From the University of Colorado at Boulder
Warming North Atlantic water tied to heating Arctic, according to new study
The temperatures of North Atlantic Ocean water flowing north into the Arctic Ocean adjacent to Greenland — the warmest water in at least 2,000 years — are likely related to the amplification of global warming in the Arctic, says a new international study involving the University of Colorado Boulder.
Led by Robert Spielhagen of the Academy of Sciences, Humanities and Literature in Mainz, Germany, the study showed that water from the Fram Strait that runs between Greenland and Svalbard — an archipelago constituting the northernmost part of Norway — has warmed roughly 3.5 degrees Fahrenheit in the past century. The Fram Strait water temperatures today are about 2.5 degrees F warmer than during the Medieval Warm Period, which heated the North Atlantic from roughly 900 to 1300 and affected the climate in Northern Europe and northern North America.
The team believes that the rapid warming of the Arctic and recent decrease in Arctic sea ice extent are tied to the enhanced heat transfer from the North Atlantic Ocean, said Spielhagen. According to CU-Boulder’s National Snow and Ice Data Center, the total loss of Arctic sea ice extent from 1979 to 2009 was an area larger than the state of Alaska, and some scientists there believe the Arctic will become ice-free during the summers within the next several decades.
“Such a warming of the Atlantic water in the Fram Strait is significantly different from all climate variations in the last 2,000 years,” said Spielhagen, also of the Leibniz Institute of Marine Sciences in Keil, Germany.
According to study co-author Thomas Marchitto, a fellow at CU-Boulder’s Institute of Arctic and Alpine Research, the new observations are crucial for putting the current warming trend of the North Atlantic in the proper context.
“We know that the Arctic is the most sensitive region on the Earth when it comes to warming, but there has been some question about how unusual the current Arctic warming is compared to the natural variability of the last thousand years,” said Marchitto, also an associate professor in CU-Boulder’s geological sciences department. “We found that modern Fram Strait water temperatures are well outside the natural bounds.”
A paper on the study will be published in the Jan. 28 issue of Science. The study was supported by the German Research Foundation; the Academy of Sciences, Humanities and Literature in Mainz, Germany; and the Norwegian Research Council.
Other study co-authors included Kirstin Werner and Evguenia Kandiano of the Leibniz Institute of Marine Sciences, Steffen Sorensen, Katarzyna Zamelczyk, Katrine Husum and Morten Hald from the University of Tromso in Norway and Gereon Budeus of the Alfred Wegener Institute of Polar and Marine Research in Bremerhaven, Germany.
Since continuous meteorological and oceanographic data for the Fram Strait reach back only 150 years, the team drilled ocean sediment cores dating back 2,000 years to determine past water temperatures. The researchers used microscopic, shelled protozoan organisms called foraminifera — which prefer specific water temperatures at depths of roughly 150 to 650 feet — as tiny thermometers.
In addition, the team used a second, independent method that involved analyzing the chemical composition of the foraminifera shells to reconstruct past water temperatures in the Fram Strait, said Marchitto.
The Fram Strait branch of the North Atlantic Current is the major carrier of oceanic heat to the Arctic Ocean. In the eastern part of the strait, relatively warm and salty water enters the Arctic. Fed by the Gulf Stream Current, the North Atlantic Current provides ice-free conditions adjacent to Svalbard even in winter, said Marchitto.
“Cold seawater is critical for the formation of sea ice, which helps to cool the planet by reflecting sunlight back to space,” said Marchitto. “Sea ice also allows Arctic air temperatures to be very cold by forming an insulating blanket over the ocean. Warmer waters could lead to major sea ice loss and drastic changes for the Arctic.”
The rate of Arctic sea ice decline appears to be accelerating due to positive feedbacks between the ice, the Arctic Ocean and the atmosphere, Marchitto said. As Arctic temperatures rise, summer ice cover declines, more solar heat is absorbed by the ocean and additional ice melts. Warmer water may delay freezing in the fall, leading to thinner ice cover in winter and spring, making the sea ice more vulnerable to melting during the next summer.
Air temperatures in Greenland have risen roughly 7 degrees F in the past several decades, thought to be due primarily to an increase in Earth’s greenhouse gases, according to CU-Boulder scientists.
“We must assume that the accelerated decrease of the Arctic sea ice cover and the warming of the ocean and atmosphere of the Arctic measured in recent decades are in part related to an increased heat transfer from the Atlantic,” said Spielhagen.
