I’ll have a lot more on this study later, but for now just a short rebuttal.
I believe this study is hopelessly flawed due to the fact that the authors take the data from the weather stations at face value without considering bias due to measurement error or siting error, both of which are rampant in the US surface station network.
Read my report at left.
While not all situations with poorly sited weather stations affect trends, a weather station like this one at the University of Arizona’s parking lot in front of the atmospheric science department is represenative of the kinds of problems that would lead to an increased number of new high temperature records set.
Plus then there’s the error problem. For example we saw this summer that Honolulu set new record highs, but they turned out to be in error. The kicker is that NOAA let the records stand anyway! The problem is that a number of climate stations are at airports. Watch this NWS employee say on record that these airport weather stations are “placed for aviation purposes…not necessarily for climate purposes.”
So take this NCAR study with a grain of salt, since the authors did not address any of these issues.
From NCAR: Record High Temperatures Far Outpace Record Lows Across U.S.
BOULDER—Spurred by a warming climate, daily record high temperatures occurred twice as often as record lows over the last decade across the continental United States, new research shows. The ratio of record highs to lows is likely to increase dramatically in coming decades if emissions of greenhouse gases continue to climb.
“Climate change is making itself felt in terms of day-to-day weather in the United States,” says Gerald Meehl, the lead author and a senior scientist at the National Center for Atmospheric Research (NCAR). “The ways these records are being broken show how our climate is already shifting.”
This graphic shows the ratio of record daily highs to record daily lows observed at about 1,800 weather stations in the 48 contiguous United States from January 1950 through September 2009.
Each bar shows the proportion of record highs (red) to record lows (blue) for each decade. The 1960s and 1970s saw slightly more record daily lows than highs, but in the last 30 years record highs have increasingly predominated, with the ratio now about two-to-one for the 48 states as a whole. [ENLARGE] (©UCAR, graphic by Mike Shibao.) News media terms of use*
The study, by authors at NCAR, Climate Central, The Weather Channel, and the National Oceanic and Atmospheric Administration (NOAA), has been accepted for publication in Geophysical Research Letters. It was funded by the National Science Foundation, NCAR’s sponsor, the Department of Energy, and Climate Central.
If temperatures were not warming, the number of record daily highs and lows being set each year would be approximately even. Instead, for the period from January 1, 2000, to September 30, 2009, the continental United States set 291,237 record highs and 142,420 record lows, as the country experienced unusually mild winter weather and intense summer heat waves.
A record daily high means that temperatures were warmer on a given day than on that same date throughout a weather station’s history. The authors used a quality control process to ensure the reliability of data from thousands of weather stations across the country, while looking at data over the past six decades to capture longer-term trends.
This decade’s warming was more pronounced in the western United States, where the ratio was more than two to one, than in the eastern United States, where the ratio was about one-and-a-half to one.
The study also found that the two-to-one ratio across the country as a whole could be attributed more to a comparatively small number of record lows than to a large number of record highs. This indicates that much of the nation’s warming is occurring at night, when temperatures are dipping less often to record lows. This finding is consistent with years of climate model research showing that higher overnight lows should be expected with climate change.
In addition to surveying actual temperatures in recent decades, Meehl and his co-authors turned to a sophisticated computer model of global climate to determine how record high and low temperatures are likely to change during the course of this century.
The modeling results indicate that if nations continue to increase their emissions of greenhouse gases in a “business as usual” scenario, the U.S. ratio of daily record high to record low temperatures would increase to about 20-to-1 by mid-century and 50-to-1 by 2100. The mid-century ratio could be much higher if emissions rose at an even greater pace, or it could be about 8-to-1 if emissions were reduced significantly, the model showed.
The authors caution that such predictions are, by their nature, inexact. Climate models are not designed to capture record daily highs and lows with precision, and it remains impossible to know future human actions that will determine the level of future greenhouse gas emissions. The model used for the study, the NCAR-based Community Climate System Model, correctly captured the trend toward warmer average temperatures and the greater warming in the West, but overstated the ratio of record highs to record lows in recent years.
