bluewave

The term behavior is commonly used when referring to sea ice. Odd would be a mild term for describing the first time pressure extremes that this season has exhibited. Those extremes lead to the unusual pattern of sea ice loss this melt season.

Odd late season behavior continues on NSIDC extent. Extent has increased 95k last 2 days. It was 4.238 million sq km on 9-4 and now 4.333 million sq km for the 6th. The melt season featured a record low extent for July only to fall back to 4th place as of 9-6. Big slowdown after mid August followed by an acceleration of losses into early September. Currently in 4th place for NSIDC extent. 3.387....2012-9-17 4.155....2007-9-18 4.165....2016-9-10 4.333....2019 4.344....2011-9-11  4.433....2015-9-9 4.586....2008-9-19  4.615....2010-9-21  4.656....2018-9-23  4.665....2017-9-13 Zack Labe notes the statistical tie for record Arctic warmth this summer with 2012. https://mobile.twitter.com/ZLabe/status/1170022132216029185 Boreal summer 2-m temperatures were statistically tied (with 2012) for the warmest on record in the #Arctic [using JRA-55 data]

NSIDC daily extent down another 48k to 4.238 million sq km. This was the largest drop from 8-29 to 9-4 going back to 2007. 8-29 to 9-4 Arctic sea ice decline 2019...-409k 2018...-130k 2017...-119k 2016...-248k 2015...-98k 2014...-174k 2013...-161k 2012...-146k 2011....-291k 2010....-266k 2009....-159k 2008.....-326k 2007.....-272k

Typo. 7th place should read 2008. 3.387....2012-9-17 4.155....2007-9-18 4.165....2016-9-10 4.286.....2019 4.344....2011-9-11 4.433....2015-9-9 4.586....2008-9-19 4.615....2010-9-21  4.656....2018-9-23  4.665....2017-9-13

One of the largest NSIDC daily extent losses for the month of September on the 4th. The 112 k daily drop moves 2019 into 4th place. The late August stall followed by accelerated losses is a first for the post 2007 Arctic. It shows how volatile the Arctic pressure patterns have become. ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx 3.387....2012-9-17 4.155....2007-9-18 4.165....2016-9-10 4.286.....2019 4.344....2011-9-11 4.433....2015-9-9 4.586....2008-9-19 4.615....2010-9-21 4.656....2018-9-23 4.665....2017-9-13

Larger 97k drop yesterday puts 2019 into 5th place for lowest annual daily NSIDC extent. 3.387....2012-9-17 4.155....2007-9-18 4.165....2016-9-10 4.344....2011-9-11 4.419....2019 4.433....2015-9-9 4.586....2018-9-23 4.615....2010-9-21 4.656....2018-9-23 4.665....2017-9-13

73k daily drop on NSIDC extent as we move past the stall period with the extreme reverse dipole pattern. This puts 2019 into 6th place. 3.387....2012-9-17 4.155....2007-9-18 4.165....2016-9-10 4.344....2011-9-11 4.433....2015-9-9 4.516....2019 4.586....2018-9-23 4.615....2010-9-21 4.656....2018-9-23 4.665....2017-9-13

2019 moves into 7th place on NSIDC extent at 4.589 million sq km as the extreme reverse dipole relaxes. Just a bit above the 2007-2018 average daily minimum extent of 4.510. 3.387....2012-9-17 4.155....2007-9-18 4.165....2016-9-10 4.344....2011-9-11 4.433....2015-9-9 4.586....2018-9-23 4.589....2019 4.615....2010-9-21 4.656....2018-9-23 4.665....2017-9-13

The dipole reversal around August 20th was one for the record books. We are not that far from the 2007-2018 NSIDC annual average daily minimum extent of 4.51 million sq km.The average minimum extent before 2007 was 6.18 million sq km from 1994 to 2005. Arctic amplification really took off once minimums began to regularly fall below 6 million sq km.

