Biases in Antarctic weather stations reported up to 10°C

Steig et al in Nature

This paper just published in the AMS Journal of Atmospheric and Oceanic Technology has some broad ramifications for the claim (Steig et al, covered here) that Antarctica is warming. It appears that the radiation shields used for automated weather stations there aren’t fully protecting the temperature sensor from solar radiation exposure, and as a result are creating a false warming signal. The authors find that the summer Sun heats the shield for the electronic thermometers causing the warm bias that appears during the summer, which can be exacerbated by low wind conditions.

This may be partially due to low sun angles associated with latitude and the 24 hour day that Antarctica experiences in summer, along with snow albedo. I’m looking into the full paper and will have  a follow up post later.  See the map below, there are a lot of these AWS. As I’ve always said, if you don’t fully understand the micro-site conditions in which the measurements are made, and the instrumentation limitations, you can’t be certain of the data it produces.

Atmospheric temperature measurements biases on the Antarctic plateau

Christophe Genthon, Delphine Six, Vincent FavierLaboratoire de Glaciologie et Géophysique de l’Environnement, CNRS/UJF, Saint Martin, d’Hères, France

Matthew Lazzara, Linda KellerAntarctic Meteorological Research Center, University of Wisconsin-Madison, Madison, USA

Abstract

Observations of atmospheric temperature made on the Antarctic plateau with thermistors housed in naturally (wind) ventilated radiation shields are shown to be significantly warm biased by solar radiation. High incoming solar flux and high surface albedo result in radiation biases in Gill (multiplate) styled shields that can occasionally exceed 10°C in summer in case of low wind speed.

Although stronger and more frequent when incoming solar radiation is high, biases exceeding 8°C are found even when solar is less than 200 Wm−2. Comparing with sonic thermometers, which are not affected by radiation but which are too complex to be routinely used for mean temperature monitoring, commercially available aspirated shields are shown to efficiently protect thermistor measurements from solar radiation biases. Most of the available in situ reports of atmospheric temperature on the Antarctic plateau are from automatic weather stations that use passive shields and are thus likely warm biased in the summer. In spite of low power consumption, deploying aspirated shields at remote locations in such a difficult environment may be a challenge. Bias correction formulae are not easily derived and are obviously shield dependent. On the other hand, because of a strong dependence of bias to wind speed, filtering out temperature reports for wind speed less than a given threshold (about 4–6 ms−1 for the shields tested here) may be an efficient way to quality control the data, albeit at the cost of significant data loss and records biased towards high wind speed cases.

Received: May 13, 2011; Revised: August 01, 2011

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AWS 2010 Map

h/t to the Hockey Schtick

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71 thoughts on “Biases in Antarctic weather stations reported up to 10°C

  1. Do all of these nations employ the same defective thermometer housing I wonder? And since the optimum housing for thermometers has been settled for over a hundred years, it s curious that they could get it so wrong there. And would not be the same housing employed in the Arctic?

    REPLY: I don’t know that the thermometer housing is “defective” but more likely simply used outside of its tested range. Passive gill shield housings are pretty much a de facto standard and only made by a handful of companies. I would expect most stations in the Antarctic AWS program to the the same shield, though the Arctic is likely more randomly mixed between different shield types. -Anthony

  2. All of the tricks of the trade are utilized!. I’m surprised each thermometer doesn’t have someone assigned to it to periodically warm it with a match!

  3. Well, if this is the case, it should be easily seen in the data that most of the recent “warming” would occur in the summer months. CO2 induced warming would have its greatest impact in winter months when the air is very dry (little water vapor) and CO2 accounts for a greater portion of the total greenhouse effect of the atmosphere. Is most (all?) of the recent “warming” occurring in the summer months?

  4. Sean Peake says:
    August 10, 2011 at 11:21 am
    Could this be the same effect that produces temp spikes in Eureka?

    Sean, don’t know about the spikes, but having worked there many years ago, and any nice day and wind shifting from the north can give you warmer temps, as I have hiked north from the station and it was significantly warmer in the interior.

  5. This upward temperature bias under low wind velocity conditions was also documented by the same group in http://www.climantartide.it/introduzione/2009-Genthon.pdf

    Genthon, C., M. S. Town, D. Six, V. Favier, S. Argentini, and A. Pellegrini (2010), Meteorological atmospheric boundary
    layer measurements and ECMWF analyses during summer at Dome C, Antarctica, J. Geophys. Res., 115, D05104,
    doi:10.1029/2009JD012741

    That article also compares measurements to the ECMWF analysis and finds the analysis has an upward temperature bias.

