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Author Topic: Sep 1963 SIE from Nimbus I satellite data  (Read 6099 times)

Artful Dodger

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Sep 1963 SIE from Nimbus I satellite data
« on: April 15, 2013, 08:58:07 PM »
An important new paper is out in "The Cryosphere Discuss" online Journal showing Arctic sea ice minimum extent in September 1964 was similar to extent measured in the 1979-2000 satellite period.

Meier, W. N., D. Gallaher, and G. G. Campbell. "New estimates of Arctic and Antarctic sea ice extent during September 1964 from recovered Nimbus I satellite imagery." The Cryosphere Discuss 7 (2013): 35-53.

The PDF version of the paper is freely available.

Abstract:
Quote
Satellite imagery from the 1964 Nimbus I satellite has been recovered, digitized, and processed to estimate Arctic and Antarctic sea ice extent for September 1964. September is the month when the Arctic reaches its minimum annual extent and the Antarctic reaches its maximum. Images were manually analyzed over a three-week period to estimate the location of the ice edge and then composited to obtain a hemispheric average. Uncertainties were based on limitations in the image analysis and the variation of the ice cover over the three week period. The 1964 Antarctic extent is higher than estimates from the 1979–present passive microwave record, but is in accord with previous indications of higher extents during the 1960s. The Arctic 1964 extent was near the 1979–2000 average from the passive microwave record, suggesting relatively stable summer extents until the recent large decrease. This early satellite record puts the recently observed into a longer-term context.

The Arctic data-related charts and graphs from the paper are attached below: (there are relevant Figures for Antarctic sea ice within the paper, but discussing those here is out of scope for this part of the Forum)
« Last Edit: April 16, 2013, 08:30:03 PM by Artful Dodger »
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Daniel Bailey

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Re: Sep 1963 SIE from Nimbus I satellite data
« Reply #1 on: April 16, 2013, 02:36:52 AM »
Thanks for that, Lodger.  Very, very interesting.

Artful Dodger

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Re: Sep 1963 SIE from Nimbus I satellite data
« Reply #2 on: April 16, 2013, 04:40:45 AM »
Thanks for that, Lodger.  Very, very interesting.
Indeed, Yooper. I've been waiting patiently for these results since reading this news report back in October 2010:  8)

Technoarchaeology: Nimbus and LOIRP
« Last Edit: April 25, 2013, 05:36:21 AM by Artful Dodger »
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DrTskoul

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Re: Sep 1963 SIE from Nimbus I satellite data
« Reply #3 on: April 16, 2013, 06:47:46 AM »
Significant result!!! Eeexcellent.  :D

wili

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Re: Sep 1963 SIE from Nimbus I satellite data
« Reply #4 on: April 16, 2013, 07:52:58 AM »
Yes, thanks for this. I have read the abstract you posted but not the entire article.

I there any indication of what the total ice volume was during that time period? That seems a much more important measure than extent or area, when considering long term trends.
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

ChrisReynolds

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Re: Sep 1963 SIE from Nimbus I satellite data
« Reply #5 on: April 16, 2013, 03:27:04 PM »
Wili,

Volume in the range of PIOMAS for the 1980s. About 30k km^3 for winter max, 15k km^3 for summer min.

Lodger,

Thanks for posting this.

wili

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Re: Sep 1963 SIE from Nimbus I satellite data
« Reply #6 on: April 16, 2013, 07:15:07 PM »
Thanks, Chris. But I was wondering if there were any approximations of volume before that.

Wasn't thickness measured at various times by various explorers or submarines that could be combined with extent measures to get a ball-park figure for average volume in, say, the 1960's?

It seems to me that I have seen graphs of volume that go back well before the '80's, but I can't remember where I was viewing them, and I haven't been able to track them down.
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

Artful Dodger

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Re: Sep 1963 SIE from Nimbus I satellite data
« Reply #7 on: April 16, 2013, 08:08:33 PM »
Wasn't thickness measured at various times by various explorers or submarines that could be combined with extent measures to get a ball-park figure for average volume in, say, the 1960's?
Hi wili,

1960s satellite technology did not measure sea ice volume. But the US Navy has released submarine cruise thickness data.

... but only for the North Pole. The subs can't measure the thicker ice at the South Pole ;)



UPDATE:The attachments are up. See Figures 1, 2, 6, and 7 in my first post at the top of this thread.
« Last Edit: April 16, 2013, 08:39:09 PM by Artful Dodger »
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Sonia

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Re: Sep 1963 SIE from Nimbus I satellite data
« Reply #8 on: September 04, 2014, 04:48:01 AM »
There's some news on this at http://cires.colorado.edu/news/press/2014/nimbus.html.

It sounds like new data is up at the NSIDC now.

Artful Dodger

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Re: Sep 1963 SIE from Nimbus I satellite data
« Reply #9 on: September 16, 2014, 03:44:42 PM »
There's some news on this at http://cires.colorado.edu/news/press/2014/nimbus.html

It sounds like new data is up at the NSIDC now.

Thank you for posting that, Sonia.  8)  Here is the YouTube video released by CIRES on Aug 28, 2014: (the gentlemen interviewed was NIMBUS 1-7 Operations Manager some 50 years ago!)

Quote
50 years ago, NASA launched Nimbus to study Earth from space. Now, experts at the National Snow and Ice Data Center (part of CIRES), are recovering valuable data and images from old, long-lost film, and expanding their understanding of sea ice in the Arctic and Antarctic. Learn more from CIRES on the 1-year anniversary of Nimbus' first image:


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MA Rodger

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Re: Sep 1963 SIE from Nimbus I satellite data
« Reply #10 on: June 20, 2019, 09:56:38 PM »
I was wondering if there was anybody with an understanding of the status of the NIMBUS-5 Sea Ice data 1972-78.

I assume this is the source of the pre-1979 data plotted out in IPCC FAR (1990) Fig 7.20a & I am posting in this thread as a commenter a year ago who posted Fig 7.20 in the 2018 Melt Season thread was directed here - it seems he didn't show up from there.
https://forum.arctic-sea-ice.net/index.php/topic,2278.msg155707.html#msg155707

The shape of the Fig 7.20a graph (a dip in Arctic SIE in 1973-74 and little downward trend after the dip) matches the description given by the abstract of Parkinson & Cavalieri (1989) 'Arctic sea ice 1973–1987: Seasonal, regional, and interannual variability' I haven't sourced the full article.
https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JC094iC10p14499

But then Chapman & Walsh (1993) 'Recent Variations  of Sea Ice and Air Temperature in Latitudes' Fig 6 plots out what is surely NIMBUS 5 & 7 derived data and there is no dip. Instead it roughly matches the usual NSIDC for post-1979 values.
https://journals.ametsoc.org/doi/pdf/10.1175/1520-0477%281993%29074%3C0033%3ARVOSIA%3E2.0.CO%3B2

But I see no expanation for these differences or explanation why the pre-1979 data is not employed as part of the satellite record.