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John Christensen
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Slightly OT, but wanted to let all know that DMI has launched an Arctic weather overview page with wind, temp, temp. anomaly, and precipitation anomaly: http://polarportal.dk/en/weather/ You already can find the other DMI measures here such as SIE, ice volume estimate, sea ice temp, the DMI 80N temp, satellite images, etc.
Toggle Commented 4 days ago on PIOMAS October 2017 at Arctic Sea Ice
As mentioned in my first post, I would say we are generally moving to a regime of less-frigid Arctic winters and cool summers, so yes; in all likehood another freak warm winter. That said, the current weather is somewhat anomalous for recent years, and I am curious how this will shape temps and wind in the CAB for the coming 1-2 weeks.
Toggle Commented Oct 13, 2017 on PIOMAS October 2017 at Arctic Sea Ice
Wow - not a huge crowd here these days.. Just wanted to note that the forecast remains for a good start to the Arctic winter: High pressure in the CAB with lows circulating in the northern parts of the continents, providing early extension of NH snow cover, while cooling down the Arctic waters. And then, for my old discussion with wayne about the relationship between the AO index and Arctic cold or sea ice: The current setup seems near ideal for a cold NH winter and for expanding sea ice, yet the AO index is currently positive, meaning that the overall air pressure above 60N is slightly below average. I was therefore not correct that a negative AO index (Above normal air pressure) would overall be positive for Arctic sea ice, as the distribution of high and lows seems to be much more important than the average air pressure.
Toggle Commented Oct 13, 2017 on PIOMAS October 2017 at Arctic Sea Ice
Thank you for another great PIOMAS update Neven! Given the weather with some storm activity in the CAB in Sept, I was surprised to see that volume went up as much and suspect that to some degree a new snow layer and snow-filled ponds on the ice have been measured as sea ice increase. That said, the ecmwf forecast is now showing a high to remain in the CAB for the next week, which will slow down winds and cool down temps, so that more actual sea ice growth will be possible. This summer IMO seems to have been an exemplary example of how the atmospheric conditions are changing in a warming Arctic: - Winters are relatively warm and humid at/near the CAB due to later cover of sea ice. - The Beaufort gyre is reduced, since high pressure areas increasingly tend to be based over land areas - both summer and winter (See e.g.: http://psc.apl.uw.edu/wordpress/wp-content/uploads/schweiger/ice_volume/piomas_ice_motion_anomaly_JanMarch2017.png ) - Winter-time low pressure areas above the sea ice will increase precipitation, which in addition to higher temps will insulate the ice and reduce sea ice formation, but at the same time should reduce sea ice export via the Fram Strait. - Reversely, the well-known pattern of summertime low pressure areas in the CAB is further strengthened, lowering temps, increasing cloud cover and thereby reducing sea ice melting. It seems clear to me that this is where we are heading, and the IPCC prediction models therefore seem to be reasonably accurate, as it could take a few more decades to reach an ice-free Arctic at Sept. minimum. Consequently, I cannot agree with scientists such as Prof. Peter Wadham, who still in 2016 predicted an ice-free Arctic in 2017 or 2018: https://www.theguardian.com/environment/2016/aug/21/arctic-will-be-ice-free-in-summer-next-year The only really interesting feature that I am considering is the relationship between Greenland and the CAB: For years such as 2007, 2012, 2013, and 2017 we have seen a strong correlation between average air pressure over the CAB and the air pressure over the Greenland ice cap. Especially in the fall of 2016, where tremendous storms rolled across Greenland with high levels of precipitation in October, the storms kept entering also the CAB. This year, the air pressure over Greenland has gradually increased and been fairly high and stable over the past couple of months. It will be interesting to see if this helps blocking storms from entering the CAB also..
Toggle Commented Oct 11, 2017 on PIOMAS October 2017 at Arctic Sea Ice
I just came across this explanation from Phys.org and Claire Parkinson, Sr Climate Scientist, NASA, for lowest summer Arctic SIE that I found puzzling ( https://phys.org/news/2017-09-end-of-summer-arctic-sea-ice-extent.html ): "The three years with the lowest Arctic ice extents on record —2012, 2016 and 2007— experienced strong summer storms that hammered the ice cover and sped up its melt. "In all of those cases, the weather conditions contributed to the reduced ice coverage. But if the exact same weather system had occurred three decades ago, it is very unlikely that it would have caused as much damage to the sea ice cover, because back then the ice was thicker and it more completely covered the region, hence making it more able to withstand storms," Parkinson said." The low summer SIE in 2007, unless my memory fails me entirely, was caused primarily by a strong Beaufort gyre, extraordinary export via Fram and unprecedented in-situ melting in Beaufort due to rapid SST increase and strong bottom-melt. Also, wouldn't really agree that strong summer storms were the main differentiators of 2012 and 2016 compared to other recent summers - rather the contrary..
