with close to zero or even slightly positive SMB (a net gain in mass) as well as a record low temperature recorded at the DMI weather station at Summit  -33.0 °C. This weather along with the snowfall in early June, and following from the heavy snow in the Autumn, has led to a relatively high surface mass balance for the time of year and an unusually bright and reflective ice sheet, as shown in the albedo anomaly map on the Polar Portal (and below). Professor Jason Box of GEUS explains “when we see cold snowy conditions like this in the summer time it brings melt to a halt. The fresh snow is bright and reflects sunlight whereas in normal years dark bare glacier ice is usually exposed at this time of year and so melt rates are strong. This is why we track the albedo through the year to see how much melt we can expect”.

So far this summer there has been less melt than usual. As DMI weather forecaster Jesper Rosberg explains, “we have seen a persistent positive North Atlantic Oscillation this summer and the jet stream has been very far south of Greenland with very cold air over the ice sheet, so the precipitation falling this summer has mostly been snow, rather rain. ” 

The cold and snowy conditions have been hindering scientific fieldwork this summer. But there are still several weeks of the ablation season left and the weather for the rest of July and August will determine the surface mass balance of Greenland this year. As far as DMI scientists know this is the first time that the SMB of the Greenland ice sheet has been calculated with such a sophisticated model in near real-time and it’s all the more interesting since we have snowfall interfering with melt.