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Bob If you really wish to go OT, why not try something like this: http://www.aqua.dtu.dk/english/News/2014/05/140514_Bluefin_Tuna_caught_hunting_for_mackerel which tells a story of unprecedented bycatches off the East Coast of Greenland in August 2012. On one hand, the story of global tuna fishing is as depressing as the story of whale hunting and sea ice disappearance. On the other hand, this story also gives us a glimpse of hope, that one day in the not so distant future, the last Atlantic bluefin tuna on this planet will be able to swim across the Arctic Ocean and meet up with the last surviving Pacific bluefin tuna, and - who knows - get together for a fresh start...
Toggle Commented May 31, 2014 on Greenland 2013 in review at Arctic Sea Ice
Jai, I think you are spot on! Since 2004, the Earth has been heated up due to GHG emissions to such an extent, that natural ”heat pumps” were dominating global climate. Both 2004, -5, -6 & possibly 2007 were dominated by tropical cyclones, which were essentially evaporator-dominated heat pumps on a global scale. It was the evaporation of waste amounts of humid air over the Tropical Oceans, that drove these Tropical heat pumps. The end result was a cooling of the Tropical oceans (also known as a decade of La Nina’s or a halt in global warming). Since 2012, the Earth has moved into a condensator-dominated “Chiller”-mode, which is dominated by persistent Arctic cyclones. Condensation in the cold cores of these phenomena takes out energy from the surface of the Arctic Ocean (hence the below normal 80N+ surface temperatures in recent years from DMI) and delivers heat aloft. It is the condensation of the humid air from lower latitudes, which drives the Arctic chillers. A shift of lower latitude high pressure cells may contribute, but essentially it is the chillers driving the process. As long as we have cold ice in the Arctic Ocean (and high pressures with sublimation of snow over the continents) during spring, we will have this chilling effect in operation. At some stage in the future, the chiller will start working before the Arctic marginal seas have cooled down. This means that the evaporation of warm marginal seas water will lead to a late autumn/winter humidity content in the air, which requires more surface cooling than the sea ice can provide. The result will be a perennial ice-free Arctic Ocean.
Toggle Commented May 15, 2014 on PIOMAS May 2014 at Arctic Sea Ice
A new observation-based Nature paper is out: http://www.nature.com/news/climate-science-understand-arctic-methane-variability-1.15196 trying to make the link between melt ponds and methane emissions. It turns out that 2007 had the highest growth rate in atmospheric methane concentrations.
Toggle Commented May 15, 2014 on More on melt ponds at Arctic Sea Ice
Derek, really off topic... On the Forum, Jai Mitchell just posted this link: http://earth.nullschool.net/#2014/05/19/0600Z/wind/surface/level/overlay=mean_sea_level_pressure/equirectangular=-32.05,-40.34,819 Looking at the circulation patterns in the North and South Atlantic on the 19th May, one could get the impression, that two tropical cyclones are forecasted...
Toggle Commented May 14, 2014 on PIOMAS May 2014 at Arctic Sea Ice
OT to Neven Congratulations – Austria won the Eurovision Song Contest with this song; ”Waking in the rubble…. …. …. And rise like a phoenix Out of the ashes Seeking rather than vengeance Retribution You were warned Once I'm transformed Once I’m reborn You know I will rise like a phoenix But you’re my flame ” “You know who you are - we are unity and we are unstoppable." C.f. http://www.bbc.com/news/entertainment-arts-27360310
Toggle Commented May 11, 2014 on PIOMAS May 2014 at Arctic Sea Ice
Thank you for putting this up so quickly Neven. Please correct a typo (29,900 should be 22,900). Cheers P
Toggle Commented May 8, 2014 on PIOMAS May 2014 at Arctic Sea Ice
Neven Nice to know that you have the eastern part of your roof top reserved for solar panels to provide a hot morning shower for you and your famlily. In case you seek inspiration as to what you can do for your local community, here is a fresh example of up-scaling: http://www.whogreen.com/Dronninglund-Solar-City-Heat/ and the video: https://www.youtube.com/watch?v=8o5nAMGkbaw It’s the World’s largest of its kind: 36,000 sq m of solar panels and a heat pond containing 63,000 cu m of 90 C water. This plant will provide appr. 50 % of all heating needed in the nearby town of Dronninglund. The plant manager, Johan Frey is planning to visit Berlin and Austria in the near future to tell the full story…
Toggle Commented May 5, 2014 on Getting ready at Arctic Sea Ice
