Some supporting research conducted at New York City follows the news item below. h/t to WUWT reader Phil (not the grouchy one) -A
Heat islands: Cities heat quickly, cool slowly
By DEEPTI HAJELA
Associated Press Writer
NEW YORK (AP) — Hot town, summer in the city? No kidding.
The high temperatures blanketing the Northeast and mid-Atlantic regions of the country are making many people miserable, but those in New York City, Philadelphia and other dense, built-up areas are getting hit with the heat in a way their counterparts in suburbs and rural areas aren’t.
Cities absorb more solar energy during the day and are slower to release it after the sun sets, making for uncomfortable nights and no real relief from the heat. And because they haven’t cooled down as much overnight, mornings are warmer and the thermometer goes right back up when the sun starts beating down the next day.
Scientists have known for years about so-called heat islands, urban areas that are hotter than the less-developed areas around them.
Cities are just “not well designed to release that summertime heat,” said William Solecki, geography professor at Hunter College and director of the City University of New York’s Institute for Sustainable Cities.
The lack of nighttime relief can make the daytime high temperatures even more difficult for people to take as the days pass and the heat continues, he said.
That’s “where you start to have real problems, if your body’s not cooling down,” Solecki said. “You’re not getting that break.”
Deaths blamed on the heat included a 92-year-old Philadelphia woman whose body was found Monday and a homeless woman found lying next to a car Sunday in suburban Detroit.
The heat-islands effect is significant in the East because “we have a large population living in heavily built-up areas with lots of concrete and lots of steel, good absorbers of heat,” National Weather Service spokesman Sean Potter said.
full story here at Tampa Bay Online
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Here is some supporting research from NASA (not NASA GISS).
Keeping New York City “Cool” is the Job of NASA’s “Heat Seekers”
Jan. 30, 2006
The “heat is on” in New York City, whether it’s summer or winter. This is due to a phenomenon called the urban heat island effect that causes air temperatures in New York City and other major cities to be warmer than in neighboring suburbs and rural areas. And, in a big city, warmer air temperatures can impact air quality, public health and the demand for energy.
Image to right: A thermal satellite image of New York City captured by NASA’s Landsat satellite on August 14, 2002 at 10:30 a.m., shows the locations of the warmest air temperatures as seen in red. The blue indicates areas with cooler air temperatures. Click on image to enlarge. Credit: NASA
Recently, several innovative approaches developed by scientists, public officials, environmental activists, community organizations and others have been put in place to take a bite out of the Big Apple’s temperature problem. NASA researchers, using NASA satellite observations, weather pattern data and computer models, have recently assessed how well those strategies are working. Their study results will be discussed during the 2006 American Meteorological Society’s annual meeting in Atlanta, Ga., Jan. 29 through Feb. 2.
“We need to help public officials find the most successful ways to reduce the heat island effect in New York. With ever-increasing urban populations around the world, the heat island effect will become even more significant in the future,” said Stuart Gaffin, an associate research scientist at Columbia University, New York, and a co-author of the new NASA study. “The summertime impacts are especially intense with the deterioration of air quality, because higher air temperatures increase ozone. That has health effects for everyone. We also run an increased risk of major heat waves and blackouts as the heat island effect raises demand for electricity.”
In cities, the urban heat island effect is caused by the large number of buildings, sidewalks and other non-natural surfaces that limit the amount of land covered with vegetation like grass and trees. Land surfaces with vegetation offer high moisture levels that cool the air when the moisture evaporates from soil and plants.
Image to left: This image indicates case study areas in New York City used in the NASA study, and weather stations. Click on image to enlarge. Credit: NASA
In large cities, land surfaces with vegetation are relatively few and are replaced by non-reflective, water-resistant surfaces such as asphalt, tar and building materials that absorb most of the sun’s radiation. These surfaces hinder the natural cooling that would otherwise take effect with the evaporation of moisture from surfaces with vegetation. The urban heat island occurrence is particularly pronounced during summer heat waves and at night when wind speeds are low and sea breezes are light. During these times, New York City’s air temperatures can rise 7.2 degrees F higher than in surrounding areas.
