Got this in the mail just as I posted my open thread announcemnt. I’m too busy this weekend to say much else except to post this tweet from Bill McKibben and some past blog excerpts and invite discussion.
The reflectivity of the Greenland ice sheet has…literally dropped off the bottom of the chart. This means MELT. http://www.meltfactor.org/blog/?p=514
That graph says one thing to me – black carbon soot, especially since lower levels of Greenland, near the oceans and glacial terminae don’t exhibit the same effect:
CO2 doesn’t change ice albedo, but smoke from the industrialization of Asia does, and I think it is a factor. See why below.
It is possibly the same reason for the sea ice decline and the melt pools we’ve been seeing on the surface. Note that this year the melt accelerated quickly once the sun was regularly over the horizon in May…so that an energy dissipation in the ice when soot absorbs solar radiation.
Recall this experiment with soot on snow done by meteorologist Michael Smith of WeatherData where soot made a huge difference.
I also covered the issue in:
Greenland Ground Zero for Global Soot Warming
They say a picture is worth a thousand words, this moulin in Greenland a real eye opener:
He writes:
In the winter a huge among of snow are accumulated on the Ice (2-3 meters, sometimes more) and we are not talking about 1 or 2 square-miles, it’s about 100.000′s of square miles (up to 1 million) on the Westside of the Ice cap and a similar picture on the Eastside… when the melting season starts in april-sep… the meltwater has to go somewhere, and for sure it goes downhill in huge meltwater rivers.
The black stuff on the bottom of the lakes is carbon dust and pollution in general… but not from one year, but several decades (the topographical conditions don’t change from year to year). On a flight over the Ice Cap a sky clear day, you can see hundreds of huge lakes with the black spot on the bottom.
– Anthony
The website of Jason E. Box, Ph.D. meltfactor.org has more graphs and says:
Latest Greenland ice sheet reflectivity
These albedo visualizations are discussed here and here.
About the Data
Surface albedo retrievals from the NASA Terra platform MODIS sensor MOD10A1 product beginning 5 March 2000 are available from the National Snow and Ice Data Center (NSIDC) (Hall et al., 2011). The daily MOD10A1 product is chosen instead of the MODIS MOD43 or MCD43 8-day products to increase temporal resolution. Release version 005 data are compiled over Greenland spanning March 2000 to October 2011. Surface albedo is calculated using the first seven visible and near-infrared MODIS bands (Klein and Stroeve, 2002; Klein and Barnett, 2003). The MOD10A1 product contains snow extent, snow albedo, fractional snow cover, and quality assessment data at 500m resolution, gridded in a sinusoidal map projection. The data are interpolated to a 5 km Equal Area Scalable Earth (EASE) grid using the NSIDC regrid utility April and after September, there are few valid data, especially in Northern Greenland because of the extremely low solar incidence angles. The accuracy of retrieving albedo from satellite or ground-based instruments declines as the solar zenith angle (SZA) increases, especially beyond 75 degrees, resulting in many instances of albedo values that exceed the expected maximum clear sky snow albedo of 0.84 measured byKonzelmann and Ohmura (1995). Here, we limit problematic data by focusing on the June–August period when SZA is minimal.
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As ice accumulates on the ice cap black carbon is embedded in the ice, when a short period of net surface melt occurs the BC accumulates on the surface reducing the albedo and setting up a positive (melting) feedback.
Its no surprise this is happening on the Greenland ice cap, because this what has happened to Arctic sea ice over the last couple of decades.
New BC deposition may play a role, but its primarily embedded BC that produces this effect.
Note in the graph above that the drop in albedo this year starts in May and is clearly a solar insolation effect. I don’t have temperature data for Greenland to hand, but given the more southerly track of the Atlantic low pressure systems this year, Greenland will have had a colder (but sunnier) summer than normal.
North America and Europe cleaned up their “soot” and other particulates a few decades ago. This is definitely Asia’s contribution. The idiocy of chasing after CO2 when it is virtually all the other emissions that are the worry. If Asia let the West build their coal-fired plants, this would not be happening and yet, it is the West that is being villified by the (mainly Western) climate CO2 boffiins.
