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DMI SST map back up.
Toggle Commented 4 days ago on ASI 2016 update 1: both sides at Arctic Sea Ice
Chris, Thanks for the explanation. We seem agreed on Oct to Dec temps being caused by summer sea ice area. A step down in area then levelling of area results in a step up in Oct-Dec temperatures then a less steep rise or levelling of temps. For Jan-Mar, I am more inclined to suggest different drivers for the temperature: GHGs and warmer air flowing in from lower latitudes. (0.9m thick ice or 1m ice makes little difference compared to 0m or 0.1m so summer sea ice area effect is greatly reduced.) Displacing polar vortex or not (maybe also wavier jet stream) can then cause increased volatility in temperatures. I will accept that it is possible that there is a less steep rise hidden by noise and could take several years before this is revealed. I see Screen et al say "However, the presence of amplified warming aloft hints that processes in addition to the increased transfer of heat from the ocean to the atmosphere resulting from sea ice loss have had a contributing role in winter." Maybe enough wriggle room to stick to my inclination for different drivers of Jan-Mar temps and to expect them to continue upwards without a slowing in the rate.
>Sam Wrote "So hope is useless at this point. Fear on the other hand, fear may serve us." Perhaps it might depend on the audience and maybe a bit of both is needed. Maybe the fear is more important: I would suggest possibly most important audience is people who make investment decisions. With renewable becoming cheaper it is a matter of deployment that takes investment. Do they put huge amounts into a safe but relatively small return over long period from renewables or something more exciting and riskier? If they are convinced that economy will collapse or at least there is significant risk of collapse unless the problem is dealt with then the exciting and riskier investments will look a lot less attractive. That doesn't work unless there is some hope that massive investments deploying renewables might work to avoid the problems.
>"Do you know what Oct to March surface temperatures north of 70degN (NCEP/NCAR) have been doing over the last 10 years? They have levelled - apart from this year which is a clear outlier." Jan to March seems to be continuing upward possibly accelerating. Oct to Dec does seem to have levelled as you indicate. Is there some explanation for this or is it just noise like ENSO that doesn't really affect what you would predict for trend going forward? Oct and possibly later might be affected by heat absorbed by oceans over summer which is then given up before ocean freezes over. So I might give Oct a lower weighting when considering effect of temperatures on reducing winter volume. Last 3 years Oct might be low because ice extent at minimum was high, possibly partly explaining the levelling off? Change to Nov to Mar and the levelling off is much less clear. Perhaps also changing to 75N to 90N.
David Madsen said "CO2 levels are going to exceed 450 ppm by 2030 (not may exceed, will exceed)" I see a couple of problems with this rhetoric. It seems to say there is nothing we can do about it therefore we may as well not bother. A more hopeful message is that we are gearing up renewables as they are now becoming cheaper than fossil fuels. Even without carbon price or subsidies that creates incentive. There is a lot of deployment to do but starting to cut emissions to keep atmospheric level to less than 2.5ppm increase per year may be possible as long as sinks don't suddenly weaken. 407ppm+2.5*14=442ppm. Last 10 years increase was 23ppm only 2.3 ppm per year. Given possibility of such a challenge to what you are saying, if you are going to maintain a 'will' not 'may' stance, isn't it better to slightly reduce the claim to what is certain so you don't get challenged is this way?
Rob said: "Chris said : if April volume loss stalls then summer loss extent stalls. This does not make any physical sense to me. If summers keep on warming (due to global warming), then more and more ice (volume) will melt out during the summer." Try the following for an explanation: Summer extent declines for 2 reasons: 1. GHGs, warming of air and oceans. This reason continues to apply. 2. Less volume at maximum means thinner ice which disppears more quickly allowing albedo effect resulting in more heat absorbed and more melt. If volume at maximum levels out a bit then reason 2 reduces in its effect. Reason 1 continues but looks fairly linear and reason 2 declines in effect. Together this looks to give a reduced rate of decline.
2016.1453 .. 14.2208595 might be the minimum with Arctic just having increased 138k and typical Antarctic minimum just a couple of days away. It seems global area usually increases from now on.
2016.0986 -1.5609524 14.3651371 15.9260893 2016.1013 -1.4567810 14.4637003 15.9204817 2016.1041 -1.3401810 14.5634079 15.9035893 2016.1068 -1.2670890 14.6249723 15.8920612 2016.1096 -1.2674983 14.6272812 15.8947792 2016.1123 -1.2934796 14.6033812 15.8968611 2016.1151 -1.4321671 14.4693680 15.9015350 2016.1178 -1.5083036 14.3738375 15.8821411 Less than 9k higher than record of one week ago. With Arctic gaining just 14k a new record is within reach again.