In the recent project, NASA researchers set out to recommend ways to reduce the urban heat island effect in New York City. They looked at strategies such as promoting light-colored surfaces such as roofs and pavements that reflect sunlight, planting “urban forests” and creating “living roofs” on top of buildings where sturdy vegetation can be planted and thrive. Using a regional climate computer model, the researchers wanted to calculate how these strategies lower the city’s surface and close-to-surface air temperatures and what the consequences of these strategies would be on New York’s energy system, air quality and the health of its residents.
The researchers conducted a city-wide case study over the summer of 2002 to measure changes in air temperatures. They also used six smaller case studies during the same period in places like Lower Manhattan, the Bronx’s Fordham section, Brooklyn’s Crown Heights section and the Maspeth section of Queens. The areas were chosen for the different ways land is used and their nearness to areas with high electrical use. They also had warmer-than-average near-surface air temperatures called “hot spots” and boasted available spaces to test ways to reduce the urban heat island effect.
“We found that vegetation is a powerful cooling mechanism. It appears to be the most effective tool to reduce surface temperatures,” Gaffin said. “Another effective approach is a man-made approach to cooling by making very bright, high albedo, or reflected light, on roof tops. These light-colored surfaces, best made using white coatings, reflect the sun’s light and thereby, its heat. Interestingly, more area is available to create the lighter surfaces than to add vegetation in a city such as New York.”
This project is being conducted by and funded by the New York State Energy Research and Development Authority (NYSERDA). For more information on the NYSERDA’s Environmental Monitoring, Evaluation, andProtection (EMEP) project, please visit on the Web: http://www.nyserda.org/programs/Environment/EMEP/project/6681_25/6681_25_pwp.asp.
Reference
Rosenzweig, C., W. Solecki, L. Parshall, S. Gaffin, B. Lynn, R. Goldberg, J. Cox, and S. Hodges 2006. Mitigating New York City’s heat island with urban forestry, living roofs, and light surfaces. Presentation at 86th American Meteorological Society Annual Meeting, Jan. 31, 2006, Atlanta, Georgia.
Was just flipping through some TV channels and on, Canada’s CTV network, they were running a blurb which stated that an unnamed ‘Canadian climate expert’ said that ‘extreme heat waves like the current one are likely to become more frequent in the future due to climate change.’
So… the beat goes on.
wayne says:
July 8, 2010 at 4:12 pm
@ur momisugly George E. Smith
July 8, 2010 at 3:38 pm
Now George, that’s a real efficient system (cough), run the heat and A/C at full tilt 24/7 and just adjust the mixture to get the correct temperature. Now if that accurately describes most high-rises no wonder this globe is using so much energy and office rent is through the ceiling!
( But I take it you surely jest, could your building manager just be off his rocker or maybe just lazy? )
—————————-
wayne,
you got a little carried away there, adding “full tilt” in your portrait of the idiot engineer.
Biology has counterparts to this simultaneous, antagonistic and counter-intuitive arrangement. Your nervous system (and probably even Michael Mann’s) works on the same principle; it’s charmingly referred to as the sympathetic and parasympathetic systems; akin to driving with one foot on the gas and one on the brake. It needs to be a little more subtle than “full tilt” to really work properly!
Here in Western Washington we’re having a little mini heat wave. All sorts of records “shattered”, some from way back in 1952. But, in a couple more days, we’ll be back to the 60s f. Lovely summer we’re having.
VILLABOLO:
“ERES TU QUE NO COMPRENDES.
Why are you emphasizing longer term climate than the one I Mentioned when the CONTEXT was the cherry picked REGIONAL climates such as Australia and the Eastern states? Do you “comprende” that the very topic of this thread is, to put it in your own words, “. . . a very short-term perspective . . .” in both time and space?
—————-
Tu no comprendes, yes, but your Spanish grammar is faulty and undermines your intent to impress, as does your lack of civility.