  6. “It appears that the radiation shields used for automated weather stations there aren’t fully protecting the temperature sensor from solar radiation exposure, and as a result are creating a false warming signal.”

    Is it a false warming signal, or a false warm signal? There is a difference …

  7. I teach classes about heat transfer and thermodynamics. These are both topics that depend on accurate temperature measurement. My students are often surprised at the difficulty involved in getting temperature measured accurately even to something as coarse as plus or minus 0.5C. Even an ice/water bath may have a larger uncertainty.

    The difficulties come from three sources: 1) manufacturing and calibration of instruments and the inevitable drift, 2) the vagaries of trying to adequately control three independent modes of heat transfer, and 3) proof that the measurement is representative of the domain claimed.

    Of the five dimensions of measurement, temperature is the most challenging.

  8. Actually, this might not be limited to Antarctica and it might explain something really odd I have noticed in the NCDC “Climate at a glance” graphs.

    If you graph temperatures since 1998 to 2011, you will notice a rather significant drop in temperatures. The thing is, NONE of that drop is recorded in summer temperatures. Temperatures in summer in CONUS since 1998 are flat, no trend. On the other hand, winter temperatures show a rather eye-popping drop of -3.27 degrees/decade and the trend has been fairly steady with winter temps the last two years well below the 1901-2000 2oth century average. Spring and fall temperatures show less of a downtrend.

    I had been wondering for some time why all seasons would show a down trend except for Summer. Spring (-0.31F/decade) and Fall (-0.53F/decade) are pretty close in their trends.

    If the design of these temperature sensors results in radiative heating of the sensor, that would explain why there is such a drastic departure between summer and winter temperature trends over that 13 year period.

    REF: http://www.ncdc.noaa.gov/oa/climate/research/cag3/na.html

    First Year To Display: 1998
    Last Year To Display: 2011

    Winter/Spring/Summer/Fall temperatures.

  9. “As I’ve always said, if you don’t fully understand the micro-site conditions in which the measurements are made, and the instrumentation limitations, you can’t be certain of the data it produces.”

    One is only as good as the tools they have to attempt measuring reality. I simply wish that the majority of climate scientists would realize that ‘the map is not the territory.’

  10. What perecntage of the AWS sites in the Antarctic use these types of shields
    and where are they located?

    Does that map show all the AWS sites regardless of what type of shield they use or do all AWS use it, so we can infer that all the sites on the map are affected?

    Just trying to get my head round the scale of the problem

  11. “up to 10°C” – compared to what? Presumably true air temperature. If the old thermometers had a similar bias, then this wouldn’t contribute to a false warming, just that the temperature records are poor and too warm from sunny periods.

    What’s the defect? I’d guess that either the low sun angle is getting light and heat into the thermometer area, or that sunlight reflecting off the white surface is getting lots of light past the shield.

  12. It’s funny that what the IPCC/Hockey Team would consider ‘science’ seems to involve sidestepping what in other fields would be considered basic engineering and quality assurance.

    If you have a sensor on an aircraft that produces inaccurate measurements in extreme conditions and you have a system that relies on that data, people die and careers are broken.

    If you have a weather sensor that produces inaccurate measurements in extreme conditions and climate models rely on that data, you get piles of grant funding to prove mankind is screwing up the planet.

  13. @Ric – the long days may also just saturate the screening ability of the shield, or heat everything around it enough to radiate heat into the thermometer.

  14. It would be interesting to compare summer-only temperatures with one of these newfangled units and a conventional Stevenson screen located nearby.

    Or maybe compromise and place one of these newer sensors inside a Stevenson screen and see if it makes a difference?

  15. Know matter how smart the people making the claims you always need to take into account the fact they could be dead wrong becasue they made a simply mistake in their data collection method. .

  16. As others have said, there’s a big difference between “warming” (trend) and “warm” (bias). The first paragraph above also mentions winds, so my question would be if there’s been a decrease in average wind speeds over the last N years. That would turn a bias into a trend.

  17. RHS,

    I would assume that UHI works just as well in winter as it does in summer. At least there shouldn’t be a 3F degree difference between winter and summer trends. That is a pretty significant difference.

    Another question I would have is if Stevenson screens are still being replaced with the new sensors or has all of that work been done already? The reason I ask this is that it would account for the summer trend staying flat while the winter trend is in steep decline. So lets say the summer trend is actually declining too, but as Stevenson screen stations are replaced by the new sensors, the increase in erroneous summer high temperatures would accumulate over time and compensate for the decline in actual temperature.

