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
=================================================
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.
“””gary gulrud says:
July 9, 2010 at 12:37 pm
Physics text, Wein’s displacement law.
Also intereting to read the theory behind the choice of material for the tiles on space vehicles for re-entry.
“George E. Smith says:
July 9, 2010 at 2:23 pm”
Whoa, much to chew on there!
“…The spectrum of the emissions is dependent on the Temeprature”
My thought was the emission spectrum at Temp T is “redder” for materials of higher emissivity. Perhaps the consequence is a wash? When the sun goes down the thick airport runways aren’t still warm in the wee hours and the asphalt approach cool?
“”” gary gulrud says:
July 10, 2010 at 4:29 am
“George E. Smith says:
July 9, 2010 at 2:23 pm”
Whoa, much to chew on there!
“…The spectrum of the emissions is dependent on the Temeprature”
My thought was the emission spectrum at Temp T is “redder” for materials of higher emissivity. Perhaps the consequence is a wash? When the sun goes down the thick airport runways aren’t still warm in the wee hours and the asphalt approach cool? “””
Gary; Black Body radiation theory; which has nothing to do with Eartha Kitt; is quite central to the Physics of weather/climate Physics; even though nothing real is a true Black Body.
The radiation is believed to arise simply from the acceleration of electric charges in atoms/molecules that are in constant motion due to their Temperature.
In Classical Physics, an accelerated electric charge radiates energy continually. This is the reason for the Stanford Linear Accelerator; because if you try to add energy to charged particles particularly electrons that are being guided around in a circle; as happens in accelerators like the LHC and “Bevatrons”, they constantly radiate energy, so if you don’t add more energy during a loop than the charge radiates; then it stops accelerating. With linear accelerators; you only get one trip in the barrell; but you don’t radiate due to circling.
But back to our vibrating atoms/molecules. One of the big successes of modern Physics is that we can very precisely specify the radiation in every way; that is emitted from a black body; even though it is only a fictional device.
And more importantly; we know that NO BODY can emit more radiation at any frequency (wavelength) than can a black body at the same Temperature.
We can actually make very close approximations to real black bodies at ceretain Temperatures; they typically are insulated cavities; where radiation can enter a small hole but can’t escape without bouncing around inside for a long time. They literally are lobster pots for photons (lobster pots don’t work either).
Although the BB radiation spectrum theoretically goes down to; but not including DC (so you can turn it on), and up to infinite frequency (pretty much); 98% of the total radiated energy is emitted between 0.5 times the peak wavelength of the spectrum; and 8 times that peak wavelength. Only 1% remaisn at each end beyond those limits. The shape of the curve is exactly the same at any Temperature; and the Planck Radiation formula is a function of a single variable; Wavelength times Temperature.
In particular the Product of the Temperature, and the wavelength at the spectral peak (Lambda max) is 2897.8 KelvinMicrons roughly.
If a body can radiate efficiently over that 0.5 to 8.0 times peak range; then it doesn’t matter much what it does elsewhere it is for most practical purposes black body like; and often its total emittance is simply that of a true BB (sigma. T^4) times a total emissivity; which is a factor less than 1.0. We would call such bodies gray bodies. And their radiation still follows the SB 4th power law.
Some bodies can have strongly spectrally varying emissivities. If they have high emissivities at low frequency long wavelengths; we would call them red bodies; and if they were strong at shorter wavelengths (and weak at longer) then we would call them blue bodies; even though the wavelengths are not necessarily visible.
Unless their spectral slectivity is quite peculiart; the total radiation will generally still follow the 4th power law. Of course youc an tailor special surfaces to make them spectrally selective in a number of ways; and thermal solar collectors are examples of such surfaces.
At the presumed gloabl average Temperature of 288 K (15 deg C) the BB total emittance is 390 W/m^2, and the peak wavelength of the spectrum is 10.1 microns; so the 15 micron CO2 absorption band is on the downslope tail of that curve.
At the polar lows like at Vostok Station; the Wien Shift of the spectral peak moves it all the way to that 15.0 micron range.
On the other hand; over the hottest tropical desert of asphalt surfaces; the spectral peak can move down to 8.8 microns or lower; which reduces the GHG influence of CO2; and puts more of the LWIR spectrum inside the water atmospheric window (where it will run into the ozone dip at about 9.5-10 microns).
But if the mean global Temperature is 288 K (15 deg C) then the surface emitted radiation that is “heating” the atmosphere; which will in turn “heat” the gound; is not even recognised by the human senses as being “heat”. I don’t know about you; but 15 deg C (59 deg F) feels quite cold to me.
So pick up your telephone directory, and hold it close to your cheek; and feel all the LWIR “heat” pouring off that surface; don’t knock it; it is at least 390 W /m^2 or about 40 Watts per square foot.
So those popular demonstrator experiments; where you use a light bulb (at 2800 K) to show that air with more CO2 gets hotter than air with less CO2; are an outright fraud. Mother Gaia, does not have a lot of 2800 K light bulbs pointing up in the air to heat the atmosphere she does it with nice cold rocks and soil, and stuff.
The 2800 K lamp is not even radiating the correct spectrum to show that CO2 absorbs earth surface emissions. Hell; it is even much hotter than the Venusian surface, and the spectrum peak would be about 1.035 microns (2897.8/2800); which probably falls right on some water absorption line.
Note I am NOT suggesting that CO2 doesn’t absorb LWIR as emitted from the typical earth surface (or atmosphere); it does; but it is nowhere near the effect shown in that fraudulent lab experiment.
And I call it fraudulent deliberately; because either the perpetrators know it is a fraud; so they too are frauds; or else they don’t know it’s a frauds; in which case they are incompetent to claim to be knowledgeable about climate science; which again leaves them in the fraud camp.
We need to reflect all those heat energy back to its source and I using white paint will do the trick. I had my house painted white because of that and it seems to reduce heat. My wife didn’t like the house being white, though. 🙁