Co-author Dr. John Nielsen-Gammon (and subbed at the last minute by John Christy) presents the results of the SurfaceStations project to the 19th Conference on Applied Climatology 18–20 July 2011, Asheville, North Carolina. AMS just posted these presentations (h/t to Zeke at Lucia’s) and I’m providing them here also after converting from the AMS flv format to YouTube.
John N-G John Christy does a good (last minute) job of giving an overview of what was found, plus the differences. Watch the video below:
Zeke’s project, not yet published, was also a presentation:
It appears that the first and third videos are identical.
Hi Anthony
Just as I am settling down to view, is the 1st and 3rd video one and the same? The URL’s as subtly different but the nett affect seems the same
Andy
REPLY: Third was a cut/paste leftover, removed. thx -A
I’m still trying to figure out why the records are showing that cities have a cooler daytime high trend than the well sited rural stations. Is it because the cities are dominated by the MMTS instruments and the MMTS instruments have a better radiation shield? Or is it something else like stations in cities placed over irrigated lawns?
MB;
I wonder if it could be thermal mass; more “stuff” to soak up the joules. That would also keep the range narrower (i.e., night minimum trends in cities higher).
It is my understanding that nighttime low temperatures are limited by dew point. On clear nights the temperature drops to the dew point due to radiational cooling. On cloudy nights, there is usually no dew. It should be possible to measure the urban heat island effect by comparing the relationship between the minimum temperature and the dew point at an urban station and a nearby rural station. Because of the thermal mass in urban areas, the temperature drop would be less. My problem is that most stations do not have historical dew point data and if they do, I would have to pay for it. Does anyone know where historical dew point data is available. Would the Berkely project be making that available?
Why does JNG sound like John Christy (another co-author)? I suspect JNG was going to be the presenter. I am almost positive that’s John Christy.
John Christy gave the Fall et al presentation rather than John N-G, as John was unable to make it to the conference until Wednesday due to a last-minute delay.
REPLY: John N-G’s name was bolded in the AMS page for the presentation I converted here, http://ams.confex.com/ams/19Applied/flvgateway.cgi/id/18343?recordingid=18343 …so I took that to mean he was the presenter. With my hearing loss, I can’t often distinguish people. I’ll fix. Thx Also looks like the powerpoint was John N-G’s not Christy’s? -A
Zeke-That’s what I thought.
Anthony,
As far as I know, John N-G made the powerpoint and was planning to present it, but was unable to make it that day at the last minute, so Christy stepped in.
Anthony-“Thx Also looks like the powerpoint was John N-G’s not Christy’s? -A”
Zeke-“As far as I know, John N-G made the powerpoint and was planning to present it, but was unable to make it that day at the last minute, so Christy stepped in.”
If so he must have borrowed those graphic illustrations of the day/night boundary layer effects from John when putting the presentation together. Most of the presentation could have been put together by any of the co-authors, but those I’ve seen in several of his presentations in the past. Or perhaps Christy added those. In case you are wondering what I am talking about, it is when he explains the physical reasons for the contrasting min/max temperature results.
I have a concern that this macro type of analysis, despite being very well done, hides the real impact of UHI.
I would prefer to see an intense long term study of a few well selected representive examples.
I have looked closely at two well separated Australian sites and have found that abrupt changes in the built environment caused what were previously long term (near 100 years) flat temperature trends to be suddenly transformed into steady upward sloping trends, that have continued for many decades.
On each ocasion, I was lucky enough to have been able to positively identify the physical cause of the abrupt change.
I have not yet seen any decent long term analyses of UHI.