Toggle Commented Feb 15, 2016 on Global sea ice area record minimum at Arctic Sea Ice
Stan, re broken link: To get to the page intended by John Christensen delete the ), that has been added to link by mistake.
Toggle Commented Feb 11, 2016 on PIOMAS February 2016 at Arctic Sea Ice
>"Winter has had its best time." Per a few sources like coldest time is mid Feb to mid March when ice extent is high and winds have to travel a long way over ice and snow if they are to bring warmth to Arctic. Doesn't this mean winter hasn't had its best time yet this year? More unusually mild weather in next month would really eat into the remaining potential recovery time.
Toggle Commented Feb 11, 2016 on PIOMAS February 2016 at Arctic Sea Ice
Very close: 2016.0959 -1.5473126 14.3929777 second lowest day ever after 2006.0850 -1.5731411 14.3918705 Just over 1k above, obviously not statistically significant difference. Arctic rose just over 33k so need an Antarctic fall of 35K with the next datum. Yesterdays Antarctic fall was 42k and typical for this day is 35k. So looks like an even better chance than today is coming tomorrow.
2016.0931 -1.5001982 14.4575024 66k above record and 4k higher than 2 days previously. But this time we have an arctic drop of 22k so antarctic drop of just 44k would be enough. (Last day antarctic fall was 68k and typical fall for time of year is 42k. Looks possible bordering on probable.)
2016.0876 -1.5149544 14.4531231 is now lowest ever for time of year (being below 2006.0876 -1.4466151 14.5214624 2011.0876 -1.2477340 14.7203436 ) less than 62k more than lowest ever 2006.0850 -1.5731411 14.3918705
>"And the volume is? They're not saying," Per BBC "This February, Cryosat saw average sea-ice floe thicknesses of just over 1.7m, giving a volume across the Arctic of nearly 24,000 cubic km. Back in the winter of 2013, following strong melting during the previous summer, floe thicknesses averaged 1.5m and the volume fell below 21,000 cu km." For comparison PIOMAS has 2015 32 20.348 2015 60 22.524 avg 21.502 2013 avg Feb 19.376 so Cryosat continues to have more volume in winter.
Toggle Commented Apr 18, 2015 on CryoSat-2 sea ice thickness maps at Arctic Sea Ice
First, second and fourth look much more sensible odds to me. Third looks a bit mean, I might offer 25:1 unless 'top 5' extent means lowest 5 extent when betting at 10:1 would look like good value. I might be interested in 10:1 Not in top 5 extent but probably only a small amount for a bit of fun and only if 'top 5' means lowest 5. If it means highest 5 then odds look a little low but again what record is to be used? By NSIDC, I get the following years to result in a pay off 2014 2013 2001 1997 1996 1994 1992
Toggle Commented Mar 11, 2015 on Mad max? at Arctic Sea Ice
>"Current odds are as follows for September of 2015: 400:1 Continuous ice from NW Passage to Siberia 200:1 Ice remaining in Hudson Bay 12:1 2015 Extent lowest year on record 8:1 2015 Extent within lowest 2 years on record 5:1 2015 Extent within lowest 3 years on record 3:1 2015 Extent within lowest 4 years on record 2:1 2015 Extent within lowest 5 years on record NOTE: Race will be cancelled if Krakatoa, Pinatubo and the Yellowstone Caldera all erupt within the next few weeks!" Serious or in jest? What does "Continuous ice from NW Passage to Siberia" mean? At those rates, I think I would like to place a few hundred pounds on Extent within lowest 5 years and some more on some of the others. Which extent data is involved?
Toggle Commented Mar 11, 2015 on Mad max? at Arctic Sea Ice
I can see that 'tumbling' as in turning 90 degrees at a time would impede brine rejection. However that requires very small pieces of roughly same width as depth. Isn't that unlikely and repeatedly turning upside down more likely? If just repeatedly turning upside down, doesn't the brine have an easy path back down along the route it has carved when going in the opposite direction? Does that impede brine rejection all that much?
Toggle Commented Jan 4, 2015 on Fram Strait 2014 at Arctic Sea Ice
What Tilling and colleagues see in the data is a very strong link between autumn thickness and the degree of melting in a year. "You might think, for example, that wind conditions would be important because they can pile the ice up and make it less susceptible to melting, while at the same time exposing more water to freeze," the University College London researcher explained. "But we've looked at this and other factors, and by far the highest correlation is with temperature-driven melting." Am I following this correctly? If there is a lot of melt during spring & summer then autumn thickness tends to be thin. Err, yes I think I would expect that not only for the obvious reason but also because lower ice at maximum tends to cause more melt. Presumably there is something a little more subtle than that she is trying to get at?
