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Topics - DavidR

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1
Arctic sea ice / FireStorm in Siberia
« on: July 22, 2019, 03:40:14 PM »

This may amount to nothing but there is quite a large cyclone being fueled by fires in Siberia at the moment. On my estimate its about 1000 kms across and drawing in a lot of heat and smoke from the surrounding areas. Rather like those pictures of what happens when you light  too many  candles on a birthday cake.

https://en.wikipedia.org/wiki/Firestorm

If it happened to drift north over the Arctic Ocean I  can't see it being anything but destructive either this year or, by dumping a great deal of soot, in later years.   

https://worldview.earthdata.nasa.gov/?p=arctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Graticule,Coastlines&t=2019-07-22-T00%3A00%3A00Z&z=3&v=540709.4034312759,1297218.1613725103,4472869.403431276,3173186.1613725103

2
The poll is for the minimum Daily sea ice extent in 2018 as measured by JAXA. There is another poll for the NSIDC September Average.

Jaxa September minimums for the past 15  years have been:

2003     5933760
2004     5683663
2005     5179300
2006     5625046
2007     4065739
2008     4500623
2009     5054055
2010     4622092
2011     4269199
2012     3177455
2013     4809288
2014     4884120
2015     4257003
2016     4017264
2017     4472225

I  have attached a graph showing the declines from August 1st to minimum for the past  15 years.

In the July poll 72 votes were cast and the average prediction was 4086806.  This is approximately  300K  below the NSIDC September Average poll figure. The average difference between the two measure since 2005 is approximately 300K. 

3
Arctic sea ice / NSIDC 2018 Arctic SIE September average: August Poll
« on: July 29, 2018, 08:24:58 AM »
ATTENTION: There are two polls on the ASIF. This one is for NSIDC sea ice extent September average (which is also used for the SIPN sea ice outlook), the other is for JAXA sea ice extent daily minimum (provided by ADS, previously by IJIS). Make sure you are aware of the difference before voting.

These are the September averages for the last 13 years (in millions km2,):

    2005: 5.50
    2006: 5.86
    2007: 4.27
    2008: 4.69
    2009: 5.26
    2010: 4.87
    2011: 4.56
    2012: 3.57
    2013: 5.21
    2014: 5.22
    2015: 4.62
    2016: 4.51
    2017: 4.80

75  voters voted in the July  poll with  an average prediction of 4.387 M km^2. This is 300K above the JAXA daily  minimum in line with  the average differences between the two  figures since 2005

I  have attached a graph showing the difference between the daily minimum and September average for  the past thirty years.  It should be noted that NSIDC does not necessarily use a standard 'average' of daily values when calculating their reported average. 

4
Arctic sea ice / NSIDC 2018 Arctic SIE September average: July poll
« on: June 30, 2018, 07:18:57 AM »
ATTENTION: There are two polls on the ASIF. This one is for NSIDC sea ice extent monthly minimum or September average (which is also used for the SIPN sea ice outlook), the other is for JAXA sea ice extent daily minimum (provided by ADS, previously by IJIS). Make sure you are aware of the difference before voting.

These are the September averages for the last 13 years (in millions km2,):

    2005: 5.50
    2006: 5.86
    2007: 4.27
    2008: 4.69
    2009: 5.26
    2010: 4.87
    2011: 4.56
    2012: 3.57
    2013: 5.21
    2014: 5.22
    2015: 4.62
    2016: 4.51
    2017: 4.80

5
This poll has been reverted to  last years format to make for an easier comparison.

The poll is for the minimum Daily sea ice extent in 2018 as measured by JAXA.

September minimums for the past 15  years have been:

2003     5933760
2004     5683663
2005     5179300
2006     5625046
2007     4065739
2008     4500623
2009     5054055
2010     4622092
2011     4269199
2012     3177455
2013     4809288
2014     4884120
2015     4257003
2016     4017264
2017     4472225

6
Its time for the regular June poll on this years likely JAXA extent minimum. The graph shows minimums since 2003.

The poll is open for 15 days and you should be able to  change your vote.