###
===============================================================
This statement prompts some things I’d point out that temper it:
“Air temperatures in Greenland have risen roughly 7 degrees F in the past several decades”.
In those remote locations like Nuuk, Greenland, what have we there? Remote pockets of humanity. Humanity building little cities of warmth in the cold Arctic, growing cities:
With 15,469 inhabitants as of 2010, Nuuk is the fastest-growing town in Greenland, with migrants from the smaller towns and settlements reinforcing the trend. Together with Tasiilaq, it is the only town in the Sermersooq municipality exhibiting stable growth patterns over the last two decades. The population increased by over a quarter relative to the 1990 levels, and by nearly 16 percent relative to the 2000 levels.
Nuuk population growth dynamics in the last two decades. Source: Statistics Greenland
Nuuk is not only a growing city, where UHI might now be a factor (but don’t take my word for it, see what NASA had to say about it at AGU this year), it is also a place where the official GHCN thermometers used by NASA are right next to human influences…like turboprop jet exhaust, such as this one in Nuuk’s airport right on the tarmac:
Nuuk Airport looking Southwest Image: Panaramio via Google Earth
Nuuk Airport, Stevenson Screen. Image from Webshots – click to enlarge
Hmmm, I wonder what happened in Nuuk? The plot below is from NASA GISS (see it yourself here). That “instant global warming” line seems out of character for natural variation in Nuuk. Note the data discontinuity. Often that suggests a station move and/or a change in station environment.
Sometimes a line like that with indicates airport construction near the thermometer, something I documented here.
And here’s the interesting thing. Nuuk is just one data point, one “raging red” anomaly in the sparsely spaced hands-on-human-measured NASA GISS surface temperature dataset for the Arctic. The patterns of warm pockets of humanity with airports and GHCN stations repeat themselves all over the Arctic, because as anyone who has visited the Arctic knows, aviation is the lifeline of these remote communities. And where do they measure the weather data? At the airport of course. Aviation doesn’t work otherwise.
See my complete report on the weird temperatures from Nuuk here. And while you are at it, read my report about the weird temperatures from Svalbaard, another warm single data point from NASA GISS. Interestingly, at that station a local citizen did some science and proved the UHI effect at the airport.
Yes these are just two examples. But there is no denying these facts:
- Remote communities in the Arctic are islands of anthropogenic warmth
- These communities rely of aviation as a lifeline
- The weather is measured at these airports, it is required for safety
- Airports release huge amounts of waste heat, from exhaust, de-icing, terminal buildings, and even tarmac in the sun.
- The majority of GHCN weather stations (used by NASA GISS) in the Arctic are at airports.
Remember Nuuk and Svalbarrd’s thermometers, and then ask Jim Hansen why NASA GISS, a “space studies agency”, doesn’t use satellite data but instead relies upon a surface record that another division of NASA says likely has significant UHI effects that NASA GISS doesn’t filter out sensibly (they only allow for 0.05°C downward adjustment).
And finally, can you really trust data from an organization that takes incoming data for that station and shifts it more than an entire degree C in the past, making a new trend? See the difference between “raw” (which really isn’t raw, it has a scads of adjustments already from NOAA) compared to the GISS final output in this chart:
The data is downloaded from GISS for the station, datasets 1 and 2 were used (raw-combined for this location and homogenized) which are available from the station selector via a link to data below the charts they make on the GISS website. The data is plotted up to the data continuity break, and again after. The trend lines are plotted to the data continuity break, and there’s no trend in the raw data for the last 100+ years.
The curious thing is that there’s no trend in the raw data at Nuuk until you do either (or both) of two things:
1. You use GISS homogenized data to plot the trend
2. You use the data after the discontinuity to plot the trend
I believe the data discontinuity represents a station move, one that exposed it to a warmer local environment. And clearly, by examining the GISS data for Nuuk, you can see that GISS adds adjustments that are not part of the measured reality. What justification could there possibly be to adjust the temperatures of the past downwards? What justification in a growing community (as shown by the population curve) could there be for doing an adjustment that is reverse of waste energy UHI?
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I am always slightly surprised when climate scientists use the Medieval Warm Period as a fashion accessory for their papers – just pop it in, or out, as required.
I am surprised, too, that the wee shelfish are such accurate thermometers, with the handy ability to station themselves at very specfic depths while they live – do these creatures drop vertically to the sea floor when they die, regardless of ocean currents, and cling to the spot where they landed after death, defying those same currents and the vagaries of tides and weather for centuries?
