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John Christensen
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Hi gkoehler - "This has also been the 3rd or 4th year in a row with below normal DMI 80+ summer temperatures. Is that a negative feedback for summer Arctic sea ice decline,i.e. a true shift, or just random fluctuation?" I suspect the below normal DMI 80N temp is a result of the broken ice pack: In the past with a more dense pack, surface temps could rise a bit more in summer, but with a broken/scattered ice pack the more effective heat exchange between cool water and air will keep temps down until the ice is fully gone and temps could rise further. When you go back to years of 1995 and prior you see the slightly higher summer temps at DMI 80N.
Toggle Commented Sep 27, 2018 on PIOMAS September 2018 at Arctic Sea Ice
Maybe assessing sea ice thickness during summer months is not a priority to NASA.. ;-)
Toggle Commented Sep 24, 2018 on PIOMAS September 2018 at Arctic Sea Ice
On ICEsat-2 and sorry for off-topic note Neven! I just read an article on DMI about ICEsat-2, which will attempt to measure sea ice thickness by using a laser pulse sonar-like device. The article also said that DMI continues working on their sea ice snow cover models, which will further improve the ICEsat-2 thickness measures - basically splitting the total thickness into snow and ice components. It therefore sounds to me like the ICEsat-2 thickness readings will be combined with different models to estimate snow cover, which therefore also should lead to differences in sea ice volume estimates.. Still, hopefully the thickness estimates will now become so robust that snow cover models can more easily be aligned to improve the overall Arctic snow and ice models.
Toggle Commented Sep 24, 2018 on PIOMAS September 2018 at Arctic Sea Ice
I will therefore likely be 0.3-0.4 off the mark for an early June projection. Your revised forecast of Aug. 5 was: "I usually don't do revisions of my projections, because it is a bad habit, is better studying why a forecast was wrong than to change it. But it looks very much like my April projection was wrong, 2018 is poised to surpass 2012". I cannot tell if your projection is for NSIDC Sept average SIE or JAXA minimum SIE, but with JAXA SIE minimum the difference between minima (So far) is: 2012: 3.389 2018: 4.594 Diff: 1.205
Toggle Commented Sep 23, 2018 on PIOMAS September 2018 at Arctic Sea Ice
Agreed; any range has a midpoint - mine is 5.1 for Sept NSIDC average SIE. The sea ice area increase has stalled again and most metrics are showing small SIE declines in past few days, so the Sept average SIE seems more likely to reach 4.7-4.8, especially with contraction forecast in the area north of Laptev and Kara.
Toggle Commented Sep 23, 2018 on PIOMAS September 2018 at Arctic Sea Ice
Good morning wayne, I wouldn't be foolish enough to have called the minimum SIE yet - where did you see that? My prediction for NSIDC September average SIE made June 6th at 4.85 – 5.35 (V3) still stands. You on the other hand adjusted your prediction on August 6-8: “I count September or October Maxima less than 4 million for sure as days go by will see how much less than 4 will be.” Who will be closer you think?
Toggle Commented Sep 22, 2018 on PIOMAS September 2018 at Arctic Sea Ice
Greenland weather stations can be seen here: http://polarportal.dk/en/greenland/surface-conditions/ Nansen was north of Franz Josef Lands with sleighs, dogs and one companion - nowhere near the NE passage. They experienced open or newly frozen lanes as early as the first days of April. In summer they had slush ice, sleet and extensive pools - all providing plenty of moisture. Check out the DMI 80N temp, which shows that average temperatures in the period 1958-2002 were above freezing point for two months straight. A very moist climate for the brief melting period around the Pole is therefore the norm and has been as long as we have known. I don't see your point with the circulation of the Gyre - while we can observe a slowdown or even shortterm reversal of the Arctic circulation in main summer month, the Arctic climate is dominated by high pressure winter climate (Hint = Ice)..
