Australian Politics Forum - Problems with Sea Ice Data

lee Gold Member Offline Australian Politics Posts: 21563 Gender:	Problems with Sea Ice Data Apr 12^th, 2016 at 1:25pm 'The daily sea ice extent images are sporadically displaying erroneous data. NSIDC is investigating with our satellite data providers.' http://nsidc.org/arcticseaicenews/2016/04/a-problem-with-the-f17-dmsp-satellite/
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BatteriesNotIncluded Gold Member Offline MediocrityNET: because people died for this! Posts: 26966	Re: Problems with Sea Ice Data Reply #1 - Apr 13^th, 2016 at 12:48pm Yeh, some article was saying the instruments were supposedly past their use by date years ago! The numbers did seem curiously low....
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bogarde73 Gold Member Offline Anti-Global & Contra Mundum Posts: 18443 Gender:	Re: Problems with Sea Ice Data Reply #2 - Apr 13^th, 2016 at 2:39pm The main problem I see with sea ice is the chunks are too big to fit in your whisky glass.
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John_Taverner Gold Member Offline Australian Politics Posts: 2217 Gender:	Re: Problems with Sea Ice Data Reply #3 - Apr 13^th, 2016 at 2:57pm Welcome to the Environment board, Bogie. Have a drink: Wild cherry picking brandy with melting Arctic ice. I offer it to all climate change deniers. I'm not saying that you fit the bill in that respect, or otherwise, but it helps cool people down in this time of rising global temperatures. [/quote]
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John_Taverner

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Re: Problems with Sea Ice Data
Reply #4 - Apr 13^th, 2016 at 3:05pm

lee wrote on Apr 12^th, 2016 at 1:25pm:

'The daily sea ice extent images are sporadically displaying erroneous data. NSIDC is investigating with our satellite data providers.'

Of course there are checks and balances that indicate when the images sporadically play up. It just means that they occasionally have to repeat runs until the check sums are correct. It doesn't affect the integrity of the data (if that's what you are quietly alluding to).

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lee

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Re: Problems with Sea Ice Data
Reply #5 - Apr 13^th, 2016 at 3:20pm

John_Taverner wrote on Apr 13^th, 2016 at 3:05pm:

lee wrote on Apr 12^th, 2016 at 1:25pm:

'The daily sea ice extent images are sporadically displaying erroneous data. NSIDC is investigating with our satellite data providers.'

Of course there are checks and balances that indicate when the images sporadically play up. It just means that they occasionally have to repeat runs until the check sums are correct. It doesn't affect the integrity of the data (if that's what you are quietly alluding to).

John. you really are too paranoid. I merely passed on an interesting tit bit. It also appears to be affecting BoM.

You know - like the girl who went up to a man's apartment for a midnight snack.

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John_Taverner

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Re: Problems with Sea Ice Data
Reply #6 - Apr 14^th, 2016 at 8:20am

lee wrote on Apr 13^th, 2016 at 3:20pm:

John. you really are too paranoid. I merely passed on an interesting tit bit. It also appears to be affecting BoM.
.

Of course you did. I was just adding my slant to that interesting tit bit.

Relax, I would never accuse you of trying to cast doubt on climate data.

Quote:

Please note that our daily sea ice images, derived from microwave measurements, may show spurious pixels in areas where sea ice may not be present. These artifacts are generally caused by coastline effects, or less commonly by severe weather.

and
Quote:

Isolated areas of missing data occasionally occur in near-real-time sea ice data. The daily extent map shows any areas of missing data as dark gray regions, speckles, or spider web patterns. However, in the time series chart we account for the missing data by averaging the extent for that region from the day before and the day after the gap, a mathematical technique called interpolation. Interpolation is an appropriate approach because ice cover changes slowly.

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« Last Edit: Apr 14^th, 2016 at 8:26am by John_Taverner »

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BatteriesNotIncluded Gold Member Offline MediocrityNET: because people died for this! Posts: 26966	Re: Problems with Sea Ice Data Reply #7 - Apr 14^th, 2016 at 12:13pm bogarde73 wrote on Apr 13^th, 2016 at 2:39pm: The main problem I see with sea ice is the chunks are too big to fit in your whisky glass. Possibly too salty aswell!
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BatteriesNotIncluded

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Re: Problems with Sea Ice Data
Reply #8 - Apr 14^th, 2016 at 12:16pm

John_Taverner wrote on Apr 13^th, 2016 at 2:57pm:

Welcome to the Environment board, Bogie. Have a drink:

Wild cherry picking brandy with melting Arctic ice.
I offer it to all climate change deniers. I'm not saying that you fit the bill in that respect, or otherwise, but it helps cool people down in this time of rising global temperatures.

[url]https://s-media-cache-ak0.pinimg.com/474x/e2/09/19/e20919f46e362b55ec5e11d28d3ec
c7a.jpg[/url]

[/quote]
How salty is it seems to be the question?