I could see Asia’a industrialization increasing Greenland’s ice melt significantly over a period of years.
But just from 2011 to 2012!?
So, no surprise, what needs to be reduced is real, old-fashioned, Dickensian dark Satanic mill-style pollution in the form of carbon soot & other particulates, not CO2, the new-fangled, supposedly deadly, poisonous pollutant that is actually healthy, naturally-occurring plant food.
What’s most telling would seem to be that there DOES seem to be some trend downward in midsummer from year to year (with a few exceptions — e.g. 2006 was on the higher side in June/July). It’s hard to tell from eyeballing the graph though.
The soot thing doesn’t seem to make complete sense to me however in terms of what I’m assuming are the elevation numbers (500m to 2,500m) Wouldn’t even fine soot tend to disproportionately settle out at lower altitudes and therefore increased levels of fine soot in the atmosphere have MORE of an effect on albedo and ice-melting at 500-1000 than at 2000-2500?
Or am I completely misunderstanding/inverting things? I have NO expertise in climatological stuff beyond the sort of things I’ve picked up from the general news and from the impressive postings here at WUWT.
– MJM
What may be a factor is the huge forest fires in Russia. The west coast of Canada was choking on smoke from over there a few weeks ago. With the way the winds blow up through the Arctic all that soot from the fires could have made it to Greenland.
Hmm….. when I see a graph like that I immediately think instrument failure. Or perhaps some sort of interference. It doesn’t make any sense to have albedo 500-1000m but zero at 2000-2500m. If I cared enough I would probably go check that angle, but I don’t. But, before we start pronouncing that soot from Asia just did something this year never done before, someone should check to make sure the needle isn’t stuck.
Some of the neighboring blog pages have good background data, see http://www.meltfactor.org/blog/?p=453 and http://www.meltfactor.org/blog/?p=476
One interesting effect is when the previous winter’s snow melts, exposing the old dark surface. And probably messing up future ice core records. 🙂
Well, okay curiosity got me. Now I’m even more skeptical of the measurements….. we have albedo at 500-1000m, but none at 2000-2500m, but then magically we have some at 2500-3200m.
http://polarmet35.mps.ohio-state.edu/albedo/2500-3200m_Greenland_Ice_Sheet_Reflectivity_Byrd_Polar_Research_Center.png
I don’t know enough about what exactly they are measuring, but that’s bunk. Light doesn’t work that way. It’s just another thing to get hysterical about and a method to ignore the fact that our temps haven’t risen in 15 years.
Hm, well, sure would be nice to see a record of Greenland’s Albedo going back about a hundred years, rather than a paltry decade or so. Last time I checked that wasn’t long enough to detect climate trends, right?
Why is it, that when we learn a new fact about our world, that we have the hubris to assume we caused it.
When the data, points in a different direction.
(excluding the profit motive).
u.k.(us) says:
July 21, 2012 at 6:37 pm
Why is it, that when we learn a new fact about our world, that we have the hubris to assume we caused it.
—————
It would be pretty easy to determine if the soot is of human origin.
James Sexton says:
July 21, 2012 at 6:01 pm
Equipment failure was my first thought too, and had started to write a comment about that. Then I figured I should check where the data came from, and found it was MODIS. I figured it would be unlikely to fail just over Greenland, so then I read those other blog pages and saw the comments about a season’s snow melting and that made a lot of sense.
Also, it’s not zero at 2000-2500m, the bottom of that graph is 72%, and the 500-1000m graph goes down to 40%. The graphs don’t have a double slash mark to note that. Please gnash your teeth now.
I wonder if the way they measure albedo is compatible with what matters. Even though the sun is “up” in the arctic, it’s at a low angle. I see that much of that black bottomed “lake” in the picture is actually in the shade. If many of the lakes are narrow and surrounded by steep sides, they may not look as “black” from the sun’s angle as they do from straight overhead.
So we have 12 years of data, and it all, more or less, follows a pattern. Question is: How long has this pattern been going on?
The puddle in the icecap has a dark bottom. Is it carbon, or might it be something else. Real scientists go up on the icecap and find out, instead of theorizing. Theories are like belly buttons – Everybody has one.
