Poorly sited U.S. temperature instruments not responsible for artificial warming

By: Dr. Jeff Masters , 5:57 PM GMT on January 25, 2010

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Former TV weatherman Anthony Watts, who runs the popular global warming contrarian website, "Watts Up With That", was convinced that many of the U.S. network of surface weather stations had serious flaws in their siting that was causing an artificial warm bias in the observed increase in U.S. temperatures of 1.1°F over the past century. To address this concern, Watts established the website surfacestations.org in 2007, which enlisted an army of volunteers to travel the U.S. to obtain photographic evidence of poor siting of weather stations. The goal was to document cases where "microclimate" influence was important, and could be contaminating temperature measurements. (Note that this is a separate issue from the Urban Heat Island, the phenomenon where a metropolitan area in general is warmer than surrounding rural areas). Watts' volunteers--650 strong--documented the siting of 865 of the 1,218 stations used in the National Climatic Data Center's U.S. Historical Climatology Network (USHCN) for tracking climate change. As reported in Watt's 2009 publication put out by the Heartland Institute, the volunteers "found stations located next to the exhaust fans of air conditioning units, surrounded by asphalt parking lots and roads, on blistering-hot rooftops, and near sidewalks and buildings that absorb and radiate heat." Watts surmised that these poorly-sited stations were responsible for much of the increase in U.S. temperatures over the past century, due to "a bias trend that likely results from the thermometers being closer to buildings, asphalt, etc." Watts concluded, "the U.S. temperature record is unreliable. And since the U.S. record is thought to be the best in the world, it follows that the global database is likely similarly compromised and unreliable".


Figure 1. A poorly sited temperature sensor in Marysville, California, used for the USHCN. The sensor is situation right next to an asphalt parking lot, instead in the middle of a grassy field, as it is supposed to be. The sensor is also adjacent to several several air conditioners that blow their exhaust into the air nearby. Image credit: surfacestation.org.

Analysis of the data disagrees with Watts' conclusion
While Watts' publication by the Heartland Institute is a valuable source of information on siting problems of the U.S. network of weather stations, the publication did not undergo peer-review--the process whereby three anonymous scientists who are experts in the field review a manuscript submitted for publication, and offer criticisms on the scientific validity of the results, resulting in revisions to the original paper or outright rejection. The Heartland Institute is an advocacy organization that accepts money from corporate benefactors such as the tobacco industry and fossil fuel industry, and publishes non-peer reviewed science that inevitably supports the interests of the groups paying for the studies. Watts did not actually analyze the data to see if taking out the poorly sited surface stations would have a significant impact on the observed 1.1°F increase in U.S. temperatures over the past century. His study would never have been publishable in a peer-reviewed scientific journal.


Figure 2. Annual average maximum and minimum unadjusted temperature change calculated using (c) maximum and (d) minimum temperatures from good and poor exposure sites (Menne 2010). Poor sites showed a cooler maximum temperature compared to good sites. For minimum temperature, the poor sites were slightly warmer. The net effect was a cool bias in poorly sited stations. The dashed lines are for stations ranked by NOAA, while the solid lines are for the stations ranked by surfacestations.org.

Fortunately, a proper analysis of the impact of these poorly-sited surface stations on the U.S. historical temperature record has now been done by Dr. Matthew Menne and co-authors at NOAA's National Climatic Data Center (NCDC). In a talk at last week's 90th Annual Meeting of the American Meteorological Society, Dr. Menne reported the results of their new paper just accepted for publication in the Journal of Geophysical Research titled, On the reliability of the U.S. Surface Temperature Record. Dr. Menne's study split the U.S. surface stations into two categories: good (rating 1 or 2) and bad (ratings 3, 4 or 5). They performed the analysis using both the rating provided by surfacestations.org, and from an independent rating provided by NOAA personnel. In general, the NOAA-provided ratings coincided with the ratings given by surfacestations.org. Of the NOAA-rated stations, only 71 stations fell into the "good" siting category, while 454 fell into the "bad" category. According to the authors, though, "the sites with good exposure, though small in number, are reasonably well distributed across the country and, as shown by Vose and Menne [2004], are of sufficient density to obtain a robust estimate of the CONUS average". Dr. Menne's study computed the average daily minimum and maximum temperatures from the good sites and poor sites. The results were surprising. While the poor sites had a slightly warmer average minimum temperature than the good sites (by 0.03°C), the average maximum temperature measured at the poor sites was significantly cooler (by 0.14°C) than the good sites. As a result, overall average temperatures measured at the poor sites were cooler than the good sites. This is the opposite of the conclusion reached by Anthony Watts in his 2009 Heartland Institute publication.