Wait! is my Sceptometer attempting to alert me to something? Nah, it’s just the shelfish I ate too many of for dinner last night…
re: Sorry but you are wrong about the reflectivity of water versus angle. The reflectivity increases to 50% at a glancing angle of 5 degrees. The tilt angle of the earth is 23 degrees, so during the summer time even open water at the pole
will absorb. On top of this, the ocean is not totally flat. At small angles of incident light, waviness results in reduced reflectivity because of the steepness of the reflectivity-vs.-incident-angle curve and a locally increased average incident angle. Therefore absorption will be larger in wavy water than in flat still water.
I read a published, peer reviewed study about a year ago that clearly outlines why loss of polar sea ice is a net negative feedback. I have to take their word over yours.
Being an amateur not reading all comments , so i could repeat a staement which is already in the pipeline , i would like to draw your attention to the unysis sst anomaly map showing a clear warming locally in the fram strait , not in the midatlantic part of the gulfstream , but solely in the fram strait itself and in northern open water leading to the icecap between canada and greenland . From my simple-minded point of view there is one logic explanation for this fact : A heating of the ocean-floor by volcanism .
Has there been a survey of the oceanfloor in this area in the recent years ? And has this phenomenon in the arctic been investigated in the recent years ? Throwing around grand theories is a nice occupation when you have nothing to do otherwise , but would not it be better to stay silent until all facts are above the table ? Mother nature may have lots of pleasant surprises for us as long as we do not know all the facts . Incomplete science could even be worse than incomplete accounting .
This is an interesting summary of data from 3 Greenland stations:
http://www.meltfactor.org/blog/?p=294#comments
Dr. Box appears to specialize in this particular area.
Notice the lngterm trend is more modest than 7 degrees F in the last few decades.
There is also a statement that the temperature reading at Prins Christian Sund is not at an airport. Does anyone know where the reading is actually taken? Also given the number of cruises to this area, I am not sure that the above statement that there has been no change in the local population is actually true.
The researchers used microscopic, shelled protozoan organisms called foraminifera — which prefer specific water temperatures at depths of roughly 150 to 650 feet — as tiny thermometers.
In addition, the team used a second, independent method that involved analyzing the chemical composition of the foraminifera shells
——————————–
Is anyone else concerned about this definition of “independent”? Using foraminifera to infer temperature in two different ways would seem to require some common assumptions, e.g. that specific foraminifera map to a time period. Thus how can it said to be an “independent method”?
Mycroft says:
January 28, 2011 at 4:00 am
Whats the betting Trenberth try’s to jump on this study for his “missing heat”!
Yep. They must have found it./sarc off
Peter Plail says:
January 28, 2011 at 2:37 am
“eadler says:
January 27, 2011 at 8:42 pm
But if the water is choppy only part of the total area of open sea is absorbing. For every ripple or wave there is a reverse side which is absorbing less sunlight.
Add to that the fact that choppy water is usually caused by wind, which will probably add cooling due to evaporation.
Add to that the possibility that not every day in the Arctic is sunny and I would guess that windy days are more likely to be associated with cloud cover.
This calculation is far more complex than consideration of just albedo and incident light angles.
And to add another factor. 15% ice cover, which is the common measure of ice extent, is affected strongly by prevailing winds and tides. A quick peep at our host’s sea ice pages shows Ric Werme’s side-by-side comparison of ice concentrations for Jan 2007 and Jan 2011 (about halfway down the page). My unscientific eyes can determine that this year’s ice is considerably more concentrated than 4 years ago, suggesting that the low extent this year does not mean less ice just tighter packing. And don’t forget that 2007 was a record low, so I would say the the ice this years is looking a lot less vulnerable than previous years (I was going to say looks a lot more healthy, but I’m not sure that the impending cold swing is exactly good news).”
The state of the ice in the Arctic in January is totally irrelevant to whether the Arctic Ocean is absorbing sunlight in the summer months. What is relevant is the ice coverage in the summer time. If you look at summer extent, or area the story is the same. There is a downward trend which has intensified in the 21’st century.
Lets wait for the report. I am interested to see whether they use the the foraminifera over the last 150 years and show it consistent with the observation data (and which observation data; looks a bit rocky with their claims for increases in Greenland temperatures).
Also, how well recognised and accepted are these two methods of historical measurement?
Ken Lydell says:
January 27, 2011 at 7:12 pm
I have had more than a snootful of knee-jerk anything when it comes to climate science. I am sick of it whether it comes from the skeptical corner of the ring or from the warmist corner.
