[wxqc] Analysis

[Dave Helms]

Hi Marion,

If you have a good radiation shield that allows free ventilation without 
direct sun to the sensors, it is OK and even encouraged that you site it 
in the open without being covered by tree branches.   The idea is for 
the sensor to sample the ambient air (e.g. well mixed air which is 
representative of the greater area) and the sensor to be allowed to cool 
at night without the issue of trapped heat. 

Phillip's QC graphs of MADIS statistics are off-line tonight, but here 
is MesoWest QC for your station:
http://www.met.utah.edu/cgi-bin/droman/meso_base.cgi?stn=C5915

... Things look good according to Mesowest.  As for the MADIS QC 
statistics, I can't access your data on Phillip's web pages right now 
but will check back again in a day or two.  As noted by Victor, your 
remote location on the western slopes of the Olympic Range likely cause 
some challenges for the MADIS QCMS methodology which works best with 
stations in close proximity and no significant nearby land/sea 
discontinuities.  I am inclined to agree with Mark at UW/AS about the 
soundness of your reports.

Thanks for sharing your reports with CWOP and NOAA!

Dave
CW0351

Marion C. Maher wrote:

> Hi Dave, thanks for your response, and sorry it took so long to get 
> back to
> you.  I am CW5915.  My sensor has an aspirated shield, or one with vents
> that look like gills.  It does not have a fan.  I did also move it to a
> better location.  It is never in the sun, and is not near any heat 
> source,
> or concrete or asphalt that is heated by the sun, so I am puzzled as 
> to why
> the QC site says that I am experiencing a solar radiation problem.  I 
> have
> sited it the best way I can for my location and for the buildings, roads,
> trees, etc. in the area.  I received a response today from Mark Albright,
> University of Washington Atmospheric Sciences that I have attached.  
> He says
> my data is OK and I think my data is OK, even though the quality check 
> site
> still has a big red X for my temperature data.  So I guess I will 
> continue
> on as I am doing, and hope that my data is being useful.  Anything you 
> can
> add to further educate me would be helpful and appreciated.
>
> Thanks,
>
> Marion
>
> ----- Original Message ----- From: "Dave Helms" <dshelms at comcast.net>
> To: "Discussion of weather data quality issues"
> <wxqc at lists.gladstonefamily.net>
> Sent: Friday, June 30, 2006 10:01 PM
> Subject: Re: [wxqc] Analysis
>
>
>> Hi Marion,
>>
>> What CWOP station ID are you?  We really need this info when people ask
>> for feedback on QC for their station.
>>
>> The hardware instructions you refer to are not correct, you should read
>> the CWOP Station Guide to get a sense of proper siting:
>> http://mywebpages.comcast.net/dshelms/CWOP_Guide.pdf
>>
>> Without looking at your station time-series, siting temperature sensor
>> under a house eve causes you to measure the trapped heat under the eve,
>> and not the ambient, well mixed, atmospheric temperature.  The LaCrosse
>> "cone" itself, which I suspect you have, is not a proper radiation
>> shield as it traps heat due to a lack of ventilation.  We suggest the
>> Cone be replaced with a Gill-type shield (see the CWOP Guide).
>>
>> Hope this helps,
>>
>> Dave
>> CW0351
>>
>> Marion C. Maher wrote:
>>
>>> I am new to uploading data to CWOP and am still in the stage of 
>>> figuring
>>> things out.  When I first started uploading, the analysis said that my
>>> temperature readings were too high, so I "tweaked" the data on the WUHU
>>> software to 99% of normal, and then for a few weeks it said the 
>>> readings
>>> were good.
>>>
>>> The last few days the analysis says that I am experiencing a solar 
>>> heating
>>> problem.  My
>>> sensor is located on a 1x1" board on the North side of the house 
>>> about 6
>>> feet off of the ground, and about 4 feet below a deep eave.  This was a
>>> method the instructions that came with the equipment said could be 
>>> used to
>>> locate the sensor.  This location never gets the sun, it is always 
>>> in the
>>> shade.  It also has a radiation shield that came with the unit
>>> that has vents, no fan.
>>>
>>> I also have questions about the analysis process, is this done by
>>> comparing
>>> data from other local sources?  If so, the closest source you have 
>>> listed
>>> is
>>> the one at Quillayute Airport, 8.6 miles west and quite a bit lower in
>>> elevation.  They are only 3 miles or so from the coast and thus
>>> temperatures
>>> are lowered by the proximity to the ocean and the lower elevation.  
>>> I am
>>> sure you know this already and I don't mean to have an attitude of 
>>> telling
>>> you your business, as I am also sure you are quite a bit more 
>>> experienced
>>> at
>>> this than am I.  If you can educate me and are willing, I would greatly
>>> appreciate it.
>>>
>>> I am also wanting to know what "unverified" means in the response 
>>> that the
>>> WUHU software is getting from CWOP about my data.  Is there something I
>>> need
>>> to do or correct to have a "verified" status?
>>>
>>> Thank you for your response and education, it is greatly appreciated.
>>>
>>> Marion
>>> Forks, WA
>>>
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>>>
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>>>
>>>
>>>
>>>
>>
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