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Cato Uticensis
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Thanks Neven for this fantastic contribution, intellectually honest as usual and rich of food for thought. I can just fully agree with you on what you have so clearly illustrated. Personally I'm impressed by the difficulty in making forecasts on complex systems like arctic ice, for all the possible feebacks, positive and negative, intervening and contributing to the final outcome in terms of ice volume and extension. To which extent do these feedbacks oppose the "natural" decline of ice extension and volume due to global warming? And is it possible that the Arctic ice will be able to find a new equilibrium where ice does not totally disappear in spite of temperatures increasing globally? And what is the influence of El Nino events on the Arctic ice? Is it possible, for example, that it took a couple of years for the Arctic to manage the excess of heat coming from the latest Nino, thus possibly contributing to the current rebound? Too many questions, I know. I just reckon this system is probably much more complex than I myself liked to imagine it.
Toggle Commented Sep 8, 2017 on PIOMAS September 2017 at Arctic Sea Ice
Thanks Neven, clear as usual. Transport from the Fram has been considerable in the last few weeks, and the Beaufort+ won't be at all beneficial from this point of view I guess...
Toggle Commented Apr 7, 2017 on PIOMAS April 2017 at Arctic Sea Ice
Hi folks and hi Neven, quite a long time since my last time here, and here we are, keeping "going down", springsteen would sing. I have a question for Neven: good sense suggests that we're getting closer to the moment when the persistence of a high-pressure pattern over the Arctic is more detrimental to the ice than favourable. Currently HP is still associated with relatively low temperatures but I expect that in the next week the story will be much different. When does this normally happen? This switch of HP from "icing agent" to "melting agent"? By mid April, more or less? And the melting ponds? When are they starting to form? Thanks a lot, and I keep the chance to thank you once more for the fantastic work you do with this blog.
Toggle Commented Apr 7, 2017 on PIOMAS April 2017 at Arctic Sea Ice
Sarat, I'm a simple man. As a record recovery for ice extension in the month of September has just been achieved, it's honestly difficult for me to be convinced that this recovery is due to record-high temperatures. What would have we said, if there had been no recovery at all? That it would have been caused by record-high temperatures. I tend to be skeptic when whatever happens is attributed to record-high temperatures. I think it would be wise asking ourselves why ice extension is increasing so quickly in September in spite of experiencing the warmest year ever or likewise. The point is, the Arctic is quite a complex system, whose behaviour hasn't been fully understood in its entirety. Every melting season is a lesson learned, and this is no exception. Anyways I expect an extension decrease for the next 4-5 days due to a "malignant" dipole which will lead to ice compaction...
Toggle Commented Sep 28, 2016 on ASI 2016 update 7: minimum time at Arctic Sea Ice
Sarat, if a big quantity of liquid water changes state into solid (ice), then a big quantity of heat is released as latent heat of solidification. This well explains a phenomenon which is apparently in open contradiction with physical reality. Otherwise explained, the "cold" is used as latent heat to achieve the change of state from liquid to solid, rather than as sensible heat causing a decrease in the air temperature. Once the change of state has happened, air temperature will drop as sensible heat will prevail over latent. Sorry for the quality of my English, it's not very easy for me to write in a proper scientific language unfortunately...
Toggle Commented Sep 28, 2016 on ASI 2016 update 7: minimum time at Arctic Sea Ice
Wadhams has been predicting disappearance of arctic ice for the last few years, every year. All the newspapers of the world have been flooded with his forecast of ice disappearance in September 2016. He is not even respected by his own colleagues. His tendency to overindulge in announcements of imminent disasters cast discredits over all the people who take climate change seriously, and professionally.
Toggle Commented Sep 2, 2016 on 2016 Mega-Dipole at Arctic Sea Ice
PS: IMHO we are very close to the minimum. The synoptic configuration in the next few days is leading to ice dispersion and a relevant cooling over the Arctic and less transportation through the Fram. See what happens. I guess there's not much to decide, regarding the outcome of the competition with 2016 gaining the second place of the podium, after 2012.
