Guest post by Steven Goddard
NSIDC Arctic Ice Extent Just a few pixels from “average”.
May 1st is May Day . “Mayday” is a universally understood distress call signifying that an aircraft or other vessel is headed on a collision trajectory. 2009 Arctic ice extent is on a collision trajectory with normal, which could be disastrous for AGW alarmists. “May Day” is an international holiday celebrated on May 1. In the Soviet Union it celebrated the worker’s “liberation” from capitalism, though they hadn’t yet thought up “cap and trade” at that time.
I have more news to report about the ongoing mystery of why NSIDC shows Arctic ice extent much closer to the 1979-2000 average than NANSEN is to the 1979-2007 average. It should be the other way around.
Dr. Walt Meier at NSIDC has again graciously responded to further questions:
Dr. Meier:
It is possible that there could be inconsistency in the Nansen data. I’m not familiar with their processing. I am confident that our dataset is consistent. However, it may simply be due to the ice conditions. Most of the time, the differences between algorithm should be an offset – though this offset can vary over the course of the year (particularly summer vs. winter). However, there can inconsistencies in this depending on the character of the ice cover.
My suspicion is that much of this is due to the Bering. The ice in the Bering is very broken up and, basically, on its last legs. It could be that our algorithm is more sensitive in picking up the ice than the Nansen algorithm. Or it could be that our algorithm is overly sensitive and is not catching open water.
Remember that the threshold for ice extent is 15%. So if you have low concentration ice, even small differences in the algorithms can result in relatively large differences in extent. If Nansen consistently shows 5% less ice that NSIDC, when there is 90% ice, that makes no difference, but where there is ~15% ice, it can make a difference. From other imagery, it looks like there is a lot of area with concentrations in the ballbpark of 15%.
Me:
If it were due to Bering Strait ice, I would expect to see a convergence between the two data sets as the Bering ice melts. It looks to me like they are actually diverging over the last week or two though?
Any ideas from the readers?
UPDATE: Dr. Meier just responded, minutes after posting this article:
Dr. Meier:
It is the Bering Sea, not the Strait and as it begins to melt, with all the old, broken up, sparse ice, you see the divergence. As it melts out completely, I expect that we’ll see things go back to being more consistent.
Addendum from Anthony:
A question to Dr. Meier: When are we going to see a date/time stamp on the NSIDC imagery? NANSEN has one.
This NSIDC graphic above is one of the most widely displayed and quoted on the net today, yet it lacks this most basic feature found in many scientific images presented for public consumption.
I realize the curve itself is marked against the x axis, but it is not easy to determine an exact date. Science is exacting, it would seem prudent to add a date/time stamp. Otherwise, the appearance of exacting science presented to the public is one of sloppiness, IMHO.
Ok, that’s fine. But the claim is that loss of mass is just another piece of evidence for AGW (which is not my position). If mass/volume decreases, it must be added to the ocean thereby raising water levels and killing everyone on the planet in 5 years!
Bela,
I suggest you read the previous articles on this blog if you’re concerned about Massive Ice Loss.
Here to help you start:
http://wattsupwiththat.com/2009/04/17/the-antarctic-wilkins-ice-shelf-collapse-media-recycles-photos-and-storylines-from-previous-years/
OT:
It would bee nice if the navigation for the articles was sorted with numbers (ex. 1 2 3 … last) instead of “See more entries”
Here’s the code to replace it.
————————-
Also it would be even better if you could add a page with a list of All the articles (just the tittles).
I can help if you want me to.
the code for navigation:
Bela,
The Grace satellites, while a great example of engineering, is showing such small changes in ice balance, that the numbers are within the margin of error (of the measurements themselves and of the adjustments required to account for other normal changes in gravity). When combined with gravity changes due to land subsidence, post-glacial rebound, ocean temperature, soil moisture changes, mantle plumes and plate tectonics, the measurements are not reliable enough.
For example, Grace measurments of Greenland have to be corrected for changes caused by post-glacial rebound in Hudson Bay and in Scandinavia.
And if Antarctica is losing 156 cubic kilometres of ice volume per year, then that should be compared to the 30,000,000 cubic kilometres that is there already.
And I believe there has been some corrections of even these numbers recently showing ice loss on parts of the coastal regions of Antarctica and ice gain in the interior.
http://adsabs.harvard.edu/abs/2008AGUFM.G31A0643Y
ftp://ftp.csr.utexas.edu/pub/ggfc/papers/EPSL_9011.pdf
Good site for ice levels in the Canadian Arctic including the NW Passage.
http://ice-glaces.ec.gc.ca/WsvPageDsp.cfm?ID=1&Lang=eng
And for temps in the Canadian Arctic
http://www.weatheroffice.gc.ca/canada_e.html
Having used “Mayday” in my aviation career,(Usually when something important has just quit working , has fallen off the aircraft or has started smoking when it shouldn’t)
The “Mayday” here is the warmist oh, Zeppelin which has now sprung a leak and is heading into the Arctic icepack…
Bela (03:19:43) : There was not just one speaking of mass loss.