Excuse me! With all due respect, your suggestions are highly misleading our young novellist. The most likely course for an object left on the North Pole around AD 1800 would be the following: Two trips around the Arctic Ocean with the sea ice in the Beaufort Gyre – roughly 5 years in total (+/- a couple of years). Exit one autumn day through the Fram Strait with the MYI also known locally as “Storis”. Drifting south along East Greenland for half a year and then drifting north on the west coast of Greenland for another six months – 1 year in total. Ice floe may eventually end up in the Disko Bay area, where it is: 1) either eaten by a whale for breakfast (highly unlikely), or it may 2) be washed up on top of an iceberg from the Jakobshavn glacier following a major calving event Sitting on top of the giant Iceberg, it will slowly cross the Baffin Bay and start its journey southwards along the east coast of Canada. 2-3 years later it will appear off New Foundland on top of a piece of black ice. In the dense fog during the summer night, it will not be noticed by a Basque cod fisherman and the object will be caught up in the wooden wreckage of his boat. This driftwood will then be taken across the Atlantic ocean by winds and currents, eventually reaching the Barents Sea a couple of years later. The object will be frozen into the pack ice north of Svalbard and slowly drift towards the North Pole. So the object will most likely be back at the North Pole some 12 years after it had started its journey… After doing 18 rounds like this since AD 1800, the object is most likely on its way to melt out just north of Novaja Zemlja later this summer, where it will be washed ashore as a symbol of the recklessness of leaving unidentified objects on the North Pole ;o)
Toggle Commented Apr 7, 2014 on Research for a novel at Arctic Sea Ice
Chris, I told you, it would be difficult to find each other in a dark tunnel... However, I was referring to your diagram #5 with the label: "Summer Jet Record Wet after 2007 - GPH.png". Hope this helps. I will need more time to dig into Francis et al. (2009) and other links you provide.
Chris, Coming from either end of a black tunnel and try to meet in the middle, may still be a bit difficult. I will however give it a try. As I read Jennifer’s hypothesis, she claims that the gradient between the tropics (highest GPH) and the Arctic (lowest GPH) at the top of the dense troposphere (~250-300 hPa) is now less steep than in the old days, because the Arctic has warmed more than the tropics. Hence the Jet Stream is slower now and the phase speed of the Rossby waves has gone down and the meanders (horizontally) are wider now. So far so good. You then try to introduce the Coriolis force, which – to my knowledge - has not changed in recent years. It will presumably affect all the stream flows I mentioned. Could we please leave this apparent force aside for a moment as an explanatory factor. I hope we can agree, that gravity is driving all the flows I mentioned? I agree that the Coriolis Force is influencing the meandering pattern, but hope you also agree, that inertia is not driving the process we are discussing? I really like your diagrams at: https://drive.google.com/folderview?id=0B3pB-kdzoLU3WkloQVg1Z09uNUE&usp=sharing – the 1st one clearly illustrates the spiraling pattern of the Jet Stream. Presumably it is driven by evaporation over the warmer parts of the Atlantic and the Pacific oceans, then circles the NH once before it fiddles out over the Arctic. Either the moisture in the Jet Stream precipitates out or the flow descends to a lower pressure level. Maybe somewhat similar to the Colorado River, which runs out of moisture before it hits the Pacific Ocean. Your 5th diagram clearly shows the changing “atmospheric topography” through which the Jet Stream has been flowing in recent wet UK summers – that means the Jet Stream has been running east on the southern side of the Greenland high and then straight into the “valley” over the UK and then all the way up to the Russian rim of the Arctic Ocean. I think this leaves open the possibility, that advection aloft via the Jet Stream may both explain the recent wet summers in the UK as well as the vanishing sea ice to some extent. On re-reading Francis & Vavrus, 2012: (http://marine.rutgers.edu/~francis/pres/Francis_Vavrus_2012GL051000_pub.pdf ), I could not help noticing in Fig 4, that over the past 15 years, the 500 hPa troughs over the western Atlantic (during Summer) and the eastern US (during Autumn) have become more narrow. This is an indication, that the jet stream waves have become more compressed. It will be interesting to see, whether the shortening of the Jet Stream wave length is now also taking place during the winter months. If this is the case, we may have found an explanation for your very wet Winter weather this year.