Why did the poorly sited stations measure cooler temperatures?
The reason why the poorly-sites stations measured cooler temperatures lies in the predominant types of thermometers used at the two types of sites. An electronic Maximum/Minimum Temperature System (MMTS) is used at 75% of the poor sites. These MMTS sensors are attached by cable to an indoor readout device, and are consequently limited by cable length as to how far they can be sited from the building housing the indoor readout device. As a result, they are often located close to heated buildings, paved surfaces, air conditioner exhausts, etc. It turns out that these MMTS thermometers have a flaw that causes them to measure minimum temperatures that are slightly too warm, and maximum temperatures that are considerably too cool, leading to an overall cool bias in measured average temperatures. In contrast, only 30% of the "good" sites used the MMTS sensors. The "good" sites predominantly used Liquid in Glass (LiG) thermometers housed in wooden shelters that were more easily located further from the buildings where the observers worked. Since the poorly-sites stations were dominantly equipped with MMTS thermometers, they tended to measure temperatures that were too cool, despite their poor siting.


Figure 3. Comparison of U.S. average annual (a) maximum and (b) minimum temperatures calculated using USHCN version 2 temperatures. Temperatures were adjusted to correct for changes in instrumentation, station relocations, and changes in the time of observation, making the trend from good sites show close agreement with poor sites. Good and poor site ratings are based on surfacestations.org. For comparison, the data between 2004 - 2008 taken by the new high-quality U.S. Climate Reference Network (USCRN, black dashed line) is shown, and displays excellent agreement for that time period. Image credit: Menne 2010.

Independent verification of recent USHCN annual temperatures
Clearly, the siting of many of the surface stations used to track climate change in the U.S. is not good. To address this issue, in 2004 NOAA created the U.S. Climate Reference Network, a collection of 114 stations in the continental United States for the express purpose of detecting the national signal of climate change. The stations were sited and instrumented with climate studies in mind, and can provide an extremely high-quality independent check on the old USHCN network. Each of 114 stations at 107 locations (some stations were installed as nearby pairs) is equipped with very accurate instruments in a triplicate configuration so that each measurement can be checked for internal consistency. As shown in Figure 3, the USCRN air temperature departures for 2004 - 2008 are extremely well aligned with those derived from the USHCN version 2 temperature data. For these five years, the the difference between the mean annual temperatures measured by the old USHCN compared to the new USCRN was just 0.03°C, with a mathematical correlation coefficient (r-squared) of 0.997. Menne et al. concluded, "This finding provides independent verification that the USHCN version 2 data are consistent with research-quality measurements taken at pristine locations and do not contain spurious trends during the recent past even if sampled exclusively at poorly sited stations. While admittedly this period of coincident observations between the networks is rather brief, the value of the USCRN as a benchmark for reducing the uncertainty of historic observations from the USHCN and other networks will only increase with time". The authors finally concluded, "we find no evidence that the CONUS temperature trends are inflated due to poor siting".

Crediting Anthony Watts
The surfacestations.org effort coordinated by Anthony Watts has made a valuable contribution to science, helping us better understand the nature of the errors in the U.S. historical temperature data set. In his talk last week at the AMS conference, and in the credits of his paper, Dr. Menne had some genuinely grateful comments on the efforts of Anthony Watts and the volunteers of surfacestations.org. However, as of this writing, Watts has made no mention on surfacestations.org or on wattsupwiththat.com of Dr. Menne's study.

I'll have a new post Wednesday or Thursday.

