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Comments 97351 to 97400:
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Riccardo at 00:58 AM on 27 January 2011A Flanner in the Works for Snow and Ice calculations
Ken Lambert read this again ... "your eq. 2 in #8 is wrong since it applies only for constant F which is the case only in steady state." I think you should put more effort in the definition of the quantities you use. Compare this: "It is the net of all the forcings operating on the climate system." with this "That is all the warming forcings minus all the cooling forcings including S-B and WV and Ice albedo feedbacks." Please clarify what you mean by forcing and what by feedback, I maybe got confused by your ambiguity in the definitions. -
michael sweet at 00:52 AM on 27 January 2011Ten temperature records in a single graphic
HuggyPops Bear, Did you read the graph in the moderator response to you at #5. That gives a 2000 year record. If you search this site you can find the Vostock ice core record which goes back 450,000 years. When you say "Yes if we only rely on figures of the last 150 years or so" immediately after you are given 2000 years of data it appears that you are unwilling to read data you are given. Why didn't you read the data the moderator provided for you? If you only ocnsider the last 150 years of data it might make sense to imagine a natural cycle caused the warming. If you actually look at the much longer data record available it is clear that the warming is not natural. -
Paul D at 00:31 AM on 27 January 2011Rebuttal to 'Scientist's Can't Even Predict The Weather Right'
Harold Pierce (jr?)@48 "After watching weather reports on the TV over 50 years, I have concluded that the earth's climate has not changed much at all." Well maybe 300 or 500 years ago, such an anecdote might be accepted as wise words. But in this day of science, someone watching TV and making a personal assessment doesn't really add to human knowledge or provide any evidence. -
damien at 00:12 AM on 27 January 2011Ten temperature records in a single graphic
"As with all our climate graphics, this is under a Climate Commons license ... " Creative commons? -
Ed Davies at 00:03 AM on 27 January 2011Ten temperature records in a single graphic
@caerbanog #7, are the extra readings the ones differentiated by the "duplicate" field or just the "modifier"? I have to admit that I couldn't understand the description of the duplicate field so my own version of this just ignores it and uses the last data value for each station, but it does take the modifier as part of the station identification. -
Eric (skeptic) at 23:24 PM on 26 January 2011It's not bad
I finally cracked open my new weather calendar. It starts with two rambling pages by Gregory McNamee detailing a few disasters but constantly pointing out benefits (e.g. dust storms fertilizing the oceans) and claiming that scientists are lowering their predictions of sea level rise. Some of what he says is ridiculous, like heavy rain being good for ducks. He ends with "Climate change is a fact. The numbers suggest other facts as well, among them that even if the world's governments too every step possible to counter that change, temperatures are likely to rise worldwide by an average of 3.6 Fahrenheit (2.6C) by the beginning of the twenty-second century. This may well profoundly alter the way our kind conducts its life on Earth. On the other hand, it is unlikely to be as catastrophic as some people fear - and that may be the best good news of all, even as we dream up news ways to keep alive, and even flourish, under a climate change regime." -
Ken Lambert at 22:32 PM on 26 January 2011A Flanner in the Works for Snow and Ice calculations
Riccardo #20 Eqan (2) is not wrong. Read this again.... ""Delta E = F x delta t; where delta t is the time increment t2-t1 and F is a constant forcing. Therefore; Delta T = F x Delta t / K .......Eqan (2) If F was a variable forcing then F x Delta t would be replaced by the integral of function F wrt t."" You can call my 'F' - 'Q' if you like - it does not alter the relationships. I have already covered the case where F is a variable function over time. If I had an integral symbol on my keyboard I could substitute "Fconstant x Delta t" with "integral of function F wrt t". I don't think that you understand that F is the forcing imbalance. It is the net of all the forcings operating on the climate system. In a steady state F will be zero by definition. In a warming state F will be positive and in a cooling state F will be negative. -