However, the model results are important because they show that, in all likely scenarios of future greenhouse gas emissions, record daily highs should increasingly outpace record lows over time.
“If the climate weren’t changing, you would expect the number of temperature records to diminish significantly over time,” says Claudia Tebaldi, a statistician with Climate Central who is one of the paper’s co-authors. “As you measure the high and low daily temperatures each year, it normally becomes more difficult to break a record after a number of years. But as the average temperatures continue to rise this century, we will keep setting more record highs.”
An expanding ratio
The study team focused on weather stations that have been operating since 1950. They found that the ratio of record daily high to record daily low temperatures slightly exceeded one to one in the 1950s, dipped below that level in the 1960s and 1970s, and has risen since the 1980s. The results reflect changes in U.S. average temperatures, which rose in the 1950s, stabilized in the 1960s, and then began a warming trend in the late 1970s.
Even in the first nine months of this year, when the United States cooled somewhat after a string of unusually warm years, the ratio of record daily high to record daily low temperatures was more than three to two.
Despite the increasing number of record highs, there will still be occasional periods of record cold, Meehl notes.
“One of the messages of this study is that you still get cold days,” Meehl says. “Winter still comes. Even in a much warmer climate, we’re setting record low minimum temperatures on a few days each year. But the odds are shifting so there’s a much better chance of daily record highs instead of lows.”
Millions of readings from weather stations across the country
The study team analyzed several million daily high and low temperature readings taken over the span of six decades at about 1,800 weather stations across the country, thereby ensuring ample data for statistically significant results. The readings, collected at the National Oceanic and Atmospheric Administration’s National Climatic Data Center, undergo a quality control process at the data center that looks for such potential problems as missing data as well as inconsistent readings caused by changes in thermometers, station locations, or other factors.
Meehl and his colleagues then used temperature simulations from the Community Climate System Model to compute daily record highs and lows under current and future atmospheric concentrations of greenhouse gases.
About the article
Title: “The relative increase of record high maximum temperatures compared to record low minimum temperatures in the U.S.”
Authors: Gerald A. Meehl, Claudia Tebaldi, Guy Walton, David Easterling, and Larry McDaniel
Publication: Geophysical Research Letters (in press)
RRKampen, I am sick and tired of your BS. You do not respond to anyones refutations and you do not provide any substantive proof of your claims. To dismiss temperature monitoring inaccuracies as nonsense, without explaining why it is nonsense, does not wash. As I said previously, I feel sorry for you. I hope you do not work in this field, as you are unqualified.
Anthony-
Maybe I’m being overly picky, but in your stations review: for all the charts at the end of the report, is that the raw data or homogenized data? Would that be important to note in the report?
REPLY: Well there are several charts in the report, without know which ones you are referring to I can’t say. If you are referring to station siting data the question is moot, since it is never homogenized. – Anthony
(Corrected version, once more I forgot a closing tag for italics)
Re: Ralph (02:23:18) :
Here ıs some of the raw data for the CET. Now the scales may be a bıt smaller, but can you see a great rıse ın temperature ın the 1980s??
http://www.cru.uea.ac.uk/cru/climon/data/cet/
So how dıd the Hadley offıcıal graph suddenly develop that great rıse ın temperature??
Same pattern in Holland. We call it the ‘temperature jump’ and it is as of 1988.
It is real.
Gene:
It’s not just the dust bowl (which didn’t just affect the US if I recall, Australia was also hard hit).
This was posted earlier, and verifies that many of the extreme temperatures were observed during that period.
It’s not just a black eye for the study, it is a fatal flaw.
Since they had all the data they should have easily been able to break down the last 10 years individually (2000-2009). I wonder why they didn’t show that chart?
