UPDATE: the question has arisen about “occupied” aka “manned” weather stations in Antarctica (Stevenson Screens etc) versus the Automated Weather Stations. This picture on a postage stamp from Australia, celebrating the Australian Antarctic Territory in 1997, may help settle the issue. Note the Stevenson Screen near the “living pod” on the right.
Here is the larger photo of the first day of issue card, the Stevenson Screen is also just visible above the snowbank in the lower right. Rather close to human habitation I’d say. Looks like its in the middle of an AHI (Antarctic Heat Island).
Here’s another picture of a Stevenson Screen close to a building in Antarctica, from the British Antarctic Survey:
![[10004058]](http://www.photo.antarctica.ac.uk/external/guest/image/water/70/10004058)
Location: Fossil Bluff, Alexander Island
Season: 1994/1995
Photographer: Pete Bucktrout
It seems that folks are all “wild about Harry” over at Climate Audit, with the revelations occurring there, and no good kerfluffle would be complete without some pictures of the weather stations in question. It seems a weather station used in the Steig Antarctic study , aka “Harry”, got buried under snow and also got confused with another station, Gill, in the dataset. As Steve McIntyre writes:
Gill is located on the Ross Ice Shelf at 79.92S 178.59W 25M and is completely unrelated to Harry. The 2005 inspection report observes:
2 February 2005 – Site visited. Site was difficult to locate by air; was finally found by scanning the horizon with binoculars. Station moved 3.8 nautical miles from the previous GPS position. The lower delta temperature sensor was buried .63 meters in the snow. The boom sensor was raised to 3.84 m above the surface from 1.57 m above the surface. Station was found in good working condition.
I didn’t see any discussion in Steig et al on allowing for the effect of burying sensors in the snow on data homogeneity.
The difference between “old” Harry and “new” Harry can now be explained. “Old” Harry was actually “Gill”, but, at least, even if mis-identified, it was only one series. “New” Harry is a splice of Harry into Gill – when Harry met Gill, the two became one, as it were.
Considered by itself, Gill has a slightly negative trend from 1987 to 2002. The big trend in “New Harry” arises entirely from the impact of splicing the two data sets together. It’s a mess.
So not only is there a splice error, but the data itself may have been biased by snow burial.
Why is the snow burying important? Well, as anyone skilled in cold weather survival can tell you, snow makes an excellent insulator and an excellent reflector. Snow’s trapped air insulative properties is why building a snow cave to survive in is a good idea. So is it any wonder then that a snowdrift buried temperature sensor, or a temperature sensor being lowered to near the surface by rising snow, would not read the temperature of the free near surface atmosphere accurately?
As I’ve always said, getting accurate weather station data is all about siting and how the sensors are affected by microclimate issues. Pictures help tell the story.
Here’s “Harry” prior to being dug out in 2006 and after:
Harry AWS, 2006 – Upon Arrival – Click to enlarge.
Harry AWS, 2006 – After digging out – Click to enlarge.
You can see “Harry’s Facebook Page” here at the University of Wisconsin
It seems digging out weather stations is a regular pastime in Antarctica, so data issues with snow burial of AWS sensors may be more than just about “Harry”. It seems Theresa (Harry’s nearby sister) and Halley VI also have been dug out and the process documented. With this being such a regular occurrence, and easily found within a few minutes of Googling by me, you’d think somebody with Steig et al or the Nature peer reviewers would have looked into this and the effect on the data that Steve McIntyre has so eloquently pointed out.
Here’s more on the snow burial issue from Antarctic bloggers:
The map showing Automated Weather Stations in
Antarctica:
Click map for a larger image
The Gill AWS in question.
From Polartrec
Theresa was placed at this location partly to
study the air flow in the region. Looking out the window of the plane we can
definitely see the air flowing!!! Jim estimates the wind at about 25 miles per
hour.
Wind blown snow at Theresa
With the temperature around 0F the wind chill
was about 20 below, it is obvious this is going to be quite a chore.
Starting to dig out Theresa
The weather station has not been working, so
George needs to figure out what is wrong with it and then fix it. The station is
almost buried in the snow so we will also need to remove all of the electronics,
add a tower section and then raise and bolt all of the electronics and sensors
back in place.
George unhooking the cables.