Jesús Rosino at 22:29 PM on 26 January 2011Spanish translation of The Scientific Guide to Global Warming Skepticism
MattJ, Alexandre, The nickname fo the translator is "the lie" because his/her blog is "the lie is out there", a wink to "the truth is out there" (from X-Files) but implying that what they said was the truth is in reality the lie (conspiracy theories in general). -
David Horton at 22:27 PM on 26 January 2011Ten temperature records in a single graphic
"does the water heat at a consistent rate from start to finish" - yes, if you apply consistent heat from start to finish! I'm guessing that Mr Bear thinks that the water starting to bubble is a sign of more rapid heating perhaps. -
Riccardo at 22:13 PM on 26 January 2011A Flanner in the Works for Snow and Ice calculations
Ken Lambert your definition of forcing as including, to make it short, everything is quite uncommon; MarkR definition, which is kind of standard, is different. Anyways, given your definition, your eq. 2 in #8 is wrong since it applies only for constant F which is the case only in steady state. Beware, it does not need to "steadily approaches zero as temperature equilibrium is reached". If for example if you have a linearly increasing (in time) forcing (using the standard definition), your F will aproach a constant value different from zero. -
Eric (skeptic) at 21:42 PM on 26 January 2011Arctic icemelt is a natural cycle
Muoncounter, in the Science is Settled thread you said "What is becoming apparent is that prior predictions of these 'larger changes' were conservative. That suggests the natural cycles aren't so natural any more." I agree that the local warming feedback you referred to there is probably underestimated. What you did not consider in that thread is that the (likely natural) cycle of positive AO in the first half of the 90's also contributed to ice loss. What we will need to look at next is whether the ice loss from AGW and local feedback overwhelms the recovery we should see from negative AO and La Nina. Amd as I said in my previous post we still don't know the effect of AGW and ice loss on the AO. -
JMurphy at 21:24 PM on 26 January 2011Ten temperature records in a single graphic
HuggyPopsBear wrote : "My mind asks if it is the last few percentages that heat quicker, why can this not be the same for the atmosphere as we climb out of a mini Ice age?" But does your mind also ask how we are climbing out of that "mini Ice age" ? What are the natural processes involved which are causing that ?Moderator Response: ...which is covered in the Argument "We’re coming out of the Little Ice Age." -
JMurphy at 21:16 PM on 26 January 2011We're heading into cooling
Henry justice, for your own benefit you need to read further on this site. Start here, then look here. After that, look at the list of Skeptical arguments - all yours are covered. If you need to know more, comment on one of the above 'argument' threads. Finally, try to get your information from websites (like this one) that contain facts, figures and rational information - not from dodgy sites like the one you included in your post. -
HuggyPopsBear at 21:14 PM on 26 January 2011Ten temperature records in a single graphic
Thanks Daniel I will ..........Moderator Response: [Daniel Bailey] Per Hansen 2011, we are already at temps equal to the Holocene Maximum now. And still rising... -
Eric (skeptic) at 21:11 PM on 26 January 2011Arctic icemelt is a natural cycle
#27 Trueofvoice, yes, recovery is slower due to the negative AO (and negative NAO) bringing lots of very warm air into NE Canada. It's possible we could see the negative AO regime bringing us less ice in general. #26 Albatross, I agree that it is too short a time period to tell if negative AO is a trend or just a random excursion. The paradox paper in the other thread called it red noise causing episodic behavior. -
HuggyPopsBear at 21:09 PM on 26 January 2011Ten temperature records in a single graphic
