Beam me to Planet Gore !
Posted on 12/15/2010 9:02:44 AM PST by Signalman
We know that more and more temperature stations have been sited in urban areas over the last few decades, and surely this has had an impact on the measurement of the globe’s temperature. But not to worry, say scientists, the raw data have been homogenized in order to compensate for this.
Have they compensated enough? Just how much uncertainty is in the land-based temperature record for the last 50 years? A new report from NASA shows some results that I think are surprising.
Summer land surface temperature of cities in the Northeast were an average of 7C to 9C (13F to 16F) warmer than surrounding rural areas over a three year period, the new research shows. The complex phenomenon that drives up temperatures is called the urban heat island effect.
Dr. Marc Imhoff, leader of the study, says that urban areas located in forested regions have a much more pronounced urban heating effect than in desert areas. Adjustment is neither an easy nor accurate task (emphasis added):
However, accurate comparisons have long eluded scientists because ground-based air temperature sensors tend to be unevenly distributed and prone to local bias. The lack of quantifiable definitions for urban versus non-urban areas has also hindered comparisons
But thanks to satellites, progress is being made in understanding the urban heat island effect. Satellite data have been used to compare various urban settings. Ping Zhang, a scientist at Goddard and a lead author of the research:
“This, at least to our knowledge, is the first time that anybody has systematically compared the heat islands of a large number of cities at continental and global scales,”
Research by NASA scientists shows that compact urban areas have a higher urbean heat island effect that sprawling cities, and depend greatly on the surrounding environment, as mentioned above.
Taking the UHI effect has been the subject of much controversy over the years. This new study shows that it may have been signficnatly understated, at least in some areas.
Providence, R.I.; Washington, D.C.; Philadelphia, Pa.; Baltimore, Md.; Boston, Ma.; and Pittsburgh, Pa.; had some of the strongest heat islands of the 42 northeastern cities analyzed.
These 3 examples have all trended upwards over the last 30 or 40 years. The actual siting and history of each station would have to be examined individually. So one can imagine what a mess this is and how arbitrary all this could be. Here we can be thankful for satellites.
The warming indeed is man-made, but in a different sense. The urban warming is what has impacted people in the summertime, especially at night.
The U.S. Environmental Protection Agency estimates that, between 1979 and 2003, heat exposure has caused more than the number of mortalities resulting from hurricanes, lightning, tornadoes, floods, and earthquakes combined.
“It is the lack of cooling at nighttime, rather than high daytime temperatures, that poses a health risk,” said Benedicte Dousset, a scientist from the University of Hawaii who also presented data about heat islands at the AGU meeting.
Urban planners will have to take this into account when designing cities in the future. Trees, trees and more trees can help a lot. Meanwhile, all this leaves James Hansen with a pile of almost useless data. See full post and images here. H/T Marc Morano
Icecap Note: See this Icecap post under About Climate Change on Urban Heat Island Contamination. It is also discussed in detail in the body of this SPPI special report with Joseph D’Aleo and Anthony Watts with help of many other scientists and in some of the case studies. Also SPPI has posted this report by former NASA scientist Dr. Ed Long comparing raw and modified urban and rural stations.
The study also calls into serious question, the decisions by NOAA and CRU to exclude an urban adjustment (assume it can be accounted for with only an additional 0.05C/century uncertainty).
But not to worry, say scientists, the raw data have been homogenized in order to compensate for this.Oh yeah... they COMPENSATE, alright.
They COMPENSATE all the time.
It's called:
Hide the decline.
Screw NASA. It is a joke now. They were good when the Gemans ran NASA.
I live in the country. It was 2 Deg this morning. TWO. Where’s my global warming??!!!!
Wouldn’t you know it, the liberals finally come up with an idea I can support 100% (warming the earth by a few degrees) and then they fail to perform it.
Duh.
Look at weather records for the three Washington, DC area airports.