Oliver Ramsay says:
July 8, 2010 at 8:30 pm
wayne,
you got a little carried away there, adding “full tilt” in your portrait of the idiot engineer.
I’m sure many got a smile of that one (darn, forgot that happy face at the end!). The “full tilt” was the punch.
I was joking. I don’t doubt some systems, such as hositals and hotels/motels, run on that type of instant demand system, hot or cold, it’s still seems not very efficient unless throw away heat from the HVAC is the heating side, then, no loss, but then again, everyone is always comfortable. Please, take it a little lighter, it was mean that way. I have the highest respect for all engineers I have come across and if they say it may not appear that way but is more efficient, then to me it’s more efficient.
villabolo says:
July 8, 2010 at 2:21 pm
gary gulrud says:
July 8, 2010 at 1:40 pm
“ERES TU QUE NO COMPRENDES.
Disculpe Usted. Indeed, I do not understand what with the ocean’s heat capacity being 3000 times that of the atmosphere and here we have 30 years of satellite data covering 95% of the earth and a recent record spike displaced the average almost as much as the prior negative dip having aborted El Nino Grande 2007 and now we look forward to a similar decline in 2011 and here we’re all droning on about local weather trends.
If you’re a Cal Tech physics jock I might care to listen though.
Anybody got a picture of New York kids playing in the water from a hydrant opened by a grinning fireman? Seems you hardly ever see that anymore. Possibly the water losses in the tunnels north of the city, the ones that have drowned at least one small town, have made it infeasible to cool a neighborhood street and the associated kids with water from a hydrant. Here in the intermountain west, an area larger than the overheated east, it’s been a cool beginning to summer. Spring snows and greater than normal rainfall have filled the irrigation ditches with cold water. Today, when my thermometer read 98f at 1500, I fired up the pump and lowered the surface temp of my lawn 12 degrees in less than an hour. The grass loves it.
The idiots at the Seattle Times beg to differ. It will be warmer in 30 years, they promise.
http://seattletimes.nwsource.com/html/businesstechnology/2012308276_apussciheatwavesfuture.html
Prepare now for a temp increase of almost nothing. About the same as putting on a shirt.
Oliver Ramsay,
Thank you for confirming that Villabolo is a fake, unable to write correct Spanish grammar.
He’s like the 54 year old white professor who is a 14 year old girl …on the internet.
DonS: Or it could be that evil CO2 emitting, mountain top removing, dirty coal burning, electricity is powering air conditioners in each home. It would be best for the government we lived in the earth’s temperate zones, like caves.
George E. Smith says:
July 8, 2010 at 10:07 am (Edit)
It’s a poor explanation for the phenomenon. The granite, contcrete, asphalt, and brick of the cities has much greater heat capacity than the earth. As a result, they do not cool as fast at night as the surrounding fields. It’s not because they are hotter, it is because they have stored up a lot of heat during the day.
Charles Higley says:
July 8, 2010 at 6:04 pm
I have been bothered by this paper. How on Earth did they separate the solar heating from the heat released by energy usage, which we all know always eventually devolves into heat energy? I also am dubious about their assertion that cities absorb more solar energy than elsewhere. How can they determine that, in light of electrical usage being higher during the day when the Sun is up, both in doing business and air conditioning?
One of the biggest problems of climate science is separating the multitudinous factors involved. Here we have another example of specifically ignoring the real complexities and presenting a fabrication that sounds logical until you really think about it.
Or is this mostly elaborate opinion and spurious conclusions?
I don’t think they are fabricating anything in the story, they are just ignoring a tiny factor that can safely be ignored.