SH (Scott?) Fascinating read at the LDEO site you referred me to: http://www.ldeo.columbia.edu/res/div/ocp/drought/medieval.shtml I took note of the very thorough analysis of past mega-droughts you presented. It stroke me that, in the years of those Medieval mega-droughts in your place (~AD 936, 1021-51, 1130-70, 1240-65, 1360-82), we had Nordic people living comfortably in southern Greenland and no multi-year sea ice off the east coast of Greenland. On the other hand, we have often wondered, why our Viking ancestors took their long boats south in those years, raping, plundering and drinking their way through Paris, Rome and Cairo. If your hypothesis is right, and if the summer weather was miserable in Scandinavia (and the British Isles for that matter), no wonder they fled south. Chris, I will come back to your response in the morning. Cheers P
Part 2 Again, according to my old textbook, meanders in rivers deposit material on the convex bar and erosion takes place on the concave bank. By analogy this would mean that the Jet Stream would deposit energy over the Pacific Hot Spot and “erode” Arctic air masses over the Bering Sea. Similarly over the Atlantic: High SSTs are being reinforced south of the UK and Arctic air is being “eroded” north of Scandinavia, as we see with the dwindling sea ice around Svalbard. Apparently, the Polar Jet Stream above 250 hPa has been stronger this winter, whereas the Jet Stream below this level has been weaker. This weakening of the Jet Stream may be an extension of the general weakening of the observed Hadley Cell circulation since May/June last year. In the absence of a strong weather-forming Jet, I will again postulate, that basic climatology takes over. This includes the important influence of topographical barriers, such as the Rocky Mountains, which Jennifer also mentions. Acknowledging that the Rockies is a solid topographical barrier to the lower parts of the Jet Stream, it has been fascinating to see the persistence of the ridge and through pattern over the North Pacific/American continent these past 18 months. Various Jet Stream “films” exposed on the ASI blog show, that the wavelength is shortened (waves are compressed) and the waves get “stuck” on the western side of the Rockies, whereas the wave patterns on the eastern side have been more variable over the course of the past year and a half. As the atmosphere picks up moisture from the warmer Tropical and Subtropical oceans, this high “load” in combination with a weaker Jet Stream may have helped to maintain a “stuck and convoluted meander” west of the Rockies. The jet bends south over North America and helps to pull down Arctic air for months on end as we have seen. When the dry and cold air mass leaves the continent, the turbulent air picks up moisture again from the warm Gulf Stream and new storm systems intensify, as they cross the Atlantic and hammer into the British Isles. Previously, I have alluded to the “lack of weather” under the “new normal”. Similarly, it may now be the case, that the Rockies have come to play a more dominant role because the traditional strong temperature gradient between the Tropics and the Arctic has diminished – eventually leading to a more permanently weaker Jet Stream. It is also quite likely, that this “stuck pattern” has now finally been demolished by the onset of early spring in the Northern Hemisphere. Now the warming has started in the Tropics and Subtropics in earnest, and the temperature difference relative to the Arctic has just about exceeded the threshold for a viable Hadley Cell. Come March/April and - if the temperature gradient again goes below the threshold - we are back to “the new normal”. If Kevin and Jennifer could agree on a common indicator (such as duration of Jet Stream flow with sinuosity > 1.5) it would be extremely interesting to see whether this indicator shows an increasing trend over the past 15 years. On the other hand, if Kevin could “tweak” his model to include atmospheric water vapor as a driving force behind a more meandering Jet Stream, then the two of them might be able to resolve the issue, and we would have more reliable climate models.