Jeff Masters

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Regardless of whether these stations are warming or not - we need a massive upgrade to our climate network. Some of these stations are in horrible locations and poorly maintained (actually a large percentage).
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Quoting JeffMasters:


Pretty much everything science has to say about how the universe works is a theory. For example, gravity is a theory--but one that has rather obvious observational evidence to support it. Human-caused global warming is also a theory that has strong observational evidence to support it. The latest IPCC summary concluded that there is a greater than 90% chance that the majority of the planet's warming in recent decades was caused by humans. I agree with the IPCC's assessment. The IPCC science is not perfect (as the recent flap over their erroneous inclusion of a non-peer-reviewed article claiming the Himalayan glaciers may melt by 2035 proves), but there is much to like about the strength of the science in the 2007 IPCC report. Science is rarely perfect, and it is the job of scientists to continually assess current theories and correct any deficiencies found. The error in the Himalayan glacier forecast has been found and will no doubt be corrected in the next IPCC report, which will be even stronger than the 2007 report.

Jeff Masters



Thank you for your answer I am well aware of what you speak. I am not contending anything about global warming per say. However I have had some disagreement on the statement that although global warming may very well exist, just as any other theory it must be falsifiable if not, than it is not scientific. Not to say it is stupid or foolish to believe in something that is not scientific.

To me for the common person (not that i'm anything special) there seems to be a blur between science and beliefs when speaking of global warming.
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According to the Science & Public Policy Institute:

The IPCC is not and never has been an organisation that examines all aspects of climate change in a neutral and impartial manner. Its internal procedures reinforce that bias; it makes no attempts to clarify its misleading and ambiguous statements. It is very selective about the material included in its reports; its fundamental claims lack evidence. And most importantly, its actions have skewed the entire field of climate science.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting JFLORIDA:
Future met - there has been indications of rapid warming for 40 years conservatively - right?


Really? perhaps. Well regardless, AGW is overhyped, and is often used for political propaganda.

lol, I don't I am not going to argue GW again, so this my last post on this subject for a while.
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Quoting futuremet:


No offense Dr Masters, but it is not inconvenient to falsify data. There is a possibility that the IPCC scientist could have done that. Then again, we have about a couple of decades to wait and see if the globe is really warming at this alarming rate.This gives them adequate time to propagate their claims, and to get people to believe them.


Or even faster than that. When solar activity picks back up in the next few years, global warming will accelerate again, then positive feedbacks like methane will take over. Currently, global warming is having an effect on our ocean temperatures.
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The NASA interview with Gavin Schmidt also highlights the topic of this blog.

NASA
: What about the meteorological stations? There have been suggestions that some of the stations are located in the wrong place, are using outdated instrumentation, etc.

Gavin Schmidt
: Global weather services gather far more data than we need. To get the structure of the monthly or yearly anomalies over the United States, for example, you just need a handful of stations, but there are actually some 1,100 of them. You could throw out 50 percent of the station data or more, and you get basically the same answers. Individual stations do get old and break down, since they're exposed to the elements, but this is just one of things that the NOAA has to deal with. One recent innovation is the set up of a climate reference network alongside the current stations so that they can look for potentially serious issues at the large scale and they haven't found any yet.
http://www.nasa.gov/topics/earth/features/gavin-schmidt.html
Member Since: September 22, 2005 Posts: 11 Comments: 2032
Quoting futuremet:


No offense Dr Masters, but it is not inconvenient to falsify data. There is a possibility that the IPCC scientist could have done that. Then again, we have about a couple of decades to see if the globe is really warming at this alarming rate.


The IPCC has become nothing more than an organization that releases propaganda. There are many who are calling for it to be disbanded. Their recent falsifications and scandals do not help.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Current global SST observations:




The Mercator Ocean forecast for EIGHT days from now:



Notice the bulge in the SSTs, pointing toward southern Chile at the exact longitude of Pine Island Bay.
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Hey JF, you have mail, but in case you need to know:

The WU mail feature is a great way to communicate with other bloggers without taking up main blog space. It can be used for private messages, sharing a laugh, and many other uses. There is a blue button located at the top of your page titled "mail." By clicking on this button one can view his mail inbox. Located within this section is all the mail that you have sent and received. If you have new mail and are not in the mail section, the mail button (located at the top of the page) will turn red and read "new mail!"
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Quoting AstroHurricane001:


That degree of warming is significant and cannot be explained by natural cycles. This is true at almost every station on Earth.