RR Kampen (05:24:49) :
‘Sew’, Ron? Nice one 🙂
“Eindhoven just broke the november second decade record, +17.3° up from +17.1° C in 1995; more stations will follow tomorrow”.
So what, is the town on fire, are people dying? Do we have to raise the dykes by 7 meter and close down Pernis, Schiphol and distribute personal carbon allowances?
Take all cars from the roads and drive horse carts again?
Your pushing pure alarmism.
Ok, I’ll be more specific. 🙂 Starting on page 18 through page 28, From GISS raw and adjusted station data is available. Just wondering which data you use for those temperature charts.
REPLY: raw data from GISS.
Ron, you are pushing paranoia! Where have I ever posted ‘alarm’?? Have you remembered I am on Lomborg’s side as to taking measures against AGW? Will you remember imo Kyoto was and is total rubbish? Thank you. Back to temperature and (global) climate (change) then.
David Ball, I do not always have the time to sort out nonsense refutations. Also I do not tend to answer identical questions more than once.
If ever you can prove temperature monitorings all over the world to have gone wrong all of a sudden in the past few decades, then you will have to prove the freezing point of water went down in just about all of the mountain regions in the world. How is that for a refutation of the idea that all temperature monitoring in the world is inaccurate?
REPLY: Now I’m with David, you’re either an idiot or a zealot incapable of assimilating information. Find someplace else to spew nonsense. – Anthony Watts
Will do, Anthony – this is my last post here. If clear contradictions must make a case, I must have strayed into a church. Goodbye.
REPLY: Taking two unrelated things, measurement environment and a physical law, and demanding the physical law be changed in order to prove the fault of the measurement environment is in fact idiocy and the sort of thing we’ve seen from church before. Such as the edict Galileo had to endure at the hands of the church. His observations were inconvenient, so the church made him say that the physical laws he observed don’t exist. AGW is the new earth centered religion and you’re a cardinal. Congratulations. – Anthony
Then I think you missed my irony. I will state my point without the irony then, for clarity.
If global temperature goes up, there will globally be physical consequences of that.
If global temperature does not change, there will globally be no temperature-related physical changes.
Now what we see is that according to temperature observations, temperatures are going up, as e.g. corroborated by the article opening this thread.
Obviously the possibility instrumental error has to be researched, I can only applaud that.
But if you see physical changes all over the globe which obviously relate to a rise in temperature – e.g. glaciers are receding all over the world with only very few and isolated exceptions – then the thermometer readings indicating a rising trend MUST imply the existence of a REAL phenomenon: real temperature rise.
It MUST imply that IF there is inaccuracy in temperature monitoring, these errors can actually only UNDERestimate the factual temperature increase.
I am leaving out the unlikely fact that apparently virtually all instrumentation virtually all over the world, rural places or not, changed more or less simultaneously as of the latter couple of decades.
I am leaving out the unlikely fact that every shrinking glacier seems to have its own local explanation for shrinking, Kilimanjaro thus, Bolivian Andes so, Himalaya other et cetera – I’m granting you all that.
Many people here are quite knowledgeable qua climate. Virtually none seem to appreciate this simple reasoning though. Contrary so: some get mad at me. THAT is like religious authority, the type of authority that demands me to follow suit in crooked reasoning and to question none. Why?
Now as an aside – I wonder where I’ve left the ‘A’ of AGW in the above! Where’s the alarm?
RR Kampen (07:59:34):
Kampen says he’s stating what he predicts will happen for “clarity”. In fact, what he is demonstrating is that he is controlled by Cognitive Dissonance [CD].
Notice that Kampen does not even admit the third possibility: that the global temperature could decline — yet he labels as ‘religious’ anyone who disagrees with his “simple reasoning”.
A typical response of those afflicted with CD is the use of psychological projection: imputing their own faults onto others. In this instance, Mr Kampen’s own religious belief that global temperatures can only go up, or at the very worst, will stay the same, perfectly demonstrates the closed mind explained in Eric Hoffer’s The True Believer.
