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Urban Heat Island (UHI): City heat in global temperatures – Studies and IPCC´s role

Posted by Administrator (admin) on 9th February, 2010
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IPCC originally used the biggest investigation on UHI made by Thomas Karl, 1988. In this study of more than 400 ”City-rural” temperature pairs, he reached a clear and detailed connection between city size and the resulting erroneous heat pollution in the temperature trends. He found, that the smallest cities med population of just 2000 added 0,06 degrees Celsius in heat to the temperature trend. However cities with 10 million inhabitants shows 2,57 Celsius city heat in the measured temperature trend. These results are valid for the years 1900-1984:

These results does not include the years 1984 – 2010, and thus, the city heat for this period is not included.

 

There are invetigations showing a vary low error trend or UHI (typically just 0,05 Celsius corresponding to the IPCC view point)

1)       Wang, for China. He has now a police involved swindle accusation due to this work. CRU´s Phil Jones name appears in one of these Wang papers on UHI.

2)       Peterson. It turned out, that Peterson did not add his numbers correctly… Steve McIntyre got no less than 0,7 Celsius simply by redoing the simple recalculation of Petersons data. But worse, Peterson had also put City-temperature datasets in the rural category and vice versa. By simply putting City trend correctly in one pile, and then rural trends in another pile, the UHI was easilu shown to be 2 full degrees Celsius in difference between city stations and rural stations. And data used was the very data the IPCC themselves had relied on when Peterson used them. So its hard for IPCC to claim something wrong in the data behind this 2 degrees UHI result: http://climateaudit.org/2007/08/04/1859/

Finally an investigation exists used by IPCC, where the author has decided not to compare City temperatures with rural temperatures. This for no written reason. In stead of just comparing the difference in temperature trend between the city thermometer and the rural thermometer, this study does some indirect assumptions on how winds should affect things out side cities, and then conclude a very low UHI on this ground.

 

IPCC says: UHI is 0,05 Celsius

NOAA goes further now: UHI is 0,00 Celsius.

CRU/HadCrut says that their UHI – correcting is to completely remove city stations with city effect – that they don’t correct the numbers for UHI. But far most of their used stations are infact from cities. Jones writes in a mail that they in 1986 removed 38 out of 2500 stations due to UHI.

GISS has carried out thousands of ”UHI-corrections”, but nearly half of their corrections induces extra heat to their results. SO we can conclude, that GISS believes that almost just as many cities pollutes the temperatures with cold as cities that pollutes thes temperatures with heat. (Why have we never heard of Cities that makes temperatures colder when they are everywhere? Why have we never heard of problems with ”Urban Cold Island”? People painting their roofs black to compensate Urban Cold Island?). More: http://climateaudit.org/2008/03/01/positive-and-negative-urban-adjustments/

 


Last changed: 9th February, 2010 at 08:27:17

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