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Neven
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Be careful, John. The forecast keeps moving more and more towards high pressure over the American side of the Arctic. If that moves slightly more to the CAB, 2016 will at least follow regular decrease rates of the past few years, which means it will stay low.
Toggle Commented yesterday on 2016 melting momentum, part 2 at Arctic Sea Ice
I see what you mean now, David. Interesting idea, but difficult to assess. Also: What we perceive as large patches of open water on true-colour satellite images, often contain small ice floes that passive microwave sensors or the stuff used for operational analyses do pick up.
Toggle Commented 2 days ago on 2016 melting momentum, part 2 at Arctic Sea Ice
Yeah, I saw that. Made CAMAS go up more than 0.5%. :-)
Toggle Commented 3 days ago on 2016 melting momentum, part 2 at Arctic Sea Ice
I like the idea of using MASIE as the area measure for compactness. MASIE would be the extent measure (hence the SIE in MASIE). Assuming these have no ice they would not be included in SIE or SIA. Everything that looks like water, be it open water or melt ponds, is included in SIA. For SIE it would have to be 85% water or more in a grid cell, and the total cover is deemed 0 km2. However if there's 15% ice or more, the grid cell is considered to be completely covered with ice. Again, this is the primary reason sea ice extent exists as an alternative calculation to sea ice area: to reduce the impact of melt ponds. Even though above compactness measures show the ice equivalent to previous years the attached image visually looks like the pack is much less concentrated than in any year before. Is there something I am missing? Taras, compactness tells us something about how much water the satellites are seeing, a combination of open water/leads and melt ponds. If, as you say, the ice pack looks quite dispersed, meaning there is a considerable amount of open water between floes, but compactness is not lower than in other years, this - in theory - means that there is relatively less melt ponding than in previous years. The state of the ice in 2016 is not good at all, and with albedo feedbacks, the Arctic is right now much more sensitive to weather than it has ever been, so if even an average summer gets us to 3.8, a bit of melt-inducing weather will easily get us much lower. I agree, Rob. I just state my views as of this moment. They can change within a week. I don't think the last word about this melting season has been said. Whether it is this year or next, or even the next five years, it appears the sum of conditions is degraded multi-year ice, increased underwater temperatures, lots of smoke and pollution from wildfires, and who knows what else. Because of the deeply dishonest nature of opposition efforts to undermine both information and collection of information, we all "hope" for something to be a wakeup call. Well said, Susan. Whether there's a record melting season or not, it's the long-term process that is the real - and worrying - story here. Although it was nice to have two rebound years after 2012, this year and last year are a clear continuation of the trend. If things stay the way they are or get worse even, it's just a matter of time before a less benign combination of conditions from May to August will force everyone to hit the snooze button again.
Toggle Commented 3 days ago on 2016 melting momentum, part 2 at Arctic Sea Ice
I've seen the polls but I'm curious to know how much of an extent you think we're likely to have come mid September. Well, in the recent June poll I have voted for 'between 4.0 and 4.25 million km2 (2012, 2007 and 2011+2015 ending at 3.63, 4.30 and 4.63 million km2 respectively. Given current conditions and forecasts I might be tempted to go one bin up to 'between 4.25 and 4.5 million km2', but there's still some weeks left to go before the July poll opens up. There has to be one or two periods of weather conditions that are conducive to melting for this year to end up in the top 3. On the other hand you could say that it is already quite remarkable for this year to still be so low despite weeks of weather that is good for ice retention. OK...then the simple question is: why has it been breaking records all year so far? Because of winter weather and weather conditions until they switched a few weeks ago (when weather conditions perhaps matter most for the melting season outcome). And there's always the wild card: ocean heat flux. The article linked above is on the switching from El Nino to La Nina predicted for this Summer as ocean temps are currently cooling. I'm not saying that's why 2016 melt has gone from record setting to much less likely to break any records, but it's worth considering. Even if there was a correlation between ENSO and Arctic sea ice - which there isn't, as far as I can see - there is no way it would be this direct. In the forum you explain it mighy remaing favorable for ice. Well, the forecasts keep flip-flopping. Now they've returned to forecasting domination of high pressure over the American side of the Arctic. If these areas push towards the Central Arctic, that 'mess in the Beaufort', as Rob Dekker aptly calls it, is going to be struck hard. This is important with regards to longer-term trends, as there could be very little multi-year ice left at the end of the melting season. There will also be more transport towards the warm Atlantic and more compaction, and so on. Like I said, just a few weeks of such weather and 2016 can still make it to the top 3. It's going to take an exceptionally warm and sunny July though (like we saw last year) for 2016 to become a title contender again.