Just get out your calculator and punch in a few numbers. I’m going to take a normal house lot from around my area and imagine a city totally filled with houses, no parks or gaps. Let’s say 120’ x 70’ lot or ~780 m^2 area per house. From comments from neighbors most electric bills go up about 2 to 3 times normal in the hottest part of the summer. That’s 800 kWhr to 2400kwHr or 1600 kWhr excess per month or 1600 kWhr / 780 m2 = 2 kWhr/m2/month or ~2.7 W/m2. See tiny compared to the insolation and low albedo causing extreme heat in the cities so no fabrication of facts, it’s the asphalt, concrete, buildings, roofs and for that matter anything vertically built, they all cause heat capture and retention if not white enough and low to the ground. But does the HVAC energy increase it, yes, but nearly immeasurable compared to the larger effects mentioned. You can add other energy use as cars, machines, etc to that but I think you will also find it is so tiny it’s ignorable compared to the sun’s influence.
You might also question why I mentioned any vertical structure. The only way for heat to escape is where you can visually see the sky. The infrared photons see the same thing that your eyes see. If you have tall buildings around you see very little sky. Walla, that’s why it’s so hot in the city! The infrared photons find it hard to escape as they bounce from structure to structure.
And the moisture mentioned in the NASA article, it’s key too. A fine water mister is what I use on the hot patio in the summer, drops it 20 degrees at least.
Hope that helps you see the exact subject of the articles, UHI from structures in the summer sun.
This, I think, is an example of warm nights in cities compared to more rural areas around them. Yes, it’s the famous Darwin again. Bureau of Meterology data as sold to the public. Minimum averaged monthly temperatures are plotted at 2 locations about 15 km apart. The biggest difference in this example appears to be in the winter months (Southern Hemisphere, remember)
http://i260.photobucket.com/albums/ii14/sherro_2008/Darwinoverlap.jpg?t=1278676356
wayne says: about calculating heat effects
As a favour, can you please select an airport with a weather station, use the area inside the perimeter for sq m, calculate the energy needed to lift X aircraft (daily) to a height of 100m using say 100 tonnes per aircraft, then turn it into watt per sq m at ground level, then temperature change? Please?
Maybe it should then be doubled because aircraft land and use reverse thrust too.
There is a lot of talk about heat around airports, but mainly about jet wash and asphalt near temperature sensors. The above calculation would show if there is an underlying effect of general heating from fuel, and its magnitude. I have not seen this calculated before.
I wouldn’t be so quick to discount vehicles. In a busy city they’re producing as much waste heat as air conditioners. Lots of BTUs in a gallon of gas or diesel. Also don’t forget that almost the total electric bill ends up as waste heat. Very little of it is converted to stored mechanical or chemical energy. Commercial and industrial use is much greater than residential as well. Plus when you mention tall buildings you can multiply the residential rate calculation you used by the number of floors in the building as residential is usually limited to one or two stories. They are also packed much closer together.
Good point on the taller buildings blocking infrared escape. I had mentioned the air being stagnant as they tend to block the winds and hadn’t considered them blocking infrared radiation as well.
Phil Jones flippant dismissal of all that by saying the urban heat islands have been unchanging urban heat islands for the entire 20th century so while it effects absolute temperature but not the temperature trend is so stupid and wrong I can’t believe he got it past peer review. The average height of buildings, density of construction materials, the amount of energy (which turns into waste heat) consumed per capita, and the population density have all been steadily climbing the past century. UHI effect has NOT been anywhere close to constant.
My last comment was in reply to
wayne says:
July 9, 2010 at 12:53 am
Forgot to put the addressee at the top of it.
@willis
re; rate of things cooling at night
To make it more clear in general it’s the density of the materials. Grass and dirt are a lot less dense than concrete, asphault, steel, and glass. That’s why they store more heat during the day and emit more at night. Plus the grass and dirt presumably have some water content so they don’t get as hot during the day as dry, non-porous materials. As they heat up the evaporation rate increases and water vapor carries away a lot of heat in form of latent heat of vaporization.
Speaking of latent heat of vaporization it seems that’s another big missing factor in GCMs. The water cycle is essentially a heat pump that transports heat from the surface through the densest portion of the greenhouse gases near the surface and releases that heat when the water vapor condenses back into clouds. The surface layer of greenhouse gases below the clouds then acts as an insulator keeping the heat away from the surface instead of trapping it there.
