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RunInCircles
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I have been watching the north pole web cams for a few years. My memory tells me that the melt ponds always start freezing over by the last week in July or the first week in August. Does anybody else remember it this way? How many think that the block of ice just north of Alaska will still be there at the end of this melt season?
Toggle Commented Aug 15, 2015 on Jenga July 2015 at Arctic Sea Ice
Thanks Kevin
Help me understand. One of the features of Cyrosphere today is their view of snow cover. I have never seen this much snow cover left in June. Other comments indicate snow cover is low in the northern hemisphere but this is not even close to what I am seeing on their map? Can somebody explain please?
John I when you ask about the DMI lower temperatures don't forget that 1st year ice melts about 1.7 degrees cooler than MYI. The DMI temps look to me to be held a little bit lower because there is much more first year ice.
2013 should turn out to be a very interesting year and it should provide the answer if the arctic ice is deceasing ala the exponential trend or the Gompertz trend. My estimate 2.98 Million Km^2. Since I am inclined to believe the exponential decline over the gompertz although Wipneus's gridded data does show Gompertz behavior I take the prediction for 2.1 Km^3 from PIOMAS and I divide it by the average September thickness these last 3 years of 1.1 m and I multiply it by 1.56 to get extent instead of area. This provides my estimate of just under 3MKm^2. My reason for going with the exponential decline is that when old ice melts the density of the melt is very low and forms a barrier undeneath the ice keeping the warmer water away from the ice reducing bottom melt. When the melt is first year ice this low density layer is significantly reduced and as a result the ice melts faster. With the ever smaller amount of old ice the ice bottom melt rate wil be enhanced and PIOMAS will continue to show an exponential decline. Since the North Pole Web Cams clearly show that melt ponds are totally frozen over by the beginning of August this bottom melt controls the September minimum.
Thanks Neven I do not think the ice was as thin but could it have been fractured with large leads? I've always wondered why 2005, 2006 winter showed such low concentration whilst the years since 2007 have much greater concentration. Could just be the sense technology has been upgraded since.
Toggle Commented Mar 4, 2013 on The cracks of dawn at Arctic Sea Ice
To the Forum: I have always looked back at the Cryosphere today comparison graphs. These may not show leads but they do show when the ice is solid versus having flaws in its structure. Spring of 2006 is still in the lead for the amount of area in the arctic basin with less than 100% concentration. Just look down the page for the compare link on Cryosphere Today. Compare March 1 2006 with March 1 2013. Do any of the other images which show cracks today have archives back to 2006? It would be interesting to go back and look at the lighter colored areas seen back then? Are we getting ahead of ourselves predicting dire consequences from never before seen cracks?
Toggle Commented Mar 4, 2013 on The cracks of dawn at Arctic Sea Ice
I originally completely bought into the exponential loss of sea ice volume. The reasoning seems simple more open water absorbs more heat increasing the rate at which more open water appears. Physical phenomina where the rate of change is porportional to the amount are exponential. It is important to remember that ice volume is an effect of energy into the system and energy leaving the system. But the arctic is much more complex than this. Some of the extra energy into the open water in the system simply heats up the water and does not get close enough to the ice edge to melt any ice. So we have a chaotic system where storms and weather act to move energy around which sometimes bring more energy into the ice. I wanted to increase my understanding so I retrieved the images from the US Navy arc volume graphs 2010 - 2012 and compared the ice thickness from May 15, July 15 and Sept 15 for those years. The story they tell is that the massive volume loss occurs from the edge of the ice inward. The melting in the central part of the ice is a very small percentage of the overall volume loss. In fact if I compared the thickness in the ice that survived this year with ice in the same area in Sept 2011 and 2010 I was surprised to discover that much of that ice was a little thicker in 2012 than in 2010. Not by much 0-20 cm but it was not thinner except close to the edges. So as the central ice gets smaller the area of the band at the edge where most of the rapid melting occurs gets smaller and the extra heat in the rest of the arctic needs more chaotic weather to reach the edge. This could be one of the contributors to creating a sigmoidal loss instead of an exponential crash to zero in the near future. I do not know the answer and I can only wait for more data to indicate the most likely path. Also, since the arc graphs are designed to show the maximum thickness instead of the average this may be misleading me. However, if real this more complex view of the ice may be leading some scientists to believe 2020 or 2030 is more likely than 2016.