Toggle Commented Sep 21, 2018 on PIOMAS September 2018 at Arctic Sea Ice
wayne, You should do more fact-checking before critiquing others.. 1. "Greenland is surrounded by water at present, aint so cold" Wrong; Greenland is cold at present: http://polarportal.dk/en/weather/nbsp/current-weather/ 2. "But the biggest player were clouds ever since 2012". Wrong again, Arctic summers are in fact characterized by a maximum in cyclone activity (Serreze and Barrett in 'The Summer Cyclone Maximum over the Central Arctic Ocean' (2008): "A fascinating feature of the northern high-latitude circulation is a prominent summer maximum in cyclone activity over the Arctic Ocean, centered near the North Pole in the long-term mean." Dr. Fridtjof Nansen wrote this about weather on June 24, 1895, being around 82N: "At midday I got up and went out to take a meridian altitude. The weather was brilliant, and it was so long since we had had anything of the kind that I could hardly remember it." But you are correct that moisture is needed for clouds. Well, the Arctic sea ice pack never seemed to be in short supply of moisture in summer months, as Fridtjof Nansen also referenced in his diary in 1895, July: "..large pools of water now formed on the ice-floes. Already on the 8th and 9th of June such a pool had begun to to appear around the ship, so that she lay in a little lake of fresh water. Some of these fresh-water pools were of respectable dimensions and depth. There was one of these on the starboard side of the ship, so large that in the middle of July we could row and sail on it with the boats."
Toggle Commented Sep 21, 2018 on PIOMAS September 2018 at Arctic Sea Ice
Thank you Neven! BTW, Zachary Labe has a great selection of SIE graphs here: http://sites.uci.edu/zlabe/arctic-sea-ice-extentconcentration/
Toggle Commented Sep 20, 2018 on PIOMAS September 2018 at Arctic Sea Ice
Thank you for another great PIOMAS update Neven - and congrats with making the cut on the 4.5 M km2 on the JAXA SIE! The three factors mainly shaping this melting season since March seem to be: - The SSW event late March, which reinforced the Arctic circulation and caused improved ice conditions for late winter/early spring - The CAA/Greenland cold spot: This area was significantly colder than other recent years, with more ice clinging to the western part of the CAA. - Lack of ice north of the Fram Strait, both due to unusual weather in this area and general lower ice volume having moved towards this strait into the North Atlantic. Regarding polls: Is there a chart on ASIF of the NSIDC Sept Avg. SIE?
Toggle Commented Sep 20, 2018 on PIOMAS September 2018 at Arctic Sea Ice
wayne - when the sea ice area is increasing, then the area of ocean surface covered by sea ice is increasing.. Being mid-September it is quite normal that some melting still takes place at the outer boundary of the ice pack, while smaller lanes and melt ponds are starting to freeze over at the center of the pack. This is why the sea ice area minimum is reached earlier in September than the sea ice extent minimum. This is also how the Arctic sea ice cover typically grows in September to November/Dec until the SST and air temps at the ice pack boundary get low enough to cause in situ freezing at the boundary of the pack. Being situated in the Arctic I am surprised you have not noticed yourself..
Toggle Commented Sep 17, 2018 on PIOMAS August 2018 at Arctic Sea Ice
Hi wayne, You may not have noticed, but the ROOS sea ice area has been increasing over the past couple of days.. https://arctic-roos.org/observations/ice-area-and-extent-in-arctic Extent drop during sea ice area increase is consolidation, not melting, and with the sun headed south there is no turning back to significant melting that could bring 2018 anywhere into the vicinity of 2012. Not even by a far stretch of imagination.
Toggle Commented Sep 16, 2018 on PIOMAS August 2018 at Arctic Sea Ice
I guess I don't see the confusion: Sea ice extent: With the 15% rule is a simplified metric, created due to the limited ability to accurately measure sea ice cover by satellite during summer months caused by extensive cloud cover. Sea ice area: Calculates sea ice cover with e.g. a measured 50% cover in a grid resulting in 50% counted as covered. This measure provides a number closer to the 'actual' sea ice cover, but is less reliable during sommer months with heavy cloud cover. That said; the cloud cover has now eased, and I prefer using the SIA metric for the non-sommer period, as it provides a number closer to the actual sea ice cover.