Not going to, but I could easily post a hundred station record time-series plots here from around the globe that show none. Zero.
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Quoting JeffMasters:


Pretty much everything science has to say about how the universe works is a theory. For example, gravity is a theory--but one that has rather obvious observational evidence to support it. Human-caused global warming is also a theory that has strong observational evidence to support it. The latest IPCC summary concluded that there is a greater than 90% chance that the majority of the planet's warming in recent decades was caused by humans. I agree with the IPCC's assessment. The IPCC science is not perfect (as the recent flap over their erroneous inclusion of a non-peer-reviewed article claiming the Himalayan glaciers may melt by 2035 proves), but there is much to like about the strength of the science in the 2007 IPCC report. Science is rarely perfect, and it is the job of scientists to continually assess current theories and correct any deficiencies found. The error in the Himalayan glacier forecast has been found and will no doubt be corrected in the next IPCC report, which will be even stronger than the 2007 report.

Jeff Masters


No offense Dr Masters, but it is not inconvenient to falsify data. There is a possibility that the IPCC scientist could have done that. Then again, we have about a couple of decades to wait and see if the globe is really warming at this alarming rate.This gives them adequate time to propagate their claims, and to get people to believe them.
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If your interested in another take on a related topic :)

A critique by the Science and Public Policy Institute and the
Center for the Study of Carbon Dioxide and Global Change


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NASA Climatologist Gavin Schmidt Discusses the Surface Temperature Record
Gavin Schmidt, a climatologist at NASA's Goddard Institute for Space Studies (GISS) in New York City, studies why and how Earth's climate varies over time. He offered some context on the annual surface temperature record, a data set thats generated considerable interest and some controversy in the past. GISS updated its surface temperature record with 2009 data this week, and reported that the last decade was the warmest on record.
http://www.nasa.gov/topics/earth/features/gavin-schmidt.html
Member Since: September 22, 2005 Posts: 11 Comments: 2032
Quoting Floodman:


So who profits from falsifying weather data? Where is the money trail that leads to the "Grand Conspiracy?". On the CC side, there are numerous companies that can be tied to studies that disprove it; so if there is an organization trying to falsify data and cause a general alarm about this thing, who is it? Or is the contention that it's a bunch of Birkenstock-wearing tosspots that just happen to be wanting to cause mass hysteria and panic for the sake of chaos?

You have to admit that most human endeavors are driven by the profit they produce, so who profits from a general alarm about CC? I'm fascinated and can hardly wait to hear the answers...

This post wasn't poitned at you in particular, Canewarning, it's out here for general consumption...


CC?
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Yo JF, you have mail
Member Since: June 28, 2006 Posts: 24 Comments: 8185
IPCC claims about glaciers are exaggerated.

Link
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Dr. Jeff Masters,

I would really like to see a couple of topics discussed this off season.

One reason I write this is that I am [doh!] not nearly as skilled as yourself in writing a good discussion of scientific principles easily digested by everyone.

I have been looking for some discussion on reinvestigating the hurricane as a Carnot heat engine on the you-know-where list, but it has not been forthcoming.

I would love to see a multi-part series that discusses how we represent the function of the heat engine in hurricanes, currently. Also interesting would be a discussion of the supposed violation of the laws of thermodynamics as posed by Makarieva, et al. http://rspa.royalsocietypublishing.org/content/early/2010/01/18/rspa.2009.0581.abstract
Abstract:
In several recent studies, a heat engine operating on the basis of the Carnot cycle is considered, where the mechanical work performed by the engine is dissipated within the engine at the temperature of the warmer isotherm and the resulting heat is added to the engine together with an external heat input. This internal dissipation is supposed to increase the total heat input to the engine and elevate the amount of mechanical work produced by the engine per cycle. Here it is argued that such a dissipative heat engine violates the laws of thermodynamics. The existing physical models employing the dissipative heat engine concept, in particular the heat engine model of hurricane development, need to be revised.