    This has also brought to mind something E.M. Smith noted in his blog sometime back when he was looking at temperatures reported at stations around the SF Bay area. That is, some stations seemed to show a very significant and sharp step up in temperature at a certain time of the morning. If this is due to low sun angle or reflected sun penetrating the shade vanes, that might account for that.

  18. I’d have to go back and research a bit, but there seems to be an awful lot more data points on that map than were referenced in Steig et al, especially towards the center of the continent.

  19. Well this should be a new chapter for the IPCC to flog. I mean really, the world’s best scientists, doing the best research and gathering the most accurate data . . . what’s a small 8-10 degree discrepancy.

    Climate Scientology marches on.

  20. What will they say at RC?

    REPLY: They’ll either ignore it or say it doesn’t matter, just like with all the issues raised with the hockey stick. One they use the word “robust” to describe anything, there is no turning back with them. – Anthony

  21. I am at a loss to understand why Steig et al used only a handful of thermometers, weighted especially on the western peninsular area. The map shows Antarctica to be a veritable spotted dick of thermometers.

    Before snipping the metaphor please know that spotted dick is an english dessert:

    “Spotted dick is an English steamed suet pudding containing dried fruit (usually currants) commonly served with custard” (Wiki)

  22. Al Gore was recently in Aspen, Colorado, overheard saying, “these thermometer thingies, they’re B*LL$h!+!!!”

    Gore also remarked on the fact that it was “Big AWuhl Wat made muh carbon credit sacrament payments not work so wayull, but buhtwean me & Karl Marx, we dun made tha planet stop warmin, although it ain’t stopped warmin.”

    “Also, my wife is a liar. Oh. Wait my wife ain’t no liar, cuz that book ain’t out yet.

    But it was BIG AWULL WAT made muh WIFE get fed up and leave me. See how ‘fed up’ has FED in it, and how them BIG AWULLz iz always a’ palloootn muh FED with rePugNaKunz?”

    And with that Gore proceeded to launch his platform of paying poor and disillusioned urban youth to stand outdoors in antarctica and estimate the temperature in their neighborhood slang lingos, saying the program would provide “much needed relief for waterless urinal businesses previously LOCKED OUT of the MARKETs in Antarctica by “creationists who couldn’t tell climate math from useless doodles.”

  23. Wayne, you are correct about changes in wind speed affecting reported temperature, especially in the Antarctic winter. There are both decadal trends in wind speed and wind speed changes due to (seemingly slight) changes in sensor location which must be accounted for in any temperture study. My impression, however, is that the wind effects are usually ignored in the Antarctic studies.

  24. For Crosspatch, who says: “I would assume that UHI works just as well in winter as it does in summer.”

    Assume the UHI is caused by two major but different sources of heating — (A) solar and (B) various urban sources of heat such vehicle emissions. The amount of blacktop and development would be the same summer and winter. If solar heating in summer is greater than in winter, due to the sun being more directly above in summer but with fewer hours of light and sunlight at a lower angle in winter, then UHI might be higher in summer.

    Also, possibly more important, the recent study by NASA, hilighted on WUWT, showed summertime UHI effects higher by 7 to 9 degrees C on average in the eastern US compared to neighboring areas, with the largest UHI occurring when neighboring areas were forested instead of farmland. In winter, forested areas don’t have green vegetation and water retention and don’t cool the land the way they do in summer.

    This is a qualitative argument that UHI may well be higher in summer. I don’t know of quantitative measurements of the difference between summer vs. winter UHI.

    Link:

    http://wattsupwiththat.com/2010/12/14/image-the-urban-heat-islands-in-the-northeast/

  25. John

    Well, it should be easy enough to tell. Look at the winter lows for downtown Indianapolis oe Denver compared to a small town outside of the city. Then look at the summer lows.

  26. This is starting to make sense to me. It seemed that the Antarctic sea ice should not have been steady/increasing while W Antarctica warmed up, because W A should have a disproportionately high effect on sea ice.

    If, instead, the thermometers were being incorrectly heated by the sun, my thinking goes like this:

    Henrik Svensmark’s theory is that clouds are driven by GCRs, and in turn drive global temperature. The late 20thC warming was driven by decreasing cloud cover (confirmed by Earthshine). The Antarctic does not warm in parallel, because ice albedo is stronger than cloud albedo. But .. the reduced cloud cover lets in more sunlight, hitting the thermometers where it shouldn’t, and bingo! W A gets a spurious warming trend.

    The observed behaviour of Antarctic sea ice would, to my mind, confirm that the W A temperature rise could well have been spurious. Further confirmation would come if the spurious warming is now declining again.

    Reasonable?