________________________
My, that’s quite a chip on your shoulder. You may want to consult your physician to have it removed.
KD
“”””” eadler says:
January 27, 2011 at 8:42 pm
Mark Wagner says:
January 27, 2011 at 7:12 pm
“The point is that sea ice represents a part of the total albedo of the earth, and as such, when the Global Sea ice is at or near a record minimum, the extra sunlight that is not being reflected is being asborbed into the ocean.
There you go again. There IS no “extra sunlight not being reflected” at that latitude. Even in polar summer, the sun is low to the horizon and weak, and what little sunlight there is reflects off the water at low angles. (Ever see how much light is reflected off the ocean at sundown? That’s the MAX angle you get even in polar summer.) Meanwhile, the now un-insulated water makes a fine radiator of ocean heat to space. Especially during dark (or “evening”) hours and polar winter.
The poles aren’t a cold sink. They’re a radiator.”
Sorry but you are wrong about the reflectivity of water versus angle. The reflectivity increases to 50% at a glancing angle of 5 degrees. “””””
Well actually, the very reference you cite (wiki) shows more like 60% reflectivity at 5 deg off grazing incidence (85 deg incidence angle). It gives 505 for the p polarisation and 70% for the s polarisation, and others have pointed out the water ripples are a red herring, because the other side of the ripple gives a compensation.
There’s one little (fine tuning) adjustment that you need to make to your observations. For the sunlight incident at 85 deg incidence angle; where the reflectance averages about 60%, the incident solar irradiance is only cosine(85) times the surface level insolation; which is 8.7% of the insoaltion at the zenith sun location. So you only have 60% of 8.7%, which is about 5.2%.
Oh I almost forgot; for direct overhead sun, you have an Air Mass One situation, with just once times the atmospheric thickness of atmosphere to penetrate. For other incidence angles the air mass increases as 1/cos(incidence angle) and for 85 deg incidence angle that is 1/0.087, which is about 11.5.
So your five degree off grazing incidence sunlight came through 11.5 times the atmospheric air thickness, which filtered out virtually all of the high eenrgy part of the solar spectrum so the reflected emittance is about 5.2% of the AM-11.5 solar irradiance, and only the farred and infrared part of that which is no more than 45% of the total solar spectrum energy.
So 45% of 5.2% is 2.34% of the incident sunlight tops.
No matter how you slice it; there simply isn’t very much sunlight in the polar regions to reflect; even at 60% reflectance. This cronic lack of sunlight has a remarkable effect on the local weather and climate; it gets bloody cold as a result of this lack of incoming energy; and even less outgoing.
And for good measure, even though that AM-11.5 attenuated sunlight is also spread over 11.5 times the surface area, ALL of that surface area is continuously radiating in the LWIR region but at a reduced Temperature of about 270K (-3 deg C) rather than 288 K, so the total emittance is about 301 W/m^2, instead of the 390 you get at 288 K.
So the whole surface radiates at the full local temperature rate; but the incoming sunlight from a highly attenuated and very small area is spread over that enlarged oblique surface.
The solart spectrum albedo reflected polar sunlight is peanuts compared to the LWIR emittance from the open water; which as I said is why there is all that ice there in the first place.
Is it true that the name of that place is pronounced “New-ark”. We have a Nuuk here in the USA, which is every bit as dismal as Svend’s place up there in Greenlandia.
“And here’s the interesting thing. Nuuk is just one data point, one “raging red” anomaly in the sparsely spaced hands-on-human-measured NASA GISS surface temperature dataset for the Arctic. ”
Am I looking at the same picture? There are dark red points all across Siberia, northern Canada, Alaska, etc. And wouldn’t the urban heat island effect be even more pronounced in countries that have developed larger cities over the years like the USA, coastal Brazil, southeast Asia, for example? Why would the Arctic areas be darker than more developed areas if this was truly a consistent problem with the land-based temperature data? Or is it not a consistent problem?
Some of the arguments seem to grasping at straws, but the point made concerning the Nuuk “instant warming” graphic may be a valid one. Maybe the surface stations project should do a global averaging calculation with all the suspected bad surface temperature stations removed? Has that been done? If so, what were the results?