Marcus I am in no position nor are any of us to get into a verbal battle, my question was genuine enough though open I suppose for a little satire. I look at a kettle and I ask, does the water heat at a consistent rate from start to finish, or is it just the last say 10% that heats quicker? My mind asks if it is the last few percentages that heat quicker, why can this not be the same for the atmosphere as we climb out of a mini Ice age? Is it unnatural for such a climb? Yes if we only rely on figures of the last 150 years or so. However we know that the world once was warmer and had higher CO2 ppm. We know the pole caps were once fertile places, so why the need before data is proved should one get excited at the prospect of human induced global warming. It could be a natural phenomena.Moderator Response: See the Argument "We’re coming out of the Little Ice Age," and comment further over there. -
Ken Lambert at 19:55 PM on 26 January 2011A Flanner in the Works for Snow and Ice calculations
MarkR #15 The forcing I labelled 'F' is the net imbalance forcing. That is all the warming forcings minus all the cooling forcings including S-B and WV and Ice albedo feedbacks. My F is the net warming imbalance of 0.9W/sq.m currently (09)estimated in the Trenberth paper (Aug09). Riccardo #12 == see above. Energy/time = Power which has the unit Watt (Joule/sec). The unit of area simply divides it into a rate per sq.m. "In your derivation in #8 you omitted the outgoing flux; this is why you get and ever increasing temperature even for a constant forcing, which is unphysical" My forcing F is the *net* forcing as described above. It will not remain constant as the various component forcings change. The main cooling forcing S-B will rise with T^4, so F will be a complex function which steadily approaches zero as temperature equilibrium is reached. ie: "You integrate F(t) wrt time 't'. This effectively gives you the area under the F curve - whatever the F function is and this represents the total energy gained by the mass between times t1 and t2." In reality at time t2, F approaches zero and the total energy absorbed by the Earth system will be equal to the area under the F curve representing (1) equilibrium Temperature rise x specific heat of the masses heated; plus (2) phase change heat of ice melted; plus (3) latent heat of extra water evaporated. -
Dikran Marsupial at 19:51 PM on 26 January 2011Rebuttal to 'Scientist's Can't Even Predict The Weather Right'
h pierce "they don't make predictions or projections and their climate models produce only senarios since phenomena such as clouds, aerosols and in particular black carbon are difficult to model and their effects on climate are not well undersood" No, they are called projections primarily because they are contingent on assumptions about forcings (e.g. anthropogenic carbon emissions), rather than becuase of the limitations of the models. That is why e.g. Hansen gave three emissions scenarios and a projection for each one of them. He didn't know how emissions would evolve, so he could only make projections for a set of scenarios rather than a prediction. Even if the model were perfect, he could still only have made projections. "I doubt the climate scientist can model the pattern of weather for the various regions of the earth for period of about 30 years, for example, from 2070 to 2100. " Of course climate modellers can *model* the pattern of weather for various regions for thirty years, the do so quite routinely. What they can't do is *predict* the pattern of weather for thirty years. But then again, they wouldn't claim that they can becuase climate projections are based on simulating weather not predicting it. -
Arkadiusz Semczyszak at 19:11 PM on 26 January 2011Ten temperature records in a single graphic
I think it's best to look at a graph of temperatures Tamino, or (shorter period of time) here And temperature in the Arctic has its own rights. In one place is growing - in the second falls., because: “North Atlantic Ocean temperatures respond to changes in the Arctic Oscillation, locally represnted by the North Atlantic Oscillation. When temperatures are warmer in northern Europe, they are often colder on the northwest Atlantic side.” -
Ari Jokimäki at 17:37 PM on 26 January 2011Ten temperature records in a single graphic
There's also a new reanalysis: 20th Century Reanalysis. -
garythompson at 17:22 PM on 26 January 2011Ten temperature records in a single graphic
Thanks for the link Bibliovermis. so low volcanic activity in the 30's is one of the main reasons for the warming. i noticed the word used in the site you referenced was 'believed'. was there a graph of volcanic activity superimposed on the temperature graphs of the 20th century to validate that? i didn't see it in the post.Moderator Response: Since this comment is about that other post, the appropriate place to put this comment is on that other thread. -
