bluewave

Impressive stall in sea ice extent gains this week. It allowed 2019 to pull a little closer to 2012. NSIDC extent

Updated for the 8th warmest September at LGA. 9...2019....LGA...8

Notice the much greater amplitude of the Arctic pressure pattern swings since 1990. This would seem to match the 2009 corals study.The record summer Arctic dipole pattern from 2007 to 2012 and new lowest extent. Rapid reversal in 2013 and 2014. Then stronger dipole anomalies in 2016 and 2019. Continuation of the long term Arctic sea ice decline with very choppy volatility from year to year. https://www.sciencedaily.com/releases/2009/01/090113101200.htm Swings In North Atlantic Oscillation Variability Linked To Climate Warming 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.”

NSIDC extent dropped to the second lowest minimum on record. 2019 was effectively tied with 2016 and 2007. https://nsidc.org/arcticseaicenews/ Table 1. Thirteen lowest minimum Arctic sea ice extents (satellite record, 1979 to present) RANK YEAR MINIMUM ICE EXTENT DATE IN MILLIONS OF SQUARE KILOMETERS IN MILLIONS OF SQUARE MILES 1 2012 3.39 1.31 Sept. 17 2 2019 2007 2016 4.15 4.16 4.17 1.60 1.61 1.61 Sept. 18 Sept. 18 Sept. 10 5 2011 4.34 1.68 Sept. 11 6 2015 4.43 1.71 Sept. 9 7 2008 2010 4.59 4.62 1.77 1.78 Sept. 19 Sept. 21 9 2018 2017 4.66 4.67 1.80 1.80 Sept. 23 Sept. 13 11 2014 2013 5.03 5.05 1.94 1.95 Sept. 17 Sept. 13 13 2009 5.12 1.98 Sept. 13 Values within 40,000 square kilometers (15,000 square miles) are considered tied. The 2018 value has changed from 4.59 to 4.66 million square kilometers (1.80 million square miles) when final analysis data updated near-real time data, dropping 2018 to a tied ninth position with 2017.

That’s a remarkable stat. Just saw it posted on twitter. Record warmth and high pressure over the Arctic since May. https://mobile.twitter.com/AlaskaWx/status/1175034044578295808 https://mobile.twitter.com/ZLabe/status/1170022132216029185

Very impressive Arctic Amplification this September with so much open water. https://www.arctictoday.com/arctic-sea-ice-is-close-to-its-annual-minimum-extent-but-thats-just-part-of-the-picture/?wallit_nosession=1 As the autumn equinox looms and winter darkness approaches, Arctic sea ice has dwindled to what appears to be one of the lowest minimums in the satellite record. “We are basically right now in a dead tie for second place,” Mark Serreze, director of the National Snow and Ice Data Center, said on Wednesday. Ice extent — defined as the area where there is at least 15 percent ice coverage — dropped to 4.1 million square kilometers on Tuesday, matching minimums set in 2007 and in 2016, according to the Colorado-based NSIDC. It will take a few more days to know whether this year’s minimum has been set and the freeze season has started, Serreze said. Total ice extent can waver up and down at this time of the year because of shifting winds and a contest between freeze at the highest latitudes and continued melt in the more southern parts of the Arctic, he said. This year’s minimum extent has no chance of matching the record-low 3.4 million square kilometers (1.32 million square miles) hit in 2012, Serreze said. Still, it fits into a trend to more open water over longer periods of the year, he said. All that open water reinforces the warming cycle in the far north, strengthening the phenomenon known as Arctic Amplification, he said. When waters lack ice cover, they absorb more solar heat, he said. “You’ve got to get rid of all that heat,” he said. “Where does that heat go? Up into the atmosphere.” While annual minimums are useful markers for long-term trends, the expanding durations of open water are turning out to have more immediate significance, said Rick Thoman, climate scientist with the Alaska Center for Climate Assessment and Policy at the University of Alaska Fairbanks. That is especially the case for the waters off Alaska — the Bering, Chukchi and Beaufort seas — where ice has been especially scarce, even in the past winters, he said. The official Arctic-wide minimum extent is only part of the picture, he said. “For Alaska, it doesn’t make much of a difference if it’s No. 1 or No. 4. There hasn’t been any ice anywhere near Alaska for a very long time and the water that’s there is extremely warm,” Thoman said. In the waters off northern and northwestern Alaska, sea-surface temperatures were generally running 3 to 6 degrees Celsius (5.4 to 10.8 degrees Fahrenheit) above normal during the second week of September, according to data gathered by ACCAP. That sets the stage for a delayed freeze season, he said. “We can be absolutely certain that freeze-up in the Beaufort, Chukchi and at least the central Bering will be late,” he said. Delayed freeze likely means a warmer-than-normal fall and, when the winter freeze arrives, ice that is thin and more susceptible to midwinter meltdowns similar to those that occurred in the past two years in the Bering and the Chukchi, he said. The past years’ winter ice loss may have been highly unusual, but repeat occurrences could become more common if southerly winds return, Thoman said. “I think you’ll see the big collapses like we’ve had in the past two years. That requires that sustained southerly flow. We won’t see that every year,” he said. Thoman noted that with the exception of the extreme low in 2012, annual minimums over the past decade have been generally in the same ballpark. That is because the very high-latitude ice, unlike ice at lower Arctic latitudes, has relatively brief period of the year when there is direct sunlight shining on it and causing melt from above, he said. “We have melted all the easy, low-latitude ice now,” he said. Melting out ice at the highest latitudes will require a different process, he said. “That’s going to come from the ocean. That’s going to come from underneath,” he said. Serreze, too, said the highest-latitude ice has lingered despite widespread melt elsewhere in the Arctic. At those very high latitudes — for now — there is still multiyear ice that survives melt seasons, he said. But more changes are expected in the future, he said. “We are kind of in new territory,” he said. “We have not been here before, so every year we’re learning.” https://mobile.twitter.com/ZLabe/status/1175055129290010624 Well above average temperatures over nearly the entire #Arctic Ocean so far this September. This is especially found in areas where there is a lack of sea ice cover.

