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Well the GAC is over and the extent difference is only about 200K above 2012. PIOMAS becomes less accurate as the ice gets thinner so the difference now with 2012 is probably within the margin of error. It has been a hot summer in the Arctic particularly above 80N which suggests plenty of capacity for late melt. A couple of years ago a suggested formula for Area and Volume was posted on the forum. Area = 1.282(Volume^0.5136). This formula predicts an increased decline in Area once volume drops below 5K km^3 as occurred in 2012 and a precipitous decline when it drops below 3K. It will be interesting to see if the same process occurs this year.
Toggle Commented Aug 10, 2019 on PIOMAS August 2019 at Arctic Sea Ice
Jim, No I was referring to Kris's comment above. I start from the following page from NOAA-ESRL. It provides the times series for the selected area so it is easy to display trends, rank months etc. Kris's dismissal of that site without providing a link to one he finds more useful is disappointing.
Toggle Commented Aug 10, 2017 on PIOMAS August 2017 at Arctic Sea Ice
Kris, I am happy to take a look at any other source of monthly data for specific regions that you can point me to. At the moment NOAA-ESRL is the best source I know of monthly data that can be selected for a defined area. eg 67n+, 80N+, 30E-60W etc. It provides 70 years of data, While it doesn't exactly match other estimates, it matches the trends very well. None of the various estimates in the Arctic exactly match each other but they all give a clear message. Neven, If you want I can send you my spreadsheets after I up date them each month.
Toggle Commented Aug 9, 2017 on PIOMAS August 2017 at Arctic Sea Ice
According to the NOAA-ESRL measurements 2017 has been colder than 2013 and 2014 in both the Arctic and the high Arctic (80N+) over most of the May - Jul period and on average. Despite this on August 1st the ice was nearly 4% thinner than 2012. From now to the end of the melting season an average melt (1.5M km^2 since 2002) will see 2017 close to 2007. A melt close to the trend (1.8M) km^2 will see a result well below 4M km^2 and hence below 2007. With the very thin ice we started with, and looking at the way 2016 plummeted towards the end of the season, I expect that 2017 will end up with extent midrange between 2012 and 2017.
Toggle Commented Aug 9, 2017 on PIOMAS August 2017 at Arctic Sea Ice
It's worth observing as well that the gap between 2017 and 2016 increased by almost 200 km^3 over the month. It is only really an extraordinary closing of the gap between day 158 and day 173 that saw 2012 approach 2017. 2011 the other big mover in June got 500 km^3 closer but still sits 750 km^3 behind in third place. For the rest of the melting season 2012 had a fairly average melt by volume. As indicated a fairly average melt would see a record low volume and probably low extent and area. Even last year's area came within a couple of hundred 1000 km^2 of the 2012 record low.
Toggle Commented Jul 5, 2017 on PIOMAS July 2017 at Arctic Sea Ice
Mikeemikey, Read all about the Arctic Council here: or here
Jim, Although 2012 has now passed 2017 it has also completed its' June dive and now declines at a very sedate rate for the next two weeks. 2011 crosses below 2012 in two days and it is likely that 2017 will do so within three. 2017 is only 76K behind 2012 and has the second greatest loss this month. With the much thinner ice this year it is easy to envisage 2017 with a substantial gap below 2012 by the end of the month.
Toggle Commented Jun 14, 2017 on Melting momentum: May 2017 at Arctic Sea Ice
Iceman, a more realistic neutral assumption would be the 2007-2016 average which puts 2017 well below 2012. If Pettits graph only showed the past 10 years only one trajectory would put 2017 above 2012. Reversion to the mean on the current trajectory only means return to the slope which would be a negative anomaly of 6 which would still put the volume near record lows. The thickness graph suggest less than a quarter of the remaining ice extent is thick enough to be a contender for surviving the summer.