Toggle Commented Oct 9, 2017 on Excellent melting season summary at Arctic Sea Ice
I would agree with navegante that Rob normally makes a prediction for the NSIDC average Sept ice extent, which certainly is higher than the daily minimum. The NSIDC average Sept extent should be around 4.9-5.0 mill, unless we see strong spreading of the ice in the coming 10 days.
Toggle Commented Sep 20, 2017 on PIOMAS September 2017 at Arctic Sea Ice
Thank you for a great update Neven! It has been an amazing melting season so far given the extreme low max numbers on area, extent and volume that we saw in April. To the point that the cloudy and cold summer weather could be a negative feedback let me add a couple of observations in support: 1) In 2013, 2014, 2015, and now in 2017 there is a very visible temperature drop in the DMI 80N chart ( http://ocean.dmi.dk/arctic/meant80n.uk.php ) during May, where the cyclonic weather pattern gets in place - also slightly visible in 2012, but not in 2016. 2) At Summit in Greenland a record low temperature for July was reached in 2016 (Since 1981) and it was broken by a new record low recorded early July 2017. Research indicates that cyclonic weather patterns are most common in the Arctic during summer months, so this is not a new phenomenon, but it may be that the heating of surrounding continents and reduction in permafrost areas contribute to isolating the northernmost Arctic region, with higher difference in temperature compared to land masses. The above normal snow coverage could have assisted in enhancing this effect. If this negative feedback is in fact in play, then we will probably continue seeing mild winters combined with below normal summer melting - until freak weather patterns result in a repeat of 2007, which the Arctic sea ice will be much less likely to survive in coming years.
Toggle Commented Sep 8, 2017 on PIOMAS September 2017 at Arctic Sea Ice
It's PIOMAS time again Neven.. ;-)
Toggle Commented Sep 7, 2017 on PIOMAS August 2017 at Arctic Sea Ice
Related to warm sea water undermining west Greenland glaciers, though different from the situation at Petermans Glacier: If you play the sequence of the Greenland accumulated surface mass balance (SMB) from Sept. 1, 2016 to now, you will notice how the area feeding the Jacobshavn Glacier develops a negative anomaly already in Sept. '16 and how this negative balance has grown in the past year: http://polarportal.dk/en/groenlands-indlandsis/nbsp/isens-overflade/ By now, the entire area feeding into the glacier valley has a significant negative mass balance, while Greenland overall has received a significant surplus of precipitation in the past year. Even the front hills left and right of the Jacobshavn Glacier glacier front have a positive anomaly.. It seems clear that this area is impacted not so much by air temperature or precipitation deficit, but by increased glacier speed, which again most likely is caused by (warm) sea water still reaching further underneath the glacier.
Thanks Jim, had not noticed that! Yes, navegante; surface temps are starting to creep downwards ever so slowly in the high north - will be interesting to see how this next (last?) summer storm plays out.
Toggle Commented Aug 7, 2017 on PIOMAS August 2017 at Arctic Sea Ice
Great update, thanks Neven! I agree with the conclusions so far, but the deepening of the low this coming week will result in mixing with warmer surface waters, and with the Arctic sun descending we will start seeing more negative impact from the storms. Too bad we no longer have the compactness ratio: Have you given thought to using arctic-roos area divided by arctic-roos extent to have some indicator on this? Seems very compact this summer..
Toggle Commented Aug 7, 2017 on PIOMAS August 2017 at Arctic Sea Ice
Still 5-6 days out, but ecmwf is forecasting an intense low just north of the CAA.
Toggle Commented Aug 4, 2017 on PIOMAS July 2017 at Arctic Sea Ice
Welcome to you Tony! To your question: Yes, clouds and general low pressure is the norm for the Arctic during summer months, primarily due to cold surface temps compared to surrounding continents - quite similar in fact to sea clouds appearing off the cost of Oregon due to cold Pacific surface temps. Specific to the Arctic, Neven put together some great info here: http://neven1.typepad.com/blog/2013/06/on-persistent-cyclones.html
Toggle Commented Aug 1, 2017 on PIOMAS July 2017 at Arctic Sea Ice
Hi Rob, I would agree with Neven: In recent years area and extent has gone so low that it could cause a decrease in volume melt rate for remaining ice. Reflecting a drawn out end to summer ice rather than a sudden crash possibly.. A separate observation for this season is an apparent reduction in north-bound sea current in the eastern Fram Strait: We have in recent years seen wide open water to the north-west/north of Svalbard, but this area got filled with south-bound sea ice early in the year and has stayed ice-filled, which to me seems to indicate a reduction in north-bound sea current, but also could be due to an increase in south-bound sea ice flow. A reduction in sea current would better explain the slight increase in sea ice in northern parts of Barents as well, so is where I am leaning, but have seen no news on Fram current.