These are the daily September minimums (in millions km2):

1980's Avg:   7.23
1990's Avg:   6.55
2000's Avg:   5.48
2000:   6.04
2001:   6.55
2002:   5.53
2003:   5.93
2004:   5.68
2005:   5.18
2006:   5.63
2007:   4.07
2008:   4.50
2009:   5.05
2010:   4.62
2011:   4.27
2012:   3.18
2013:   4.81
2014:   4.88
2015:   4.26
2016:   4.02
2017:   4.47

7
The rest / Mount Agung volcano eruption 2017
« on: September 26, 2017, 10:46:36 AM »
Vulcanologists are predicting a significant volcanic eruption of Mount  Agung in Indonesia in the next few days.

http://www.abc.net.au/news/2017-09-19/mount-agung-volcano-evacuations-amid-fears-of-bali-eruption/8959240

There is an expectation that it could be as significant for global weather as the My  Pinatubo  eruption in 1991. The Mt Pinatubo eruption reduced global Temperatures by  about 0.1 degree for three years after which  it resumed the previous climb having no long term effect.

In the Arctic the effect  lasted about  three years and temperatures were lowered by 0.5 degrees.  If this eruption is as big as Mt Pinatubo we should expect a recovery in the Arctic Sea Ice extent, and volume over the next three years.   



8
Arctic sea ice / Poll: 2017 PIOMAS Maximum Monthly Figure
« on: March 04, 2017, 03:51:27 AM »
We are approaching the end of the freezing season with PIOMAS set to peak next month. Probably at record low levels.  We could be as low as 20K km^3 at the maximum. Twice recently  we lost 19.5K Km^3 in a year.

Jim Pettit’s excellent graphs on Arctic Volume at
     https://sites.google.com/view/pettitclimategraphs
show how close we are coming to the point where the volume of ice lost in the year will equal the volume at the peak of the freeze.

So as a change  from a poll on extent here is a poll on peak volume. Closes on the 21st March to allow all the February data to become available.
Votes can be changed up until then.

The result will be the figure used at http://psc.apl.washington.edu/research/projects/arctic-sea-ice-volume-anomaly/ which is the one Jim uses in his graphs.

9
Arctic sea ice / How close can NSIDC area get to 2012.
« on: September 04, 2016, 07:53:28 AM »
Area is now just 370K above the 2012 minimum but it is unlikely to get there. In the next three weeks we should know.  As we can now see weather predictions  for the immediate future it would interesting to see how accurate our estimates of weather effects can be.

If the minimum comes before Sept 24 the we should all  finish the season off with a winning estimate.  ;D

As Crandles pointed out this is the DAILY CT calculation I  was thinking of.  And in the absence of the CT Area figures we will be using Wipneus's estimates which are accurate enough.

It is true the are minimum will  probably occur before the end of the poll, which  is why  everyone should be a winner!

10
The forum / Forum Decorum
« on: May 26, 2016, 02:39:55 PM »
Decorum: behaviour in keeping with good taste and propriety.

Various people have made suggestions about how to make the forum more focussed and less cluttered. Here are some of them, feel free to add your own pet peeves.
  • Consider whether readers of the forum would benefit from your comment before posting.
  • Posting multiple times in a row is generally against forum etiquette. If you have something additional to add and your post is still the last in a thread, edit your post.
  • If you have multiple people to reply to, do it in a single post.
  • When quoting someone else, try to cut away all the text that isn't pertinent to your answer.
  • Avoid comments which contain more blurb than information
  • Avoid personal comment which says very little of interest.
  • Avoid long winded sign offs. 1 line is acceptable, 3 lines or more is a self indulgence.
  • Avoid reposting images in the same thread. .
  • Where possible include a link rather than regurgitating swathes of information. But can we please have at least a small synopsis of what the link is referring to.
  • And those left-open parentheses : I have to say I  don't personally  agree with  complaints based on poor spelling, language difficulties or predictive text
  • Avoid starting multiple threads about the same subject,  check for an existing thread
  • Use a different thread if the subject is off topic for the one you are on
  • If you think a particular poster is behaving inappropriately, try sending them a PM and explain to them what you think they are doing wrong and how they could improve.
  • keep calm and reply tomorrow
We can tolerate some of this stuff, but rather not in well-frequented threads.
It should be understood that these types of "rules" aren't meant to censor. Each and every one of us has a personality, and that should be allowed to shine through in our comments .