Toggle Commented 3 days ago on 2016 melting momentum, part 2 at Arctic Sea Ice
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Happy Solstice, everyone! Credit: NASA/Kathryn Hansen The previous post on melting momentum was running long, so here's an addition dealing with compactness, the final piece of information we have to assess the amount of melting momentum. Just before the start of July, the month of big melt. First, a couple... Continue reading
Posted 4 days ago at Arctic Sea Ice
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The situation in the Beaufort Sea - important for the ice long-term - looks particularly worrying, IMO. I may be wrong to be worried (too much), as this comment on the ASIF by A-Team shows that ice may be more dispersed now than it has ever been on record, but there is clearly much less preconditioning going on than there was in previous years.
Toggle Commented Jun 17, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
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Melting momentum, it's what I call the absorption of heat and solar radiation during May and June that does not directly lead to melt and a reduction in ice cover, but rather comes into play during July and August (I had a more wordy explanation last year). As important as... Continue reading
Posted Jun 17, 2016 at Arctic Sea Ice
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Yes Neven, we are looking at different forecasts, as I make reference to 15 hours later than yours :) Ah, okay. Time is relative, after all. :-) I'll have a post on melting momentum later today which I'm sure you'll like.
Toggle Commented Jun 16, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
We must be looking at different forecasts, unless you want to put in some links. This GFS forecast for Saturday, for instance, doesn't look like 'more than 50% of the Arctic' is going to go below freezing temps. As for the ECMWF, like I said, pressure isn't going to go particularly low, and when it does go lower, it's accompanied by high pressure over the American side, which means more winds due to an increased pressure gradient. A dipole, in fact, but with the low over the Central Arctic and not on the Siberian side. Either way, we've reached that stage where forecasts oscillate wildly after 4 days out. But what we can say for sure, is that this isn't like 2013 at all, the best year for ice retention in the last decade. It's no 2012 either, the worst year for ice retention. It's something in between, with the exception that a lot has happened already. The situation in the Beaufort Sea - important for the ice long-term - looks particularly worrying, IMO.
Toggle Commented Jun 16, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
May I note that currenty 2016 is still in the lead for ice extent and area and volume, possibly rivaled only by 2012. Just saying. Sure, the fact that 2016 has been so low all year so far (don't forget snow cover), is what makes me think that 2016 will go low, even if less melting momentum is being built up right now. But given the past 10 days and the coming week, the lead in extent and volume is going to be gone. I expect both 2011 and 2012 to be lower in PIOMAS volume at the end of this month. 2012 is already lower in sea ice area, and extent-wise I expect this year to be battling it out with 2010, 2011, 2012 and 2014 at the end of the month (see first graph in this blog post).
Toggle Commented Jun 14, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
It may be nonsense what I'm about to say, but I've noticed that although cyclones are dominating, the pressure isn't particularly low and the ice pack is more visible than I had expected it to be. Extent has stalled because of a total lack of compaction, but dispersion isn't all that good for the ice pack either, and it is gently being pushed apart, with clear skies in some regions like the Kara Sea, the CAA and even parts of the CAB. Solar radiation obviously trumps everything at this stage of the melting season, but things aren't looking as cloudy or cold as they were in 2013 and 2014, or perhaps even last year. But I'm not sure yet how melting momentum compares to similar years. Either way, it will still take one or two periods of weather conducive to melting for this year to approach top 3 minimum territory.
Toggle Commented Jun 14, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
I wanted to open an NSIDC September monthly average poll at the start of the month, but totally forgot about it. Of course, given the fact that there have been polls during the three previous melting seasons, it'd be cool to stay consistent and do this one again (I'm not going to do CT SIA though). Sorry for opening it so late, but better late than next month. Here's the link, poll will be open for 1 week, so please vote, everyone! NSIDC September/average SIE is the one that is used for the SIPN Sea Ice Outlook.
Toggle Commented Jun 13, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
Thanks, John! Temperature above 80N just seems vicious. Not so much the point it is at now, but rather the fact that it has been above average for more than 97% of the time this year.
Toggle Commented Jun 11, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
And again: Over on the Arctic Sea Ice Forum, there's still three days left to vote on the JAXA daily minimum poll for June. Don't forget to vote!
