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John Christensen
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NP Rob, it could also be argued that due to northward movement of the jet stream caused by positive AO, remaining ice of peripheral seas would be under increased stress.. Let's see what happens
Toggle Commented 2 days ago on 2016 melting momentum, part 2 at Arctic Sea Ice
"Over the last 10 years 2012 has had the fourth biggest drop in extent over the next 14 days. 2007 and 2013 dropped approximately 400K km^2 more. The average is barely greater than 2012. What odds are you offering for 2016 dropping less than 2012?" The next 2-3 weeks include the steepest decline in extent of the melting season, as we both have the sun near maximum and heat having accumulated, often resulting in 15-20% of ice extent being lost in the last week of June and first week of July, based on today's date. So we should expect days of steep decline.. And yes, I could have selected 2007 or 2013 (which would have been justified from Rob's comment), but they both start higher, so I felt it being more fair to select 2012, which is comparable to this year from a current extent perspective. Given the AO forecast ( http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml ) while there will be areas of high pressure we should have overall dominance of low pressure areas, which given the already low extent should allow us to fare better than 2012. Odds: I would say about 70% chance of 2016 faring better than 2012 for the next 14 days, given the difference in weather/forecast.
Toggle Commented 3 days ago on 2016 melting momentum, part 2 at Arctic Sea Ice
"Be careful, John. The forecast keeps moving more and more towards high pressure over the American side of the Arctic" Agreed, predicting future is a gamble, but the 2012 extent saw a sharp drop starting 2-3 days from now, so we would need very favorable conditions to keep up with that.
Toggle Commented 3 days ago on 2016 melting momentum, part 2 at Arctic Sea Ice
"2016 will thus probably continue to drop faster than other years." Rob, 2012 extent has dropped faster than 2016 if you compare from June 1st, May 1st or from spring extent max, so what is your reference period? Given the weather forecast, I will bet you £10 (They are really cheap today) that 2012 will loose more extent in the next 14 days than this year, starting today.
Toggle Commented 3 days ago on 2016 melting momentum, part 2 at Arctic Sea Ice
Agreed Rob; extent is going down quickly in the peripheral seas, but not in the CAB, where temps are held back by the low. It will be very interesting to see if PIOMAS follows DMI, where we are still seeing very restrained volume decline: http://polarportal.dk/en/havisen-i-arktis/nbsp/sea-ice-extent/
Toggle Commented 4 days ago on 2016 melting momentum, part 2 at Arctic Sea Ice
Got it, thanks Rob! Agreed, that the projections used are much too conservative, and odd that the text admits that the projections 'might be' too conservative, although observations extent considerably beyond confidence bands. Similarly, it seems their projections have no clear grasp on the SH sea ice cover, but let's not open that discussion here.
Toggle Commented 5 days ago on 2016 melting momentum, part 1 at Arctic Sea Ice
Thanks Rob - and yes; I do not consider myself entirely ignorant about sea ice, but I was not aware that the IPCC had included sea ice extent projections in their publications, and have searched AR5 again, in vain. Are you aware if the projections were in AR5, or have they been published separately?
Toggle Commented 6 days ago on 2016 melting momentum, part 1 at Arctic Sea Ice
"this entire range is quite outside the IPCC projected range for 2016" Rob, Please share the IPCC project range for 2016 with us ignorants, thanks.
Toggle Commented 6 days ago on 2016 melting momentum, part 1 at Arctic Sea Ice
"If PIOMAS follows the behaviour of DMI Cice, this year's spring melt looks likely not to to be very strong." Agreed Chris, according to DMI, the June volume melt has been less than the 2004-13 average, with extent dropping relatively more. That extent has dropped more sharply than volume was to be expected with significant volume in the central areas, as discussed earlier. Suspects IMO: 1) June weather/lows in the CAB 2) Lack of conditioning (melt ponds) 3) Relative lack of Laptev bite - and why would that be?
Toggle Commented Jun 19, 2016 on 2016 melting momentum, part 1 at Arctic Sea Ice
P-maker and Sam, After the consecutive melt years of 2010 and 2011, the sea ice was in a terrible state also by May/June 2012, so if that ice could sustain the melt ponds, this year should be no different.