Last, I would like to see some discussion of the alternate theory proposed that treats the changing volume consumed by water in vapor and liquid phases as the primary driver of deepening pressure depressions.

http://www.atmos-chem-phys-discuss.net/8/17423/2008/acpd-8-17423-2008.html

"Hurricanes and tornadoes could be compared to an explosion reversed and prolonged
in time. In the ordinary explosion potential energy concentrated in the explosion
center is released in a burst, making local air pressure rise sharply and causing
dynamic air movement in the direction away from the explosion center. Conversely,
condensation of saturated water vapor within the column of ascending air in hurricanes
and tornadoes leads to a sharp drop of local air pressure. This further enhances the
ascending motion of yet accelerating air masses, as well as the compensating radial
fluxes of moist air incoming to the area where the process of condensation is most
intensive. Water vapor contained in the incoming air undergoes condensation in the
same area; this sustains the pressure difference between the hurricane center and
its environment. Hurricane could also be compared to a black hole, which sucks the
surrounding air into the center, where it partially "annihilates" due to condensation of
water vapor and its disappearance from the gas phase. Thus, hurricane is an "anti
explosion". While in explosion the gas phase appears from either liquid or solid phase,
in hurricanes and tornadoes, conversely, the gas phase of water vapor partially disappears
from air due to condensation.
"

On a molecular level, it does make sense that the phase change would create a sharp pressure deficit on the scale of a hurricane's eyewalls.

Or, maybe, there is some problem with what Makarieva, et al point out that I am unaware of...
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Quoting CaneWarning:
MYTH: Global temperatures are rising at a rapid, unprecedented rate.

FACT: Accurate satellite, balloon and mountain top observations made over the last three decades have not shown any significant change in the long term rate of increase in global temperatures. Average ground station readings do show a mild warming of 0.6 to 0.8C over the last 100 years, which is well within the natural variations recorded in the last millennium. The ground station network suffers from an uneven distribution across the globe; the stations are preferentially located in growing urban and industrial areas ("heat islands"), which show substantially higher readings than adjacent rural areas ("land use effects").



So who profits from falsifying weather data? Where is the money trail that leads to the "Grand Conspiracy?". On the CC side, there are numerous companies that can be tied to studies that disprove it; so if there is an organization trying to falsify data and cause a general alarm about this thing, who is it? Or is the contention that it's a bunch of Birkenstock-wearing tosspots that just happen to be wanting to cause mass hysteria and panic for the sake of chaos?

You have to admit that most human endeavors are driven by the profit they produce, so who profits from a general alarm about CC? I'm fascinated and can hardly wait to hear the answers...

This post wasn't poitned at you in particular, Canewarning, it's out here for general consumption...
Member Since: Posts: Comments:
The WU mail feature is a great way to communicate with other bloggers without taking up main blog space. It can be used for private messages, sharing a laugh, and many other uses. There is a blue button located at the top of your page titled "mail." By clicking on this button one can view his mail inbox. Located within this section is all the mail that you have sent and received. If you have new mail and are not in the mail section, the mail button (located at the top of the page) will turn red and read "new mail."
Member Since: June 28, 2006 Posts: 24 Comments: 8185
853. JeffMasters (Admin)
Quoting ElConando:
Dr. Masters scientifically, is Global Warming is a theory?



Pretty much everything science has to say about how the universe works is a theory. For example, gravity is a theory--but one that has rather obvious observational evidence to support it. Human-caused global warming is also a theory that has strong observational evidence to support it. The latest IPCC summary concluded that there is a greater than 90% chance that the majority of the planet's warming in recent decades was caused by humans. I agree with the IPCC's assessment. The IPCC science is not perfect (as the recent flap over their erroneous inclusion of a non-peer-reviewed article claiming the Himalayan glaciers may melt by 2035 proves), but there is much to like about the strength of the science in the 2007 IPCC report. Science is rarely perfect, and it is the job of scientists to continually assess current theories and correct any deficiencies found. The error in the Himalayan glacier forecast has been found and will no doubt be corrected in the next IPCC report, which will be even stronger than the 2007 report.