@Wayne – Riker Island is a fairly well known prison complex, i.e., mostly low-rise concrete building and asphalt (though there are some open grass areas on the eastern end)
@Wayne and @David Springer – Looking again at the infrared photos, the areas of Manhattan with the highest high-rises (Midtown around and south of Central Park) and the Wall Street area at the southernmost tip) are actually cooler than the areas with much lower building heights, such greenwich village and soho. Also, note that Brooklyn and Queens, with much lower building heights, generally show up as much hotter than Manhattan. Therefore, the tall-buildings are trapping the heat theory doesn’t seem to be the case.
(note – you can use maps.google.com or maps.bing.com to locate the various areas I am referencing)
What are some features of the areas that show up as having the highest heat – lots of asphalt and/or low-lying buildings with flat tar or asphalt shingled roofs. It should also be noted that fairly wooded areas, such as the middle portion of Staten Island, show up as blue. Therefore, the reports conclusions regarding much more reflective (white) or cooling (plants) roofing materials seems to make a lot of sense.
Willis Eschenbach said:
“It’s a poor explanation for the phenomenon. The granite, concrete, asphalt, and brick of the cities has much greater heat capacity than the earth. As a result, they do not cool as fast at night as the surrounding fields. It’s not because they are hotter, it is because they have stored up a lot of heat during the day.”
I would disagree. Certainly, asphalt concrete gets considerably hotter in direct sunlight than the others, considerably hotter. Burn your bare foot if you step on it hotter. And, the newer it is (or the less time it has been since the surface was restored with a slurry of asphalt and fine aggregate or thin overlay) the hotter it gets in comparison.
In addition, paved surfaces, to the depth paved, conduct heat better than uncompacted earth does, so even lesser depths than the depth of pavement (including aggregate with a relative compaction of 95%), the temperature at a given depth of paving will be higher than at the same depth of uncompacted earth, but lower than near the surface temperature of the paving material.. Well compacted earth or aggregate also has considerably greater heat conductivity than loose earth or aggregate. Compacting removes the small insulating air spaces that uncompacted soil has.
Over the period of time since just after WWII, vast areas of surface in and around urban areas have been paved with asphalt concrete which previously had not been paved at all other than with relative loose gravel. And most streets, roads and highways which were once paved with Portland cement concrete (“white concrete”, we highway engineers called it many years ago) have been either overlaid or replaced with asphalt concrete.
http://wapedia.mobi/en/Heat_capacity?t=5.
Specific heat capacity of building materials
Substance/ Phase /cp J/(g·K)
Asphalt solid 0.920
Brick solid 0.840
Concrete solid 0.880
Glass, silica solid 0.840
Glass, crown solid 0.670
Glass, flint solid 0.503
Glass, pyrex solid 0.753
Granite solid 0.790
Gypsum solid 1.090
Marble, mica solid 0.880
Sand solid 0.835
Soil solid 0.800
Wood solid 1.7 (1.2 to 2.3)
“”” Willis Eschenbach says:
July 8, 2010 at 10:05 pm
George E. Smith says:
July 8, 2010 at 10:07 am (Edit)
Well I don’t disagree with the heating part of it; but hot things do not cool slower than cold things; so nyet on their slow nightime cooling theory.
It’s a poor explanation for the phenomenon. The granite, contcrete, asphalt, and brick of the cities has much greater heat capacity than the earth. As a result, they do not cool as fast at night as the surrounding fields. It’s not because they are hotter, it is because they have stored up a lot of heat during the day. “””
Well I don’t disagree with your comment; but that adresses a quite different aspect of the situation.
Hey a 100 Ampere-hour Automobile lead acid battery will take a lot longer to discharge if you leave the lights on, than would a pair of AA cells. Is that supposed to be a surprise ?
And not coincidently; it takes a hell of a lot longer to recharge that 100 Amp hour car battery in the first place, than the AAs in my Mouse.
That doesn’t escape the issue that the higher the temperature of ANY object; the faster it will radiate energy (cool).