After refueling the plane, with the fuel in
the 55 gallon drums, Jim and Louie helped dig down to the electronics boxes that
were completely buried plus they built us a wind break that made huge difference
in helping us not be so cold. After about 4 hours we are almost through. As I am
hanging onto the top of the raised tower in the wind, one bunny boot wedged onto
the tower bracing, the other boot wrapped around the tower, one elbow gripping
the tower, my chin trying to hold the wind sensor in place and both bare numb
hands trying to thread a nut onto the spinning wind sensor I really appreciate
the difficulty of what is normally Jonathan’s job. After checking to make sure
Theresa is transmitting weather data we board the plane and head to Briana our
second station.
Notice the difference between this
picture and the first one of Theresa.
From Antarctic Diary
More movement
It’s been another flat-out week. The vehicle team have dug
up and moved the Drewery building, which was getting do buried snow was
almost up the windows. Team Met have been on the move too – all the
remaining instruments are now bolted securely to the Laws roof, so we headed
up the the Halley VI building site to relocate the weather station.
Jules starts digging out the weather station
Only 15km away, the Halley VI site looks a lot like Halley V. It’s flat,
white and snowy. Very snowy. The weather station had about 1.5m built up
around it!
Jules and Simon recovering the solar panel
In the hole!
The weather station was a survey reference point for the build project so we
had to find a suitable replacement. Could this be Antarctica’s first
pole-dancing venue?
Penguin Party memories…
After an hour or so sweating it our with shovels, the weather station popped
out and was loaded onto the sledge. Like the reference point, the station’s
new location had to be precise as vehicles are banned from the upwind
section of the site to keep that area ultra-clean for future snow-chemistry
experiments.
Weather station on the move
Driving on a compass bearing and GPS track, we found the new site just under
a kilometre away.
The final setup
UPDATE: here’s another buried station story from Bob’s Adventures in cold climes. Apparently this station is used as a reference for some sort of borehole project.
I dig weather stations
My main task for today was to get a start on raising my weather station. I’d installed it 2 years ago, and with the high accumulation at Summit, it’s getting buried. The electronics are all in a box under the snow, and the only things visible at the surface were the anemometer for measuring wind speed and direction, the thermistor for measuring air temperature, and the solar panel to keep the batteries charged.
The buried weather station. The flat green bit is the solar panel, which was about 1.5 meters off the surface when I installed the station. Can you guess why I would mount it facing down?
In the morning I downloaded all the data from the station, and checked to see that it was all in order. Then it was time for digging. I’d carefully made a diagram when I inastalled the station, so I knew exactly where to dig. A couple of hours later I’d found my box!
At the bottom of the pit with the datalogger electronics.
I brought everything up to the surface, and then was about to fill in the pit, when I realized at least one more scientist at Summit might want to make measurements in it; the pit’s already dug! So tomorrow I’ll help Lora with some conductivity measurements, then fill in the pit, re-bury the box just beneath the surface, and it’ll be ready to go for another 2 years!
And there’s more….
The Australians seem to have AWS problems as well. From the Australian Antarctic Division:
On Monday two groups headed out, with Largy and Denis going up to the skiway to check on the condition of the equipment stored there for the winter and beginning preparations for the coming summer flying season.
Bill, Brian and Ian went up to the Lanyon Junction Automatic Weather Station (AWS) to check its condition and retrieve some of the sensors in preparation for the annual servicing of the various remote units.
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And the University of Maine, participating in USITASE, has the same troubles, they write:
We reached our first major destination at the end of today’s travel, the site of the Nico weather station. There are several automatic weather stations spread out over the surface of Antarctica. These stations measure things like temperature, wind speed and wind direction and then relay this data back to scientists via satellite. Anything left on the surface of the snow will eventually be drifted in and buried by blowing snow. This particular weather station (NICO) has not been seen in several years. They tried to locate it via airplane a few years ago and were unsuccessful. Our task was to find the weather station, record its position with GPS, and mark the location with flags so that in the near future, the weather station can be raised and serviced.