NSIDC 5 day trailing average extent dipped to 4.153 million sq km on 9-18. http://nsidc.org/arcticseaicenews/faq/#average-vs-daily Values within 40,000 square kilometers (15,000 square miles) are considered tied. Why do you use the 5-trailing average to announce the minimum/maximum and not the daily extent? We use a 5-day trailing average to smooth out the day-to-day variability from the influence of weather (such as storms causing false retrievals) and coastal or surface effects on the data. Five days is a typical synoptic timescale that helps create a continuous curve that is easier to follow and interpret. ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx Lowest 5 day average 3.387....2012-9-17 4.153....2019...9-18 4.155....2007-9-18 4.165....2016-9-10 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

Values within 40,000 square kilometers (15,000 square miles) are considered tied. Very large daily drop for so late in the season. ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx Lowest 5 day average 3.387....2012-9-17 4.155....2007-9-18 4.165....2016-9-10 4.170....2019...as of 9-17 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

Any guesses for this October?

10k daily NSIDC extent decline moves 2019 into 3rd place place on 9-15. Only 6k behind the 2nd place 2007. Currently in 3rd place for NSIDC extent.  3.387....2012-9-17 4.155....2007-9-18 4.161....2019 4.165....2016-9-10 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

The late season acceleration of sea ice losses is in response to the return of the strong Arctic dipole anomaly. This was the dominant pattern from May through August 20th. A new Arctic high pressure record was set for this period. Now high pressure has returned to near record levels for this time of year.

Arctic sea ice pulling closer to 2007 and 2016. Now at 4.171 million sq km for 9-14 with a 38k NSIDC daily decline. ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx Currently in 4th place for NSIDC extent.  3.387....2012-9-17 4.155....2007-9-18 4.165....2016-9-10 4.171....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

Large 71k NSIDC daily extent decline for so late in the season. The 9-13 extent drops below the previous minimum recorded back on 9-4. This puts 2019 in 4th place not far behind 2007 and 2016. ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx Currently in 4th place for NSIDC extent.  3.387....2012-9-17 4.155....2007-9-18 4.165....2016-9-10 4.209....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

NSIDC extent continues to bounce up and down with the rapidly changing dipole conditions. 9-4......4.238 million sq km......lowest of season so far 9-9......4.342...... a 5 day increase of +104k 9-11.....4.280........a 2 day decline of -62k

There were 2 new monthly record low average NSIDC extents in 2019. The records occurred in April and July. There have been 9 new monthly records since 2016. ASO are the only 3 months without a new monthly record low average extent since 2016. https://mobile.twitter.com/ZLabe/status/1157122835409596416 NSIDC monthly record lowest average sea ice extents Jan...2018 Feb.. 2018 Mar...2017 Apr....2019 May...2016 Jun....2016 Jul.....2019 Aug...2012 Sep...2012 Oct...2012 Nov...2016 Dec...2016

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