Reading the FTP site is best, here’s an attempt to get the Class 5 description readable in full:

Class 5 (error >/= 5 C): Temperature sensor located next to/above an artificial heating source, such a building, roof top, parking lot, or concrete surface.

exaggeration [sp] of the rating of the station is rather untenable unless one has a presupposed position on the matter.

Please check
ftp://ftp.ncdc.noaa.gov/pub/data/uscrn/site_info/CRNSiteSurveyChecklist.pdf
Please note this excerpt:

Classification for Temperature and Humidity

Class 1: Flat and horizontal ground surrounded by a clear surface with a slope below 1/3 (<19 degrees). Grass/low vegetation ground cover 3 degrees.

Class 2: Same as Class 1 with the following differences. Surrounding Vegetation 5 degrees.

Class 3 (error 1 C): Same as Class 2, except no artificial heating sources within 10m.

Class 4 (error >/= 2 C): Artificial heating sources /= 5 C): Temperature sensor located next to/above an artificial heating source, such a building, roof top, parking lot, or concrete surface.

It appears ambiguous to me whether this means that any “concrete surface” is an “artificial heating source”. If so, the station is class 5 by definition. Clearly the ranking system was not written with volcanoes or forested regions in mind.

I’d expect the specific heat of most rocks would be about the same (s.h. is the number of calories to raise the temperature of one gram of the material one Kelvin). I’d also expect the heat conductivity of the concrete to by much higher than volcanic cinders, though I’m most familiar with cinders from Arizona and Oregon. If Hawaiian cinders have few/no gas bubbles, then their conductivity ought to be on a par with typical concretes.

Mike Helfert
mhelfert42@yahoo.com

Note that not all cities show a warming relative to their rural surroundings. For example, Hansen et al. (JGR, 2001) adjusted trends in urban stations around the world to match rural stations in their regions, in an effort to homogenise the temperature record. Of these adjustments, 42% warmed the urban trends: which is to say that in 42% of cases, the cities were getting cooler relative to their surroundings rather than warmer. One reason is that urban areas are heterogeneous, and weather stations are often sited in “cool islands” – parks, for example – within urban areas.

Does anyone know where these COOL urban weather stations are situated.

Thanks

REPLY: they can be purchased from Novalynx in Auburn, CA

http://www.novalynx.com/380-605.html

I can be reached at: info [-at-] surfacestations dot org

REPLY: Generally yes

I think that’s because CO2 was voted to that office by the Greens. It was probably a disputed election that the water vapor advocates claim was stolen by all the CRN 5 stations false reporting of results. :)

Both the cinders and the slab add to this uncertainty, even if they have different signs.

Two uncertainties does not make things any more certain.

AG

CRN 5 maybe, it might be a cooling greater than 5C of course all bets are off after the next major eruption.

Bill

granted, the concrete slab in a pleasant, green meadow needs a five. because that’s a tremendous change from the local environment. but will that same slab in a lava field generate an anomaly of >5C?

The concrete is likely to be cooler than the cinders, which could be spread on top of the concrete.

BTW: Is a volcano considered an artificial heat source?