We arrived at the coordinates of the station around 10 pm. Our initial scans of the horizon were not productive, so Matthew and John took the lead tractor (with our crevasse-detecting radar) out to survey a grid near our stopping point. The radar should detect a large metal object like a weather station, but the survey was also unsuccessful. After a fine pasta and tomato sauce dinner, John went outside for an evening constitutional. He saw a shiny object out in the distance – further inspection with a pair of binoculars determined that it was the top of the NICO weather station! Several of us marched out to the station, which was actually about a half mile distant, marked the location with bright orange flags and recorded the position via GPS for future reference. Only the top foot or two of the station was still visible. John was in exactly the right place at the right time to see a reflection from this object while we were near the kitchen module, and so allowed us to complete our first task successfully.
Tomorrow, we drive on.
This regular burial and digging out of stations brings the whole network of AWS stations to be used as sensitive climate measurement stations into question.
George E. Smith, from way back in the 60s or 70s, I read an article re: people at the south pole mentioning CO2 snow. I haven’t been able find anything via google though. I had to have read it in either NG, Science News or Discovery magazine.
On learning science back in the 50s and 60s, it was certainly more hands on than kids are allowed today. I remember being ecstatic at 12 upon finding my father’s ‘Modern Chemistry’ by Charles Dull, and learned chemistry from that book through making, er ‘firecrackers’ and rockets.
Anthony,
You ask “Show how snow burial of an AWS could result in a cooling bias”. The answer is fairly straightforward. Lets assume for a moment that AWS stations are checked at least every few years, and cleared of snow as needed when they are checked. The effect of burying the station in snow would have a pronounced effect on the trend over those few years that the station remains buried, but would have less effect on the long-term trend (as it would show a quasi-periodic cycle caused by the burying and unburying). Now suppose, as is probably reasonable, that the AWS network was less rigorously maintained in its early years (say, the 1950s-1970s). This would be due to the lack of technologies to prevent burying, less frequent checkups, etc. In this case, during any given year during the 1950s-1970s the station in question would be more likely to be buried than in a given year from the 1970s to present, and a spurious cooling trend would be introduced. My point is that we cannot realistically tell the effect of snow burying on the trend unless we know how the frequency at which the station was unburied changes over time.
As for the arguement that the location of sensors close to buildings at arctic bases introduces a warming bias, well, prove it. Again, there is only a bias IF it affects the trend, not the temperature reading. So unless bases have grown over time, or introduced new practices that change the albedo or create a new major waste heat source in the vicinity of the monitor, there would be no “Antarctic Heat Island” effect.
Snowjob event in Buffalo, NY too.
http://www.buffalonews.com/home/story/570235.html
Wow, I’ve spent half an hour reading this and Climate Aud, most of the good stuff seems to happen in the comments. Once again I find myself in need of a meta-blog that distills the situation to something I can digest. I see that automated stations frequently get buried which seems like it would have an obvious effect on readings. But are the automated stations used for climate modeling? Did the Steig paper use AWS or only manned stations, and what really was the effect of the Gill-Harry splice? Sign me “Still confused.”
Zeke
Translation, the measurements cannot be trusted. I think that is the thrust of this thread. We can speculate as to the actual temperatures but we really don’t know. It seems like the Nature story was just that a story. My personal speculation was the temperatures were cooler than reported.
anna v (04:47:40) :
I always thought wind chill factor was only a means devised to show effects on exposed skin and, unlike heat index, has no effect once skin is covered.
stan (04:37:59) :
You have been treated better than you deserve. If you don’t want people to personalize a dispute, perhaps you shouldn’t have been personally disparaging in your initial comment.
There was nothing personally disparaging in my comment. I asked a fair question. I am not aware of any focus on examining the quality of Antarctic data in advance of responses to the Steig paper (I might be wrong about that, of course). I asked why, a couple of people have given reasoned responses, but you wish to reject the question as being ‘personally disparaging’. May I suggest that you equivalently upbraid all other posters who raise questions as to whether there is bias in the work of Hansen, Mann, Steig, etc.?
Richard M (06:55:41) :
From other references i’ve seen it appears the entire study is based on a cherry picked starting date. I believe you have criticized these kind of efforts in the past. Does this mean you now support cherry picking starting dates or will we hear from you later that this entire report is nonsense?
The start date is the beginning of the records. How do you consider that to be a cherry pick?
“Why do you energetically challenge findings that suggest supposed warming whilst uncritically accepting any evidence of supposed cooling?”
Good point. We really shouldn’t accept much of anything the AGW Climate Scientists put forth, as the current Steig/Mann Antartic Warming fiasco also seems to indicate. They simply aren’t proceeding scientifically.