Chris, Thanks for sharing your thoughts with us. As I read through your wise reflections, I also had a chance to listen to the podcast with Jennifer and Kevin sorting out the giant Jet Stream issue. Earlier this Boreal winter, the “stuck meander” over the North Pacific/North American continent did spur the discussions in another thread. More recently, the “stuck meander” over the UK has been the key issue. I took the time to re-read my old textbook on the subject of meanders to look for an analogy, which may help to explain the phenomenon. Meanders are – according to Gregory & Walling, 1973: 247-257 – a common feature of many natural systems. A number of factors influence the wave length of these features – including the amount of material transported in the stream. When the amount of material in the stream increases, the wavelengths get shorter and the meanders get wider. A few examples serve to illustrate the huge natural variability of these phenomena: 1) meanders on glacier surfaces transport melted ice (H2O) (see http://onlinelibrary.wiley.com/doi/10.1002/jgrf.20135/abstract ), 2) meanders on the surface of karst landscapes transport dissolved CaCO3, 3) meanders in ocean currents transport dissolved sea salt (NaCl), 4) meanders in tidal streams transport flocculated clay minerals, 5) meanders in river valleys transport bottom load and suspended sediments 6) meanders in “atmospheric rivers” transport mainly evaporated H2O. By analogy it is inferred that an increase in atmospheric water vapor content due to anthropogenic global warming should lead to shorter wavelengths, or - if you wish - larger meanders. Hence the hypothesis put forward by Jennifer (http://thinkprogress.org/climate/2013/04/16/1867371/video-explains-how-loss-of-arctic-ice-weakens-jet-stream-amplifies-extreme-weather/) could be tested using a simple measure of the wave length of the Jet Stream meanders (e.g. duration of flow with sinuosity > 1.5). If the wavelength has been systematically shortened over the past few decades, this should not necessarily indicate, that the temperature difference between the Tropics and the Arctic has decreased. Alternatively, a link from a wavier Jet Stream to increased evaporation from tropical and subtropical oceans areas may be substantiated. End of part 1.
Chris, You have several times stated your conviction, that recent wet summers in the UK are due to loss of Arctic sea ice. I was just wondering, whether this paper is on your “to do” list, when it comes to reading during the weekend: http://www.ametsoc.org/2012extremeeventsclimate.pdf see Tett et al. p. 532-535 in particular. Simon is a distinguished professor at the university of Edinburgh, and a former top scientist at the UK Hadley Centre. He has so far not been able to reproduce a connection between wet UK summers this century and dwindling sea ice in the Arctic. Apparently, either his model experiment is flawed or your assumptions are wrong. I would appreciate, if you could comment on this discrepancy at your convenience.
In the old days, the most popular navy song in those tracts went like this: “Rule Britannia!, Britannia rule the waves…” According to Armitage (2000) "Rule, Britannia'" was the most lasting expression of the conception of Britain and the British Empire that emerged in the 1730s, "predicated on a mixture of adulterated mercantilism, nationalistic anxiety and libertarian fervour". Nowadays, with 44 feet waves pounding her coastlines, with tidal waves running up her estuaries and with flood waves washing down her river valleys, I think the lyrics must go more like this: “.. Britannia ruled by waves!”
Toggle Commented Feb 14, 2014 on Looking for winter weirdness 2014 at Arctic Sea Ice
John Please have a look at the Barrow Web Cam: http://seaice.alaska.edu/gi/observatories/barrow_webcam and the Healy Web Cam: http://icefloe.net/Aloftcon_Photos/index.php?album=2013 and the North Pool Web Cam: http://psc.apl.washington.edu/northpole/NPEO2013/18.jpg and the Canadian Met Service analysis: http://weather.gc.ca/data/analysis/935_100.gif and the DMI NE Greenland satellite imagery: http://ocean.dmi.dk/arctic/images/MODIS/NEW/201308141358.jpg and the ECMWF 240h forecast: http://www.wetterzentrale.de/topkarten/fsecmeur.html and tell me once more that all of this is the result of a negative feedback. You’d better put the kettle on for that cup of coffee you promised me a while ago. My bike is pumped and ready to roll! Cheers P