Toggle Commented Jun 4, 2017 on PIOMAS June 2017 at Arctic Sea Ice
None of this looks good and the ESRL temperature figures for March put 2017 as the hottest on record for the Arctic for both SST and 2m Air temperatures. That all suggests everything is primed for a larger tather than a smaller melt. The lowest volume on record is clearly an option and with two of the past 7 years losing 19.5K a figure below 1.5 K km^3 is quite possible at the minimum. The hyperbolic trend on the remaining volume indicates an annuial loss over 400 Km^3 per year and a total wipeout withing 6 years. Anything is possible.
Toggle Commented Apr 5, 2017 on PIOMAS April 2017 at Arctic Sea Ice
Increasing CO2 may also be coming from forest fires that are increasing across the arctic and in other areas. A 30,000 ha (75,000 acres) fire in Australia can generate 1 million tonnes of CO2. Over the 15-year period from 1984 to 1998, wildfires burned approximately 315,000 acres per year in Alaska, most of this being in the subarctic portion of the state. This figure more than quadrupled during the 5-year period from 1999 to 2013; over this period, wildfires burned approximately 1.3 million.(EPA, 2016a). This is just in Alaska, it does not cover Canada or Siberia where we have seen significant fire activity over the past few years. acres per year across the state I doubt that Arctic forests regenerate at the speed of Australian forests to reabsorb the CO2.
Toggle Commented Feb 15, 2017 on PIOMAS February 2017 at Arctic Sea Ice
Comparing the annual rise and fall at Mauna Loa suggests that the annual absorption of CO2 has been trending just below 6 ppm/pa since 1990 while the annual emissions, natural and man made, have been steadily increasing. Overall absorption has increased from 5 to 6 ppm/pa while emissions have gone from 6 ppm to 8.25 ppm. There was a substantial increase in absorbtion in 1991 and 1992 which has some impact by flattening the trend line. However there certainly does appear a distinct leveling out of absorption over the past 20 years. This is probably not sufficient time to provide a definitive trend but certainly bears watching.
Toggle Commented Feb 14, 2017 on PIOMAS February 2017 at Arctic Sea Ice
John Christenson Given the weather forecast, I will bet you £10 (They are really cheap today) that 2012 will loose more extent in the next 14 days than this year, starting today. Over the last 10 years 2012 has had the fourth biggest drop in extent over the next 14 days. 2007 and 2013 dropped approximately 400K km^2 more. The average is barely greater than 2012. What odds are you offering for 2016 dropping less than 2012?
Toggle Commented Jun 24, 2016 on 2016 melting momentum, part 2 at Arctic Sea Ice
D_C_S CORRECTION: How does it compare to 2010? 2010 was record lowest in extent for this time of year according to NSIDC. 2016 has been lower than 2010 for more than 90 days. This may not be true in a few days as 2010 is going through a period of rapid decline.
Toggle Commented Jun 24, 2016 on 2016 melting momentum, part 2 at Arctic Sea Ice
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. Surely if a grid cell has no ice it is not considered in SIA. So polynyas that cover a complete cell would not be counted in either SIA or SIE. This means that open water within the pack covering a complete measurement cell is not part of the compactness equation but should be. Simple example 3 * 3 cell grid. Centre grid is empty other 8 cells are 100% full. SIA/SIE gives a figure of 100% But actual compactness is more like 88%. In an area like Beaufort with large areas of open water the compactness figure could well be artifically high.
Toggle Commented Jun 23, 2016 on 2016 melting momentum, part 2 at Arctic Sea Ice
I like the idea of using MASIE as the area measure for compactness. Using just extent and area ignores cells within the pack that are ice free. What can be seen from the satellites at the moment are many patches of open water within the pack. Assuming these have no ice they would not be included in SIE or SIA. But they would still be allowing warming via albedo further within the pack than usual. As a consequence it would be easier to melt out the CAB than usual.
Toggle Commented Jun 22, 2016 on 2016 melting momentum, part 2 at Arctic Sea Ice
The ESRL-NOAA data, with area weighting, shows the 80N+ area as the hottest since 2010 in May and as the hottest on record by a big margin for the first 5 months of the year. SO DMI may not be perfect but its a good first estimate.
