On Fri, 11 Aug 2017 07:14:31 -0700, Jim Thompson
<To-Email-Use-Th...@On-My-Web-Site.com> wrote:
>On Thu, 10 Aug 2017 22:45:32 -0700, Jeff Liebermann <
je...@cruzio.com>
>wrote:
Yep, it's in a lousy location. Also, plenty of potential of getting
high temperature readings from jet exhaust if the wind is blowing in
the right direction. Still, it's better than an airport rooftop,
where it can measure the HVAC equipment output. The very high record
temperatures might be due to jet exhaust, sensor error, or bad siting.
Dunno.
Weather station siting is a PITA in urban areas. The basic problem is
a tradeoff between minimizing outside influences and maintaining
security. Putting the main weather station in the middle of an empty
field is great for accuracy, but not so great if someone can just
drive up and haul off the entire weather station. Finding a suitable
and secure location in the middle of a huge heat island (Phoenix AZ)
is difficult.
Agricultural weather networks are far better at siting their sensors,
usually in flat open fields. For example, the California CIMIS
network:
<
http://fruitsandnuts.ucdavis.edu/Weather_Services/about_CIMIS_stations/>
Arizona may have something similar. Digging... This one should be
nearby:
<
http://cals-mac.arizona.edu/weather-station>
<
https://cals.arizona.edu/azmet/>
The anemometer isn't high enough (should be about 10 meters high) but
everything else looks acceptable.
NWS Proper Siting (which includes ASOS):
<
http://www.nws.noaa.gov/os/coop/standard.htm>
"The sensor should be at least 100 feet from any paved or
concrete surface".
Right...
The other part of the puzzle is that these stations were never
designed to have their data used for climate research, where accuracy
and consistency are paramount. They're designed to give airport
managers and pilots a good idea of the local conditions for
determining takeoff speed and maybe provide some numbers for the local
weather guessers. For these, a few degrees one way or other is good
enough. When climate research became fashionable about 20 year ago,
the airport ASOS system was drafted into service and the data crammed
into various climate models. When the models became muddles, the data
from all these inaccurate weather stations was averaged together on
the assumption that the errors were random and would cancel each
other. That's not the case as thermal heat islands always have a
positive temperature bias. See the reader comments on the situation
(2008):
<
https://climateaudit.org/2008/01/10/inside-the-ho83-hygrothermometer/>
The subject line is correct. Your record temperatures were caused by
humans. In this case, by jet exhaust, bad siting, and sensor errors.