Yeah, these wild swings in the NAM have increased in amplitude as the climate has warmed. While the long term sea ice trend is down, it will probably be an up and down bumpy ride along the way.That’s why calling the exact date for the eventual ice free state will continue to be tricky. Maybe the best we can do is just say some time between 2030 and 2050. https://www.eurekalert.org/pub_releases/2009-01/whoi-sls011309.php PUBLIC RELEASE: 13-JAN-2009 Study links swings in North Atlantic oscillation variability to climate warming WOODS HOLE OCEANOGRAPHIC INSTITUTION SHARE PRINT E-MAIL Using a 218-year-long temperature record from a Bermuda brain coral, researchers at the Woods Hole Oceanographic Institution (WHOI) have created the first marine-based reconstruction showing the long-term behavior of one of the most important drivers of climate fluctuations in the North Atlantic. The North Atlantic Oscillation (NAO) is a wide-ranging pressure seesaw that drives winter climate over much of North America, Europe and North Africa. Past reconstructions of the NAO have relied mainly on terrestrial, or land-based records, such as tree ring chronologies combined with ice cores and historical climate data. Those records do not fully capture oceanic processes linked to NAO variability, and short instrumental records from relatively few locations limit the understanding of ocean-atmosphere dynamics with regard to NAO behavior. "By analyzing the coral, we were able to look at changes in the ocean relative to changes on land," said Nathalie Goodkin, lead author of the study published in the December issue of the journal Nature Geoscience. "Because they are slow growing and have long life-spans, corals can provide high resolution records that are well dated and centuries long." As they grow, corals accrete seasonal and annual growth layers, similar to tree rings. The proportions of trace elements versus the major element (calcium) found in the layers of the skeleton largely depend on the temperature of the seawater in which it was formed. By analyzing the strontium to calcium ratio in the Bermuda brain coral, Goodkin and colleagues -- WHOI scientists Konrad Hughen, Scott Doney and William Curry -- were able to reconstruct monthly changes in ocean temperatures and evaluate variability of the NAO during both cold and warm periods from the Little Ice Age (1800�) to modern day. The research team found the variability of the NAO decade-to-decade (multi-decadal scale) has been larger, swinging more wildly, during the late twentieth century than in the early 1800s, suggesting that variability is linked to the mean temperature of the Northern Hemisphere. This confirms variability previously reported in past terrestrial reconstructions. "When the Industrial Revolution begins and atmospheric temperature becomes warmer, the NAO takes on a much stronger pattern in longer-term behavior," said Goodkin. "That was suspected before in the instrumental records, but this is the first time it has been documented in records from both the ocean and the atmosphere." The North Atlantic Oscillation is described by the NAO index, calculated as a weighted difference between the polar low and the subtropical high during the winter season. In a positive phase, both the low-pressure zone over Iceland and high pressure over the Azores are intensified, resulting in changes in the strength, incidence, and pathway of winter storms crossing the Atlantic. In a negative phase, a weak subtropical high and a weak Icelandic low results in fewer and weaker winter storms crossing on a more west-east pathway. The NAO index varies from year to year, but also exhibits a tendency to remain in one phase for intervals lasting more than a decade. An unusually long period of positive phase between 1970-2000 led to the suggestion that global warming was affecting the behavior of the NAO. "Anthropogenic (human-related) warming does not appear to be altering whether the NAO is in a positive or negative phase at multi-decadal time scales," said WHOI paleoclimatologist Konrad Hughen. "It does seem to be increasing variability. Clearly, this has implications for the future." "As temperatures get warmer, there's potential for more violent swings of the NAO -- the phases becoming even more positive and even more negative," Hughen added. "If the NAO locks more into these patterns, intense storms will become more intense and droughts will become more severe." The climatic influence of the NAO extends from the eastern United States to Western Europe, impacting human activities such as shipping, oil drilling, fisheries, hydroelectric power generation and coastal management. Improving the ability to predict shifts in the phase and intensity of the NAO is a prerequisite to mitigating the economic impacts of future climate change. While additional modeling and palaeoclimatic studies are needed, a broad distribution of marine records could advance our knowledge of NAO variability and serve to improve future projections, said Goodkin, now an assistant professor in the Department of Earth Sciences at the University of Hong Kong. ### A WHOI Ocean and Climate Change Institute Fellowship, and grants from the National Science Foundation and Woods Hole Oceanographic Institution supported this work. The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the oceans and their interaction with the Earth as a whole, and to communicate a basic understanding of the oceans' role in the changing global environment. Related links: Nature GeoScience: Increased multidecadal variability of the North Atlantic Oscillation since 1781 http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo352.html