Toggle Commented Jul 13, 2017 on PIOMAS July 2017 at Arctic Sea Ice
Thank you very much for the melting momentum update Neven! I would agree with Dr. Schroder that we should see slightly below average sea ice meeting this season due to lower melt pond fraction, seeming caused by lower than average high north temps (DMI 80N). I am also very curious about the impact of Greenland, which often is given little space for consideration for the sea ice: The relentless storms last fall has caused much higher precipitation than usual (http://polarportal.dk/groenlands-indlandsis/nbsp/isens-overflade/ ), and the measured albedo of Greenland has improved as a consequence. In 2012 we saw the heat dome over Greenland, which caused very warm air to flow down to surrounding sea surfaces, but this year the ice cap will help keep things temperate. Back to lurking.
Toggle Commented Jun 19, 2017 on Melting momentum: May 2017 at Arctic Sea Ice
I'm sure the bear was praying that news of the latest Russian Arctic military base and additional nuclear ice breakers was just a bad dream.. http://www.dailymail.co.uk/news/article-4421072/Russia-unveils-new-Arctic-military-base.html
Toggle Commented Apr 20, 2017 on Praying polar bear at Arctic Sea Ice
Coming SSW event? I noticed on the DMI forecast that temps just north of the CAA may dip below -40C on Jan. 7th. As such a low temperature is rather unusual for recent years, I was wondering if this might be related to a sudden stratospheric warming event?
Toggle Commented Jan 4, 2017 on PIOMAS December 2016 at Arctic Sea Ice
I fully concur with you Susan; the value of this blog stems from Neven's character, being insightful, communicating clearly, but most importantly from a high degree of respect for other people's opinion. We can all learn from that, as the respect for other people will be necessary in making progress from this situation. The other character trait coming to the forefront now is the optimist/pessimist dimension, which a lot of the comments are hinting at. What Neven seems to be searching for, is the elusive combination of being aware of the situation, being respectful to others, while avoiding the pessimism - avoiding falling into despair. That may just require a glass of good wine and music at times..
Toggle Commented Dec 15, 2016 on PIOMAS December 2016 at Arctic Sea Ice
Neven, Are you sure the twitter quote was by Viddaloo? While I agree that he does not seem to be very reflective about the use of extrapolation or the interpretation of annual averages, he has been quite consistent since he opened a blog on Wunderground back in Nov. 2015: https://www.wunderground.com/blog/viddaloo/comment.html?entrynum=0 But if true, then Dr. Jeff Masters should check the blog account on his site also.
Toggle Commented Dec 13, 2016 on PIOMAS December 2016 at Arctic Sea Ice
Neven, It seems like I have become more successful in lurking than you have yourself.. ;-) That said; I admire your desire to keep the ship leveled O Captain my captain!
Toggle Commented Dec 13, 2016 on PIOMAS December 2016 at Arctic Sea Ice
Neven, In agreement with the many comments above: Thank you very much for having managed this great blog with an even-keeled approach to understanding and communicating changes for the Arctic sea ice. Wishing you well and good luck with the continued house project! Kind regards, John
Toggle Commented Dec 6, 2016 on Sabbatical (I hope) at Arctic Sea Ice
OK viddaloo, so then you also agree that for the majority of the time since the Sept minimum and currently, we have slightly more sea ice volume than in 2012?
Toggle Commented Nov 16, 2016 on PIOMAS November 2016 at Arctic Sea Ice
"Yes, I remember! And I'm very happy they went through the trouble of improving their model so that it would become more reliable. If only PIOMAS would do the same, and listen to well–founded criticism!" That is just great, viddaloo, and then since DMI apparently listened to well-founded criticism (Did they?) do we now agree that 2016 has had more sea ice than 2012 for the vast majority of the time since minimum in September? - because we now like the DMI volume model more than the PIOMAS volume model..
Toggle Commented Nov 16, 2016 on PIOMAS November 2016 at Arctic Sea Ice
"2016 minimum Arctic sea ice volume was lowest ever according to DMI" viddaloo, Remember that we were in agreement earlier that the DMI volume model is not reliable, so would it make a difference if it is lower or higher than 2012?
Toggle Commented Nov 15, 2016 on PIOMAS November 2016 at Arctic Sea Ice
Politics is becoming more polarized with both sides screaming at each other - until one or both sides take up more tangible means to defeat the other. This is the scary part.
Toggle Commented Nov 10, 2016 on PIOMAS November 2016 at Arctic Sea Ice