And who is it who turns on the “cool” switch at night ? Those dense concrete and granite buildings do their best “cooling” in the heat of the mid-day sun, when they are hottest. We just don’t notice because the sun is replacing that heat as fast as the building is losing it. We only notice the cooling at night because the sun shuts off the heating.
I guess my point; if I was even trying to make a point, is that heat islands of their own accord are NOT a climate problem. Sure they are relatively efficient absorbers and storers of incoming solar energy; as well as the various other energy releases that go on in cities as others here have alluded to; but those same properties also make them efficient re-radiators of heat energy 24 hours a day. So they take a longer time to cool, than does the immediate air on top of those buildings; and yes as a result of that time lag, the buildings will run at a Temperature bias above other surrounding materials.
None of that is a climate problem; the climate reporting problem comes when they place an official Temperature recording station in the middle of one of those structures; which of itself is also not a problem; but then they claim that their reading is a perfectly good proxy for the Temperature at some other place up to 1200 km away from those buildings.
Urban Heat Islands DO NOT create errors in weather/climate data measurements. Failure to observe well understood data sampling rules DOES.
“”” Oliver Ramsay says:
July 8, 2010 at 8:30 pm
wayne says:
July 8, 2010 at 4:12 pm
@ur momisugly George E. Smith
July 8, 2010 at 3:38 pm
Now George, that’s a real efficient system (cough), run the heat and A/C at full tilt 24/7 and just adjust the mixture to get the correct temperature. Now if that accurately describes most high-rises no wonder this globe is using so much energy and office rent is through the ceiling!
( But I take it you surely jest, could your building manager just be off his rocker or maybe just lazy? )
—————————-
wayne,
you got a little carried away there, adding “full tilt” in your portrait of the idiot engineer.
Biology has counterparts to this simultaneous, antagonistic and counter-intuitive arrangement. Your nervous system (and probably even Michael Mann’s) works on the same principle; it’s charmingly referred to as the sympathetic and parasympathetic systems; akin to driving with one foot on the gas and one on the brake. It needs to be a little more subtle than “full tilt” to really work properly! “””
Now Wayne; why would I jest; I just explained roughly how the environmental controls in this building are set up; and a lot of others like it; and you’d rather believe I am joking. If my keyboard had a micophone; and a thermometer ky, I would let you listen to the airc oming out of the ceiling vent that is maybe 13-15 feet above the floor of my cube, and about a cube diagonally to the side; so that air coes down on me at about qa 45 degree angle, all day long; and my keyboard thermometer would tell you that it is warm air; not AC air, nor Hot air; but warm air; at about whatever the room temperature is.
I should add that this is a former Hewlett Packard building that is at leadsst 35 years old, and maybe 40. Back when thisa building was built; I worked for a competitive company ina different building; and that building contained NO wall light switches. It was cheaper to leave the lights on all the time; than to install the extra copper wire needed to run light switches; so you would have to go back to a breaker box to turn off any bank of lighting.
And most of the housing built here in silicon valley at least up to that time was built with basically NO internal insulation of any kind. I owned a house; that had a flat tar paper roof with white rock spread all over it; with zero insulation anywhere in the house. Fully 50% of the entire perimeter walls were glass; single pane ordinary battleship plate glass. The heating system consisted of hot water piping that was inside the concrete slab on which the house sat; so much of the heating energy went to heating the rest of planet earth. It took two weeks in winter to bring the floor temperature up to a liveable 68 deg F or so.
Power was so cheap back then, that this is how things were done. So why would I jest ?