Toggle Commented Oct 6, 2012 on PIOMAS October 2012 (minimum) at Arctic Sea Ice
I was reviewing the data from the Navy thickness charts and although there is less ice left at the end of this season versus 2010 the remaining ice is thicker than the ice in the same locations were in 2010. So we lost more extent but the thickness of the very center of the ice pack increased. Can anybody verify that PIOMAS shows the same behavior?
Toggle Commented Oct 4, 2012 on PIOMAS October 2012 (minimum) at Arctic Sea Ice
Werther The bottom row of Neven's graph page right in the center. Just roughly I get a lower limit of 3.8MK extent from my prediction.
Toggle Commented Jul 4, 2012 on Fringe fries part 2 at Arctic Sea Ice
Let me throw this out there and ask the community to help me refine this prediction. For ice that is more than 250 Km from the ice edge the melt for the entire month of July is about 0.75 meters. August and Sept about 0.5 meters. Interpreting the Navy thickness graph as being the maximum thickness and assuming average thickness is 0.5 times what is shown I still come to the following conclusions. The ice north of Alaska barely reaches the 75degree line all the way to the mid Chukchi. The ice north of Eastern Siberia melts all the way to the 80degree line. Any ice west of the New Siberian Islands to Greenland melts to the 85degree line. What do the rest of you think?
Toggle Commented Jul 4, 2012 on Fringe fries part 2 at Arctic Sea Ice
The discussion about MODIS imagery not showing holes and cracks in the ice is a little like not seeing the soccer ball from space and claiming that there is obviously not a game being played. Each pixel is 250 x 250 meters. 62,500 sq meters. How many soccer fields are in each pixel? Yes water on the ice reports as a lower area number. Water on the ice has always reported as a lower area number. But MODIS does not have enough resolution to make claims that area numbers are wrong and end up shilling for the deniers. It is just another measure of sea ice and it is not wrong!
I have been watching the snow melt on the Cryosphere Today graphic. The siberian snow melt was early which leads me to think that the albedo dropped early for at least that section of the arctic. That combined with the early open spots leads me to the conclusion that the melt will be greater this year over the last couple of years. I vote for a area min around the 9th of Sept at 2.75 and an extent min for the month at 4.45
Peter Thanks for the reply and the link to last years data.
Toggle Commented Feb 28, 2012 on 2012 minimum global sea ice area at Arctic Sea Ice
The Barrow Mass Balance Site has been repaired. Current thickness 1.35 meters. Does anybody remember how the thickness this year compares to the thickness at the end of February last year? I know it reached a maximum around 1.7 meters in May of 2011.
Toggle Commented Feb 27, 2012 on 2012 minimum global sea ice area at Arctic Sea Ice
I have not really been following the CryoSat. news very closely but since there are no sea ice thickness maps being released yet I am assuming that the system doesn't work well enough to derive thickness data. I am really hoping somebody closly in touch with the actual state of progress can tell me how wrong I am and let me know when I will be able to see some progress.
I am predicting 13.2 - 13.4 because the low ice area is north of 75 latitude. This area has 60 days more before the sun will even start to provide insolation. There is very little difference in albido until the angle is above 15 degrees between ice and water. So I expect growth in Kara and Barents to continue and this should increaase the total beyond what most are predicting.
Toggle Commented Feb 5, 2012 on 2012 Maximum Area Pool at Arctic Sea Ice
@ Hugues Here is a link to the expected ice loss provided by the GCM's used by scientists to predict the future of the arctic. http://www.realclimate.org/images/seaice10.jpg This shows the same tailing off of ice loss as the Gompertz curve shows. You have to be open to the possibility that the models are picking up something that occurs at lower levels of ice. I think the exponential trend is correct but I must accept the possibility that I could be wrong. @ Lodger You do not have any mathamatical justification for your claims that the Gompertz curve fits better than the exponential curve. First of all the current behavior of the fitted Gompertz is exponential. Around the knee it will start to deviate from exponential. Second the RMSE differences are so small between the 2 curves that it is statistically insignificant.