Toggle Commented Sep 12, 2018 on PIOMAS August 2018 at Arctic Sea Ice
A nice view of current sea ice area compared to 2012 sea ice area is found here: http://web.nersc.no/WebData/arctic-roos.org/observation/ssmi1_ice_area.png Seems like the sea ice area is about 25% larger than six years ago.
Toggle Commented Sep 12, 2018 on PIOMAS August 2018 at Arctic Sea Ice
wayne, You know they created the sea ice area metric specifically for those, who cannot get their arms around the sea ice extent metric.. ;-)
Toggle Commented Sep 12, 2018 on PIOMAS August 2018 at Arctic Sea Ice
Hi wayne, I wanted to follow up on our exchange from end of July above, where you stated: "your logic trying to protect an experimental model fails in an elementary way, near all time low extent maximas, automatically imply lesser volume. You see volume has 3 components, no surface sea ice means no volume at all. And I know your data is irreproachably correct, yet fails explaining anything of current value." So I have used area, extent and volume models combined with Arctic weather oversight in general to make my prediction, while you have acquired: "rock solid data, not subject to errors" This data apparently caused you to revise your prediction on Aug. 5th for Sept average minimum SIE from slightly above 2012 to surpass 2012 levels and bring new record low SIE. How is your data holding up currently?
On the Northwest Passage: It seems the passage has not opened this year - if not that might be a first in this decade?
Toggle Commented Sep 4, 2018 on PIOMAS August 2018 at Arctic Sea Ice
Hi Jim, Yes, I noted this 'GAC2018' also in the forecast back on 8/23. It seems like we have seen the worst and that it will dissipate in the next days. So far, the impact does not seem severe, but agree that due to increased mixing we could see further drops - or more likely that the mixing will retard the onset of freezing of surface waters..
Toggle Commented Sep 2, 2018 on PIOMAS August 2018 at Arctic Sea Ice
Hans and Rob, Yes; as we enter September we will see how the predictions meet with reality. Based on the recent slowdown and unless extreme weather sets in, I would think Rob's prediction of 5.18 with the gut feeling that this should be the high end, will be quite close. I entered 4.85 - 5.35 on June 6th and still have good faith that the Sept NSIDC avg. SIE will be found in this range.
Toggle Commented Sep 2, 2018 on PIOMAS August 2018 at Arctic Sea Ice
"Any chances it could reach the Arctic basin?" javimozo: It will reach the Arctic basin after a counter-clockwise circumnavigation of Greenland: https://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=nhem&pkg=z500_mslp&runtime=2018051800&fh=0
Toggle Commented Aug 24, 2018 on Circumnavigating Greenland at Arctic Sea Ice
GAC2018?? Hold on to your hats! From Tropical Tidbits it seems like considerable amounts of warm moisture is moving up fast through the Atlantic and converging into a massive cyclone about a week from now. The forecast could still change, but if this will occur, it would be the worst time possible with sea ice at minimum and SST at maximum. A lot of slush in the making it appears - and possibly a 'GAC2018'..
Toggle Commented Aug 23, 2018 on PIOMAS August 2018 at Arctic Sea Ice
You are probably right Jim - these days we should probably be content with getting a paddle board floating in the ponds.. ;-)
Toggle Commented Aug 20, 2018 on Circumnavigating Greenland at Arctic Sea Ice
Hi Rob, I agree with your assessment in large and expect the minimum NSIDC SIE to reach 4.5 - 4.8 MKM2 - or even 4.9 if little compaction will take place. If so, the Sept average extent that we have been projecting for, should be within assessed range, where I had listed 4.85 - 5.35 back on June 8th.
Toggle Commented Aug 20, 2018 on PIOMAS August 2018 at Arctic Sea Ice
"That, is scary. Very scary." Hi Ethon, I am not sure where you see the scary part about sailing in a melt pond on top of sea ice..
Toggle Commented Aug 20, 2018 on Circumnavigating Greenland at Arctic Sea Ice
No problem Jim - just wanted to reconfirm in any case.
Toggle Commented Aug 20, 2018 on Circumnavigating Greenland at Arctic Sea Ice