Toggle Commented Aug 14, 2013 on Third storm at Arctic Sea Ice
The third Persistent Arctic Cyclone (PAC-C Aug13) died off a couple of days ago. It lasted six days – peaked below 980 hPa - and fulfilled the general criteria suggested earlier ahead of “PAC-B Jul13” (see http://neven1.typepad.com/blog/2013/07/the-naming-of-arctic-cyclones.html ) . A few questions were raised during this event, e.g. whether this was a real “storm”?. In Denmark we use the term “snowstorm” when at least 10 cm of snow falls within 6 hours and wind speeds exceed 10 m/s. Similar criteria are used in lowland parts of Sweden and Germany. New evidence from a recent GRL paper ( http://onlinelibrary.wiley.com/doi/10.1002/grl.50517/pdf ) point to the fact, that even moderate winds (8-12 m/s) have a significant impact on the heat transfer from ocean to ice. Measurements taken north of Svalbard last year on a 0.8 m thick ice floe documented that - during windy conditions (similar to conditions this year during PAC-B & -C) - the heat flux from the ocean increased to near 70 W/m2. Others have asked about the energy source for this storm. Advection of moist air from much lower latitudes (as alluded to here: http://neven1.typepad.com/blog/2013/07/second-storm.html?cid=6a0133f03a1e37970b01901e9abeaa970b#comment-6a0133f03a1e37970b01901e9abeaa970b ) may be one of the sources, leading to condensation and snow fall over the ice pack. A rough back-of-the-envelope calculation gave a record low (since 1948) SST gradient from the Caribbean to the Barents Sea of roughly 17 K (30-13 deg C) during the storm. The distance is roughly 11,000 km, which means that the average gradient is around 0.0015 K/km. This number happens to be in the same ballpark as the Equator to Pole temperature gradient applied by W. Langford (see the second diagram in slide 25 in his presentation: http://www.fields.utoronto.ca/programs/scientific/10-11/biomathstat/Langford_W.pdf ). It is a disturbing fact that such a low temperature gradient may have led to direct advection of moist air all the way from the Caribbean to the Barents Sea at the same time as the low was churning in the Arctic. If NH single cell configuration and persistent Arctic cyclones is one and the same thing, we may indeed be closer to the tipping point, than we thought. The lasting impact from this particular cyclone remains to be seen, as the clouds disappear later in the melting season. Recent photos from some of the buoys show up to 15 cm of fresh snow on the remaining ice floes, which may affect both albedo and insulation of the sea ice. Do I have to mention, that a new deep Arctic cyclone has appeared in the far end of the current weather forecasts…
Toggle Commented Aug 14, 2013 on Third storm at Arctic Sea Ice
OLN, allow me to suggest PAC-C "Cyclops" Aug13 as an appropriate name in line with previous suggestions for PAC-A "Avatar" and PAC-B "Bush". More on the Cyclops can be found here: http://en.wikipedia.org/wiki/Cyclops Cheers P
Sorry Neven! Wrong link. Here is your original one: http://neven1.typepad.com/blog/2012/08/a-love-story-and-a-clearance-sale.html Cheers P
Toggle Commented Aug 4, 2013 on PIOMAS August 2013 at Arctic Sea Ice
Neven, I was referring to this post of your's: http://neven1.typepad.com/blog/2012/08/the-untold-drama-of-northern-snow-cover.html which came out, when I Googled "End of Summer Clearance Sale". I'm sorry I did not provide this link, but I thought that Kevin's story provided the best context for a new searchable headline, which would allude to the current gloomy prospects for the remaining sea ice towards the end of this summer. In case you wish for an alternative headline, I would also like to suggest: "Three strikes and you're out" to symbolize the expected impacts of the forthcoming third persistent Arctic cyclone this year.