From your link:
For millions of years, Antarctica, the frozen continent at the southern end of the planet, has been encased in a gigantic sheet of ice. Recently, the Gravity Recovery and Climate Experiment (GRACE) satellite has been taking sensitive measurements of the gravity for the entire Earth, including Antarctica. Recent analysis of GRACE data indicate that the Antarctic ice sheet might have lost enough mass to cause the worlds’ oceans to rise about .05 inches, on the average, from between 2002 and 2005.
.05inches X 33.3yrs = 1.665 inches/century.
A tad alarmist, wouldn’t you say. I also wonder about the accuracy of “about .05 inches”.
As the arctic sea ice extent line once again neared the average line, NSIDC has bent the line down, again. Probably just another normal procedure to better represent the current ice trend but still something to spur some of my cynicism.
Oh never mind.
The horse comes before the cart, except when they’re reversing.
Warming comes before CO2, except in the movie.
French imperative verbs come before their object pronouns, except when they’re negative.
If you want to say “Don’t help me!” you can say “Ne m’aidez pas”.
However, if you actually want to be rescued, you should try “Aidez-moi” or “Venez m’aider” or “il faut que vous m’aidez”.
Or, even better; Mayday, Mayday!
Flanagan (04:57:46) :
There is very little multi-year ice in the Barents Sea. The Svalbard and Franz Joseph archipelagoes pretty well blocks the ice from the north. Most of the multi-year ice comes south through the Fram strait. The recent expansion of ice in the Barents sea has occurred through the usual process of the ice there being blown south, which opens up leads south of Svalbard and (especially) Franz Josephs Land which then re-freeze, as is obvious if you have been following the process.
Glenn (23:54:59) :
Got this pic from ICECAP, of a “NASA Observatory” image that seems to show some Arctic ice detail, and compared it to Cryosphere. Anyone see a clear discrepancy?
http://www.examiner.com/x-1586-Baltimore-Weather-Examiner~y2009m4d29-NASAs-Earth-Observatory-10th-anniversary-top-10-images
Look what I found on the 9th photo in that slide show:
“Our Sun experienced fewer spots in 2008 than it had since the 1957 launch of Sputnik. As of March 2009, the Sun was still in its quiet pattern, explaining recent cooling.“
from: http://www.elnino.noaa.gov/lanina_new_faq.html
Contrasting El Niño and La Niña winters, the jet stream over the United States is considerably different. During El Niño the jet stream is oriented from west to east over the northern Gulf of Mexico and northern Florida. Thus this region is most susceptible to severe weather. During La Niña the jet stream extends from the central Rockies east- northeastward to the eastern Great Lakes. Thus severe weather is likely to be further north and west during La Niña than El Niño.
Yeah, it’s the day after Mayday, but yesterday was just as bad…
I’m sitting (as we approach noon) at 50 something degrees with rain showers. In California. I think I know what the albedo change looks like…
For the past 40 years or so I’ve lived in the same area. May is usually warmer and dryer. Yeah, it’s possible to have days like this in April and May and be “normal”. What’s different this time is the duration (IMHO). No, I have no metric for this, but my personal experience base remembers more BBQ and early tomatoes and a lot less “still harvesting kale, and peas with new flowers” along with a lot less “several days in a row of overcast and drizzle”. I’m sitting here thinking “Do I have any dry wood for a fire?” when a typical May has “Where’s the lemonade and turn on the AC”.
So how many anecdotes make a pattern?
Fabius Maximus (08:54:57) : […] compare 1 May to past May firsts, or show a long-term graph of the data. […] With such strong seasonal swings, comparing May first vs. the average tells us little.
What you ought to have said was ‘comparing May first vs. the average of prior May firsts since that is what “the average” in the graph really shows. It shows the average of prior years for each day of the year…
So the fact that this May 1st is the same more or less as the average of all other May firsts (which is what is shown on the May 1st date of the average curve) is very useful. It says that we are absolutely normal for arctic ice.
Flanagan (04:57:46) :
You write: “The problem is that the Barents sea, which makes almost all the difference with previous years, is always completely ice-free in the summer.”
This is somewhat true, but the longer the Barents sea holds ice it does to some degree prevent melting of other ice areas. So, more ice in Barents sea is just more ice.
The area around the Barents sea has been really cold for months, which has obviously contributed to the ice formation.
Pamela Gray (10:33:43) : Loopiness allows mixing and extreme weather pattern variation. Hot here, cold there.
I find it helpful to think of it as a spherical lava lamp. Hot tropical air (powered by a 30 year accumulation of ocean heat) makes blobs headed to the cold pole. Colder than typical polar air makes blobs of cold headed south. A big ‘heat engine’ driven by the differential temperature redistributing the heat from the topical oceans to the polar zones for radiation away.