Toggle Commented Dec 16, 2014 on In the meantime: CryoSat at Arctic Sea Ice
D has linked the Average for month the end of month figures are Day 151 31 May: 2014 20.288 4th lowest 2013 20.498 2012 19.591 2nd lowest 2011 19.483 lowest 2010 20.229 3rd lowest 2009 22.431 2008 22.878 2007 21.891
Toggle Commented Jun 3, 2014 on PIOMAS June 2014 at Arctic Sea Ice
>"Looking at the data I see that modelled volume reached 23,104 km3 on April 15th, which is slightly more than the 292,900 mentioned. Maybe the folks over at the PSC calculated the max differently." The average of the 30 days in April comes to 22.931 so I suspect this is a rounded monthly average rather than a single day maximum. Probably best not to expect too much accuracy at one day level so I would expect scientists to look more at monthly average than a one day max. Whether you use a monthly average or single day this is second lowest, above 2011 by about 0.42 or 0.427. So little difference. Shape of curve in April this year is unusually flat ending month at 3rd lowest. Not really sure why this is. Any ideas?
Toggle Commented May 8, 2014 on PIOMAS May 2014 at Arctic Sea Ice
If updating ASIGs, displaying piomas v2.1 and current year would be better; the image to display should be: Thanks for this and all the work you do.
Toggle Commented Apr 15, 2014 on PIOMAS April 2014 at Arctic Sea Ice
>"I thought it'd be a nice way to pass our time while we wait for the latest PIOMAS update." Which is now out 31 March 14 value 22.609 just below 2011 minimum maximum of 22.677, is second lowest for 31 March 14.
Toggle Commented Apr 7, 2014 on Research for a novel at Arctic Sea Ice
If the novel writer is looking for more learned comment Maslanik et al 2007 includes "The area where at least half of the ice fraction in March consists of ice that is at least 5 years old has decreased by 56%, from 5.83 * 10^6 km2 in 1985 to a minimum of 2.56 * 10^6 km2 in 2007. Most of the perennial pack now consists of ice that is 2 or 3 years old (58% in March 2006 vs. a minimum of 35% in March 1987). The fraction of 5+ year old ice within the MYI decreased from 31% in 1988 to 10% in 2007. Older ice types have essentially disappeared, decreasing from 21% of the ice cover in 1988 to 5% in 2007 for ice 7+ years old. The greatest change in age distribution occurred within the central Arctic Basin. In this area (region 1, Figure 1), 57% of the ice pack was 5 or more years old in 1987, with 25% of this ice at least 9 years old. By 2007 however, the coverage of ice 5+ years old decreased to 7%, and no very old ice (9 + years old) has survived. From 2004 onward, and in particular in 2006 and 2007, the remaining oldest ice has been confined to a small portion of the Arctic (regions 6 – 8); essentially a relict of the perennial ice cover of 20 years ago."
Toggle Commented Apr 7, 2014 on Research for a novel at Arctic Sea Ice
P-maker "The object will be frozen into the pack ice north of Svalbard and slowly drift towards the North Pole." Huh? From north of Svalbard or anywhere along Atlantic edge of ice pack which is likely south of Svalbard it is only heading one way with the Transpolar Drift towards the Fram Strait. Anyway as I mentioned above, Beafort Gyre has weakened recently so gyre was more likely to take object from north pole area towards Ellesmere.
Toggle Commented Apr 7, 2014 on Research for a novel at Arctic Sea Ice
>"The ice mass balance buoys that started near the North Pole this time last year emerged through the Fram Strait before Christmas:" Yes but the Beaufort Gyre used to be stronger than it has been recently. One or two trips round the gyre seems possible at up to about 8 years per loop, but probably wouldn't remain frozen either coming to top and melting in summer or sinking to sea bed. Getting stuck somehow in landfast shelf seems extremely unlikely but would allow a 200 year timescale. Stuck in a 20m ridge that tends not to move much is also unlikely but much more plausible than in a landfast shelf. I would imagine two or three decades might be possible before being dropped to sea floor or melted at surface during summer on a trip around the gyre. Polar bears can be inquisitive. Taking an object back to a den on land does not seem possible to me, but a transfer from a ridge near a landfast ice shelf to that ice shelf in autumn so it is then buried in snow and remains frozen might just be within realms of possibility. There have been a few videos posted of polar bears being inquisitive with remote control video cameras.
Toggle Commented Apr 7, 2014 on Research for a novel at Arctic Sea Ice