Kampen can not even admit the possibility that global temperatures could decline — despite the strong empirical evidence that the planet has already been cooling for most of the past decade. Belief is everything, and facts are simply entities to be juggled until they make sense to the CD ravaged mind.
RR Kampen: Maybe you’re getting harsh comments because you’re often posting a lot of nonsense without checking sources properly. Please see my comments in the October weather thread, where you e.g. claimed that only the northernmost part of Scandinavia was colder than normal in October, when in fact the /southern/ part (at least parts of southern Norway and the whole of Denmark) was colder than normal while the northernmost part was slightly above normal. Germany was also below normal. Granted, the Netherlands was slightly above normal, but just slightly.
RR Kampen you must be new to this site. Anyone with half a brain if they have followed this site will see for themselves that most of the temps monitors, and not just in the U S, are put in warm biased areas, besides that the fact they closed the rural sites or they just close the monitor down altogether. Look at the pictures this site has shown. These pictures arn’t doctored either. On roof tops, next to air condition units, and as the report shows, over asphalt parking lots.
In 1950, great numbers of city streets in a good many cities were constructed of Portland Cement (white) concrete. These were converted over the years to asphalt concrete, substantially increasing the heat island effect. From 1950 to a few years ago, growth of urban areas increased with the continuing housing boom. Houses constructed with asphalt shingles, streets paved with asphalt concrete. Along the San Bernardo freeway, from San Bernardino, CA to Los Angeles, only orange groves to be seen on both sides in 1958. As of today, nothing to be seen but housing tracts. More paved land, fewer green plants, increased temperatures. Heat Island Effect, Heat Island Effect Heat Island Effect.
As a transportation Engineer in about 1972, working for California Department of Transportation in Los Angeles, I made an estimate of how much asphalt concrete in paving there was then (streets and parking lots). My rough estimate (Los Angeles Air Basin) was at least 2300 square miles of asphalt concrete paving.
The conversion from both Portland Cement Concrete (PCC) and plain old sand and gravel parking lots to asphalt concrete paving and the constant increase in area of asphalt shingles was continuous and rapid during the period of time covered by this article, across the entire United States, as was the conversion from raw land or land used for agriculture to urbanization.
Given the huge difference of (increased) area which was converted from raw land, PCC streets and agricultural land to asphalt covered areas, I would have expected a relatively constant increase of temperature over the period of time covered.
I would imagine that the American Asphalt Institute would have good data as to the amount of asphalt which has been put in place over this period of time. While some of this would have been for repaving already existing asphalt concrete streets, most would have been new asphalt concrete covering of previously raw land, and increased area of asphalt shingled new housing. Asphalt, asphalt asphalt equals higher temps, higher temps higher temps. The change due to vast areas being covered with one asphalt covering or another has been tremendous over the last half Century over the entire United States.
My concern in 1972 over the large amounts of area being newly covered with asphalt concrete on a constant basis was that asphalt concrete emits hydrocarbons into the air, and while a small amount per square foot, in total the additional hydrocarbon emissions due to this source were very large. But I worked for what was essentially a highway building agency, there was little interest and a desire to not know. But this also added greatly to the Heat Island Effect in newly urbanized areas as well.
Roger Pielke Sr. reports on the bias and selectivity in climate reporting.
http://pielkeclimatesci.wordpress.com/2009/11/13/bias-in-news-reporting/
Problematic and poorly done selective compilation of biased data gets more attention than seemingly solid science.
LarryOldtimer (09:15:01) :
Urban development is like a giant storage radiator, absorbs heat during the day, lets it out during the night, don`t you think they know this.
Thank you for the PDF. I had no idea it all started with whitewash. That’s appropriate!
Let’s hope that what begins with whitewash must end with the crumbling of the whole AGW edifice.
The infrared photography of the surface stations is a nice touch.
It would be gratifying to see Anthony Watts receive an honorary doctorate for this fine work.