But also, it’s the AGW’ers who are ginning up GW into a “we’re all gonna die” scenario, that is, if we don’t return to the Stone Age post haste – which comprises an agenda.
So it’s up to them to at least prove to begin with that the “Globe” is warming, not anyone else – which they just took another swipe at concerning the Antartic, an area which Steig himself claimed everyone had ~ “not paid much attention to”, thus starting another suspect “narrative” in order to suddenly bolster the GW claim.
This is simply the way things are developing. If the ipcc and its Climate Scientists had set out to do an actual scientific analysis of Global temperatures to begin with, all of this helter-skelterism wouldn’t be occurring, with the rest of us trying/needing to play “catch up” 24/7 so as to check and counter an unscientific AGW agenda.
Instead, Science would be proceeding as it should, with the chips falling where they may.
Zeke,
I understand where you are coming from, but your point is pure speculation. The automated weather stations should be pulled from Steig’s database, and his analysis should be re-run.
Things you find at the Doctors office… The February National Geographic there had an article about Mount Washington in the frozen north east… including pictures of a guy chipping ice off of the mount and platform.
They claimed it was a regular duty.
So what happens to a Stevenson Screen or an automated station when one of these ‘killer ice storms’ comes through and coats everything in 3 inches of rhyme or solid ice? What happens when we have 6 foot blowing drifts and 1/3 of the Heartland is without power or cleared roads?
Somebody has one heck of a lot of devotion to go out in that stuff and clean up (roads, power, and even temperature measuring stations…) Admired from afar in pleasant but lacking any water California…
(May it please the Rain Gods, just enough to reach 1/2 “normal” would be appreciated! – but that’s our pattern in this type of weather cycle. Just hope it doesn’t take 30 years for the Rain Gods to hear and shift the PDO back…)
Zeke Hausfather (08:14:45) :
“As for the arguement that the location of sensors close to buildings at arctic bases introduces a warming bias, well, prove it. Again, there is only a bias IF it affects the trend, not the temperature reading.”
Err…it’s called “heat transfer”…
Warm building heats cold thermometer…makes thermometer warm…max and min temperatures get messed up…along with the trend…
And I’m sure being buried in snow doesn’t affect the trend either…hey, why have any siting requirements at all? Just make up your own rules. BBQs, A/C exhausts, sewage plants – OK!
Nothing seems to matter in climate “science”…
@ur momisugly march 20:41:
I posted a simple question on RealClimate’s website about that re-analysis of Antarctic temperature. I asked how I should understand the fact that Antarctic sea ice extent is at a (at least) 30 year maximum when the place is warming up. Not exactly what you would expect, methinks.
Guess what, they censored it.
Speaks volumes about their objectivity, don’t you think?
It’s been noted before here that Zeke Hausfather’s blog is funded by grants from greenie foundations with a “save the earth” agenda.
Naturally, they believe that AGW is proven beyond any doubt. Zeke isn’t going to bite the hand that feeds him.
If his blog is ever funded by a skeptical foundation that thinks AGW is not a problem, I’m sure we’ll read about it here.
John Philip (02:49:27) said:
“RealClimate (Gavin) respond here. Turns out the conclusions of the study are not dependendent on the automated weather station readings”
As long as the data and code are not available, this is a black box for anyone else except a few people.
you may discover errors in databases, warming biases, inconsistencies, poor justifications , dubious screening, starting date issues,
or come to the same or the other conclusion by your own calculation, but further on this is all about
trust and confidence into the authors’ skills.
and not science.
after all, i do neither trust or have confidence in the authors’ skills.
So now we can see why Western Antarctica shows up as “warm” on the temperature maps.
By the way, interpreted anew, the overall finding here may be ominous vis a vis a leading indicator of continental ice expansion globally.
Lucy Skywalker 02:45:12. Thank you for correcting my typo; it is Pen Hadow. I had just seen Pen Hadow on the BBC Breakfast program explaining the purpose of his new expedition and wanted to quickly post a note before dashing out in the snow to work, so I didn’t check it as thoroughly as I normally would.