IAD and BWI had about half a dozen nights below freezing before DCA had a single one this fall. Routinely, especially in the colder months, DCA runs about 3 to 7 degrees warmer for nighttime lows on average than IAD or BWI. In fact, Tallahassee, FL had it’s first below-freezing night this fall before DCA did, but BWI and IAD had several by that time.
Like Marysville, the site is surrounded by asphalt, and the surface is unnatural – its wood chips over weedmat, and I’ll have to say it was hot as hot to walk on.
But the kicker is the “accessories” they’ve added for convenience of running the hygrometer and for night observations. Yes is another fine high-quality USHCN site. I winder how many times they forgot to turn off the light? Its a 65 watt bulb by the way."
Its no more complicated then this.
The weather reporters on a daily basis are far from accurate. They call for sun it rains, they call for rain the sun is out. They call for 2 inches of snow you get 2 feet, they call for a major snow storm and you get flurries.
Its is hard for people to have much faith in the scientists long term predictions when we know they can not get it right from one day to the next.........
GLOBULL warming is all lies and the people that propagate this crap should be executed for doing so.
LLS
Not surprisingly measured 20th century temperatures have tracked along well with the spread of agriculture ~ particularly the spread of irrigated agriculture.
So, why is that? Well, it turns out that if you want to WARM UP an area you plant lots of plants ~ the Potsdam Institute in Germany discovered that more than a decade ago in its study of the Sahara.
(NOTE: It's not that the Sahara is "hot" but that it's "dry", and that's due to the failure of the monsoons to be drawn ashore ~ there are plants that can be grown in the Sahara that will heat up the area and provide thermals that draw in monsoons.)
Irrigation increases the average relative humidity level, and that increases the retention of solar heat.
Note that I referred to "measured temperatures", not global average temperatures. Up until 10 years ago all of our temperature data came from local stations located mostly at airports ~ near urban centers. Even stations in rural areas were necessarily co-located with the introduction of higher yield crops using improved photosynthetic pathways ~ and that increased the sort of heating the Potsdam Institute found.
The Earth could be warming up, or maybe it's not, but Fur Shur we don't know from the older data since that was distorted by failure to determine local "heat island effects".
All we have is the last 10 years of satellite data, and that shows NOZING HOPPEN!@
It was built by dredging the East bank of the Potomac and dumping the Spill on the West bank.
The humidity levels at DCA are quite a bit higher than most anywhere except the Gulf of Mexico.
Even if you removed DC and left it open fields DCA (located in Virginia BTW) would still be a serious heat island all by itself due to the humidity levels (water being, of course, a major greenhouse gas).
And it’s even more complicated than that.
As you suggest, it’s very difficult to give an accurate 3-day forecast, even an accurate 1-day forecast.
And yet AGW “experts” are basically giving a ONE HUNDRED YEAR FORECAST!
But it’s even worse than that. The same people who do the best they can with the 1-day/3-day/10-day forecasts are NOT the same people giving the 100-year-forecast.
The people giving the 100-year-forecast have NO FORECAST EXPERIENCE OF ANY KIND!!!
They are a bunch of “theorists” running “models” on what are basically Climate Computer Games with the inputs being skewed data from poorly located “temperature sensing stations”.
They are liars. Each and every one of them. Liars and thieves. And they want my money, and your money and all the money they can get their filthy hands on.
An urban heat island effect would lead to higher temperatures at night. How does a “greenhouse” effect work in the dark?
Interesting that you bring up the Sahara. Freeman Dyson, who says that it might be possible that GW is happening, though caused by what would be very difficult to say, claims that if there is GW one of the results most probably will be a wet Sahara. At all times in the past when the global average temperature was higher than it is in recent millenia, the Sahara was wet.
So what’s a wet Sahara worth? According to Dyson, it’s worth a lot, a whole hell of a lot. It might be worth having all the other “problems” that will come with a warmer climate, if there is a warmer climate, caused by as-yet-undetermined causes.
This is not a big issue with me (the whole wet Sahara thing) since I don’t believe there is any warming, but rather actual cooling. However, since you mentioned the Sahara, and since Dyson is such a clever fellow, I thought I’d throw this in.
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