Bibliovermis at 17:12 PM on 26 January 2011Ten temperature records in a single graphic
Gary, This is addressed in argument #39, It warmed before 1940 when CO2 was low. -
garythompson at 17:05 PM on 26 January 2011Ten temperature records in a single graphic
From the graph in this post, one might surmise that the global temperatures started increasing around 1930. The CO2 data I have seen at the Mauna Loa site goes back to 1958. CO2 concentrations didn't really start accelerating until the 70's from that data. What is the explanation for the beginning of the temperature rist in the 30's? -
Trueofvoice at 16:18 PM on 26 January 2011Rebuttal to 'Scientist's Can't Even Predict The Weather Right'
"I doubt the climate scientist can model the pattern of weather for the various regions of the earth for period of about 30 years, for example, from 2070 to 2100." No one would bother to try projecting annual variability over a thirty year period. In effect you'd be generating noise to disguise the long-term trend from yourself. -
Albatross at 16:14 PM on 26 January 2011Arctic icemelt is a natural cycle
True @27, Essentially, in broad terms, yes. Arctic sea ice extent in December 2010 and January 2011 have been running at or near record lows. Hudson Bay only froze over completely over a month later than average. There is still no sea ice along the Labrador coast. -
Trueofvoice at 16:08 PM on 26 January 2011Arctic icemelt is a natural cycle
Re # 23, Am I missing something? A negative Arctic Oscillation allows cold Arctic air to slide south, while warmer southern air moves north. Wouldn't this effectively slow recovery of the ice during winter? -
Albatross at 15:43 PM on 26 January 2011Ten temperature records in a single graphic
Great Job Robert and John, thanks for this. Hope generating the ERA-interim global SAT data was not too much work. There is one more data set that one could add, and it may not be too much work....the RATPAC data. Gosh golly, look at this, RATPAC shows more warming than the surface data and shows 2010 to be the warmest on record....
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Albatross at 15:36 PM on 26 January 2011Arctic icemelt is a natural cycle
Eric @25, Actually I agree with you re #24. With that said, we have had two winters, back-to-back as it happens with incredibly low bouts of the AO, but two data points are obviously not enough to establish whether or not this marks the beginning of a long-term trend. I'm curious to see whether this is evidence of a transition to a new state or simple internal climate variability. Time will tell. The mechanisms and physics behind Arctic amplification in this case, are very well established. -
muoncounter at 15:05 PM on 26 January 2011The science isn't settled
#59: "New theories are nice, but not a sign of "Settled Science"." According to Serreze and Francis 2005, Recognition of the ice-albedo feedback as an important climatic process can be traced to the early work of Croll (1875). That hardly makes it a 'new theory.' Further, Our synthesis of the available evidence points to the Arctic as in a state of preconditioning, less advanced than that shown in the ACIA simulations for 2010–2029, but setting the stage for larger changes in future decades. This preconditioning is characterized by general warming in all seasons, a lengthened melt season, and an initial retreat and thinning of sea ice, all accompanied by strong expressions of decadal-scale climate variability. What is becoming apparent is that prior predictions of these 'larger changes' were conservative. That suggests the natural cycles aren't so natural any more. -
Eric (skeptic) at 14:58 PM on 26 January 2011Arctic icemelt is a natural cycle
Muoncounter, you are looking at short term fluctuations. Last year AO also looked like it bottomed in December but then hit an all-time low (since 1954) in February. -
muoncounter at 14:50 PM on 26 January 2011Arctic icemelt is a natural cycle
#23: "we're still in strongly negative territory" What you're looking at is the three month running mean, which is strongly negative, but that's a hindcast. The daily record and the forward looks are here:
-- replaces the auto-updating graph.
Sure looks like it bottomed in mid December.