Does it matter? From other references i’ve seen it appears the entire study is based on a cherry picked starting date
Well you have to start somewhere! And any start date is open to accusations of cherry picking. Steig’s paper [incidentally Lucy S, on your website you say the study was published as a ‘Letter’ in Nature and thus escaped peer-review, Letters to Nature most certainly are peer-reviewed We are not talking Letters to the Daily Telegraph here] starts in the International Geophysical Year when many manned research bases and meteorological stations were established and hence the bulk of the data available dates from that year. If you have a better choice I am sure the authors would be all ears. They have made it clear that …
Our paper — by itself — does not address whether Antarctica’s recent warming is part of a longer term trend. There is separate evidence from ice cores that Antarctica has been warming for most of the 20th century, but this is complicated by the strong influence of El Niño events in West Antarctica. In our own published work to date (Schneider and Steig, PNAS), we find that the 1940s [edit for clarity: the 1935-1945 decade] were the warmest decade of the 20th century in West Antarctica, due to an exceptionally large warming of the tropical Pacific at that time. (RealClimate)
So I am not sure what the thrust of the point is? The study addresses a defined period and finds a statistically significant warming trend over that period, with shorter and more regional cooling trends contained within that overall finding. I don’t really see how that could be made more clear.
Manfred – You can find the article in any library, the data from the study is here, all the code is here so I am afraid the thrust of your point escapes me also.
Anna v: “Wet a thermometer in the wind and ask it.”
You just described wet bulb temperature: http://www.engineeringtoolbox.com/dry-wet-bulb-dew-point-air-d_682.html
Again. That is measuring something different than air temp.
JP: Eric’s measurements have been rerun with AWS stations removed. There is a post about it up on RC today, and it doesn’t really change much.
Frank K.: I’m completely aware of heat transfer and the potential effect of warm buildings. However, what it being analyzed here is not the temperature at the station. Its the trend in temperature at the station. Co-location with a station will have absolutely no effect on trend over time if the station itself does not significantly change.
I do need to correct my initial post, however, in light of the fact that the AWS stations “only started to be deployed recently” according to Gavin. My point about the effect of burying on the trend holds true only if the station has been unburied more than once over the temperature record (which if probably still the case, since most of the AWS stations seem to be at least 15 to 20 years old).
Per Gavin at RC the AWS monthly data for Steig’s report is located at:
http://www.antarctica.ac.uk/met/READER
I eyeballed all 65 station’ss data and it’s pretty spotty. There were no more than 26 stations installed by 1990. Installations by year for the 1980’s (1980 being the first year) were as follows:
1980-2 1986-5
1981-2 1987-4
1983-1 1988-2
1984-2 1989-1
1985-2 1990-5
Manfred:
The data and code is available:
http://web.gps.caltech.edu/~tapio/imputation
http://www.antarctica.ac.uk/met/READER
Knock yourself out.
A few of dumb questions
What is the accuracy and precision of the temperature sensors used in the Antarctic surface stations? I assume there are different makes and models with different accuracies and precision. Is this an issue?
re snow covered sensors and bias
1. Wouldn’t a snow covered sensor give a false warmer reading in the Antarctic winter, and a false cooler reading in the Antarctic summer? Wouldn’t the snow cover insulate against temp changes on the surface? Would when (summer or winter) the sensor was covered affect the bias?
2. Wouldn’t a covered sensor show very small seasonal temperature changes, and the lack of seasonal changes should alert someone that there is a problem with that site?
re heat transfer from buildings Zeke (8:14) I think you are assuming that any heat transfer from buildings is constant. If the the heat and or the heat transfer is variable, then the affects would be variable and both the record and the trend from that record is compromised.
Unfortunately, this is not true. Several years ago I wanted to verify AGW supporters list. Therefore I contacted one Nobel Physics Laureate (the real Nobel Prize, not the “peace” one). The reply I got back was quite upsetting, in line with AGW cult: “those evil oil industry, and so on and so forth..”
Zeke Hausfather (10:06:46) :
“I’m completely aware of heat transfer and the potential effect of warm buildings. However, what it being analyzed here is not the temperature at the station. Its the trend in temperature at the station. Co-location with a station will have absolutely no effect on trend over time if the station itself does not significantly change.”
Unfortunately, Zeke, co-location will indeed have an impact on the trend unless the trend you seek is the temperature trend in the vicinity of the warm building. And it is also very unlikely that the building(s) will remain the same over several decades of observation.
But again, I ask, why have any siting standards at all !!?? You’re saying they won’t affect the trend…so why bother?