"I for one would really like a 'Like' button.": Unfortunately  this is not currently possible on this platform

11
Arctic sea ice / Hansens predictions for Future Ice
« on: May 04, 2016, 01:50:21 PM »
Original quote re Hansen by ktonine on the IJIS thread.
"If I'm not mistaken, this is essentially what Hansen has predicted - short-term global cooling as a result of global warming, thanks to melting Greenland. Predictions Implicit in “Ice Melt” Paper and Global Implications:"



I think what Hansen's study misses is what's implicit if the anomalies he projects are realized. The 2080-2100 image is more dramatic and, IMO, the departures it shows would be sufficient to allow ice sheets to begin regrowing across NRN Europe and NRN North America (which is not mentioned in his papers).
<snippage>
Ice sheets? Nonsense. That's a HUGE stretch.  Actually it's not a stretch; energetically, its unreachable.  The forcing from CO2 is already too high, the increased albedo from open arctic water will provide far and away additional capture heat to render it impossible.  Very functionally, the ice sheets grew in part because there was an Arctic ice pack to aid in bouncing heat back out of the hemisphere.  I think you are absurdly overestimating the effect of the feedback from Greenland melt.

I don't know about that. I think Quebec would be insulated from the warmer Arctic Ocean by the freshwater streaming south through the CAA that originates in Greenland/summer melt. This was visible last year as sea ice, for the first time in satellite history, advanced into Hudson Bay from the northeast, rather than forming on the shore from the west and building east.

The projections from Hansen are very dramatic (below -- 2065, 2080, 2096). I don't think it is unreasonable that a little tweaking of output could yield a yearly temp decrease of 5C or more in places like Quebec and despite increased GHG forcing I think that *IF* the kind of anomalies projected by Hansen due to melt are indeed realized, ice sheets would reform.

http://www.columbia.edu/~jeh1/2015/20150704_IceMelt.pdf

It should also be noted that the speed with which we get from a small area of - anomalies to a huge one is VERY fast. The changes projected between 2065 and 2096 are enormous! And given today's maps are already beginning to look like output for the mid 20th century (and the fact that Hansen has said they underestimate sensitivity), we may already be off the cliff.
This thread is for discussions related to  James Hansen's predictions that  have been erroneously discussed on the IJIS thread. Please continue the discussion here.  Thank you

12
Arctic sea ice / The Plateau Hypothesis
« on: April 04, 2015, 07:37:31 AM »
I’ve posted this to clarify the hypothesis mentioned in various places on the forum for anyone who is interested.

I define the plateau as the period when the sea ice remains within a set range of the maximum extent for the year. The plateau commences when the ice first reaches that level and ends when the ice is last within that range. The period will change depending on the measure used, extent or area; the source of the data eg IJIS , NSIDC; and the length of the measure 1 day, 2 day or 5 day averages.

The objective of the hypothesis is to determine whether the duration of the near maximum conditions is an indicator of the likely fall of extent over the year. Other readers have argued that the peak itself is not a good indicator. My initial idea was that a short sharp peak could indicate significant melt while a long duration could indicate consolidation of the ice and therefore a smaller melt.

To test the hypothesis I first checked the NSIDC extent using a 200K loss as the plateau, for the period from 2006. In all cases with NSIDC and CT Area I use the 5 day average not the daily peak.


This was exactly the reverse of my original idea. The graph suggests that the longer the duration of the plateau the greater the extent loss in that year. Over 44K per day according to the graph. As the plateau lasted 51 days this year, this would have disturbing implications for 2015.