Toggle Commented Sep 2, 2016 on 2016 Mega-Dipole at Arctic Sea Ice
I think that, once more, this melting season has provided a very interesting lesson. Talking about "worst case scenarios", I think this year has put together an impressive series of negative factors that in the end by far offset the lack of pre-conditioning, namely: 1) very early melting leading to inevitable sea water warming and associated huge positive anomalies for seawater temperature 2) Persistence of LP systems leading to ice dispersion 3) Very windy conditions leading to water-ice mixing, higher exposure of ice to warm water, bottom melting etc. 4) Heat surplus in ocean waters at the beginning of the melting season after the huge el nino event 5) Worst possible dipole configuration at the end of melting season with strong and warm winds from Pacific ocean, very long fetch, huge compaction and Fram export. The only favourable event was represented by cloudy conditions which limited radiation, but overall in my humble opinion this has by far been offset by all the other factors. Overall, in my view, one of the most unfavourable combination of events throughout the melting season. One more lesson learned I guess.
Toggle Commented Sep 2, 2016 on 2016 Mega-Dipole at Arctic Sea Ice
Agree 100% with your post Neven. PS: the pics of the Wrangel arm are just fantastic :)))
Toggle Commented Aug 30, 2016 on 2016 Mega-Dipole at Arctic Sea Ice
Yes John, and based on the latest GFS update transportation could be relevant for the next 7 to 10 days... Let's wait and see whether the next runs confirm the current view. There's much alignment between ECMWF and GFS,with other models like GEM slightly less ominous, as you say... But the forecast looks solid overall.
Toggle Commented Aug 24, 2016 on 2016 Arctic cyclone, update 3 at Arctic Sea Ice
Based on synoptic charts, the next 7 days will be very challenging for arctic ice, due to the persistence of a huge LP system along the siberian coast of the arctic, coupled with a smaller but the same persistent HP on Beaufort and CAA. Very strong winds leading to compaction, warmer air pumped in from Pacific ocean and even increased transportation through the Fram. This configuration in my view is much more impacting than the arctic cyclone. I wouldn't be surprised if we got >100,000 kmq drops in the next few days and as of today I can't see 2016 do any better than 2007. Second place after 2012 should be a rather easy catch IMHO.
Toggle Commented Aug 24, 2016 on 2016 Arctic cyclone, update 3 at Arctic Sea Ice
Sometimes we tend to assume that the Arctic is an isolated area which does not "communicate" with the rest of the planet in terms of synoptic configurations. I have heard several statements like "open water generates LP in the Arctic" or "more ice generates HP" and the like. Unfortunately things are much more complex IMHO. For example, the persistence of a very strong HP at the high latitudes of the Pacific ocean has forced LP systems to move to the Arctic as the main circulation has never been able to win the opposition provided by the subject Pacific HP. This could mean that the root cause of such a cloudy and unsettled summer in the Arctic could be found in the patterns of ocean-atmosphere climate variability such as, for example, the AMO or the PDO. And it is rather intuitive that small masses of water whose temperature is close to 0 C are less impacting than the dynamics of much bigger and warmer water-atmosphere systems in the Atlantic and Pacific oceans. When I asked a professional meteorologist about a potential negative feedback relevant to the lower Arctic ice extension in summer, he replied that in principle a negative feedback cannot be excluded, but the origin of such feedback should be carefully investigated, as the impact of cold waters on the "local" formation of LP systems in the Arctic is negligible, if not laughable at all.
Toggle Commented Aug 22, 2016 on 2016 Arctic cyclone, update 1 at Arctic Sea Ice
Thanks Neven for this update in a thrilling end of season indeed! Based on a pure synoptic analysis approach I expect that from today onwards there will be few opportunities for further compaction, and many more for dispersion. The position of the minimum IMHO should not bring too much damage to the ice, unless the LP moves towards Beaufort and Bering areas. The centre of the LP (and therefore the strongest winds) as of today, seems to be positioned in the area where the ice is more compact and thick and this should somewhat limit the "mixing and churning" effect. Moreover, the extension of the cyclone should completely eliminate opportunities for advection of warmer air from the south for quite a few days, while favouring a general cooling due to the persistence of very low values for the geopotential. Overall, I expect that the following 5 days will be critical for the final outcome of the melting season, i.e. whether 2016 will end up within the top three or not.
Toggle Commented Aug 13, 2016 on ASI 2016 update 5: big cyclone at Arctic Sea Ice
I'm not following much as I'm on holidays... Looks like next 7-10 days will be dominated by LP conditions on the Arctic (what a surprise!) including a very deep cyclone forming at about h 96. Very much will depend on the position of such cyclone, whether it will affect the very low-concentration tongue in ESS-CAB or not.. In the former case further big drops in extent might very well be expected. Otherwise dispersion would probably prevail, thus helping with extent. From now on, heating from radiation will be less and less significant as weather conditions will prevail. Radiation would probably be negligible anyways, considering the forecasts for the following 7-10 days... In my very humble opinion 2007 and 2012 are out of reach today, and the real competition is between 2015 and 2016. It will probably be the (super?)-cyclone to determine the third place on the podium...