This is one of the most extreme dipole reversals on record for late August. The Arctic went from record high pressures to record low pressures in just a few weeks. It’s the first time in over a decade for a small gain in extent from 8-22 to 8-27. Shows what can happen with a rapid shift to colder and stormier conditions. 8-22 to 8-27 sea ice extent change 2019...+55k 2018...-134k 2017...-213k 2016....-507k 2015....-451k 2014....-165k 2013....-152k 2012....-431k 2011....-177k 2010....-262k 2009....-254k 2008....-439k 2007.....-71k

The extent loss rate began to stall a few days before the storm around the 20th. The record breaking high pressure regime that had been in place since May reversed. So the ice pack became less compact and spread out with colder temperatures.

Larger 94k daily drop on 8-22 for NSIDC extent. This moves 2019 into 8th place at 4.628 million sq km. ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx 3.387....2012-9-17 4.155....2007-9-18 4.165....2016-9-10 4.344....2011-9-11 4.433....2015-9-9 4.586....2018-9-23 4.615....2010-9-21 4.628....2019 4.656....2018-9-23 4.665....2017-9-13 

2019 is at the 10th lowest NSIDC extent as of 8-20. 3.387....2012-9-17 4.155....2007-9-18 4.165....2016-9-10 4.344....2011-9-11 4.433....2015-9-9 4.586....2018-9-23 4.615....2010-9-21 4.656....2018-9-23 4.665....2017-9-13 4.734....2019

Loss rate has slowed enough last few days for NSIDC extent to fall behind 2012 by 242k as of 8-15. .............2012......2019  8-13.....4.889......4.966.....77k behind 8-14.....4.724......4.970.....246k behind  8-15....4.679......4.921.....242k behind  8-16....4.619 8-17.....4.545 8-18.....4.520 8-19.....4.405  8-20.....4.313 NSIDC updated their projection for the September minimum. They are now calling for a 2nd place finish behind 2012. https://nsidc.org/arcticseaicenews/2019/08/dead-heat/ The ASINA team conducted a revised analysis of the likely course of the 2019 Arctic summer sea ice minimum, using rates of loss from several recent years. While sea ice extent is now above extent for the same date in 2012, overall our projection for the minimum is lower than estimated in our previous post. Using the average decline rate of the past 12 years, from 2007 to 2018, the 2019 minimum is estimated to be 3.75 million square kilometers (1.45 million square miles). If the 2012 decline pattern is applied from August 14 forward, sea ice reaches 3.44 million square kilometers (1.33 million square miles). This is still above the 2012 summer minimum extent of 3.39 million square kilometers (1.31 million square miles). However, nearly all of the recent rates of sea ice loss lead to 2019 being second lowest in ice extent, surpassing 2007 and 2016.

NSIDC daily extent holding steady on the 14th allowed 2019 to fall behind 2012 by 246k. But the area was able to move closer to 2012 than it has been over the last week. ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx .............2012......2019 8-13.....4.889......4.966.....77k behind 8-14.....4.724......4.970.....246k behind  8-15.....4.679  8-16.....4.619 8-17.....4.545 8-18.....4.520 8-19.....4.405  8-20.....4.313 NSIDC area https://cryospherecomputing.tk/

97k daily decline for NSIDC extent. This places 2019 only 77k behind 2012 as of 8-13. Models indicate a continuation of the record breaking high pressure regime over the Arctic since May. Surface pressures are forecast to exceed 1040 mb around the Chukchi Sea region next 3-4 days. This would be at record levels for this time of year. ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx .............2012......2019 8-13.....4.889......4.966.....77k behind 8-14.....4.724 8-15.....4.679 8-16.....4.619 8-17.....4.545 8-18.....4.520 8-19.....4.405 8-20.....4.313