Toggle Commented Jun 17, 2016 on 2016 melting momentum, part 1 at Arctic Sea Ice
Great entry, thanks Neven! - And a great melt pond extent graph by Wipneus! It is surprising that May did not come out more negative from a melt pond fraction perspective given very clear skies and high temps in April. Given what we saw in July 2015, the impact of cloudiness/clear skies may be more centralized around mid-summer, i.e. May-July rather than April-June..
Toggle Commented Jun 17, 2016 on 2016 melting momentum, part 1 at Arctic Sea Ice
Hi Neven: "Mind you, given the fact that 2015 sea ice extent" Should be 2016, right? You can delete my comment then, thanks. [Fixed now, thanks; N.]
Toggle Commented Jun 17, 2016 on 2016 melting momentum, part 1 at Arctic Sea Ice
Are bets open for end-July volume match with 2015 yet? ;-)
Toggle Commented Jun 17, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
Agreed Neven, and with the AO turning quite positive again in the next couple of days, the general cloud cover will increase. That said, the AO clearly is not the full story, as June overall should turn out with just slightly positive AO, but with clouds overall well-positioned to dampen preconditioning - weather rules still.
Toggle Commented Jun 17, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
Sorry, bad edit: The consequences of a cyclone in June are different from what they would be in August.
Toggle Commented Jun 16, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
Hi Sarat, You should read this on cyclones: http://neven1.typepad.com/blog/2013/06/on-persistent-cyclones.html The consequence in June from what it would be in August - GAC-2012..
Toggle Commented Jun 16, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
Thanks Sarat, yes; you have day-to-day fluctuations up or down on these. DMI seems to be one day ahead of the other charts (or maybe they just use a different time stamp), and the latest change brings the drop back to somewhat average: http://ocean.dmi.dk/arctic/icecover.uk.php
Toggle Commented Jun 16, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
Hi Sarat, "Sharp drops in extent in the past few days" Where did you see those?
Toggle Commented Jun 16, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
wayne, Since the composition of melt ponds, cracks and drainage of sodium chloride can impact the temperature of the ice column, I would not extrapolate the data from one buoy to the entire Arctic ice pack, but rather put faith in the remote sensoring tools, even knowing the limitations of these.
Toggle Commented Jun 16, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
Hi Cato, "considerations about % of arctic below zero for a few hours are not so essential, I reckon..." What you are seeing is night time temps in that area; even with sun around the clock you will see around 78-83 degrees N that temperatures during main night hours can dip below freezing, which helps lower temps in melt ponds. In the far north (85-90N), sun radiation seems to be strong enough to keep temps above freezing around the clock.
Toggle Commented Jun 16, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
Your note was entered in-between Neven, otherwise I would have added that the main forecast I was looking at was for the AO and secondly that a low will remain over the central Arctic Ocean, which I think will be beneficial to the ice come mid-late August: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml However, this is clearly not ideal weather, as it has been in the past week, but that can be said for most of the recent years - except for 2013, that is.
Toggle Commented Jun 16, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
I was also reviewing extent loss since max extent, where 2016 lands with an average level of extent loss. This shows the amazing impact of weather in these critical high-summer weeks, as this melting season was preconditioned for immense losses - the greatest melt in history..
Toggle Commented Jun 16, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
Yes, given this forecast I expect extent to get close to 2014 by the end of June, with 2013 and 2015 being the recent years with higher extent.
Toggle Commented Jun 16, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
Thank you for elaborating wayne! "I find General Circulation Predictions a walk in the park compared to the very complex nature of not so simple sea ice." - remember that Edward Lorenz, studying weather models and the circulation patterns got inspired to come up with the chaos theory.. ;-) As mentioned further up, I do not see the conditions being in place to stay at the decline rates seen in 2012, but let's see.
Toggle Commented Jun 14, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
I read your blog wayne, seems dramatic: "Make no mistakes in judgement, this is the greatest melt in history." How would you define "greatest melt" in terms of quantity and time period?
Toggle Commented Jun 14, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice