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We are really going to miss you, Neven, but on the other hand, I hope that you can relax, fulfill other goals and have a great family life! Happy Sabbatical! And come back, from time to time!
Toggle Commented Nov 22, 2016 on Sabbatical (I hope) at Arctic Sea Ice
Congratulations Neven! And thank you and all, for all this work!
Toggle Commented Aug 11, 2016 on 1000 Forum members at Arctic Sea Ice
It was really interesting to see the importance that the 2016 Olympics opening ceremony gave to Global Warming. The message of cities flooded for sea level rise is one example. Unfortunately, actions like the planting of seeds by the athlets, are incompatible with the huge fireworks that follow. The true is that many of the trees planted will have difficulty surviving. On my humble opinion, we (humans in general) are not completly aware that global warming is real. We, as a society, are acting like if global warming is a science fiction movie, not a real danger. Hope we change our actions (not just a message) in the near future.
Toggle Commented Aug 6, 2016 on PIOMAS August 2016 at Arctic Sea Ice
Also, according to Climate Reanalyzer, from Friday to Wednesday, there is going to be above 0 ºC Kara, Laptev and even Arctic Basin (not all at the same time but big areas). Seems to me that it is to early for having that heatat the ASI.
Toggle Commented Apr 20, 2016 on Meanwhile, on the other side at Arctic Sea Ice
What concern me most is the graph that shows the age of the ice, because it can be seen that the cracks affects all types of ice (old and new). It will be great to see this graph updated, with the status one or two weeks from now. Great post Neven!
Toggle Commented Apr 15, 2016 on Beaufort quick update at Arctic Sea Ice
Nothing important to say on the subject, except that I really appreciate your work, Neven. Thanks!
Toggle Commented Apr 8, 2016 on Beaufort under early pressure at Arctic Sea Ice
Thank you. Even that I haven't write on the last couple of years, Neven's Blog and Forum are the best source of information, so thanks everybody for all your work.
Toggle Commented Apr 18, 2015 on CryoSat-2 sea ice thickness maps at Arctic Sea Ice
Congratulations, Neven. Excelent post and thank you for al this work.
Toggle Commented Jun 18, 2013 on On persistent cyclones at Arctic Sea Ice
Congrats to A-Team for this fantastic animation!
Toggle Commented Apr 4, 2013 on On the move at Arctic Sea Ice
How much Arctic sea ice has been lost? 50% extent or 80% volume?
Toggle Commented Mar 14, 2013 on Slogan contest at Arctic Sea Ice
Hi, Neven. I didn’t thank you for setting up the Forum (that I should…), but I want to be the first one to congratulate you for reaching the 100,000 views in only 16 days. Great success!
Toggle Commented Mar 8, 2013 on Arctic Sea Ice Forum at Arctic Sea Ice
I used to think that I was cool Running around on fossil fuel Until I saw what I was doing Was driving down the road to ruin Traffic Jam Song - James Taylor
Toggle Commented Jan 25, 2013 on Slogan contest at Arctic Sea Ice
Permafrost or melted-frost? Methane emissions will kill us all.
Toggle Commented Jan 25, 2013 on Slogan contest at Arctic Sea Ice
News from Nasa on the topic of Sea Ice Volume and PIOMAS: http://www.nasa.gov/topics/earth/features/seaice-forecasting.html InSIE, it seems important: "The September mean ice extent for the corrected model were slightly closer to the actual result than the control forecast run, but both were fairly far off from the actual record minimum. This may have been due to unusual weather over the summer, including a large Arctic storm in August, or to deficiencies in the model simulation of the new very thin ice conditions of the Arctic. Lindsay said winds have a bigger impact on the thinner ice of recent years than on thick ice. It may be possible to redo this experiment, using this summer's atmospheric conditions in the forecasts. "This would tell us the impact of the observations for the weather we actually experienced," said Lindsay."
Toggle Commented Jan 10, 2013 on PIOMAS January 2013 at Arctic Sea Ice
I someone doesn'n know and it is interested, there is Al Gore in a "24 Hours of Reality" at Internet right now: http://climaterealityproject.org/
Thank you for your comments (Aaron Lewis, Werther, P-Maker). I agree with Werther in that we should “have high esteem for the professional credibility of the NSIDC staff”. They have made great work and they have been the Arctic sea ice (ASI) reference for several years. By example, I want to highlight the following article: http://www.cee.mtu.edu/~reh/papers/pubs/non_Honrath/stroeve07_2007GL029703.pdf In page 2, they made a graph that has been used for five years to express the necessity of revising the ASI models. It is very interesting that this article was made public one semester before the ASI had that incredible drop at August 2007. Also, after the 2007 sea ice melt, the NSIDC said that we could have an Arctic free of ice at 2030. Surely, that was relevant five years ago. Unfortunately, we are finding that the concept of sea ice extent is not working properly. So, it is important to concentrate at least in sea ice area. Furthermore, the PIOMAS sea ice volume should be a big concern, even if thickness is hard to measure. If we think in volume, we could have the collapse by 2016. So now we have to express that SIE will not work well as the Arctic sea ice collapse. I have been thinking in Werther’s comment “Dip in to support Protégé/Juan Garcia” and what I want to do is to write an article here. I know that this blog is important on the global warming community, so I will consider an honor if Neven accepts to publish my article. Best regards, Juan C. Garcia
Hi, P-maker: Thank you for your comment. What if this happens next year? I will say: What if this happened on October 2012? From my point of view, it is statistically wrong to have a 2012 monthly average above the 2007 October value.
I have been thinking about the method used to calculate the NSIDC monthly average and the impacts that could have in the future, so let’s image the following scenario: We are at Sep. 1st, 2019. The NSIDC shows an Arctic sea ice extent (SIE) of one million km2, concentrated basically at the Arctic Basin. The ice extend is decreasing and by September 10th, the sea ice is almost gone. So, we have Arctic free of ice for the first time in several thousand years. By September 20th, some ice starts to build up around the continental coasts. By the end of the month, one million km2 has freeze. On October, everybody is surprised that the NSIDC has announced a September SIE monthly average of 1.18 million km2. There was not a day with more than one million km2 at September. So, what will be the reason for this monthly average? The answer will be the method used to calculate the NISDC monthly average. The normal NSIDC satellite grid at the arctic is 35km.* 35km. = 1,225 km2. The 15% of that is 183.75 km2. So basically, if a normal grid has a monthly average of 184 km2 or more, it accounts as 1,225 km2 for that month. There are several ways in which a grid can qualify as a 100% SIE. By example, a grid at the Arctic Basin: Day(%)- % - Sea Ice (km2)- Daily graph (km2) Sep 1 - 100% - 1,225 - 1,225 Sep 2 - 100% - 1,225 - 1,225 Sep 3 - 85% - 1,041 - 1,225 Sep 4 - 65% - 796 - 1,225 Sep 5 - 50% - 613 - 1,225 Sep 6 - 30% - 368 - 1,225 Sep 7 - 14% - 172 - 0 Sep 8 - 10% - 123 - 0 Sep 9 - 8% - 98 - 0 Sep 10 - 3% - 37 - 0 Total: 5,696 km2 Average (divided by 30): 189.9 km2 It adds to monthly average: 1,225 km2 The NSIDC affirms that the ice at the beginning of September at the Arctic Basin accounts for 720,000 km2 and the freeze at continental coasts accounts for the rest, so there is a monthly average of 1.18 million km2 for September 2019. Let’s have another example. A 325 km2 ice floe is moving from one grid to another on a sea free of ice (except for that floe). It stays 6 days in one grid, 15 days in second one and 9 days in a third one. At the end, it has made that 3 grids count as with 100% ice, so it accounts for 1,225 km2 * 3 = 3,675 km2. That looks incredible, but it counts for more than 10 times his size. So, if someone is looking for the negative feedbacks that will make the Gompertz curve, the NSIDC method for calculating the monthly average seems that will be one important negative feedback. Rather artificial, but as I understand the method, it will work that way.
Piotr Djaków: Thank you also for your clear explanation. I didn’t understand the NSIDC answer when I read it the first time. Now I can understand that the brief period in which 2012 was above 2007 could make a difference. As I say, I don’t like this procedure, but I find worthless to revise 2007 and 2012 grid by grid, so from my personal point of view, this subject is over. Bringing the other subject, anyone knows why the DMI graph change so much? Even that they made a brief explanation, I also find difficult to believe that the 2012 minimum Sea Ice Extent changed so much (from ~2.5 to ~3.9 million km2). See: http://ocean.dmi.dk/arctic/icecover.uk.php http://ocean.dmi.dk/arctic/old_icecover.uk.php Best regards, Juan C. Garcia
I asked NSIDC about the October average and they gave the same answer that Piotr Djaków gave us. I don’t like this procedure. I find misleading that a monthly average with the daily values of October bring a result of 5.8 to 6.1 million km2 (depending of the 5-day daily average), but with this procedure NSIDC obtains an average of 7 million km2. I also don’t like the concept of sea ice extent (15% or more ice always means 100% ice), I prefer sea ice area and specially sea ice volume. But anyway, I don’t believe that NSIDC will change their November Analysis. Here is the NSIDC answer and my question (and I thank NSIDC for their answer): ________________________ Your request (#17037) has been deemed solved. Kara, Nov 07 14:18 (MST): Hi Juan, Thank you for contacting NSIDC. The numbers are correct. The end of the month had quite an uptick. Also, the graph shows daily plotted extent calculations (greater than 15% concentration), whereas for the average monthly extent, an average has to be calculated for each grid cell in the satellite data. This can result in the inclusion of grid cells in monthly averages which are exluded in daily calculations. I hope this helps clear it up a bit. Regards, Kara ______________________ NSIDC User Services CIRES, 449 UCB University of Colorado Boulder, CO 80309-0449, USA Phone: +1 303-492-6199 Fax: +1 303-492-2468 Email: nsidc@nsidc.org WWW URL: http://nsidc.org National Snow and Ice Data Center * Distributed Active Archive Center ______________________ Juan Garcia, Nov 06 10:33 (MST): From my point of view, your November Analysis underestimates the 2012 October average. Looking at your daily Arctic Sea Ice Graph, I find difficult to believe that the 2012 October average is 7 million km2. Visually, it looks more than 6 million km2. That would mean that there is a new NSIDC October record, that it is around 770,000 km2 under the 2007 value. Best regards, Juan C. García
I also like to hear that explanation. Even that I understand your argument, but I don't understand why it didn't happened the same in 2007. From my point of view, there is still less ice in 2012 than in 2007, so the monthly average should reflect this fact.
Thank you, Piotr Djaków, for your comment. It is true that the NSIDC makes public their daily data. It can be found in the Sea Ice Index Data, file NH_seaice_extent_nrt.csv, on the following page: ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/ I’m not sure if this data has already the 5-day average that NSIDC uses in their graph. But let’s assume that it is incorporated. In April 2012, NSIDC change its method of calculating the values from a 5-day centered average to a 5-day trailing average. That is explained in the following page: http://nsidc.org/arcticseaicenews/faq/#diff-min-values The 5-day trailing average could be better because the value does not change after it is made public that day, while the 5-day center average has to be corroborated two days later, when the true values are known. But the 5-day trailing average has the disadvantage of not representing the true value for that day. That is, to find October 1 value, they use the range form September 27 to October 1. Knowing that the values are increasing day by day, the Sept. 27 to Sept. 30 values will always be less than the October 1 value, so the daily October values are underestimated. This tendency is easily corrected. The value of October 3 trailing average uses the values of Sept. 29 to Oct. 3. This value is exactly the same that would be the 5-day center value at Oct 1. So to correct the underestimation of a 5-day trailing value, it’s enough to calculate the October average from 0ctober 3 to November 2, that is 6.09 million km2. The NSIDC can make some corrections to their monthly average, and they surely did it. But it seems that some make a mistake and change a 6 million km2 to a 7 million km2. The true is that we should have a new October record, that it is ~ 770,000 km2 under the 2007 value.
Hi again, Wipneus: The point is that I do not believe that the difference is because NSIDC applies a different calculation procedure. Being clear, I believe that there is a huge mistake on the NSIDC November analysis (blasphemy!). NSIDC says that 2012 October average is 7 million km2, but this average is overestimated. According to their daily graph, the October average should be from 5.7 to 6.3 million km2. https://docs.google.com/open?id=0B2LnyvgsEMtOZXFDNWJLSHpab2s
Toggle Commented Nov 6, 2012 on Looking for winter weirdness 2 at Arctic Sea Ice
Hi Wipneus: I have been thinking if the 5 day average that NSIDC uses could make the difference between the daily graph and the October month average, but at this moment, I believe that there is an inconsistency between what they report daily and the October monthly average. If we visually analyze the graph, we found more or less 11 days that the 2012 October value was approximately 250,000 km2 above the 2007 October value, but the other 20 days the 2012 value was under 2007. Even if removing the 5 day average would mean that we have to remove the first 5 October days, where the 2012 value was substantially under the 2007 value, these days would be replaced by 5 days that the graph shows at the beginning of November, in which 2012 is also under 2007. So for me it is very difficult to believe that 2012 October average was 230,000 km2 above 2007, when only 11 days where 250,000 km2 above 2007, and the 20 other days where under 2007 (some of the 2012 days substantially below 2007). So, there is an inconsistency on the NSIDC November analysis. I don’t know how to include a graph in a Typepad comment, but here is a link to the graph which explains what I mean: https://docs.google.com/open?id=0B2LnyvgsEMtOVURkYnRSQTh1cTQ Best regards, Juan C. García juancgarcia22@yahoo.com.mx
Toggle Commented Nov 6, 2012 on Looking for winter weirdness 2 at Arctic Sea Ice
The NSIDC 2012 November analysis is now public. I cannot understand why 2012 SIE October average is above 2007, if the first fifteen days of October-2012 where substantially below 2007, while the last second part of the month where just slightly above 2007. Other thing that I notice is that DMI Centre of Ocean and Ice change their values at their graph. While they explain the nature of the change (“The plot above replaces an earlier sea ice extent plot, that was based on data with the coastal zones masked out. This coastal mask implied that the previous sea ice extent estimates were underestimated.”), it seems to me that the stats change a lot. I cannot believe that 2012 minimum change from ~ 2.5 to ~3.9. Does anybody have the answer to these questions? For reference, see: http://nsidc.org/arcticseaicenews/ http://nsidc.org/arcticseaicenews/2012/10/open-water-means-a-warm-arctic/ http://ocean.dmi.dk/arctic/icecover.uk.php
Toggle Commented Nov 5, 2012 on Looking for winter weirdness 2 at Arctic Sea Ice