Toggle Commented Jun 11, 2016 on ASI 2016 update 2: closing the gap at Arctic Sea Ice
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During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Because of issues with data based on the SSMIS sensor aboard DMSP satellites, I mainly focus on higher-resolution AMSR2 data from the Japan Aerospace Exploration Agency (JAXA), as reported on the... Continue reading
Posted Jun 11, 2016 at Arctic Sea Ice
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Speaking of DMI. I don't know if it's your mail that did the trick, John Christensen, but the DMI SST anomaly map is back! I immediately made a comparison with previous years on the 2016 melting season thread over on the Forum. So not really sure that it has been a "good" first week for sea ice in June. Definitely, Colin. Like I say in this blog post that large patch of high-volume ice in the ESS is having it tough right now, and in days to come. The heat will then move to the Beaufort again, while the CAA continues to be bathed in a combination of clear skies and high temps. The snow is vanishing everywhere, and ice is being pushed towards warm Atlantic water. But it's no first half of June 2012 (see here, for instance), the month with the largest volume drop in the PIOMAS record. I noticed some of the melting momentum effect in 2011, but it was really pronounced in 2012, although it took me a while to realize just how important preconditioning through melt pondings can be for the final outcome of a melting season. Right now, there are many things going on at the same time, which makes it difficult to assess impacts on a deeper, largely invisible level, especially when compared to other years. But I'll try to analyse as best as I can when the month is over. I'll have a melt pond May analysis next week, as soon as Dr Schröder sends me his (modelled) melt pond distribution maps. And there'll be some stuff in the next ASI update as well (hopefully a CAPIE replacement).
Toggle Commented Jun 8, 2016 on PIOMAS June 2016 at Arctic Sea Ice
the weather conditions in the Arctic have drastically changed recently. Low pressure conditions are prevailing and are forecast to persist for the following 7-10 days, based on the latest runs from ECMWF and GFS. I hope this will help slowing down the melting of ice and in particular the formation of melt ponds, a key factor in June as I've learnt from Neven Absolutely. 2016 has been running the show so far, going low on every possible level, all over the Arctic. But now it's 2012's turn to get in a few punches. In fact, if the current forecast comes about (it's getting more inconsistent now that the weather gets more capricious as the Arctic warms, the further out you go) and things stay that way until the end of June, I may be tempted to say that a new record is going to be very difficult. July would have to approach 2015 levels to turn things around. But we first have to see what happens exactly with regards to temperature, sea level pressure and melt pond distribution. Still, the first week of June, that crucial month, hasn't been good for melting, and thus good for the ice. Naturally, this is what the next ASI update will be about.
Toggle Commented Jun 8, 2016 on PIOMAS June 2016 at Arctic Sea Ice
Continuing the serious outlook, if we see PIJAMAS dropping to the floor then we'll have a naked Arctic Ocean but even halfway down would result in an alarming exposure. Not to worry, it will then soon be winter, 24/7 darkness. ;-)
Toggle Commented Jun 8, 2016 on PIOMAS June 2016 at Arctic Sea Ice
Thanks, Lodger! And thanks for the heads-up, Lennart. Too bad though that it is implied that I'm saying the Arctic will be ice-free this year, taking a quote from the first ASI update. I've said this, also one of the themes of this PIOMAS update: If you would write a scenario for how the first ice-free September comes about, it would look something like this. I don't think Arctic sea ice extent will dip below the 1 million km2 mark this year, simply because the ice in the Arctic's core is too thick to melt out. Nevertheless, quite an honour to be quoted in the Volkskrant. Mom will be proud. ;-)
Toggle Commented Jun 8, 2016 on PIOMAS June 2016 at Arctic Sea Ice
more volume in the Central Arctic Ocean would increase chances of higher minimum extent and volume by Sept In principle, yes, but that in turn depends on the distribution of volume within the Central Arctic. As you can see on the comparison maps most of where there is more ice this year than in 2011 and 2012, is north of the Canadian Arctic Archipelago, where it is expected that ice will hold out the longest in the long-term. So, that's not really an obstacle per se for 2016 to go as low as 2011 and 2012. If one takes an average for the year (more or less) and adds/subtracts deviations from that average from each monthly result, the resulting "smoothed" volume should highlight volume trends more clearly, I would think. Thoughts? You mean something like this on Wipneus' PIOMAS page?
Toggle Commented Jun 8, 2016 on PIOMAS June 2016 at Arctic Sea Ice
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Another month has passed and so here is the updated Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center: As of May 31st the 2016 trend line is lowest on the graph. A sea ice volume decrease... Continue reading
Posted Jun 7, 2016 at Arctic Sea Ice
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There was no recession in 2014 or 2015. Not in the books, no. :-B
Toggle Commented Jun 6, 2016 on Crisis in the Cryosphere at Arctic Sea Ice
Thanks! Have you noticed the interesting excursion the Antarctic freeze-up is taking? No, not really. I saw that the rate of increase slowed down on the UB SIE map that's on the ASIG Daily Graphs page, but as I know very little about Antarctic sea ice, I don't know what to make of it. I occasionally would check out the images of Antarctic sea ice on the Cryosphere Today website, but things are still a mess there because of the F17 SSMIS sensor issues.
Toggle Commented Jun 4, 2016 on ASI 2016 update 1: both sides at Arctic Sea Ice
Also check out RobertScribbler's latest: Siberian heatwave wrecks sea ice as Greenland High settles in