Mark Wagner says:
January 28, 2011 at 6:02 am
“re: Sorry but you are wrong about the reflectivity of water versus angle. The reflectivity increases to 50% at a glancing angle of 5 degrees. The tilt angle of the earth is 23 degrees, so during the summer time even open water at the pole
will absorb. On top of this, the ocean is not totally flat. At small angles of incident light, waviness results in reduced reflectivity because of the steepness of the reflectivity-vs.-incident-angle curve and a locally increased average incident angle. Therefore absorption will be larger in wavy water than in flat still water.
I read a published, peer reviewed study about a year ago that clearly outlines why loss of polar sea ice is a net negative feedback. I have to take their word over yours.”
My post was about reflectivity of the open ocean relative to ice. I showed you a graph of the reflectivity of water versus angle and pointed out the earth’s axis is tilted at about 23 degrees. Does the peer reviewed study you read a year ago deny this?
Do you have a link to that peer reviewed study? Are you sure you have this right? Why should the one peer reviewed study, you read a year ago, be taken as gospel, since the positive feedback for global warming of the polar ice cap is accepted by almost all scientists who study climate. Here is one study which indicates a direct effect of exposed Arctic Ocean on the air temperature above it.
http://www.sciencedaily.com/releases/2010/04/100428142324.htm
Using the latest observational data from the European Centre for Medium-Range Weather Forecasting, Dr Screen was able to uncover a distinctive pattern of warming, highly consistent with the loss of sea ice.
“In the study, we investigated at what level in the atmosphere the warming was occurring. What stood out was how highly concentrated the warming was in the lower atmosphere than anywhere else. I was then able to make the link between the warming pattern and the melting of the sea ice.”
George E. Smith says:
January 28, 2011 at 11:39 am
““”””” eadler says:
January 27, 2011 at 8:42 pm
Mark Wagner says:
January 27, 2011 at 7:12 pm
“The point is that sea ice represents a part of the total albedo of the earth, and as such, when the Global Sea ice is at or near a record minimum, the extra sunlight that is not being reflected is being asborbed into the ocean.
There you go again. There IS no “extra sunlight not being reflected” at that latitude. Even in polar summer, the sun is low to the horizon and weak, and what little sunlight there is reflects off the water at low angles. (Ever see how much light is reflected off the ocean at sundown? That’s the MAX angle you get even in polar summer.) Meanwhile, the now un-insulated water makes a fine radiator of ocean heat to space. Especially during dark (or “evening”) hours and polar winter.
The poles aren’t a cold sink. They’re a radiator.”
Sorry but you are wrong about the reflectivity of water versus angle. The reflectivity increases to 50% at a glancing angle of 5 degrees. “””””
Well actually, the very reference you cite (wiki) shows more like 60% reflectivity at 5 deg off grazing incidence (85 deg incidence angle). It gives 505 for the p polarisation and 70% for the s polarisation, and others have pointed out the water ripples are a red herring, because the other side of the ripple gives a compensation.
There’s one little (fine tuning) adjustment that you need to make to your observations. For the sunlight incident at 85 deg incidence angle; where the reflectance averages about 60%, the incident solar irradiance is only cosine(85) times the surface level insolation; which is 8.7% of the insoaltion at the zenith sun location. So you only have 60% of 8.7%, which is about 5.2%.
Oh I almost forgot; for direct overhead sun, you have an Air Mass One situation, with just once times the atmospheric thickness of atmosphere to penetrate. For other incidence angles the air mass increases as 1/cos(incidence angle) and for 85 deg incidence angle that is 1/0.087, which is about 11.5.
So your five degree off grazing incidence sunlight came through 11.5 times the atmospheric air thickness, which filtered out virtually all of the high eenrgy part of the solar spectrum so the reflected emittance is about 5.2% of the AM-11.5 solar irradiance, and only the farred and infrared part of that which is no more than 45% of the total solar spectrum energy.
So 45% of 5.2% is 2.34% of the incident sunlight tops.
No matter how you slice it; there simply isn’t very much sunlight in the polar regions to reflect; even at 60% reflectance. This cronic lack of sunlight has a remarkable effect on the local weather and climate; it gets bloody cold as a result of this lack of incoming energy; and even less outgoing.
And for good measure, even though that AM-11.5 attenuated sunlight is also spread over 11.5 times the surface area, ALL of that surface area is continuously radiating in the LWIR region but at a reduced Temperature of about 270K (-3 deg C) rather than 288 K, so the total emittance is about 301 W/m^2, instead of the 390 you get at 288 K.
So the whole surface radiates at the full local temperature rate; but the incoming sunlight from a highly attenuated and very small area is spread over that enlarged oblique surface.