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Eric (skeptic) at 14:39 PM on 26 January 2011The science isn't settled
I am asking what happened to the old theory of amplification by positive AO. New theories are nice, but not a sign of "Settled Science".Moderator Response: Thank you for parsing this comment and the previous one into the relevant threads! -
Eric (skeptic) at 14:37 PM on 26 January 2011Arctic icemelt is a natural cycle
muoncounter, thanks for the AO link, but I already look at that almost every day since it affects my own weather (an aside: AO predictions this year have been less accurate than usual). That site has the long term trends here http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/month_ao_index.shtml and we're still in strongly negative territory. As I said on the other thread, AGW is responsible for ice loss. AO is also a factor and negative AO should bring a recovery in ice. Another factor is last year's El Nino and a decline in ice. This year should see a continued recovery due to negative AO if that theory holds (paper linked on other thread). That still leaves the question on the other thread of the effects of AGW on AO according to models. -
muoncounter at 14:26 PM on 26 January 2011The science isn't settled
#57: Eric, Look at this AO time series, which has AO going positive very soon and respond here. Between Serreze (autumn warmth), Flanner (decreased albedo in the Arctic Ocean) and Tedesco (decreased albedo in Greenland), what part of arctic amplification do you object to? -
Eric (skeptic) at 14:06 PM on 26 January 2011The science isn't settled
#55 muoncounter, Serreze et al doesn't explain why the models predict higher AO when AO is going lower. The paper references this 1998 paper with the same model-predicts-positive-AO theme http://tinyurl.com/6gy9zl9 in the context that these other factors like AO might have something to do with some of the ice loss. Then they drop the subject. The specific paper that I would be delighted to read is the one that explains why AO is not going positive like the models predict. #56 Bibliovermis, the term CAGW is disliked by some here, but what I am trying to do is distinguish between the settled science of AGW and the extreme Arctic warming predicted in the models due to positive AO feedback loop and the amplification that the Serreze describes. -
Marcus at 13:56 PM on 26 January 2011Ten temperature records in a single graphic
Well, Huggy, given that the primary source of past warming-The Sun-has been in a *cooling* cycle for the last 30 years, it suggests the current warming trend is moving in the *opposite*-accelerating-direction to that which the *Natural* forcings would suggest. Of course, Huggy, I'd also be interested to know what natural phenomenon could cause the lower atmosphere to *warm*, whilst simultaneously causing the upper atmosphere to cool. Oh, but why believe what I say? I might just be one of those evil "government types" trying to make you pay a carbon tax....give me a *break*!!! -
Bibliovermis at 13:40 PM on 26 January 2011The science isn't settled
It appears to me that CAGW originated with the Oregon Petition. The distinction is an ideological argument ranging in form from "it's not bad" to "climate sensitivity is low". What is catastrophic is a subjective quality, unless an objective definition is developed; such as with "likely" in the IPCC reports. -
muoncounter at 13:31 PM on 26 January 2011The science isn't settled
#54: "help explain why ice decreased more than expected (than from AGW alone)" Eric, the Polyakov and Johnson paper is from 2000; the alaska scienceforum paper from 2002. Since that time, a lot more ice has gone. Serreze 2009 speaks of arctic amplification as just emerging in the late '90s, a signal that would not be evident to the papers you cite. As the climate warms, the summer melt season lengthens and intensifies, leading to less sea ice at summer’s end. Summertime absorption of solar energy in open water areas increases the sensible heat content of the ocean. Ice formation in autumn and winter, important for insulating the warm ocean from the cooling atmosphere, is delayed. This promotes enhanced upward heat fluxes, seen as strong warming at the surface and in the lower troposphere. And of course, continued sea ice discussion should go on the appropriate thread. -
climatesight at 13:29 PM on 26 January 2011Ten temperature records in a single graphic
Thanks for making that, Robert. I've been looking for a single graphic like this to use in presentations for a while! -
David Horton at 13:03 PM on 26 January 2011Ten temperature records in a single graphic