Don’t know if it’s the correct physics, but I find it a helpful image… 😉
Flanagan (10:55:11) :[…] arctic will come back to its normal extent for a few days in the last 10 years?
skeptic (11:01:56) : Let me see if I’m understanding this correctly.. right now, the sea ice has been well below average for about 95% of the graph, and at normal (giving it the benefit of the doubt) about 5% of the time. […]
A reasonable person would look at all the data and likely conclude
A reasonable person would conclude that if you are at normal you are normal and we are at normal. Or would you conclude that a fever dropping to 98.6 F means you are still at 105?
By contrast, a cherry picker would sieze on the one measurement that supports his viewpoint and write a whole blog post about it
Nah. A cherry picker would calculate the rate of increase from the abnormally low level back to normal and pronounce: “Record Rate Of Sea Ice Creation!!! More ICE Formed (per day) than in YEARS!!!”
If the datum doesn’t support you, perhaps the integral (or derivative) will… that’s the kind of thing the AGW crowd does all the time…
Fabius Maximus (23:11:31) : Comparing the current datapoint vs. a long moving average (e.g., 5 years) would show the trend far better than using a fixed average. […] Which is why technical analysts (using price patterns to predict future prices) use moving averages (or more sophisticated methods, like relative strength or stocastics), not fixed averages.
Yup. Your example would be a “price vs Simple Moving Average” (temp vs moving average of temp) and is my most basic indicator and where I start from on reaching understanding. My second “go to indicator” is the MACD the Moving Average Convergence Divergence that takes two moving averages of different length and compares them (crossovers indicate turning points most of the time). The stochastic responds faster in a trendless market so is good for fast trading flat stocks (would tell you weather better) while the MACD is slower but works best with trending markets (would tell you longer term changes happening in a truly warming or cooling climate and would call inflections in that trend fairly well).
I do think that many of the stock tools could be used to good effect in weather and climate predicting. I explain the ones I use here:
http://chiefio.wordpress.com/2009/03/15/indicators/
“E.M.Smith (13:25:56) :
Pamela Gray (10:33:43) : Loopiness allows mixing and extreme weather pattern variation. Hot here, cold there.
I find it helpful to think of it as a spherical lava lamp. Hot tropical air (powered by a 30 year accumulation of ocean heat) makes blobs headed to the cold pole. Colder than typical polar air makes blobs of cold headed south. A big ‘heat engine’ driven by the differential temperature redistributing the heat from the topical oceans to the polar zones for radiation away.
Don’t know if it’s the correct physics, but I find it a helpful image… ;-)”
Near enough but may I suggest the following:
1) Warming of air by the oceans pushes energy into the air, expanding the equatorial air masses, and the extra energy in the air is then accelerated to space.
2) Cooling of air by the oceans shrinks the equatorial air masses so that larger and more frequent surges of colder drier polar air move towards the equator across larger areas of ocean and pull energy from the oceans to try and balance the energy flow to space with energy from the oceans.
3) The air can push extra energy to space and pull it from the oceans.
4) The air cannot pull energy from space or push it into the oceans.
That says it all really.
As of today the NSIDC graph has either been altered or a decent area melted because not the line has bent downward a tad and it is running parallel to the average line meaning that it will take longer for it to hit average.
Every time it gets too close it mysteriously bends downward a little so that way it will take even longer to reach the average line…I smell something, and it smells like bias.
Garrett (19:18:58) :
As of today the NSIDC graph has either been altered or a decent area melted because not the line has bent downward a tad and it is running parallel to the average line meaning that it will take longer for it to hit average.
Every time it gets too close it mysteriously bends downward a little so that way it will take even longer to reach the average line…I smell something, and it smells like bias.
Not long ago, the line was altered upwards. If you watch it every day for a few months you will be convinced (as I have) that it’s just real data, subject to a simple smoothing algorithm. The previous couple of days were adjusted downwards retroactively, based on the information learned from the latest day. You can quibble that they should just publish a jagged graph with no smoothing but even JAXA’s AMSR-E uses a running 2 day average and it’s a lot more jagged.
If Dr. Meier wants to tell us his smoothing algorithm, I’d be interested but it’s not important. (I’ll bet it has the word “exponential” in it.)
Remember, right now the other arctic sea ice graphs show less recovery than NSIDC’s. If you’re looking for something that smells, go sniff them.
Hey, the AMSR-E graph just curled down too.
http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
This kind of zig-zagging happens a lot. Don’t let your emotions fibrillate with it.
Well, NASA satellite measurements just revealed there are very large parts of deep-arctic zones that are covered with very thin ice layers. This is especially striking if one takes a look at the sea ice concentration rightnow
http://arctic.atmos.uiuc.edu/cryosphere/NEWIMAGES/arctic.seaice.color.000.png
There are some immense patches of low-concentration ice right in the middle of the Arctic basin, which I never observed before at this time of the year. Even the multi-year ice that drifted in the Barents sea is beginning to melt now. Given the wind pattern we had, we might well be heading for a new record.