Toggle Commented Aug 10, 2016 on PIOMAS August 2016 at Arctic Sea Ice
Thanks Neven, quite sensible points as usual. The comparison between today and one year ago in terms of DMI thickness maps, in fact, is hardly compatible with the extent data from the same DMI which show quite a significant lower extent. Sometimes it feels like the more you look the less you know :)
Toggle Commented Aug 6, 2016 on PIOMAS August 2016 at Arctic Sea Ice
Neven is there any reason why the comparison between outputs from the same model relevant to different years should be disregarded? Thanks for your clarification!
Toggle Commented Aug 6, 2016 on PIOMAS August 2016 at Arctic Sea Ice
Hi everyone and thanks Neven for this latest update. It's a thrilling end of melting season, open to quite different scenarios in my view: (almost) everything is possible. Current conditions are leading to significant compaction due to the concurring action of a HP on Beaufort and CAA and LP on Laptev and ESS. On the other hand according to DMI thickness maps, there's much more ice today than 365 days ago, and this cannot be disregarded. In line with the calendar, models show temperature dropping in the next 7-10 days, with prevailing LP conditions and (so far) no super-cyclones expected any time soon. Conditions that in my view are conductive to compaction much more than melting. As usual, only time will tell.
Toggle Commented Aug 6, 2016 on PIOMAS August 2016 at Arctic Sea Ice
Just a few points from my side: Temperatures over 80o keep trending below average for the period http://ocean.dmi.dk/arctic/plots/meanTarchive/meanT_2016.png With the exception of Barents and Kara, positive see surface temperature anomalies have significantly decreased on the Beaufort and don't look so dramatic overall http://ocean.dmi.dk/arctic/satellite/plots/satanom.arc.d-01.png Talking about weather conditions, most of the LP which have formed on the Arctic have been associated with quite modest advection of warm air from the south. Even more, as they have been centered in the CAB, they have prevented significant advection of warm, continental air. And the cool trend is confirmed even by the latest model runs which show persistence of low pressure systems, associated precipitations and wide areas of below-zero temperatures on the Arctic. http://www.wetterzentrale.de/maps/GFSOPNH06_132_1.png http://www.wetterzentrale.de/maps/GFSOPNH06_36_5.png Ice extension is low, right. Let's remember where we are coming from, though. How many >100,000 km2 days have we had so far throughout this melting seasons? 5 days? 6? If it's not a record for the last 10 years we are anyway quite close to it. There is not much heat over the Arctic. It would be quite strange if there was, actually, after two months of almost uninterrupted LP conditions, plenty of clouds and very little solar radiation. Ice is still undergoing the consequences of a record-warm winter. Let's see how much these consequences will affect September minimum. One thing is for sure: as we are entering August with persisting cloudy conditions on the Arctic, we are gradually approaching the end of the melting season as the radiation effect will become progressively more irrelevant, compared to other factors. I'm not able to make any sensible forecast, but honestly I cannot perceive the current condition of arctic ice as dramatic. I can obviously be wrong, and September will tell. One more thing: unless DMI models are a pile of rubbish, there is some 3,000 km3 of ice more than in 2012: 50% more. And about 2,000 km3 more than one year ago. Doesn't really sound dramatic, does it? http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE_combine_thick_SM_EN_20160726.png
Toggle Commented Jul 27, 2016 on ASI 2016 update 4: breaking point at Arctic Sea Ice
Regarding Greenland DMI is telling a rather different story http://www.dmi.dk/uploads/tx_dmidatastore/webservice/e/n/i/b/m/Melt_combine.png which obviously is related to the different period considered for the average (starting from 1993 rather than 1980). So far the season has been generous in terms of surface mass budget, with the latest days quite hot after a long period of below-normal melting. HP will tend to persist over the next few days, so more melting is to be expected, before a cooling in one week time from now. Regarding the overall synoptic analysis, well... expect more and more cyclones. Actually I wonder what this could cause in terms of ice extension. Actually this prevalence of LP systems is starting to look rather unusual. From the one hand lack of insulation will definitely help the ice, but as we progress towards the end of melting season, the effect of insulation itself is less and less relevant as issues like dispersion or compaction play an increasingly important role. At least this is what I have understood after a couple of years following this great blog. In light of the more recent runs of ECMWF, GFS and other models, I keep my view of 2016 not ending up as top-three. I wouldn't be surprised if it wasn't even a top-five. But this is relevant to the poll I'm going off-topic I know... ;)
Toggle Commented Jul 22, 2016 on ASI 2016 update 4: breaking point at Arctic Sea Ice
Wayne, I take your point and it's true that DMI 80 is just one of the many pieces of the puzzle... It's colder than in 2015, as it is obvious after the quite different weather conditions, but it's otherwise true that in 2012 it was average or even cooler than average... I'm very curious to see what it's gonna happen with the incoming modification to the synoptic pattern in the next few days...