Small daily rise in NSIDC extent of 19k. This puts 2019 behind 2012 by -92k as of the 11th. NSIDC extent    Date....2012......2019....2019 difference  8-4......5.990.... .5.762.....+228k lead 8-5......5.768......5.596.....+172k lead  8-6......5.632......5.510......+122k lead  8-7......5.467......5.388......+79k lead 8-8......5.256.....5.390......-134k behind 8-9......5.088......5.259......-171k behind  8-10....5.118......5.093......+25k ahead  8-11....5.021......5.113.......-92k behind 8-12.....4.938 8-13.....4.889 8-14.....4.724 8-15.....4.679 8-16.....4.619 8-17.....4.545 8-18.....4.520 8-19.....4.405 8-20.....4.313

This site has it. https://cryospherecomputing.tk/

Very large daily NSIDC decline of 166k puts 2019 back in a narrow lead over 2012 by +25k. ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx NSIDC extent    Date....2012......2019....2019 difference 8-4......5.990.... .5.762.....+228k lead 8-5......5.768......5.596.....+172k lead  8-6......5.632......5.510......+122k lead 8-7......5.467......5.388......+79k lead 8-8......5.256.....5.390......-134k behind 8-9......5.088......5.259......-171k behind  8-10....5.118......5.093......+25k ahead 8-11....5.021

Large 131k daily drop on NSIDC extent. So 2019 is only 171k behind 2012. We are past the record breaking 2012 fall during the Great Arctic Cyclone. 2019 needs a 119k daily decline rate next two days to pull back even with 2012 by the 11th. The NSIDC charts use a five-day trailing average. The daily extent figures are found in the spreadsheet section under the chart. https://nsidc.org/arcticseaicenews/sea-ice-tools/ NSIDC extent    Date....2012......2019....2019 difference 8-4......5.990.... .5.762.....+228k lead 8-5......5.768......5.596.....+172k lead 8-6......5.632......5.510......+122k lead 8-7......5.467......5.388......+79k lead 8-8......5.256.....5.390......-134k behind 8-9......5.088......5.259......-171k behind 8-10....5.118 8-11....5.021

NSIDC extent held steady on August 8th. 2019 has fallen behind 2012 by 134 k during the period of the Great Arctic Cyclone. 2019 needs an average daily loss rate of 123k next few days to hold even with 2012 by the 11th. NSIDC extent    Date....2012......2019....2019 difference 8-4......5.990.... .5.762.....+228k lead 8-5......5.768......5.596.....+172k lead 8-6......5.632......5.510......+122k lead 8-7......5.467......5.388......+79k lead  8-8......5.256.....5.390......-134k behind 8-9......5.088 8-10....5.118  8-11....5.021

Updated for a 3.21 max in Livingston TWP, NJ. 2 NNE LIVINGSTON TWP 3.21 700 AM 8/08 COCORAHS

Large 122k daily drop in NSIDC extent . 2019 needs an average daily decline rate of 92k next 4 days to remain even with 2012 by the 11th. NSIDC extent    Date....2012......2019....2019 difference 8-4......5.990.... .5.762.....+228k lead 8-5......5.768......5.596.....+172k lead 8-6......5.632......5.510......+122k lead 8-7......5.467......5.388......+79k lead  8-8......5.256 8-9......5.088 8-10....5.118  8-11....5.021

2019 needs an average NSIDC daily decline rate of 98k next 5 days to be even with 2012 on the 11th. NSIDC extent   Date....2012......2019....2019 difference 8-4......5.990.... .5.762.....+228k lead 8-5......5.768......5.596.....+172k lead 8-6......5.632......5.511......+121k lead 8-7......5.467 8-8......5.256 8-9......5.088 8-10....5.118 8-11....5.021