The solart spectrum albedo reflected polar sunlight is peanuts compared to the LWIR emittance from the open water; which as I said is why there is all that ice there in the first place.”
In the Arctic summer the angle is not as shallow as you would have people believe. The 23 degree angle of tilt of the earth’s axis, plus the fact that the Arctic is defined as north of 63Deg, makes the range of effective range of angles of the sun in the Arctic summer region as 0 to 50 degrees. The lower the latitude the larger the area affected.
There is a lot of peer reviewed literature which says that the decrease in area covered by sea ice is a positive feedback. The authors can’t all be incompetent as you imply.
The sad thing is that this question could be answered very easily if the folks doing the world average temperature calculations were actually interested in the truth.
For a trivial sum (in the context of what is spent on global warming) they could place some automated temperature reporting stations in a circle around some of these isolated human habitats (say 10 miles out) and then compare the reported temps out side the local effect of any urban heat island zone with the reported station temperatures they have been relying on.
I think back to the International Geophysical Year in the 1960’s and how that same sort of systematic planned experimental testing applied to climate data could resolve many of these nagging questions.
Same could be done by placing some NIST traceable temperature monitoring equipment in the region around a few of our long lived rural stations and some of our highly suspect urban sites.
Of course that would definitively answer some of these questions and some folks might not want to risk the answers that might come out of that sort of validation studies.
Larry
hotrod (Larry L) says:
January 28, 2011 at 2:52 pm
” otter17 says:
January 28, 2011 at 1:35 pm
“And here’s the interesting thing. Nuuk is just one data point, one “raging red” anomaly in the sparsely spaced hands-on-human-measured NASA GISS surface temperature dataset for the Arctic. ”
Am I looking at the same picture? There are dark red points all across Siberia, northern Canada, Alaska, etc. And wouldn’t the urban heat island effect be even more pronounced in countries that have developed larger cities over the years like the USA, coastal Brazil, southeast Asia, for example? Why would the Arctic areas be darker than more developed areas if this was truly a consistent problem with the land-based temperature data? Or is it not a consistent problem?
Some of the arguments seem to grasping at straws, but the point made concerning the Nuuk “instant warming” graphic may be a valid one. Maybe the surface stations project should do a global averaging calculation with all the suspected bad surface temperature stations removed? Has that been done? If so, what were the results?
The sad thing is that this question could be answered very easily if the folks doing the world average temperature calculations were actually interested in the truth.
For a trivial sum (in the context of what is spent on global warming) they could place some automated temperature reporting stations in a circle around some of these isolated human habitats (say 10 miles out) and then compare the reported temps out side the local effect of any urban heat island zone with the reported station temperatures they have been relying on.
I think back to the International Geophysical Year in the 1960′s and how that same sort of systematic planned experimental testing applied to climate data could resolve many of these nagging questions.
Same could be done by placing some NIST traceable temperature monitoring equipment in the region around a few of our long lived rural stations and some of our highly suspect urban sites.
Of course that would definitively answer some of these questions and some folks might not want to risk the answers that might come out of that sort of validation studies.
Larry”
Larry and Otter,
In fact the global temperature anomaly has been tracked using exclusively rural stations, that are totally dark at night.
http://pubs.giss.nasa.gov/docs/2010/2010_Hansen_etal.pdf
“A
[128] Figure A1a shows the global distribution of pitch dark
stations (night light radiance less than 1 mW m−2 sr−1 mm−1)
and stations that are dark but not pitch dark (radiance between
1 and 32 mW m−2 sr−1 mm−1). Figure A1b compares the
analyzed global temperature change for the case of our
standard night light adjustment and the case in which pitch
dark stations are used to adjust the long‐term trend of all
other stations. As Figure A1b shows, adjustment using only
pitch dark stations has very little effect on the result. Indeed,
the global mean warming is slightly larger (by 0.01°C) using
the stricter night light adjustment. Conceivably, the slight
warming is a result of the fact that the pitch dark requirement
removes about three quarters of the airport stations from
those used. However, we have not investigated which specific
stations cause the slight change in Figure A1 because the
change is negligible in comparison with the total temperature
change and its uncertainty.”
Well my eyesight is not as good as it once was eadler; but I am still able to cut and paste reasonably well:-
“”””” In the Arctic summer the angle is not as shallow as you would have people believe. The 23 degree angle of tilt of the earth’s axis, plus the fact that the Arctic is defined as north of 63Deg, makes the range of effective range of angles of the sun in the Arctic summer region as 0 to 50 degrees. The lower the latitude the larger the area affected. “””””
“”””” Sorry but you are wrong about the reflectivity of water versus angle. The reflectivity increases to 50% at a glancing angle of 5 degrees. “””””
So why are you telling me about what I am trying to have people believe. It was NOT I, who introduced the 5 deg grazing angle incidence; it was YOU.