Nick, There is a thread on the forum discussing wildfires. You might like to try your question there. Although there hasn't been much comment since last season I am sure a question from you would reignite it.,1232.0.html From other comments in other threads,the answer might well be: Yes lower albedo caused by smoke particles will increase melt particularly in Greenland. And yes ash in the atmosphere will increase cloud cover, but cause heat retention leading to increased melting. However that is just my impression from random comments.
Toggle Commented May 16, 2016 on PIOMAS May 2016 at Arctic Sea Ice
Temperatures so far this year have been off the scale as shown in this post.;quote=76486;topic=1538.0;last_msg=76486 Globally and in the Arctic 67N+, and 80N+, temperatures have been more than three std devs above average, with previous records only 2 std deviations above average. As Dorothy said in the Wizard of Oz, we're not in Kansas anymore.
Bobcobb, you suggested "David, you're putting far too much focus on Daily totals. It was doing the same thing last year and look how well that worked out." Daily totals are just a quick shorthand to illustrate the current state of the ice. However they are backed up by other factors not least that the daily total has been at record levels for 41 days, the second longest run since 2007, and is likely to stay at records level until late June unless we have a melt that is a record low melt for the last decade. On top of that Air and Sea Surface Temperatures's have been 1 std dev above the previous record both in the Arctic and globally so far this year with an obvious impact on ice formation. Thirdly this will clearly be the hottest year on record for the Arctic with the nine hottest years becoming 2005, 2006, 2007, 2010, 2011, 2012, 2014, 2015, 2016. Note the pattern there. All records set since the satellite record began in 1979 have occurred in the third year of three exceptionally hot years. And as shown above this is going to be an extraordinarily hot year even when compared with the hottest years on record. On top of that we haven't seen the DMI 80+ measurement drop below average this year another indication of unprecedented continuous warmth.
bobcobb, when you say "You're also forgetting that the melting will have to be much bigger to catch the record." I wonder what it will have to be bigger than. 2016 extent is currently 1.1 M km^2 lower than 2012 and 800K km^2 lower than 2007. A 2007 size decline will take the ice within 100K km^2 of the 3.177M record and a 2012 size decline within 100K km^2 of a 1.99 M km^2 record. All this during the hottest year on record with record warm sea temperatures both globally and aross the Arctic over winter. We are reaching the point where the relevant question may be what would prevent a record rather than is it likely. Stating opinions on the blog doesn't really have the scientific cachet of a peer reviewed paper or the ignomy of being wrong. It is after all for illumination and enjoyment not to demonstrate scientific credentials.
bobcobb, the possibility of a record this year has been evident from the end of March when sea temperatures across the arctic and the globe were shown to be a full standard deviation above the previous records. When temperature records jump from 2 to 3 std deviations above the average speculation is inevitable. A very conservative estimate at this stage would put the likelihood of a record at 30%. The question for many of us is how could a new record be avoided. There is already a poll on the forum with 2/3rds of the respondents predicting a record.
Bill, It appears there are at least two seperate NOAA datasets, the esrl.noaa data set and the ncdc.noaa data set. The ncdc data covers the entire period of the GISS temperature record back to 1880, the esrl data only covers the period from 1948. Their daya collection methods must be different as they return different data.
Bill, I am using the data available from NOAA at It is in Celsius but is not the same as the figures provided intheir monthly reports. It does however allow me to draw out figures for 67N+ and 80N+ which is where the other figures come from. Either way it's a whole lot hotter than previous years.
Figures above should be read as: Arctic Range:: -29.0 : -22.5 :: 2016 -20.5 80N Range :: -37.4 : -27.6 :: 2016 -24.5 Global Range:: 12.8 :13.6 :: 2016 14.0
The average SST in the Arctic (67N+) has varied between -29 and - 22.5 degC for the period Jan to Mar over the last 68 years according to NOAA. This year the average was 20.5. In the high Arctic (80N+), the range has been -37.4 to -27.6, This year -24.5. Global sea temperatures have jumped by a similar outlandish amount. The previous range was 12.8 - 13.6 this year 14.0. Each of these measures is at least one standard deviation above the previous record and three above the mean. The effect all this heat will have on the summer melt remains to be seen but it certainly doesn't bode well.