  27. “August 10, 2011 at 12:25 pm

    “up to 10°C” – compared to what? Presumably true air temperature. If the old thermometers had a similar bias, then this wouldn’t contribute to a false warming, just that the temperature records are poor and too warm from sunny periods.”

    If the sensor has a bias and you never change the sensor, then taking an anomaly effectively removes the bias because what you are concerned about is the trend and not the absolute temperature. The other thing is with the bias only happening under certain conditions, you will end up with a more noisy anomaly. If you change sensors from one that has a too warm bias to one that is correct you will induce an artificial cooling trend.

  28. Considering that temperatures fall in Antarctica in sunny (cloud free) weather, it seems extremely important not to measure irradiation.

  29. steven mosher says:
    August 10, 2011 at 2:53 pm

    “August 10, 2011 at 12:25 pm

    “up to 10°C” – compared to what? Presumably true air temperature. If the old thermometers had a similar bias, then this wouldn’t contribute to a false warming, just that the temperature records are poor and too warm from sunny periods.”

    If the sensor has a bias and you never change the sensor, then taking an anomaly effectively removes the bias because what you are concerned about is the trend and not the absolute temperature. The other thing is with the bias only happening under certain conditions, you will end up with a more noisy anomaly. If you change sensors from one that has a too warm bias to one that is correct you will induce an artificial cooling trend.

    ***************************************************************************************************
    Can you tell me how the anomaly is calculated. Is it by calculating an average for a previous period, (perhaps) before the “warmer” shield was in place.
    I don’t know whether the sensor has been changed, but the shielding has. If this has changed the temperature reading upward, then the comparison with the previous temperature period(with older, colder shield) will also change disproportionately and affect the trend.

    Likewise, as you point out, if you change from an old shield/sensor which is correct, to a new, warmer sensor/shield you will induce a warming trend. This is actually what appears to have happened.

  30. The IPCC statements about “settled science” and “certainty” of outcome (of CO2 increases) depends, it seems clear to me, on PRECISE data but INACCURATE data. Temperatures that are multiples of one sensor in one place at one time may be averaged and its proximity to “truth” become better as a result, but data grouped each day at different places from different measuring devices and (in the pre-electronic days) by different people in different frames of mind cannot, it seems to me, merged together and, by averaging, have a result that is more accurate than the general reading. If 100 readings are done at one place, one time, by one person, of one event, then the actual number probably does have an error equal to a square root function, for example, but 100 readings of different places by different people must have, it seems to me no less an error of the majority reading. All errors must add, not become reduced, through manipulation. The IPCC/Hansen data, it strikes me, is less accurate than portrayed, though the statistics used to get it give many decimal places for precision.

    Certainty of outcome is model driven and may be very small. But if models are matching to observations with a large error due to inaccuracy, not precision, what happens to the certainty that results? Does not certainty fail to improve beyond whatever the accuracy, not precision, of the data is?

    Hansen and HadCru both say they describe the global temperature – not the temperature of their dataset, but the global temperature. The global temperature trends are important for accuracy more than for precision. But Hansen, with his :’superior’ data of the Arctic, has about a 0.12C warmer view of the world in a world that has warmed about 0.55C since their (same?) reference point, a 18% or so difference. Since the models are using this data to determine their fit, then the accuracy of the model fil cannot, it seems to me, fit better than the accuracy of the data being used. This does not leave us with 95% or 99% certainty, it seems to me.

    Am I wrong? Is the work on measurement, equipment, UHIE and interpolation not showing us that the accuracy of the trend is greater than the accuracy possible as described by IPCC “certainty”? Would a statement that the “settled” science produces a certainty in the probable 82% range not be more correct than the 95 – 99% range?

    And that doesn’t include the certainty in the modelling: what IS the certainty of outcome when data quality (not quantity) and modelling assumption errors are considered?

    What can we say is the accuracy of any reading? I know the error bars, but I still hear that the temperature has risen 0.05C worldwide: if none of the readings are better than 0.15C in reflecting reality, can you say that 0.05C has any meaning? And if not, what does that do to the various, finely tuned modelling results? Are they really just a smear?

  31. crosspatch says:
    August 10, 2011 at 11:31 am
    Well, if this is the case, it should be easily seen in the data that most of the recent “warming” would occur in the summer months. CO2 induced warming would have its greatest impact in winter months when the air is very dry (little water vapor) and CO2 accounts for a greater portion of the total greenhouse effect of the atmosphere. Is most (all?) of the recent “warming” occurring in the summer months?