I didn’t waste any of my time on the actual geometry; because you were concerned about the very high reflectance (50%) off open water at five degrees grazing angle or 85 deg Incidence angle.
Now if you really want to talk about more modest incidence angles that are realistic for arctic geometry; note that the Brewster angle for water, is 53 deg, or 37 deg of sun elevation angle, which is within your 0-50 deg range ( the sun can’t possibly have a zero degree incidence angle anywhere in the arctic; so you must be talking of elevation angles. And at the Brewster angle, the p polarisation reflectance i szero, and about 8% for the s polarisation or 4% for the total reflectance.
So you can have it whichever way you want to eadler You can get 60% total reflectance of damn little, at 5 deg sun elevation angle or you can get 4% of a larger amount. Now 53 deg happens to be the larger of the two non right angles of a 3-4-5 triangle; 53 deg 8 min if I remember correctly (brain is not as decrepid as the eyes) so that means cosine is 0.6 which is the surface obliquity factor; so the sea surface is 1.67 timews the projected area, and also the air mass factor is the same 1.67. Not as spectacular as the 11.5 factors for the five degree incidence but, 4%/ 1.67 is only 2.4% of the AM-1.67 reduced sunlight. Almost the same result as at 85 deg incidence angle.
As a good rule of thumb, people who deal with optical reflections off Optical Surfaces (I’ve only been at it for 50 years next month) take the total surface reflectance as being essentially constant at the Normal incidence value, up to the brewster angle of Incidence. To be pedantic, at the Brewster angle, while the p polarisation goes to zero, the s polarisation increase to make the total reflectance about double.
So water has 2% reflectance at zero degrees ((1.333-1)/(1.333+1))^2, and about 4% at 53 degrees. If you go to the trouble of completing the integration for the total reflectance from zero to the Brewster angle, oyu get about 3% average total reflectance for water. Beyond the Brewster angle, although the reflectance does skyrocket up to 1.0, the total flux outside of that for a Lambertian source is rather small.
In quality imaging optics, incidence angles as large as the Brewster angle ar almost never encountered; possibly in exotic immersion microscope objectives; but then such optics would have fancy anti-reflection coatings, to cut that reflectance. LED lamps run incidence angles up in that range; and they experience efficiency losses as a result.
And I’m not arguing whether open arctic water is a positive or negative feedback effect; I think there are both effects present; I’m simply saying that high polar ice albedo, is more imagined than real; and for the very simple reason that there isn’t much sunlight to reflect there anyway; which is why it gets cold in those regions. How easy is that ?
I’m not sure what the air/surface temperature record over recent decades at one weather station has to do with the central finding of the research that foraminifera indicate that present sea temperature in the Fram strait region are comparable if not warmer than the temperature in the MWP.
perhaps Nuuk has a rød sild industry…
A large proportion of the evidence for a MWP comes from research on foramina, if you dismiss the present data about sea temperatures derived from foramina then the evidence for a MWP is equally suspect.
Unlike tree rings which vary in response to factors other than temperature, foramina provide a very robust measure of the temperature of the water they grow in. The temperatures derived from foramina are calculated from the ratio of isotopes incorperated into the hard skeleton. Because biochemical processes preferentially use the lighter isotopes and that ratio of depletion of the heavier isotopes and increase in the lighter isotope is also modulated by temperature the isotope ratios provide an unambiguous indicator of temperature. The differential fractionation of isotopes is grounded in very basic physics, there are only two variables that alter the isotopic ratios.
The temperature and the isotopic ratio of the substrate (seawater) that the foramina grow in.
So if foramina show the same degree of alteration of the isotopic ratio now as they did during the MWP in that region then there are only two possibilities.
Either the isotopic ratio of the see water for the elements measured in foramina was very different in the MWP.
Or the sea in the Fram strait is of comparable if not higher temperatures than at any time during the last 2000 years.
That are not where they are supposed to be. The nominal location of some of those weather stations are not accurate, then they smear the false date over 1200 miles and use that data to make a wild ass guess what the temperature is hundreds of miles from the where they gathered the data.