Jeff Masters
I think it deserves its own post, Watt do you think :)

SURFACE TEMPERATURE RECORDS: POLICY DRIVEN DECEPTION?
by Joseph D’Aleo and Anthony Watts
SPPI


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Global Warming Causes Severe Storms
Research Meteorologists See More Severe Storms Ahead: The Culprit -- Global Warming

Research Meteorologists found that the temperature changes brought on by global warming are significant enough to cause an increase in the occurrence of severe storms. Severe storms are those that cause flooding, have damaging winds, hail and could cause tornados. Their study revealed that by the end of this century, the number of days that favor severe storms could more than double certain locations, such as Atlanta and New York. Researchers also found that this increase would occur during typical stormy seasons and not during dry seasons when it may be beneficial.
http://www.sciencedaily.com/videos/2009/0109-global_warming_causes_severe_storms.htm
Member Since: September 22, 2005 Posts: 11 Comments: 2032
i've been seeing some great pictures of america...
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Quoting JFLORIDA:
Now you will return the favor of referencing.


referencing what?

mail btw
Member Since: June 28, 2006 Posts: 24 Comments: 8185
cant get anymore blue skies than this...

SWFL is Rockin!
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To date, Toronto Pearson airport has recorded less than 30 cm of snowfall accumalations. The previous record low was close to 55 cm by this time of year in the season, set in 1952-53, and the current record is close to half of the old one. My location, not far from Toronto has had only ONE major storm this winter season producing over 20 cm of snow.
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842

thanks, btw, you have mail :P
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Maximum Height of Extreme Waves Up Dramatically in Pacific Northwest
A major increase in maximum ocean wave heights off the Pacific Northwest in recent decades has forced scientists to re-evaluate how high a "100-year event" might be, and the new findings raise special concerns for flooding, coastal erosion and structural damage.
The new assessment concludes that the highest waves may be as much as 46 feet, up from estimates of only 33 feet that were made as recently as 1996, and a 40 percent increase. December and January are the months such waves are most likely to occur, although summer waves are also significantly higher.

In a study just published online in the journal Coastal Engineering, scientists from Oregon State University and the Oregon Department of Geology and Mineral Industries report that the cause of these dramatically higher waves is not completely certain, but "likely due to Earth's changing climate."

Using more sophisticated techniques that account for the "non-stationarity" in the wave height record, researchers say the 100-year wave height could actually exceed 55 feet, with impacts that would dwarf those expected from sea level rise in coming decades. Increased coastal erosion, flooding, damage to ocean or coastal structures and changing shorelines are all possible, scientists say.

"The rates of erosion and frequency of coastal flooding have increased over the last couple of decades and will almost certainly increase in the future," said Peter Ruggiero, an assistant professor in the OSU Department of Geosciences. "The Pacific Northwest has one of the strongest wave climates in the world, and the data clearly show that it's getting even bigger.

"Possible causes might be changes in storm tracks, higher winds, more intense winter storms, or other factors," Ruggiero said. "These probably are related to global warming, but could also be involved with periodic climate fluctuations such as the Pacific Decadal Oscillation, and our wave records are sufficiently short that we can't be certain yet. But what is clear is the waves are getting larger."

Read full article
http://www.sciencedaily.com/releases/2010/01/100125123233.htm
Member Since: September 22, 2005 Posts: 11 Comments: 2032
Quoting CaneWarning:
MYTH: Global temperatures are rising at a rapid, unprecedented rate.

FACT: Accurate satellite, balloon and mountain top observations made over the last three decades have not shown any significant change in the long term rate of increase in global temperatures. Average ground station readings do show a mild warming of 0.6 to 0.8C over the last 100 years, which is well within the natural variations recorded in the last millennium. The ground station network suffers from an uneven distribution across the globe; the stations are preferentially located in growing urban and industrial areas ("heat islands"), which show substantially higher readings than adjacent rural areas ("land use effects").



