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Author Topic: Do we make too much of 2012 ?  (Read 2565 times)

Juan C. García

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Re: Do we make too much of 2012 ?
« Reply #50 on: June 07, 2019, 06:35:52 AM »
Would be too much 18% more on 2011 PIOMAS volume (versus 2012) or 25% on 2010, when we had 200% or more, in 20 of 40 years?
2012 doesn’t seem to be an outlier, when we are measuring ASI volume.
So, the real question for me is:
Do we give too much importance to ASI extent and we should focus more on ASI volume?
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

b_lumenkraft

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Re: Do we make too much of 2012 ?
« Reply #51 on: June 07, 2019, 06:46:33 AM »
That's a great table Juan! Thanks for sharing.

Rich

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Re: Do we make too much of 2012 ?
« Reply #52 on: June 07, 2019, 07:42:25 AM »
Would be too much 18% more on 2011 PIOMAS volume (versus 2012) or 25% on 2010, when we had 200% or more, in 20 of 40 years?
2012 doesn’t seem to be an outlier, when we are measuring ASI volume.
So, the real question for me is:
Do we give too much importance to ASI extent and we should focus more on ASI volume?

Juan, would you happen to have a chart like that for March?

I happen to think that volume is generally a better measure than a 2D measure, unless you're trying to measure albedo.

b_lumenkraft

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Re: Do we make too much of 2012 ?
« Reply #53 on: June 07, 2019, 08:12:12 AM »
For how i understand it, the problem with volume measurement is that it is widely believed to be unreliable.

Neven

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Re: Do we make too much of 2012 ?
« Reply #54 on: June 07, 2019, 12:23:56 PM »
Switching the focus (if there is any) to winter sea ice, would most probably lead to climate risk deniers entering the fray again. And having a field day.  ::)

I think it's best to focus on both winter and summer, which is what we are doing here. And the media also has plenty of stories during winter, about temperatures in Alaska or no ice in the Bering Sea.

But the spectacle is during summer. So, when something big happens then, it will get the most attention. The ASIB, for instance, 'exploded' for a couple of days, during GAC-2012.

Now, how to couple this to a strong message that gives people insight into the root cause of the problem and hope for the future? I'm working on that, despite my pessimism.
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oren

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Re: Do we make too much of 2012 ?
« Reply #55 on: June 07, 2019, 12:44:18 PM »
Juan, thanks for the table.
2007 was the real shocker.

Dharma Rupa

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Re: Do we make too much of 2012 ?
« Reply #56 on: June 07, 2019, 01:10:09 PM »
Do we give too much importance to ASI extent and we should focus more on ASI volume?

Find me daily volume numbers to drool over and I'll stop salivating over extent.

Juan C. García

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Re: Do we make too much of 2012 ?
« Reply #57 on: June 07, 2019, 02:35:19 PM »
Juan, would you happen to have a chart like that for March?

I happen to think that volume is generally a better measure than a 2D measure, unless you're trying to measure albedo.
It is kind of easy to make the tables. Just need to download the monthly data, sort it by the month and calculate the percentages.
http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/data/
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Juan C. García

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Re: Do we make too much of 2012 ?
« Reply #58 on: June 07, 2019, 02:41:10 PM »
Do we give too much importance to ASI extent and we should focus more on ASI volume?

Find me daily volume numbers to drool over and I'll stop salivating over extent.
Yes, it is easier to obtain the daily extent data and we don’t have that daily data on volume.
That doesn’t mean that we should catalog 2012 as an outlier and don’t look for volume from time to time. The true is that 2012 happened! And we can expect to happen again. The doubt is when, not if we will not see a similar year again.

Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Juan C. García

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Re: Do we make too much of 2012 ?
« Reply #59 on: June 07, 2019, 02:55:11 PM »
For how i understand it, the problem with volume measurement is that it is widely believed to be unreliable.
It has a greater margin of error, but it represents the reality better.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Juan C. García

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Re: Do we make too much of 2012 ?
« Reply #60 on: June 07, 2019, 03:15:27 PM »
Juan, thanks for the table.
2007 was the real shocker.
Yes, it is interesting that 2007 is 9th lowest on September volume, with 72% more ice than 2012. As you explained on the NSIDC poll, 2007 could be over valuated, because of its late refreeze. It is interesting that JAXA puts 2016 as the second lowest, because it just looks for the daily lowest, not the monthly average lowest. And Bremen said that 2011 daily extent was lower than 2007. On volumen, September 2016 is 3rd lowest. And on a year average, 2017 is worst than 2012.

So, things have been happening, but we don't see them, if we just look at the September monthly average extent.
I should have voted 4-4.5 but went one lower.
A lot depends on the date of refreeze, 2007 was very late and 2016 very early, hence their 0.25 difference.
« Last Edit: June 07, 2019, 03:39:09 PM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

gerontocrat

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Re: Do we make too much of 2012 ?
« Reply #61 on: June 07, 2019, 04:43:52 PM »
EDIT Seriously I really do need a holiday, my brain is thinking about the next thing while I write about the first thing.

The Arctic Volume maximum minimum is in September, but the minimum maximum is in April, not in March. Not that it makes any difference to Juan's analysis - as the graph of monthly averages attached demonstrates.

2012 was clearly the lowest volume for just 3 months- August, September and October. From mid November 2016 to mid June 2017 volume was the lowest by far. (see 2nd attached graph)
_______________________________________________________
Data availability

The Polar Science Center @ http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/data/ publishes the monthly and daily volume data once a month. The daily data has to be extracted.

Wipneus does the same when he posts his analyses on the PIOMAS thread within "Arctic Sea Ice". Sometimes, if he gets the data, he does it mid-month as well. His data also includes a file of volume by individual seas. His data has to be extracted from a .gz file.

The daily data from the Polar Science Center is a 14,750 lines of daily data from 1979. Sorting that into a table for each year with year headings as in data from JAXA and NSIDC was a real pain. February 29th screwed up the algorithm.-aargh.

So on the PIOMAS thread I post once (or twice) per month an analysis or two using the same formats as for the daily JAXA postings.

ps: Lazy me wishes these scientists dumped the data into .csv files.
« Last Edit: June 07, 2019, 06:32:45 PM by gerontocrat »
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