You are making the not necessarily valid assumption that what actually happens corresponds to what Hansen “says” is happening.
http://wattsupwiththat.com/2010/10/31/metadata-errors-in-the-global-weather-station-database/
http://wattsupwiththat.com/2010/10/19/middlesboro-kentucky-pitch-black/
http://wattsupwiththat.com/2010/02/07/munging-madagascar/
http://wattsupwiththat.com/2010/09/22/arctic-isolated-versus-urban-stations-show-differing-trends/
Larry
Louise said on January 28, 2011 at 5:03 am:
As your comment wonderfully illustrates, it not only helps to have the facts right, but also to argue with the right facts.
First off, you have generically said “…the Midlands in the UK…” I am forced to assume you are referring to the English Midlands, and either the East Midlands or the West Midlands, rather than the Scottish Midlands, the Scottish Midland Valley, or other UK areas known as “Midland(s).”
Next, what variety (i.e. strain) of grapes are you growing? You have sadly failed to mention that specific. There are many varieties available, suitable for many different climates. Further, horticulture has moved onwards since the ancient times when Greenland was far more green, with new varieties developed that do better in cooler temperatures. Thus merely saying “grapes grew then, grapes grow now” is not a valid comparison.
Also, there is growing grapes, then there is growing good grapes. This article from a garden center in the West Midlands laments how it is almost impossible to grow a good dessert grape outdoors that far north. The author mentions a nice one he had grown outdoors before, with inedible fruit, and talks about growing grape vines for the colorful fall foliage. There is much advice given on growing them in greenhouses and conservatories, which can yield good fruit with the added heat they provide.
Needless to say, way back when Greenland was far more green, there weren’t that many greenhouses and conservatories around in the English Midlands.
This definitive-sounding 2005 article from The Guardian recommends specific varieties suitable for the cool English climate, and also highly recommends growing grapes in containers. Then they can be left outside in winter, as “…they need a real winter chill to be fruitful…”, and moved “under cover” inside a greenhouse or conservatory to provide the summer warmth needed for ripening.
Lastly, you are arguing about the wrong area. I Googled this 2003 Harvard Gazette article about a definitive published report examining the climate of the past millennium:
You have blandly mentioned growing grapes in your garden in presumably the English Midlands. I have an article from the West Midlands detailing the problems with growing grapes outdoors, let alone good grapes. A similar one from The Guardian highlights the importance of selecting proper varieties for the cool English climate, and basically advises against growing grapes solely outdoors. And there is evidence from the times of old when Greenland was far more green, that outdoor vineyards were flourishing in Scotland, the northernmost and thus likely coldest part of the UK, which very likely were not grown for their decorative foliage but rather for edible fruit, using the varieties available at that time and place.
If you’re going to attempt debunking the debunking of (C)AGW, please not only have your facts right, but use the right facts.
@- kadaka (KD Knoebel) says:
“If you’re going to attempt debunking the debunking of (C)AGW, please not only have your facts right, but use the right facts.”
Well quoting Sallie Baliunas on vineyards in Scotland during the MWP is probably a bad idea if you want to practice what you preach.
There is no archaeological or documentary evidence for vineyards that far North, all 46 of the documented vineyards of the period are in the Southern third of England, below Cambridge.
Even during the Roman warm period there is scant evidence of vineyards and wine manufacture, certainly none further north than the middle of the country.
In fact while there is evidence of SOMETHING been grown by methods that the Romans used for vines, very little pollen from grape vines is found and no manufacturing tools or utensils.
It is certain that the present magnitude and regional extent of grape production from vineyards for wine is now greater in Britain than at ANY time during its historical past.
@R. Gates
Near record in 30 years of satellite observation. There is ample historical evidence it has been this low prior to satellites.
@Billy Liar says: “It’s a Piper Seneca and its piston engine exhausts point at the ground and produce no more hot air than a big car.”
Not only will prop wash carry that engine heat over to the temperature sensor, it will blow tarmac heat over to the sensor. In fact, every time the wind blows from a certain direction (in sunshine), or swirls a certain way, that UHI effect heat will blow over the temperature sensor. Don’t be such a denialist.
@ur momisugly Ken Lydell
Hard to give them the benefit of the doubt when they begin with the patently absurd and false claim that Greenland surface temperature has climbed 7 degrees in recent years.
@ur momisugly Lydell
Thanks for your mention of Ronald Reagan. Lately, the assertion has been made he was suffering from Alzheimer’s, already, while still president. And yet, he was a better president than anyone who has followed, especially the current genius. Go figure.