    This work which uses spectral analysis of DLR to quantify the contribution of the various GHGs to total DLR suggests CO2 accounts for a full third year round.

    http://journals.ametsoc.org/doi/abs/10.1175/JCLI3525.1

    The study was done at the South Pole and indicates that location should be the area of CO2′s peak impact on the GH effect, which is interesting if you are at all familiar with what observations there show in regard to temperature trends in the last fifty years

  32. This is exactly the sort of systematic sensor measurement error Hubbard and Lin warned about in their 2002 paper, “Realtime data filtering models for air temperature measurements“. In 2005, they also explicitly warned about the systematic sensor measurement errors due to snow albedo: “Surface air temperature records biased by snow-covered surface

    Steve Mosher’s demurral about anomalies is true only when the bias error is constant and the systematic measurement error is i.i.d. However, since the size and the distribution of the systematic measurement error is local weather dependent, the error will also vary systematically in magnitude and the distribution of error may skew differently over time. Bias errors are very likely to vary among any given set of mean temperatures, bias errors will vary among various data sets such as from month to month, and the standard deviation of the systematic bias errors will also vary with the data set.

    In short, unless they have been measured to be constant and i.i.d., systematic sensor measurement bias errors do not fully subtract away, cannot be assumed constant over time and cannot be assumed to be i.i.d. Systematic bias errors cannot be assumed to subtract away by taking anomalies. And even if the mean bias happens to subtract away in the difference between favored data sets, the standard deviation of the bias error does not.

  33. When were these things installed….and what was the temp jump when they were?

    I “think” I remember reading that cooling summers in Antarctica were consistent with irritable climate syndrome…..can’t keep up, everything is consistent
    Would even more cooling be even more consistent?

    Trend – schmind – bullhollocks
    10 degree too warm – is 10 degrees too warm – period

  34. Kevin Kilty said;

    “Of the five dimensions of measurement, temperature is the most challenging.”

    Well, yes and no, I’m not sure which five dimensions you refer to, but I agree that measuring temperature is more difficult than length, time, voltage, weight etc.

    However measuring optical radiation accurately is much more difficult. According to NIST if you follow all of their procedures you might get an absolute radiometric measurement in the visible light region of about +/- 2%. This involves a lengthy process that involves buying a “standard” light bulb from them and using careful spectral measurements taken every few nanometers across the spectrum. The international standard for optical radiation is the flux emitted by pure platinum in its liquid state. Even NIST can only afford to perform this measurement every few decades. They measure some light bulbs against this standard and then transfer this data to other light bulbs that you can purchase. Each transfer of data adds about 1/2 % of error.

    Absolute optical radiation measurements in the infrared are even less well developed and errors of several percent are to be expected. Relative measurements are of course quite a bit easier.
    I have done temperature and optical measurements and if I had a choice I would much rather determine the absolute temperature of a material.

    Inferring the absolute temperature of a surface by measuring the total optical radiation (satellite measurements) is even more difficult again. It involves knowledge of the emissivity (across the whole spectrum) and a bunch of other error sources. I think that the absolute accuracy of the satellite measurements are AT BEST +/- 1/2 degree F.

    Cheers, Kevin.

  35. steven mosher,

    Your comment is valid for a single station over the life of that specific instrument. Maybe. Maybe not. The instrument error may not be constant over time. As mentioned in the subject paper, low wind during summer resulted in maximum error. OK, you may say, on a year to year basis the bias is the same. That would hold true if windiness and cloudiness are constant year over year. Are you willing to assume that much?

    Of course, we’re not only interested in the single site, single instrument temperature measurements. We want to incorporate this ‘biased’ set of data into our existing network of observations. Do we just slap in the data without regard to the sometimes 0 C, sometimes up to 10 C, errors? I should hope not. How does one quantify the uncertainty we introduce? Or should we give it CRN 5 “DEFECTIVE” sticker and toss it on the junk pile?

  36. A solar bias could be critical. If I remember correctly we just passed the peak of summer time exposure due to the interaction of planetary tilt and the earth’s orbit.

  37. It seems that the shield shown here is representative of Gill-style multi-plate radiation shields: http://www.youngusa.com/products/2/11.html
    If so, the angle of the louvers or plates makes it easy to see how solar radiation could warm the core from highly reflective ground cover (snow), particularly if the sun is low in the sky (arctic condition).
    For comparison, an aspirated shield like that they seem to use as a reference for the temperature comparison is shown here:

    http://www.youngusa.com/products/2/16.html

  38. “steven mosher,

    Your comment is valid for a single station over the life of that specific instrument. Maybe. Maybe not. The instrument error may not be constant over time. As mentioned in the subject paper, low wind during summer resulted in maximum error. OK, you may say, on a year to year basis the bias is the same. That would hold true if windiness and cloudiness are constant year over year. Are you willing to assume that much?
    ####