If I understand correctly William is saying that the rate of ice loss will slow substantially when only the central basin ice is left. William has most climate scientists on his side here. Look at all of the models used in the IPCC report. They all have a sigmoid shape. This would be like the Gompertz S curve everybody has seen here. Every GCM used by the IPCC believes the rate of ice loss slows when we get to small values of ice left. I disagree with this finding of the GCM's but I do not have the data or a nice supercomputer model to back up what I think is going to happen. I don't think anybody here has sufficient data to disprove that the ice loss could slow in the future as only a small amount of ice near the north pole is left. I think that the trend right now shows that the ice loss rate is speeding up and I don't think this will slow before we have low levels of ice which I define as less than half of the ice we had this summer by all measurements extent , area, and volume. I think this happens this decade. But this is just trend analysis not a physical ice behavior ocean circulation model.
@Daniel From Tietsche et al 2011 "September sea ice volume takes longer to recover in the late 20th century when the sea ice is still thick, but it has the same time scale of recovery as sea ice extent from 2000 on" The measure of recovery used is extent but they assert that this is a proxy for complete recovery even volume. I was not sure if your post was scolding me for not recognising that their direct 1st paragragh executive summary statement used the word extent. Do you think they drew a distinction between ice extent recovery and ice recovery? @ Rob and Kevin thanks for giving me more homework! I trully do not know as much as I would like to. Your pointing out additional sources to go learn from is invaluable to me. @Al Rodger :Artful Dodger posted a link to a paper which showed strong hysteresis behavior based on ice physics alone. That link was posted within the last month.
Toggle Commented Oct 8, 2011 on October 2011 Open Thread at Arctic Sea Ice
Kevin You can actually read the paper. Look it up on the web. They said the ice recovers not just the extent.
Toggle Commented Oct 8, 2011 on October 2011 Open Thread at Arctic Sea Ice
Bob Wallace Sorry I addressed my previous post to you when it should have been crandles. His comment that they did not say the ice recovers in 2 years is what sparked me to write the above post. Not your execellent commentary.
Toggle Commented Oct 7, 2011 on October 2011 Open Thread at Arctic Sea Ice
Bob Wallace Some quotes from the paper are in order. "The model setup we use is a coarse resolution version of the IPCC!AR4 model described by Jungclaus et al. [2006]. This higher resolution model setup has been tested extensively and performs well in simulating Arctic climate [Chapman and Walsh, 2007]." WAIT A MINUTE? How does the low resolution model they used perform at simulating the artic climate? They do not justify in the paper the performance of the model they use. Another quote from the paper "We find that ice extent recovers typically within two years." So they do basically claim that the ice recovers in 2 years. "Our results suggest that anomalous loss of arctic sea ice during a single summer is reversible, as the ice–albedo feedback is alleviated by large scale recovery mechanisms. Hence, hysteretic threshold behavior (or a “tipping point”) is unlikely to occur during the decline of Arctic summer sea ice cover in the 21st century." To be fair their model predits that the ice extent will decline below 4.5MsqKm sometime after 2020 and then decline to 2MsqKm rapidly over the next 20 years. Then it takes 30 more years to decline to ice free conditions. They assert that even if an entire summer is ice free the extra heat will all radiate away by the end of Nov. The whole study reads like a set up to me. The outcome was predetermined when they selected which model to use.
Toggle Commented Oct 7, 2011 on October 2011 Open Thread at Arctic Sea Ice
Werther Actually, as an interested observer I have to comment that the scientific community does not look very wise and authoritative about now. 5 short years ago they were publishing 2070 or so as the probable date of an ice free arctic. They backed this up with all of their sophisticated computer models. The simplest trend analysis shows the loss rate is accelerating and the ice is unlikely to last 20 years even without acceleration. OOPS our model was off by 50 years? And of course there is the scientific noise such as even if all the ice is removed it will fully recover in 2 years. The next IPCC report is due out soon. The question for the scientific community is do they continue with the long time horizon prediction of their models when the ice may very well melt out within a couple of years of the report release or are they going to start saying we were wrong the ice is almost gone right now. We have just started to see the papers saying wow it looks like we don't have even until 2040. AND this may be much too conservative.
Toggle Commented Oct 6, 2011 on October 2011 Open Thread at Arctic Sea Ice
Where are we going to get ice data now that AMSR-E is broken? Can anybody tell mewhat other systems are available?