We see black streaks in the sides of the puddle. Is this from petroleum carbon, forest fire carbon, volcanic ash, coal ash, or maybe something that we haven’t thought of?
I have news for budding snow experts. Snow, when exposed to sunlight over a period of time, changes from flakes to little balls. In the mountains these little balls promote avalanches. On the Greenland icecap they probably change the albedo.
This “study” settles nothing. It does provoke some interesting questions, however.
http://bprc.osu.edu/wiki/Greenland_Ice_Albedo_Monitoring
Perhaps most remarkable about the 2012 pattern is how much darker the snow is becoming in the higher elevations net snow accumulation area. June monthly average reflectivity is below the 2000-2011 average across the southern-central area where surface elevations are above 2,000 m (6,561 feet). A purple area about 1/4 the distance north of the ice sheet southern tip at an elevation of 2,400 m (7,874 ft) has reflectivity 0.07 or 7% below the already declining 2000-2011 June (12 year) average.
The cause of the low reflectivity involves a combination of factors:
Abnormally intense melt at low elevations erases bright white snow, exposing a darker impurity rich bare ice surface. When the melt back of winter snow happens earlier, the anomaly grows.
in areas where snow remains, temperature-driven snow metamorphism reduces reflectivity by rounding the sharp ice crystal edges that scatter visible light (Wiscombe and Warren, 1980; Dozier et al., 2009; Warren, 1982). This NOAA climate watch article includes a very useful photo. Fresh snow reflects ~84% of solar energy (Konzelmann and Ohmura, 1995).
This fraction, called the albedo, decreases with increasing snow effective grain size;
Increased snow liquid water content in areas of enhanced melting increases absorption of visible light; and potentially less summer snowfall as in year 2011. Summertime snow events take the edge off the amplifying feedback by brightening the surface. With climate warming, the ratio of snowfall to rainfall decreases. It actually does rain on the lower elevations of the ice sheet. I measured 5 cm rainfall in a single 24 h period in June 1998 at Swiss Camp located at 1,150 m elevation along the central western slope of the ice sheet.
atmospheric circulation anomalies that deliver heat by advection to southwest Greenland.
The possibility of increased snow impurities like carbonaceous soot from wildfires or diesel exhaust can lower ice sheet reflectivity.
The pattern of concentrated low reflectivity around the ice sheet periphery indicates the earlier loss of winter snow in the ablation area of the ice sheet where bare ice is exposed each year (Tedesco et al. 2011) sometime during the melt season. That exposure is just happening earlier in the year. The pattern over the far northwestern ice sheet, over the Humboldt glacier is a strong suggestion of increased melting.
Cross validation Degrading MODIS instrument sensitivity identified by Wang et al. (2012) introduces the possibility that the declining albedo trends may be erroneous. To validate the MODIS albedo trends, coinciding observations from GC-Net AWS are examined. The ground truth data are situated across a range of elevations, spanning the ablation and accumulation areas. Analysis of the GC-Net data confirm declining albedo trends in the 2000–2010 period to be widespread in individual months from May–September. Trend statistics are computed where at least 7 yr of annual data are available from both GC-Net and MODIS Terra. Significance is designated here more strictly where the trend measured by the linear regression slope has a magnitude that exceeds two standard deviations of the residuals from the regression. In 41 of 43 (95 %) of monthly cases May–September, the trend is found to be significant and decreasing. In 10 of 14 (71 %) cases for which both GC-Net and MOD10A1 trends are significant, the GC-Net trend declining trend is larger than the MOD10A1 trend. It therefore does not seem that MODIS sensor degradation is enhancing an existing trend.
It seems improbable that degradation of the GC-Net photoelectric diode pyranometers are producing an erroneous declining albedo trend. If both upward and downward facing sensors degrade at the same rate, the albedo would not change in time due to progressive sensor bias. An erroneous declining trend would require that the downward facing pyranometer degrade faster than the upward facing pyranometer. If the degradation is increased by exposure to sunlight as it is with optical black lacquer pyranometers, then the upward pyranometer would be expected degrade faster, introducing an erroneous increasing albedo trend. We observe the opposite. The largest magnitude declining albedo trends are evident at the sites located in the ablation zone such as JAR1 and Swiss Camp. The more southerly yet relatively high elevation sites of Saddle and South Dome where melting is uncommon in passive microwave observations (e.g., Mote, 2007; Tedesco, 2007), declining albedo trends are observed consistently in individual months.
re: “Hmm….. when I see a graph like that I immediately think instrument failure. Or perhaps some sort of interference.”