    I would not assume any of that. I think it’s important to understand the ways in which the bias can matter as well as the ways in which it would matter less than most people imagine. So, for example. If I have a scale that aways reads 10 lbs too heavy and I’m trying to measure your weight gain or loss, and for 30 years you hit the scales at 210 ( when truth is at 200) then that bias, since it is constant, doesnt impact my estimate of the trend, which is 0. So, obviously if windiness and cloudiness change in non uniform ways you’ve got an issue. duh. (They had similar problems with arctic instruments as well.) Personally, I’d lean toward dumping the bad data rather than trying to adjust it or trying to assume away impacts. However, It’s always fascinating to see how the answers dont change much when you take the three different paths:

    1. keep the data. 2 dump the data. adjust the data.

    In the end I would always look at all three paths and report out the answer. I would not assume anything. I’d just do the sums. But philosophically i lean toward dumping bad data rather than adjusting it and living with the uncertainty that sparseness creates. CLS in polar regions is very seasonally dependent ( at least in the arctic where it varies between 300km and 1000km depending on the season. )

  39. There is a bit of chatter here on how hard it is to measure temperature. And this is most true. We develop a methodology of artifices that incorporate a presumption of physical perfection to often measure a sense rather than a constant, the subject of which is changing temperature constantly. And all are given to supposition.
    Thus I find it intriguing that Warmists can measure the temperature of an entire planet or any sub-part thereof down to a tenth of a degree and project the same seasonally, annually, and even out to a century with absolute certainty.

  40. Dave Wendt,

    Might be true but I am having a problem understanding how that is possible. Water vapor is a much more powerful GHG than CO2. Any significant water vapor in the atmosphere basically swamps CO2 to the point where CO2 is a negligible contributor to greenhouse warming.

    Summer at the poles see a breakdown of the circumpolar jet, mixing of the upper atmosphere with gas from lower latitudes and a great increase in atmospheric water vapor. Winter sees the polar atmosphere more sequestered from moisture in lower latitudes, what moisture there is precipitates out, the air gets extremely cold, extremely dry, and CO2 (which doesn’t change in atmospheric content between winter and summer). So in winter CO2 is a much larger proportion of total atmospheric GHG than in summer, the additional evaporation of snow in winter notwithstanding.

    I can’t see any way CO2 is going to result in 1/3 of the greenhouse warming during any season, there just isn’t enough CO2 to do that. We are talking about a trace gas here, not something that makes up any significant portion of the atmosphere, and a gas that isn’t really that potent of a GHG.

    I would venture that the surface temperature at the south pole in winter is due more to adiabatic warming than any “greenhouse” warming. In fact, there can’t be any greenhouse warming at the South pole in winter. Greenhouse warming means solar radiation is converted to heat, this IR is captured and re-radiated back to Earth. There is no solar radiation reaching the surface in austral winter so there can be no greenhouse warming.

  41. R. de Haan says:
    August 10, 2011 at 12:55 pm

    Nail after nail after nail driven into the AGW coffin.

    The metaphor I prefer is, “one more arrow in the elephant.” At some point a “last straw” arrow will drop the beast to its knees, and it’ll be all over but the dining.

  42. Latitude says:
    August 10, 2011 at 5:07 pm

    irritable climate syndrome…

    Excellent! I’m going to use that in place of CAWG in the future.

  43. Anymore on Steig’s latest paper about Rosby waves? That one’s the real coffin nail for his 09 paper in Nature.

  44. Spot o, Steve T and Latitude.

    In my opinion ultimately, a defective instrument is just that, defective, giving wrong data. Any data or reading from a defective instrument is considered null and void in any other field of science. Only in climate science we always hear the reply ” but it does not matter or alter the overall conclusions ” when defective data and dubious methods are uncovered.

  45. If they are defective because of direct sun shine, I have always found a that shade fixes the problem. Put a roof over them, a little parasol designed for 200 mph winds and the problem fixed.

  46. A long time ago, at the times of school a good professor of physics used to say to us:
    “Keep in mind, thermometers always measure the temperature of themselves! When you’ll use a thermometer always handle with care the result of the measurements”
    Looks to me that too much people in the climate arena should learn that teaching.

  47. Just to help out Real Climate with a response here…..

    “A more likely cause of the warming is due to the increased concentration (AG) of CO2 inside the AWS’s Stevensen Screen which now retains more of the radiated heat entering from outside. This increased heat also melts more of the ice inside the screen raising the water vapour concentration and amplifying the increase a further 3 x. These findings are in line with IPCC model predictions and provide further proof of man made greenhouse gas induced warming.”

