[wxqc] Temp Issue Maybe

Tue Jul 18 09:14:35 EDT 2006

Oh, yes! I know that.  Still makes for informative reading, and gives 
the user a better feel for some of the "why" behind instrument siting. 
I suspect we're in violent agreement here!

Gerry

Dave Helms wrote:
> ... of course Oke's WMO reports were extensively referenced in the CWOP 
> Guide (see the bibliography citations).
> Dave
> CW0351
> 
> Gerry Creager N5JXS wrote:
> 
> 
>>And, while strongly seconding Dave's comments, I also strongly recommend 
>>a read of Tim Oke's Urban Mesonets document for the WMO, which can be 
>>found at 
>>http://www.wmo.ch/web/www/IMOP/publications/IOM-81/IOM-81-UrbanMetObs.pdf 
>>and is linked off http://www.wxqa.com/resources.html.
>>
>>gerry AP009
>>
>>Dave Helms wrote:
>> 
>>
>>
>>>CWOP Guide, based on NWS COOP and ASOS standards, recommends 5 feet/1.5 
>>>meters AGL for temperature/RH sensor siting.  Read the entire 
>>>temeprature/RH section for more info:
>>>http://mywebpages.comcast.net/dshelms/CWOP_Guide.pdf
>>>
>>>Chuck Goble wrote:
>>>
>>>
>>>   
>>>
>>>
>>>>Well I raised my ISS  to just under 9 ft. My temps are right with 
>>>>Wunderground and Weather.com and sometimes a bit lower by a degree or 
>>>>two. The fan will have to wait. We had a nice little breeze today out 
>>>>of the southeast which is good because hits my ISS so it helps out a 
>>>>bit. I will see the next couple of days and see how it goes. Thanks 
>>>>dr. Lee for the info. I have had my station up since the end of Nov 
>>>>2005 so I am still fairly new at this.
>>>>
>>>>Chuck
>>>>
>>>>dr. Lee wrote:
>>>>
>>>>
>>>>     
>>>>
>>>>
>>>>>Chuck, the national weather service standard for the instrument package
>>>>>except the wind speed instrument is 3m above the ground.  The anemometer
>>>>>should be at 33ft above the ground but, no site is perfect.  Adjust your
>>>>>software or move the instrument package to a location that works with all
>>>>>graphs.  Does your instrument package have a fan that keeps the air moving
>>>>>over the sensors?  If you do not have this option on a davis you can and
>>>>>probably will get a higher temp during the day as the sun will warm the
>>>>>cover and the cover will increase the temp of the air inside around the
>>>>>sensors.
>>>>>
>>>>>The graphs are a comparison of all stations in the area you are so if there
>>>>>are other systems in town all would show the increase in temp and this would
>>>>>tend to null out the increase.  It still looks like you need a fan to keep
>>>>>the air moving inside of the instrument package to solve your problem.  Look
>>>>>at the graph of another station close to you and compare the temps during
>>>>>the day and at night to see if there is a difference and how much there is
>>>>>day and night as day time can again increase the temp inside of the
>>>>>instrument cover unless you have a fan that keeps the air moving thought the
>>>>>unit.
>>>>>
>>>>>N5IHE
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>       
>>>>>
>>>>>
>>>>>>-----Original Message-----
>>>>>>From: wxqc-bounces at lists.gladstonefamily.net 
>>>>>>[mailto:wxqc-bounces at lists.gladstonefamily.net] On Behalf Of 
>>>>>>Chuck Goble
>>>>>>Sent: Sunday, July 09, 2006 11:56 PM
>>>>>>To: wxqc at lists.gladstonefamily.net
>>>>>>Subject: [wxqc] Temp Issue Maybe
>>>>>>
>>>>>>
>>>>>>I am new to the forum so be easy with me. I will do my best 
>>>>>>to describe 
>>>>>>my issue. I have a Davis VP2 wireless standard version. I am 
>>>>>>located in 
>>>>>>Minot, North Dakota. I don't if it is an issue or what. I had my ISS 
>>>>>>located on a mast on my roof along with the anemometer. The ISS was 
>>>>>>about 5ft above the roof top and roughly 20 ft. above the 
>>>>>>ground and my 
>>>>>>temp readings where within CWOP deviations. Then I relocated my ISS 
>>>>>>about 4.5 ft above the ground. Then my temp readings are 
>>>>>>higher and now 
>>>>>>red x according to CWOP. According to the manual you want it no more 
>>>>>>than 6 ft above the ground if I remember correctly. There is 
>>>>>>not a lot 
>>>>>>of trees around and for the most part it is in an area that 
>>>>>>gets plenty 
>>>>>>of breeze when it blows.
>>>>>>
>>>>>>The couple of questions that I have is I live right in the middle of 
>>>>>>town wouldn't my temps be a bit higher due to the fact being in the 
>>>>>>middle of town the heat will dissipate slower so my temps 
>>>>>>will be higher 
>>>>>>for the most part. The other two CWOP stations one is on the edge of 
>>>>>>town and the other one which is the airport is in the wide open area. 
>>>>>>I'm thinking my temps will be different than theres. My next 
>>>>>>question is 
>>>>>>if my temps are high and my humidity is running 4.5% drier why is my 
>>>>>>dewpoint almost right on. But the graph to me does not look that way. 
>>>>>>Maybe I am reading the graphs wrong.
>>>>>>
>>>>>>I hope this is not to long. If I missed anything please let 
>>>>>>me know and 
>>>>>>I will get what info you need if I can. Sorry again if this 
>>>>>>is too long.
>>>>>>
>>>>>>Thanks,
>>>>>>Chuck
>>>>>>_______________________________________________
>>>>>>wxqc mailing list
>>>>>>wxqc at lists.gladstonefamily.net 
>>>>>>http://pond1.gladstonefamily.net:8080/mailman/listinfo/wxqc
>>>>>>
>>>>>>The contents of this message are the responsibility of the author.
>>>>>>
>>>>>> 
>>>>>>
>>>>>>         
>>>>>>
>>>>>
>>>>>_______________________________________________
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>>>>>
>>>>>The contents of this message are the responsibility of the author.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>       
>>>>>
>>>>
>>>>------------------------------------------------------------------------
>>>>
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>>>>
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>>>>
>>>>     
>>>>
>>>
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>>>
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>>>   
>>>
>>
>> 
>>
> 
> 
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-- 
Gerry Creager -- gerry.creager at tamu.edu
Texas Mesonet -- AATLT, Texas A&M University	
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