When I lived in St Louis Mo (mid 1960s) we had an oil heater system; and I frankly can’t recall what We had when I lived in Portland Oregon before that; but Northern California; is not your typ[ical climate location. The house I am in now; has never ever had the air conditioner turned on in all the years I have lived here; and the only reason I turn the heat on is because the house has no insulation in it at all, so it goes to night time temperatures in minutes (which is fine by me; I hate living in hot air heating)
“”” Dave Springer says:
July 8, 2010 at 5:20 pm
@george Smith
To be fair, min/max should work fine if you’re looking for a trend instead of a near perfect measure of the average temperture. The climate boffins are very quick to point out that the story isn’t about whether the global average temperature was exactly 52F in 1980 and it’s exactly 53F today. “””
So Dave; why is it that ONLY in climate (or weather) “science”, does violation of the Nyquist Sampling Theorem Criterion not result in aliassing noise that corrupts the recovered signal in such a way as to render even the average value erroneously; for just a factor of two undersampling rate.
Remember that climate alarmists are only talking about hundredths of a deg C changes; so they can ill afford to be cavalier about their measurement methodology.
And you talk about “trends”; so IPCC claims that the “trend” in future warming is that the Temperature will rise at a “rate” that is proportional to the logarithm of the atmospheric CO2 abundance; with a proportionality factor (aka “Climate sensitivity”) that is by their best guess something between 1.5 and 4.5 deg C per doubling of CO2; or 3.0 +/- 50%
Wow that inspires a lot of confidence that they have any idea at all what is going to happen and why. Is a 3:1 range of the “constant” of proportionality sufficient to prove that the graph is in fact a logarithmic relationship; given that so far we have actually observed about 1/3 of one of those CO2 doublings; with any kind of measuring instruments. There probably are at least 100 well recognised mathematical functions that could represent such a data stream within a 3:1 range of uncertainty of the proportionality constant, at least as well as either a quite linear or a quite logarithmic relationship.
When the AGW proponents themselves say that the choice of their 30 year or whatever baseline reference period, influences the outcome; I think they are just admitting that their methodology doesn’t enable one to know what is happening.
I know that it is possible to construct (faultily) the value of a fundamental Physical Constant of Nature to better than one part in 10^8; by simply playing around with numbers; in a manner with no theoretical validity or basis to it whatsoever; it’s been done.
So would I believe I know what today’s temperature is outside my back door; based on what a min/max thermometer tells me. Absolutely not; so I surely won’t for any other place or time; let alone for the entire globe.
Maybe statisticians can take comfort in their trends; maybe they believe that the central limit theorem will buy them a reprieve from any transgression; well not even that, will relieve them of the necessity to comply with the simple rules for sampled data systems.
And we would not even be able to have this discussion; but for the communication networks that rely on the vailidty of those very laws for their operation.
It seems that the extreme range of surface temperatures that can be found on planet earth; more or less at the very same time (in different places), ranges from a low of about -90 deg C (183 K) to about +60 deg C (333 K) and recent posts here have cited evidence of surface temperatures as high as +90 deg C (363 K); and we are excluding the temporary output of volcanic eruptions; just surfaces that go up and down in Temperature with the normal variations of weather conditions. And we are supposed to be impressed with trends of the order of 0.6 deg C (maybe) change in 150 years.
Just because these plotted graphs seem to show a pattern; which you might call a trend; does not mean that that pattern is a real phenomenon; and not simply a short time sample of simply a noisy function. I’ve looked at a heck of a lot of noise waveforms in my career; including an inordinate number of 1/f noise patterns; and the human eye can perceive apparent patterns where continued observation demonstrates there clearly is no pattern.
Intruding on the G. Smith conversation(not ignoring the rest you though I’m admittedly a fan) heat capacity and emissivity are needed together discussing the heat evolved by materials.
Asphalt, given the chart above, has a relatively high capacity, also a very high emissivity. Asphalt therefore emits at a lower frequency than a whitish surface, i.e., at a lower temperature.
Water has about twice the heat capacity of building materials but only 2/3 the emissivity therefore is an excellent store. CO2 at STP is an exceedingly poor store.
“”” gary gulrud says:
July 9, 2010 at 12:37 pm “””
Gary, part of the problem in all of the above discussion, rests with the way the Earth energy balance is represented in standard climate science teaching; in other words; the Trenberth cartoon that NOAA peddles as representing earth’s energy balance.