Toggle Commented Jul 21, 2016 on ASI 2016 update 4: breaking point at Arctic Sea Ice
"...keep thinking that 2016 will not be a top three..."
Toggle Commented Jul 21, 2016 on ASI 2016 update 4: breaking point at Arctic Sea Ice
Neven thanks for the great update. It's difficult to disagree with all the points you've made honestly. I fully agree it is stunning how the ice extent keeps fighting with 2012 in spite of weather conditions which have not been conductive to melting for many weeks. And I fully agree that the long-term trend is so clear that short-term considerations do not change anything in terms of the overall picture. Short-term is exciting, though, as each one of us has his/her own view on what is gonna happen in the next few weeks, that's why we have a poll, right? :) Regarding the next few weeks, and in spite of the quite poor performance so far, I keep thinking that 2015 will not be a top-three. Weather forecasts keep showing low pressures in action for the next 10 days, plenty of clouds and not significant temperature anomalies overall. Considering there's just 300,000 kmq difference with 2015, and keeping into account weather conditions one year ago, I tend to believe 2015 should be an easy catch. Regarding the CAB my personal opinion is that it has been suffering from the persistence of cyclones in the last few weeks leading to dispersion. In the next few days a HP system will form over the CAB, rather small, with not so high values for geopotential but that should lead to some compaction in the area. Do you agree on that? One small reference to support my theory of 2016 going to catch 2015: We remember how hot was July 2015, well, up to now the temperature chart from DMI shows quite a different situation http://ocean.dmi.dk/arctic/plots/meanTarchive/meanT_2016.png Of course, and as usual, only time will tell.
Toggle Commented Jul 21, 2016 on ASI 2016 update 4: breaking point at Arctic Sea Ice
Great update Neven! To a 'beginner' like me it's just stunning how many variables come into play for the determination of the September low. As my competences are restricted to meteorology only, I can just keep following the synoptic configuration on the Arctic which actually keeps being characterised by the persistence of LP systems. These first 10 days of July have been quite different from 2015 and the next 10 days are expected to confirm the current trend: plenty of clouds, prevalence of LP and associated precipitations. From a mere meteorological point of view conditions do not look much conductive to melting also in July, after a generous May and June. Of course all the other variables that you have mentioned remain in place and this is just what makes it so exciting to follow the ice melt season, in my opinion.
Toggle Commented Jul 12, 2016 on 2016 melting momentum, part 3 at Arctic Sea Ice
Fully agree with you navegante. Ice close to the coast is very thin and will not last for long...
Toggle Commented Jul 8, 2016 on PIOMAS July 2016 at Arctic Sea Ice
Actually I know I tend to be overoptimistic. It's all about cherry picking in the end: I want to see the glass half full rather than half empty. Honestly, considering the long-term trend it's much more empty than full I reckon. It's true the SST are high, it's true the ice extension is just miserable, in spite of the very good June, but it's also true that weather conditions (and forecast) are not quite supportive of melting on Laptev, ESS and CAB. Moreover, the ice volume data from DMI are far from depressing: as of today volume is higher than in 2015 and some 50% higher than in 2012, if I'm not mistaken (some 5,000 km3 more). It's not little in my view http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE_combine_thick_SM_EN_20160707.png On the other hand I cannot foresee the implications of the current situation in terms of ice extension, volume SST and weather conditions with regards to the minimum in September. I leave it to Neven as I will eagerly waiting for the next status updates :)
Toggle Commented Jul 8, 2016 on PIOMAS July 2016 at Arctic Sea Ice