The major proposition among deniers seems to have recently shifted from "it's not warming" (since 1998 or whenever) to "well of course it's warming" (we are at the end of, beginning of, part of a natural cycle because ...). I suppose, if you were an optimist, see this as a small step for a denier, large step for mankind, but since I'm not ... But I do wonder how you can look at a graph like this excellent one of John's and somehow convince yourself that it is perfectly obvious that the rapid temp rise you see over the last 100 years, especially the last 40 years, just happens, by an astonishing coincidence, to coincide with the the massive increase in industrial activity that began in the industrial revolution and the consequent massive measured increase in CO2 levels. I cannot begin to imagine how you could continue to hold a belief in a coincidence of that kind. -
Eric (skeptic) at 13:00 PM on 26 January 2011The science isn't settled
AGW is settled by physics and observations. However, CAGW is posited by models which say AO will go more positive as part of a positive feedback of less ice, more positive AO, more warming. See http://www.cccma.ec.gc.ca/papers/jfyfe/PDF/FyfeBoerFlato1999a.pdf and http://www.cccma.ec.gc.ca/papers/ngillett/PDFS/gcm_aochange.pdf (2002). But by about 2002 we started seeing the "paradox" http://www.atmos.colostate.edu/ao/other_papers/GRL2005-Arctic-Paradox.pdf: "We are left with an apparent paradox of more linear Arctic climate change beginning in the late 1970's and the more episodic AO." The authors don't provide an answer to the paradox. But all the authors above acknowledged that natural factors like volcanoes can have a large effect. At the same time models were being used to predict secular increases in AO (and the positive AO of the early to mid 1990's minus Pinatubo was being touted as part of that increase) other researchers were positing natural cycles (e.g. Polyakov and Johnson http://denali.frontier.iarc.uaf.edu:8080/~igor/research/pdf/50yr_web.pdf described here http://www2.gi.alaska.edu/ScienceForum/ASF15/1582.html) to help explain why ice decreased more than expected (than from AGW alone). P&J used a coupled ocean-atmosphere model of the Arctic driven by historical measurements to plot the cycles. Their implicit prediction of the current negative AO turned out to be accurate. Now negative AO is being misconstrued as a consequence of ice loss, but it is not since the models have considered ice loss and Arctic temperature anomalies all along and have predicted positive AO. So nobody misunderstands, I am not saying that the bulk of the GAT increases are from these natural cycles, they are not, they are AGW. -
Daniel Bailey at 12:59 PM on 26 January 2011Ten temperature records in a single graphic
@ caerbannog (7) Thank you for demonstrating the scientific method in action! The Yooper -
scaddenp at 12:55 PM on 26 January 2011Rebuttal to 'Scientist's Can't Even Predict The Weather Right'
Going to provide us with statements from actual climatologists in which they state that they are a sub-branch of meteorology? Climatology talks about scenarios rather than predictions because you cannot predict how societal factors will affect forcings (ie aerosols, GHG). They then DO predict (any no. of papers) what you will get for climate for a given scenario, SUBJECT to the uncertainties of various sorts, just like every branch of science does. "After watching weather reports on the TV over 50 years, I have concluded that the earth's climate has not changed much at all" So your memories of TV reports are more reliable than all those carefully measured indices done on a global basis? You expect this statement to be taken seriously? "However, in the long term weather enventally returns to its normal pattern." "Normal" is climate. Are you trying to suggest that climate cannot change? How about providing some backing for these assertions? -
Gordon1368 at 12:45 PM on 26 January 2011Ten temperature records in a single graphic
Huggy, this proves nothing, because it is not intended to be proof of anything. It is a small piece of the large amount of evidence we have that the warming we are experiencing is unnatural. -
muoncounter at 12:40 PM on 26 January 2011Rebuttal to 'Scientist's Can't Even Predict The Weather Right'