That degree of warming is significant and cannot be explained by natural cycles. This is true at almost every station on Earth.
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Quoting CatchMeifUCan:
In order to protect the new temperature station from being run into by a car, they moved it to the back of the parking lot and mounted it next to the roof of the metal garage

So we have two main places of climate research...hot metal roofs and blazing hot asphalt parking lots. Good job passing the square peg tests, "scientists". And also work on your driving skills.


Just like I said yesterday, one can make a hypothesis, and ensure it comes true through manipulation.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting tornadodude:


source please?


LOL
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BTW, JFlorida, you have mail
Member Since: June 28, 2006 Posts: 24 Comments: 8185
Ozone Hole Healing Could Cause Further Climate Warming

ScienceDaily (Jan. 26, 2010) — The hole in the ozone layer is now steadily closing, but its repair could actually increase warming in the southern hemisphere, according to scientists at the University of Leeds.

The Antarctic ozone hole was once regarded as one of the biggest environmental threats, but the discovery of a previously undiscovered feedback shows that it has instead helped to shield this region from carbon-induced warming over the past two decades.

High-speed winds in the area beneath the hole have led to the formation of brighter summertime clouds, which reflect more of the sun's powerful rays.

"These clouds have acted like a mirror to the sun's rays, reflecting the sun's heat away from the surface to the extent that warming from rising carbon emissions has effectively been cancelled out in this region during the summertime," said Professor Ken Carslaw of the University of Leeds who co-authored the research.

"If, as seems likely, these winds die down, rising CO2 emissions could then cause the warming of the southern hemisphere to accelerate, which would have an impact on future climate predictions," he added.

The key to this newly-discovered feedback is aerosol -- tiny reflective particles suspended within the air that are known by experts to have a huge impact on climate.

Greenhouses gases absorb infrared radiation from the Earth and release it back into the atmosphere as heat, causing the planet to warm up over time. Aerosol works against this by reflecting heat from the sun back into space, cooling the planet as it does so.

Beneath the Antarctic ozone hole, high-speed winds whip up large amounts of sea spray, which contains millions of tiny salt particles. This spray then forms droplets and eventually clouds, and the increased spray over the last two decades has made these clouds brighter and more reflective.

As the ozone layer recovers it is believed that this feedback mechanism could decline in effectiveness, or even be reversed, leading to accelerated warming in the southern hemisphere.

"Our research highlights the value of today's state-of- the-art models and long-term datasets that enable such unexpected and complex climate feedbacks to be detected and accounted for in our future predictions," added Professor Carslaw.

The Leeds team made their prediction using a state-of-the-art global model of aerosols and two decades of meteorological data. The research was funded by the Natural Environment Research Council's Surface Ocean-Lower Atmosphere Study (UK SOLAS) and the Academy of Finland Centre of Excellence Programme.
http://www.sciencedaily.com/releases/2010/01/100125192016.htm
Member Since: September 22, 2005 Posts: 11 Comments: 2032
Quoting JFLORIDA:



No, a source at least. Thats minimal. And the modeling you are speaking of uses a statistical method for error elimination.


source please?
Member Since: June 28, 2006 Posts: 24 Comments: 8185
MYTH: The UN proved that man–made CO2 causes global warming.
FACT: In a 1996 report by the UN on global warming, two statements were deleted from the final draft. Here they are:
1) “None of the studies cited above has shown clear evidence that we can attribute the observed climate changes to increases in greenhouse gases.”
2) “No study to date has positively attributed all or part of the climate change to man–made causes”

To the present day there is still no scientific proof that man-made CO2 causes significant global warming.

Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting JFLORIDA:
825 as usual no link to a source.

Nothing on how Global increases are categorized either.


So basically an opinion from a non expert. Right?


Just like our opinions too, huh?
Member Since: June 28, 2006 Posts: 24 Comments: 8185
The Roman Climate Optimum represents one of the warmer periods in earths history. Can someone explain this since this period was way before cars, etc.

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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.