J
Jeff Liebermann
Guest
On Thu, 01 Jan 2015 11:41:23 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:
Blundering onward...
This one is quite good on siteing.
<http://weather.gladstonefamily.net/CWOP_Guide.pdf>
Basically, what you're missing with your unspecified model Acurite
weather station is a radiation shield for the temperature sensor. What
you're trying to do is measure the air temperature, not the
temperature of the plastic box, the nearby walls, exhaust vents,
parking lot heat island, reflections from low-e glass, foliage
transpiration cooling, and a zillion other sources of error. Here's a
fun example:
<http://802.11junk.com/jeffl/crud/KSBW-WX-Station.jpg>
That's the local radio station's weather sensor array on the left,
sited over the HVAC system.
More on badly located weather stations. This site is well worth
skimming:
<http://www.surfacestations.org>
Even the official weather stations are often badly located:
<http://www.surfacestations.org/odd_sites.htm>
This is one of my early attempts at a radiation shield (pagoda):
<http://802.11junk.com/jeffl/pics/wx/slides/radiation-shield-01.html>
It was ok, but I missed something obvious. There's a gap near the top
of the wall where the cable goes through. Inside the building are
several high power transmitters, which produce lots of hot air, that
greatly affects the indicated temperature. Here's the CWOP report on
temperature and barometric accuracy. The station was removed and is
being moved to a better location sometime in the next month.
Enough for now. Your problem will be:
1. Do some reading on proper weather station siteing and Stevenson
Screen radiation shield construction.
2. Find a better weather station if you want accuracy.
3. Register with the various amateur weather web sites (Weather
Underground, CWOP, etc and see if your numbers track those of the
stations around you.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
wrote:
Blundering onward...
This one is quite good on siteing.
<http://weather.gladstonefamily.net/CWOP_Guide.pdf>
Basically, what you're missing with your unspecified model Acurite
weather station is a radiation shield for the temperature sensor. What
you're trying to do is measure the air temperature, not the
temperature of the plastic box, the nearby walls, exhaust vents,
parking lot heat island, reflections from low-e glass, foliage
transpiration cooling, and a zillion other sources of error. Here's a
fun example:
<http://802.11junk.com/jeffl/crud/KSBW-WX-Station.jpg>
That's the local radio station's weather sensor array on the left,
sited over the HVAC system.
More on badly located weather stations. This site is well worth
skimming:
<http://www.surfacestations.org>
Even the official weather stations are often badly located:
<http://www.surfacestations.org/odd_sites.htm>
This is one of my early attempts at a radiation shield (pagoda):
<http://802.11junk.com/jeffl/pics/wx/slides/radiation-shield-01.html>
It was ok, but I missed something obvious. There's a gap near the top
of the wall where the cable goes through. Inside the building are
several high power transmitters, which produce lots of hot air, that
greatly affects the indicated temperature. Here's the CWOP report on
temperature and barometric accuracy. The station was removed and is
being moved to a better location sometime in the next month.
Enough for now. Your problem will be:
1. Do some reading on proper weather station siteing and Stevenson
Screen radiation shield construction.
2. Find a better weather station if you want accuracy.
3. Register with the various amateur weather web sites (Weather
Underground, CWOP, etc and see if your numbers track those of the
stations around you.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
ut all your thermometers in one place,