Exactly what I thought. It could be due to melt, or soot, or something else, but you better be checking the data when you get an anomaly like that.
Somewhere on the intertubes you can find descriptions of the validation experiments for Modis.
Ran across it a while back when I was downloading albedo data.. too busy to look for it so, somebody else will have to find it.
I admit I can’t measure Greenland’s albedo from my couch with the instruments I’ve got, but I wonder how many of you ladies and gents fly over on a regular basis. I have not been there for about five years, but before then I did fly over Greenland every summer, and I noticed that some of the melt lakes did have dark bottoms, some did not (I attributed that to different depths), and water in them clearly varied in colour (possibly different mineral content; possibly inoculated with different bacteria).
There are not a whole lot of images on google, but those that show on top here pretty much represent the spectrum I recall seeing: http://goo.gl/LunQO
I’d say, if there was a significant amount of soot from Asia or any distant place, it would not discriminate between two adjacent melt lakes. My question to the recent travellers: how many of them appear as shown in the picture above this summer?
Also, note that Greenland is a huge source of its own pollution. This is not soot:
http://www.flickr.com/photos/rlcarney/2416512771/
I’ll bet there is orders of magnitude more of that stuff blown over and deposited on the ice cap than there is soot from China.
It has always been my contention that soot is the problem with Arctic melting. How can melt take place in a place whose average temperature is below freezing? By insolation. You can SEE the soot. And you can see it in the northwest of North America, especially in wintertime when fohn (chinook) winds cause atmospheric stratification (OK, I don’t know exactly why the atmosphere is stratified, but…). The particulate pollution can be seen as a brown smudge on the horizon with the low winter sun angle. It is certainly incongruous with the wilderness northwest of Canada. I used to see these smudges develop day by day while sitting wells in NE British Columbia for days at a stretch. One looks out the same window for days on end, and cannot help but see the smudge, more congruous with an urban setting, as it drifts across the sky. The only logical source for such a smudge is NE Asia….China’s brown coal plants with no scrubbers or controls.
Yup. This hearkens back to the ‘real’ environmental movement of the sixties, which catalyzed the cleanup of particulate pollution in North America and [western] Europe. But, while the world’s attention began to somnambulate into the quack science of CO2 emissions, the developing world and the former Soviet Bloc continued on their merry way, belching particulates. Now the particulates are here and doing their able best to melt the ice up north. What’s worse, there may be an accumulation in multi-year firn on the icecaps, making for a succession of darkened firn layers, which when melted will distribute and concentrate the albedo-crashing blackness.
Now to compare carbon soot accumulation with Antarctica…which may so far be escaping the onslaught. Keep weeping, Billy. It will permit the REAL polluters from getting the scrutiny they need.
Source Attribution of Black Carbon in Arctic Snow Environ. Sci. Technol. 2009, 43, 4016–4021 attributes most of the black carbon deposited in the Arctic to biomass burning in Russia and North America, however, this is an area of ongoing research. FWIW South and Southeast Asian industrial and biomass burning have pretty damn far to go in order to reach Greenland and almost certainly settle out before reaching there, although they have had an effect on the glaciers on the Tibetan Plateau. North China industrial emissions are hard to tear apart from the Russian ones, and there are indications that they may in part be transported to the area around Barrow..
Steven Mosher says:
July 21, 2012 at 8:00 pm
That should read “reflectivity anomaly 0.07 or 7% below the already declining 2000-2011″. Without the anomaly map and other hints, I read this as reflectivity of 0.07, which is really dark. The average reflectivity of a photographed scene is 0.19 or so, so 0.07 would be remarkably low.
The other possibility is that the black part is actually just a very large step change in depth
Has anyone checked?
I mean, we seem to assuminng that the black is because of something black, rather than just a lack of reflected light of the bottom.