In that picture the earth is an isothermal sphere at a Temperature of 15 deg C, and it’s entire surface emits LWIR at the Standard Black Body Temperature rate of 390 W/m^2 24/7 everywhere on earth; and it is driven by a weak sun bringing 342 W/m^2, of which only 168 W/m^2 is absporbed by the surface.
This leads us to believe that something else must be providing at least the difference of 222 W/m^2 just to keep up with the radiativ3e losses.
Mother Gaia doesn’t see it as being anything like that; her planet earth has a solar blowtorch that stikes a smaller part of the earth surface but at about 4 times the Trenberth rate. And THAT driver most certainly does result in a very rapid warming in the mornings. No such thing would happen under the Trenberth scenario.
People look for equilibrium situations and calculations where none exist. The earth is never in thermal equilibrium; nor can it be, simply because it rotates once in about 24 hours.
And the relationship between incoming energy, and temperature is highly non-linear; so it is not at all valid to treat the earth energy balance situation as an average based on linear assumptions.
Some have claimed here that a simple min/max average is a good value for the daily average Temperature; yet the max-min difference can routinely be 30-40 deg F amplitude (I read the daily SF Bay area weather maps).
If you integrate the daily Temperature even assuming it is sinusoidal; and then apply the fourth Power of that Temperature (K) to computing a BB radiative emittance; you get an erroneous value; that ALWAYS underestimates the true daily Radiant Emittance; which you can calculate for yourself by raising the assumed Temperature function to the fourth power, and then integrating that over the diurnal cycle. The result is always a positive offset.
And the result can be even worse when computing the LWIR intercepted by CO2 since that does not depend on the Stefan-Boltzmann total emittance; but is more in tune with the spectral peak radiant emittance; and that value goes as the fifth power of the Temperature (K); not the 4th; so the offset can be even bigger. Moreover; the actual Temperature reached shifts the spectral peak wavelength via the Wien Displacement Law so that it puts the CO2 absorption band, even further down the tail of the LWIR radiation spectrum. There is a partial compensation, in that the line width of the actual CO2 LWIR absorption lines will be Doppler broadened by the higher Temperatures; but that broadening can only expected to go as the square root of the Temperature (K). It is still a losing proposition; the significance of CO2 is diminished at the real peak Temperatures that Mother Gaia sees in her laboratory experiments, when she calculates the earth’s mean Temperature.
Which supports my contention that the earth does its finest cooling at the peak of the post prandial Temperature highs in the hottest arid deserts on the planet. It is NOT the polar regions that are cooling the earth; their rates of emittance can be down by more than an order of magnitude from the real cooling places.
And if you can’t measure real actual temperatures; but rely on min/max averagesd as representative of the “Trends” than it is no wonder that you can’t determine with any precision what is really happening. Well Gaia knows; so I just let her decide what the earth’s Temperature should be; and it seems perfectly fine by me.
“””gary gulrud says:
July 9, 2010 at 12:37 pm
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Asphalt, given the chart above, has a relatively high capacity, also a very high emissivity. Asphalt therefore emits at a lower frequency than a whitish surface, i.e., at a lower temperature.
Water has about twice the heat capacity of building materials but only 2/3 the emissivity therefore is an excellent store. CO2 at STP is an exceedingly poor store. “””
Well actually Asphalt emits at shorter wavelength higher frequencies, than a white surface would; BUT ! only because it is a higher Temperature. The spectrum of the emissions is dependent on the Temeprature; and while there might be a spectral selectivity dictated by color and or material density; thermal radiation is largely dictated only by Temperature.
Atmospheric CO2 can hardly be regarded as any kind of store of atmospheric energy. CO2 acts only as a collection mechanism for gathering energy that is immediately shared with the ordinary atmospheric gases; and does not reside for any length of time in the cO2 molecule.
And CO2 molecules in the atmosphere are orphans; there are about 13-14 complete shells of surrounding molecules, before a CO2 molecule is likely to see another in any direction around it; so they do not act in concert.