Toggle Commented Aug 4, 2013 on PIOMAS August 2013 at Arctic Sea Ice
Neven, just saw your note about insanity on the Forum. I would like to remind you, that this story: http://doc-snow.hubpages.com/hub/A-Love-Story-And-A-Clearance-Sale gave you a prominent place on the Gugl hitlist. May I suggest a new thread under the headline: End of Summer Clearance Sale Cheers P
Toggle Commented Aug 4, 2013 on PIOMAS August 2013 at Arctic Sea Ice
Neven, just saw your note about insanity on the Forum. I would like to remind you, that this story: http://doc-snow.hubpages.com/hub/A-Love-Story-And-A-Clearance-Sale gave you a prominent place on the Gugl hitlist. May I suggest a new thread under the headline: End of Summer Clearance Sale Cheers P
Toggle Commented Aug 4, 2013 on PIOMAS August 2013 at Arctic Sea Ice
Susan, you have a point there. Burning the permafrost like this ought to go under a separate headline: "Absurd impacts". Neven, please also consider opening a thread at some time on the forthcoming third Persistent Arctic Cyclone (PAC-C Aug13)
1.3 million square km, and here is a cleaned up version of the messy numbers I provided earlier: According to PIOMAS data from Wipneus: (https://sites.google.com/site/arctischepinguin/home/piomas ), average volume drop in Jul, Aug, Sep & Oct from 2000-2012 (13 years) has been 8.000 km3/13y = 600 km3 per month on average (- 2600 /+1200 km3). To use this number at face value, would constitute the “conservative bias”, as discussed by Neven here: (http://neven1.typepad.com/blog/2013/07/are-scientists-conservative-about-sea-ice.html ). Maximum volume drops in Sep year on year this century occurred in 2010 and 2007 (>2500 km3) and the maximum year on year volume gain in Sep was in 2001 (1200 km3). It is noticeable that – similar to this year - both 2001, 2007 and 2010 had Arctic mean temperatures below normal throughout the entire summer (see http://ocean.dmi.dk/arctic/meant80n.uk.php ). Both in 2001 and 2007 we lost 5500 km3 between Jul and Sep, whereas in 2010 “only” 5100 km3 was lost between Jul and Sep indicating, that we may still lose > 5000 km3 before the end of Sep this year. This will eventually lead to a year on year drop of > 2500 km3, which brings down the remaining ice volume to 1100 km3. If you spread it out a bit and use an average thickness of 1.1. m, we should end up with a mean Sep sea ice extent close to 1.3 million square km. This extent is - by the way - similar to the hypothetical melt scenario provided by A-team here: http://i1340.photobucket.com/albums/o728/OlTom67/meltScenario_zps17c002cf.gif Again referring to Wipneus’ site, both 2007 and 2010 had some of the highest Fram Strait volume exports this century – around 200 km3/month in both Aug & Sep - so a new record ice loss this year requires high export numbers through the Fram Strait, which again requires favorable wind conditions to push the remaining MYI out of the Arctic basin. With the current weather forecast, we should expect to see a strong W-E pressure gradient north of Greenland after the weekend, which could take care of that. However, Fram Strait ice export alone is not enough to get rid of the remaining ice. Other mechanism will have to kick in to help out. In principle, four mechanisms may play together, assuming that the remaining piles of ice rubble will be clogging the straits surrounding the Arctic: 1) Solar heating requiring cloud free conditions and thus a confined central PAC. 2) Advection of latent heat from lower latitudes would be a continuation of the current Jet Stream pattern 3) Advection of dry warm air aloft would require a bunch of tropical cyclones in Aug and Sep, which would also hurt the GrIS. 4) Upwelling due to katabatic winds would require an extended summer season well into Oct. Cheers P
This year’s second Persistent Arctic Cyclone (PAC) is now dead and gone. It lasted roughly 6 days with a minimum core pressure of < 980 hPa. It met all the provisional criteria, which I suggested some time ago. The naming issue is still unsolved, but with the support from Google, I tend to continue calling it “PAC Bush 2013” for the time being. I just had a quick look at some of the impacts from the storm. Apart from the drifting buoys in the Beaufort Sea, I also noticed a spectacular impact on the ice conditions in the Canadian Archipelago (as also noted by DanP further up this thread). The HYCOM ice thickness maps: http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticict_nowcast_anim30d.gif illustrate very well, how the thick MYI is being “stuffed” into the various canals on the western side, whereas water is being pulled into the Arctic trough the Nares Strait. The irony is - if this pattern continues - that we may end up with heavy MYI blocking the NW passage for a while. At the same time the Northern Sea Route is still blocked by heavy ice around Severnaya Zemyla. So the 240 odd ships waiting to get through, may better grab another biscuit, since next week’s weather forecasts nearly all have a new PAC hovering over the Central Arctic. At the same time, there is a tendency to have a high pressure ridge over Greenland. This pattern (as projected already last year) will lead to a strong pressure gradient (20-30 hPa/500-1000 km) situated just North of Greenland, which may drive the remaining MYI into the Fram Strait – blocking also this entry point to the Arctic.
Toggle Commented Jul 29, 2013 on Second storm at Arctic Sea Ice