I have lived in Las Vegas for 6 years now and am about 8 miles from the airport as the crow flies. The temperatures reported at the official weather station always seems about 4 to 6 degrees warmer than at our location at an elevation of about 2,700 feet, about a thousand feet above the airport and to the West. Anyway I dug around and found a very interesting history of weather reporting in Las Vegas(including a lot of pictures of the weather stations from way back to evidently current day) at:
http://www.wrh.noaa.gov/vef/headlines/stationhistory.pdf
The bottom line is that the weather is evidently reported from the airport between the runways. Might account for warm temps, and especially warm evenings; around here after dark, you can feel the heat radiating from the concrete where ever you go.
{ RR Kampen (06:12:09) :
(Corrected version, once more I forgot a closing tag for italics)
Re: Ralph (02:23:18) :
Here ıs some of the raw data for the CET. Now the scales may be a bıt smaller, but can you see a great rıse ın temperature ın the 1980s??
http://www.cru.uea.ac.uk/cru/climon/data/cet/ }
Might it be something to do with the PDO.
http://i446.photobucket.com/albums/qq187/bobclive/pdo.jpg
or the sun,
http://i446.photobucket.com/albums/qq187/bobclive/graph.jpg
Not central England urban just Armagh rural, nothing abnormal here.
http://i446.photobucket.com/albums/qq187/bobclive/armagh_air_temp2.jpg
RR Kampen (02:43:09) :
To attribute this phenomenon to measurements gone awry is obvious nonsense. That would, e.g., leave only one explanation for the melting of glaciers worldwide: that the gnomes have reduced the freezing point of water.
Also worldwide the temperaturemeasurements would have gone awry only in the last two decades or so, how strange.
Do not post again concerning gisstemp and global temps until you at least visit cheifIO.wordpress.com. Then come back and refute what you see there. UHI is not the only problem. Gisstemp is unmitigated canine excrement (but at least the dog hasn’t eaten his data yet – as in England).
Hilarious. I didn’t know that a high temperature on a given day had any relevance on a high temperature on a different day in a different year.
This is one of those statistical constructions that’s supposed to seem just logical enough to pass for a valid point.
But all they’re doing is presenting the data in a manner that overemphasizes what we know to be warming in the late 1990’s that carried over into 2000. Makes things look worse than they are, but does not REPRESENT what they are.
As we all know, when you plot the ACTUAL temperatures this trend disappears.
I am waiting on the edge of my seat for the results after Steve McIntyre gets his hands on this data and rips this study to shreds, just like the Hockey Stick.
Indeed interesting that you started by investigating the effects of weathering of Stevenson screen whitewash. Last summer I observed another case of weathering which might be of interest.
The gallery has my long distance view of the Baker City, OR, ASOS at:
http://gallery.surfacestations.org/main.php?g2_itemId=71112
As can be seen, the ASOS is at the end of long unpaved road. This road, surfaced with crushed rock, runs roughly parallel to the main runway of the airport, and is thus probably aligned with the prevailing winds of the area. Were the prevailing winds from the southeast, I might assume a substantial effect on the AWOS temperature readings as the air picked up heat from the surface of the road. However, the prevailing winds appear to be from the northwest, so it may be a rare weather condition that would actually affect the record.
All the same, I noticed something interesting about that road: the surface rock has weathered (darkened) considerably since it was spread. Scratch the surface with your foot, and you will discover the rock immediately underneath is considerably lighter in color. You can see this in my gallery photo at:
http://gallery.surfacestations.org/main.php?g2_itemId=71137
(As I remember, the contrast was significantly greater than it appears in the picture.)
I am surprised that this crushed rock has weathered so much in a short period of time. It would be interesting to know how much the darkening changes the surface (rock) temperature on a calm day. On an occasional day when the wind runs along the road into the AWOS setup, could it fractionally raise the temperature? If so, that effect would have grown gradually over time, without showing a step function that NOAA’s ‘adjustments’ could detect.