#48: "a theoretical branch of meteorology" Or perhaps climatology is actually defined as "the study of climate, scientifically defined as weather conditions averaged over a period of time, and is a branch of the atmospheric sciences." "their climate models produce only senarios" Please refer to the rebuttal to Models are unreliable if you want to learn about climate modeling. "After watching weather reports on the TV over 50 years, I have concluded" TV is perhaps not the best place to look for education. I've watched various doctor shows on TV for years, but I wouldn't claim to be ready to do open heart surgery. "the pattern of weather in the various regions of earth are still about the same." OK, now its time to shut the TV off and start looking around the wider world, because there's bad stuff happening out there. See It's freaking cold and Extreme weather for starters. "in the long term weather enventally returns to its normal pattern." That's one you'd have to substantiate, preferably on the extreme weather thread cited above. -
Ron Crouch at 12:36 PM on 26 January 2011Ten temperature records in a single graphic
#8 "the graph is freely available for download............into the wrong hands????" No such thing as wrong hands. That's a primary difference between many skeptics and scientists working to produce constructive answers, the data (all of it) are made available for public scrutiny, not just for the benefit of other scientists and politicians. I'm sure you appreciate being properly informed as well -- don't you? -
muoncounter at 12:29 PM on 26 January 2011Ten temperature records in a single graphic
"And this proves what?" Nicely done, Robert. I make your slope to be about 0.16 deg/decade and rising, right in line with Figure 8 from Assessing surface temperature reconstructions and Tamino's recent gem.
As for what this proves: Until you can show a 'natural cycle' that runs in a straight line for 35 years, this says 'it's not natural.' So much for all that 'ramp and sine' gibberish.
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caerbannog at 12:21 PM on 26 January 2011Ten temperature records in a single graphic
HuggyPopsBear at 11:50 AM on 26 January, 2011 And this proves what? Many graphs have been made but is this a tool refined to enhance government needs to impose a carbon tax on the world. (sniff.. sniff...) Do I smell a Poe??? -
HuggyPopsBear at 12:19 PM on 26 January 2011Ten temperature records in a single graphic
Think you missed my point, in that the graph is freely available for download............into the wrong hands???? -
caerbannog at 12:17 PM on 26 January 2011Ten temperature records in a single graphic
An update to my "Quick and Dirty Analysis of GHCN Surface Temperature Data" guest-post. Due to my failure to RTF GHCN documentation carefully, I implemented an incorrect algorithm. It turns out that multiple stations can share a single WMO identification number. Having failed to read the documentation carefully, I charged ahead and coded up my routine assuming that each temperature station had a unique WMO number. So what happened was that in the cases where multiple stations share a WMO id number, my program used temperature data from just the last station associated with that WMO number with valid data for a given year/month. However, that goof actually *improved* the results over what you would get with a true "dumb average", as Kevin C discovered when he went to reimplement my routine in Python. What happened is that many temperature stations have random data gaps. In cases where multiple stations share a single WMO id, my routine quite accidentally "filled in" missing data from one station with valid data from other stations. That had the effect of crudely merging data from very-closely-spaced clusters of stations, reducing the overweighting problem associated with dumb-averaging, and reducing the impact of big data gaps in single-station data on baseline and anomaly computations. Kevin C demonstrated that a true "dumb average" gives significantly worse results that what I computed. So I went back and tried a little experiment. I changed my code so that the temperature data for all stations sharing a single WMO id were properly averaged together to produce a single temperature time-series for each WMO id. When I did that, my results improved significantly! The differences in the results for raw vs. "adjusted" GHCN were reduced noticeably, showing an even better match between raw and adjusted temperature data. So quite by accident, I stumbled on a method considerably simpler than proper gridding that still gives pretty decent results! This turned out to be a quite accidental demonstration of the robustness of the surface temperature record! I misinterpreted the GHCN data format and still got results darned close to NASA's "Northern Latitudes" index. I'd like to say, "I meant to do that", but instead I should say thanks to Kevin C for uncovering my dumb mistake.
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