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*Sure....they're anti competitive as any subsidised job is. It wouldn't be there without the tax payer. Very damned difficult for a brainwashed collectivist to understand that I know.... (swaggy) *

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lee

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Re: Problems with Sea Ice Data
Reply #9 - Apr 14^th, 2016 at 12:53pm

What I like are the IPCC reconstructions of Arctic ice since 1900.

https://www.ipcc.ch/pdf/unfccc/sbsta40/SB40_research_dialogue_hezel_wgI.pdf

Pretty flat out to 1980.

Makes you wonder how those lost bombers in Greenland got to be 260 feet down in the ice. Of course it is only sea ice, Greenland may be an anomaly.

Or

Maybe the hot engines melted all that ice.

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The_Barnacle

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Re: Problems with Sea Ice Data
Reply #10 - Apr 14^th, 2016 at 10:21pm

lee wrote on Apr 14^th, 2016 at 12:53pm:

Makes you wonder how those lost bombers in Greenland got to be 260 feet down in the ice.

Not really, considering that the Greenland Ice sheet receives about a metre of snow every year. If you knew how glaciers work you would realise that objects can still get buried in retreating glaciers.

Or is this just another of your rather gutlessly cryptic attempts to throw a bit of doubt around hoping that some of it might stick.

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The Right Wing only believe in free speech when they agree with what is being said.

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Chimp_Logic Gold Member Offline πολιτικός Posts: 4826 Mawson Base Gender:	Re: Problems with Sea Ice Data Reply #11 - Apr 15^th, 2016 at 2:23am Why has Greenland's MELT SEASON commenced 6 weeks early this year? Gee this Min Ice Age phenomena is very confusing isnt it ladies and gentlemen Perhaps lee and his partner jethro need to submit joint apologies and implement self ban periods of the order of 3 to 4 months
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Bobby.

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Re: Problems with Sea Ice Data
Reply #12 - Apr 15^th, 2016 at 7:15am

Chimp_Logic wrote on Apr 15^th, 2016 at 2:23am:

Why has Greenland's MELT SEASON commenced 6 weeks early this year?

Gee this Min Ice Age phenomena is very confusing isnt it ladies and gentlemen

Perhaps lee and his partner jethro need to submit joint apologies and implement self ban periods of the order of 3 to 4 months

So the extent of sea ice is normal -

no apology required there.

( Antarctica is showing a lot of extra sea ice. )

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Chimp_Logic

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Re: Problems with Sea Ice Data
Reply #13 - Apr 15^th, 2016 at 10:33am

Bobby. wrote on Apr 15^th, 2016 at 7:15am:

Chimp_Logic wrote on Apr 15^th, 2016 at 2:23am:

Why has Greenland's MELT SEASON commenced 6 weeks early this year?

Gee this Min Ice Age phenomena is very confusing isnt it ladies and gentlemen

Perhaps lee and his partner jethro need to submit joint apologies and implement self ban periods of the order of 3 to 4 months

So the extent of sea ice is normal -

no apology required there.

( Antarctica is showing a lot of extra sea ice. )

Would you expect the Greenland MELT season to commence 6 weeks early during a Mini Freak Ice Age?

Mr Sir Bobby, according to my records your written apology 61B/1 is in arrears

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Mini Ice Age (2014-2029)
Dr Sircus cures cancer with Baking Soda and Magnesium - Jethro the MENTAL GIANT & his flute madness

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lee

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Re: Problems with Sea Ice Data
Reply #14 - Apr 15^th, 2016 at 11:52am

John_Taverner wrote on Apr 14^th, 2016 at 8:20am:

lee wrote on Apr 13^th, 2016 at 3:20pm:

John. you really are too paranoid. I merely passed on an interesting tit bit. It also appears to be affecting BoM.
.

Of course you did. I was just adding my slant to that interesting tit bit.

Relax, I would never accuse you of trying to cast doubt on climate data.

Quote:

Please note that our daily sea ice images, derived from microwave measurements, may show spurious pixels in areas where sea ice may not be present. These artifacts are generally caused by coastline effects, or less commonly by severe weather.

and
Quote:

Isolated areas of missing data occasionally occur in near-real-time sea ice data. The daily extent map shows any areas of missing data as dark gray regions, speckles, or spider web patterns. However, in the time series chart we account for the missing data by averaging the extent for that region from the day before and the day after the gap, a mathematical technique called interpolation. Interpolation is an appropriate approach because ice cover changes slowly.

Very good John.

'The terminology related to the aerial coverage of sea ice is closely linked to the observational techniques. Satellite remote sensing algorithms yield the fraction of the ocean surface covered by sea ice in a pixel of a certain size (the size depends on the remote sensing instrument). Sea ice concentration (SIC) is defined as the fraction covered by sea ice, and sea ice extent is defined as the cumulative area of all pixels having at least 10% or 15% SIC. The threshold of 10% (World Meteorological Organization, 1970) originates from pre-satellite era, when the concentration was estimated for the area covered by visual observations. The 15% threshold is commonly applied by the remote sensing community and, among others, the U.S. National Snow and Ice Data Center (Parkinson and Cavalieri, 2008). Sea ice area is the cumulative sum of the product of the pixel ice concentration and pixel area for all pixels having at least 15% (or 10%) ice concentration.

http://www.arctic.noaa.gov/future/bib/Vihma_accepted_in_Surv_Geophys.pdf

You disagree?

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