    There Gavin – That should fix it for you …. :-)

  48. @Mosher: “If the sensor has a bias and you never change the sensor, then taking an anomaly effectively removes the bias because what you are concerned about is the trend and not the absolute temperature.”

    We aren’t really interested in thermometer measurements over the last 20 years because they are too short to have any significance, so presumably we are comparing mercury thermometer readings with electronic thermometer readings and voila we have a discrepancy of over 10 Celsius in readings “on sunny days” which presumably is many days in Antartica since the poles have very low precipitation. Hence we have a major bias in the data that occured in the last 20 years towards greater “warming” in the readings as taken. Pretty obvious really that this was a possibility and any decent scientist would have taken this possibility of sytematic error into account but it isn’t even mentioned by Team AGW.

    I notice that the electronic thermometer at Ross-on-Wye in UK shows readings 1-2Celsius higher than the mercury thermometer that was replaced when the station was revamped and re-opened by TV weatherman Ian McCaskill in 1985. It’s obviously a widespread problem. Technological progress will ensure that not only is there likely to be more carbon burnt but more of the old manual thermometers will be replaced by electronic thermometers – an excellent source of systematic error .

  49. Are the data averaged over each grid? And what size are the grids? A number of 250,000 sq.km. grids appear to have no stations or at most one. Others (mainly on or near the West Coast, which is most affeted by wind) are reasonably populated. If we are questionning the reliability of the data, should we attach the same weight to areas where there are no, or relatively few, thermometers as we do to those where we have a number of (hopefully) fairly consistent readings?

    If there are a number of thermometers in the same grid we can discard the results from those giving extreme readings, not just the outliers but any outside, say, the interquartile range. Then unless the bias is widespread we should obtain some fairly meaningful results. The trouble is that unless there are a reasonable number of thermometers in the grid this would not be possible and with none or only two or three there is no way of ensuring that bias has been eliminated or even reduced. Hence to give the same weight to those grids where thermometers are plentiful as to those where they are rare or non-existant is to introduce yet another bias.

    When I read, as I did some time ago, that in cases where for some reason or other there are no data or some data is missing and therefore the data has been extrapolated (or intrapolated) from adjacent data, I begin to wonder how any climate scientist can ascribe a high level of probability to their models.

  50. Ryan says:

    presumably we are comparing mercury thermometer readings with electronic thermometer readings and voila we have a discrepancy of over 10 Celsius in readings “on sunny days” which presumably is many days in Antartica since the poles have very low precipitation. Hence we have a major bias in the data that occured in the last 20 years towards greater “warming” in the readings as taken. … It’s obviously a widespread problem.

    This implies that, now that the transition to electronic thermometers is about complete, global temperatures should stop rising. If greater cloudiness occurs, thanks to the Svensmark effect, a sharper-than-expected decline in temperatures will occur.

  51. steven mosher says:
    August 10, 2011 at 2:53 pm
    “August 10, 2011 at 12:25 pm

    “up to 10°C” – compared to what? Presumably true air temperature. If the old thermometers had a similar bias, then this wouldn’t contribute to a false warming, just that the temperature records are poor and too warm from sunny periods.”

    If the sensor has a bias and you never change the sensor, then taking an anomaly effectively removes the bias because what you are concerned about is the trend and not the absolute temperature. The other thing is with the bias only happening under certain conditions, you will end up with a more noisy anomaly. If you change sensors from one that has a too warm bias to one that is correct you will induce an artificial cooling trend.

    Silly me! I would just throw out the bad data and start over.

    We can’t assume the inaccuracies and biases just somehow average out. That’s poor science.

  52. @ “Mike says: August 10, 2011 at 12:05 pm [Fixed, and insults snipped. ~dbs, mod.]”

    You ‘fixed’ one occurrence. The other is clearly intentional. I’ll stand by my ‘insults’ but you snip whatever you wish.

    Watts: “…false warming signal.”

  53. crosspatch says:
    August 10, 2011 at 10:21 pm
    Dave Wendt,

    Might be true but I am having a problem understanding how that is possible. Water vapor is a much more powerful GHG than CO2. Any significant water vapor in the atmosphere basically swamps CO2 to the point where CO2 is a negligible contributor to greenhouse warming.