When I first put the idea up, one criticism was that the period was too short and my choice of extent and the 200K range was arbitrary. With the assistance of other members of the forum we gathered figures for the same period, covering  CTArea, IJIS/Jaxa, and extending the 200K level  to 300K for NSIDC extent. The relationship held up for all the measures we used, however there was still the issue of the relatively  short time frame.

Extending the time frame back to 1979 produced quite a different story.


Over the entire 36 year period of the NSIDC there is a very slight correlation the other way, almost 5K km^2 smaller loss per day of the duration.

While that would normally be sufficient to suggest that the short term correlation is only a statistical blip I decided to investigate the variations over the 36 years. 

I decided to use 15 year periods and calculate the coefficient of change for each  15 year  period.  For simplicity I have plotted them below against  the mid year of the 15 year period.


What we can see here is that for 13 years up until 1998 the coefficient was very stable. 
Y = - 0.013X +/- 0.0018. 

However following 1998 the coefficient  changed dramatically. It has switched from negative to positive and steadily increased. For the last  15 year period the graph shows a coefficient of +0.396 that  is ~ 29 standard deviations from the 13 year trend prior to 1998.


I can’t help but think that this is a little more than statistical noise and bears watching to  determine if 1998  really  was the tipping point in the relationship  between the duration of the maximum plateau and the loss of extent.

For the record the four plateaus I have, based on the relatively short past 8 years, predict:

CT Area 200K  : 2.333 M km^2
NSIDC extent 200K    : 3.191 M km^2
NSIDC extent 300K    : 3.181 M km^2 (assumes another 6 days above 300K)
IJIS/jaxa                     : 3.503 M km^2

Even with a std deviation around the trend of 600K km^2 the prediction is definitely placing the final minimum in the lowest 2 on record. 









13
Arctic sea ice / Sea Ice Prediction Network 2014 Submissions
« on: July 05, 2014, 08:35:05 AM »
The Sea Ice Prediction Network has released its call for July submissions with a required submission date of 9 July. Public as well as scientific submissions are invited. It's not a poll as you are expected to explain how you achieved your figures. 
http://www.arcus.org/sipn/sea-ice-outlook/2014/july/call

Those who have made submissions are encouraged to post their executive summaries here for discussion. 

14
Arctic sea ice / Vale: The artic canary
« on: March 21, 2013, 01:40:50 PM »
The arctic has often been described as the 'canary in the coalmine' of Climate Change.

After this weeks fracturing of the MYI above Kap Jessup I think we should recognise that the canary is dead!!!
As someone more astute than me said"

 'E's not pinin'! 'E's passed on! This canary is no more! He has ceased to be! 'E's expired and gone to meet 'is maker!
'E's a stiff! Bereft of life, 'e rests in peace! If you hadn't nailed 'im to the perch 'e'd be pushing up the daisies!

'Is metabolic processes are now 'istory! 'E's off the twig!

'E's kicked the bucket, 'e's shuffled off 'is mortal coil, run down the curtain and joined the bleedin' choir invisibile!!
THIS IS AN EX-CANARY!!"
 
Sorry folks but the Arctic Sea Ice is cactus,
It may not happen overnight but it will happen.
(This decade if not this year)

No  Flowers by request.





http://forum.arctic-sea-ice.net/index.php?action=post;board=3.0#

15
Bob Wallace's thread discussing whether we could have a grid powered by renewables morphed into  a discussion of localised off grid solutions to  generating power.

While going off grid is feasible with enough space and money can it  ever be more than a minor player in the solution.  What are the costs, and what  are the benefits to society and the individual.

At a minimum the proposal seems to  require enough solar to  meet your needs when the sun is shining, enough wind to meet your needs when the sun isn't shining, enough battery backup to  meet your needs when neither of those is sufficent, and enough extra capacity wind and solar to  keep the batteries charged.

With a global grid the entire planet becomes your offsite backup and you can still produce sufficient to  meet  your own needs, If you have the space.

I  have looked at the economics of this several times over the past  few years and have never seen a solution that  comes close to  being economically justified compared to paying my share of the global grid. 
 

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