    H2O is indeed the dominant GHG. As I understand it the only reason that CO2 is responsible for such a seemingly significant portion of DLR at the South Pole is that it’s one of the driest places on Earth. Even at its seasonal max H2O is still incredibly scarce there. Although the CO2′s contribution of one third to total DLR seems significant, the total DLR at the Pole is never more than a fraction of what is seen elsewhere (60-120W/m2 compared to well over 400W/m2 over much of the Tropics) See Figs. 8 & 9 in the paper I linked above. Data that Evans and Puckrin collected using similar techniques suggest that when H2O is responsible for more than 200W/m2 of DLR CO2′s contribution is dramatically suppressed. A situation that prevails over most of the planet, most of the time

    http://ams.confex.com/ams/Annual2006/techprogram/paper_100737.htm

  54. Let’s get this straight. We are going to spend $28 trillion to save us from warming, that is caused by a $2 heat shield?

    .

  55. The recent figures of a temperature anomaly of warming, it was stated that though the northern hemisphere showed cooling the southern hemisphere showed that the world was warming? This with the sparseness of thermometers in the south would give the warming!!! So cooling is happening it is a measurement anomaly, that shows warming.

  56. Having worked at the Pole during the ’03 Summer, the local and remote weather sensors are often times erroneous due to ice crystals, wind, ice berms etc.,

    The ‘inspection’ of the remote stations is so random it’s a true shame from a climatological standpoint.

    I and another weather person volunteered and was flown to dig out these stations and their sensors. This is obviously not implemented during the winter.

    These stations are dated, never calibrated and troubleshot. Then again, Raytheon Polar Services Corporation, the NSF and SPAWAR (i.e. government contract, good enough for government work-type) run the Pole’s day-to-day, shoddily.

    The next year I did a Summer at McMurdo Station, whereas the meteorological operations is a private company, Scientific Research Corporation. Lo and behold, a wonderful experience (though the food at Pole is infinitely better!) due to having state-of-the-art equipment, not DOS-era that is THEE software of the Pole. You know, unlike a government/government funded (tax dollar siphoned..) where accountability, balanced budget and strong work ethic is expected.. unlike Pole’s joke of a ‘weather ops’ facility.

  57. Several people – including the original writer – have mentioned “low angles” of the sun, but nobody (yet) has actually called out what those “low angles” actually are.

    Angles will vary based on latitude and time-of-day – just as they do in the high Arctic – but the following is typical:
    Latitude 70 south: Sept, max angle, at noon during the equinox, = 20 deg.
    Latitude 80 south: Sept, max angle, at noon during the equinox, = 10 deg.

    Latitude 70 south: Dec, max angle, at noon during the summer, = 43.5 deg.
    Latitude 70 south: Dec, “sunset” angle, at 1800 during the summer, = still 23.5 deg.
    Latitude 70 south: Dec, min angle, at midnight during the summer, = 3.5 deg.
    Latitude 70 south: Dec, “sunrise” angle, at 0600 during the summer, = back at 23.5 deg.

    Latitude 80 south: Dec, max angle, at noon during the summer, = 33.5 deg.
    Latitude 80 south: Dec, “sunset” angle, at 1800 during the summer, = still 23.5 deg.
    Latitude 80 south: Dec, min angle, at midnight during the summer, = 13.5 deg.
    Latitude 80 south: Dec, “sunrise” angle, at 0600 during the summer, = back at 23.5 deg.

    Second, the “low angle” of the sun during that whole period of time that the sun is above the horizon during all dates between September and March – is amplified because all of the reflected energy from the (typical) ice and snow around almost every Antarctic station bounces back “up” off of the ground ice and snow at the same low incidence angle it came in from.

    Looking at the weather screen in the link above, that means all the reflected energy from the sun for 6-18 hours of every day feeds back “up” into the thermometer right between the down-ward-sloping sun “screens”. This will NOT happen further north, back up in civilized areas where the thing was designed and tested and calibrated.

    What are the differences? Much less ground reflection (no ice, no snow all year); what energy IS reflected from the limited ice and snow present during limited parts of the year further north is coming in at higher angles, that energy is reflecting up at higher angles, and so both the inbound energy and the reflected energy is better blocked by the downward-sloping screens. Also, at virtually all locations further north, reflections are blocked by nearby buildings, trees, rocks, and hills/environment. An isolated weather station will have fewer buildings and no trees and hills blocking the sun. (Most can even get placed so there is no blocking buildings or trees at all. Thus, in the Antarctic field installation, the sun is coming in from all angles all day and night during parts of the year.

    This far south, the sun “rotates” all the way around the horizon: so the sun is not coming in from only the “expected” east-in-the-morning, west-in-the-evening – but will be coming in at midnight from the south, at 0600 from the east, at noon from the north, and at 1800 from the south again. 24 hours of heat radiation, all of it doubles from the sky and the ground.

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