[wxqc] Balancing Daytime and Night Temperature Readings

[Geoffrey Dick]

So I gather from the answers I received thus far, there are no standards
for the amount of radiation opaqueness and reflectivity of a temperature
radiation shield? 

Geoffrey Dick, WA4IKQ, CWOP Weather Station AS-140 

--------------------------------------------------------------------
> Date: Sun, 22 Apr 2007 12:24:53 -0400 (EDT)
> From: wa4ikq at nevets.oau.org (Geoffrey Dick)
> To: wxqc at lists.gladstonefamily.net
> Subject: [wxqc] Balancing Daytime and Night Temperature Readings
>
> QUESTION: How to reduce the offset between Day and Night Temperature? 
>
> Has anyone on this reflector played with the temperature radiation
> shield to balance the daytime and night temperature reading errors? 
>
> My overnight readings seem to be consistantly accurate, according to 
> the CWOP analysis.  The daytime error -1.3 degrees from the night time
> temperature.   I have done everything I could to locate the sensor in 
> an ideal location in an urban setting.
>
> Now I am down to fine-tuning things.   The radiation shield is made 
> of a white plastic, and I thought it might help to increase the 
> daytime reflectivity by covering the exposed surface with aluminum 
> foil strips in such a manner that it would not block the flow of air.  
>
> I have tried using aspiration, but that yielded only limited results.
> So now I am game for trying something different.
>
> Who can comment on their experience with adjusting the reflectivity 
> of the radiation shield with coloration paint, or metalic coatings? 
>
>
> Kind regards,
>
> Geoffrey Dick
> Winter Park, FL
> Wx Station AS-140 / WA4IKQ
>
> wxqc mailing list
> Post messages to wxqc at lists.gladstonefamily.net
> To unsubcribe or change delivery options, please go to:
> http://server.gladstonefamily.net/mailman/listinfo/wxqc
>
> ----
>
> Date: Sun, 22 Apr 2007 13:07:58 -0500
> From: Gerry Creager <gerry.creager at tamu.edu>
> Subject: Re: [wxqc] Balancing Daytime and Night Temperature Readings
>
> Realize that siting can affect this, and siting takes on a lot of 
> considerations.  It's possible that your readings reflect a valid 
> microclimate for where you're located.  Seeing errors in this analysis 
> doesn't automatically imply that your system is giving bad readings.  It 
> does give you the opportunity to determine if there's something worth 
> changing, or to satisfy yourself that it really is all OK.
>
> For what it's worth, MY report from last night looks like this:
>     DATE     UTC   *   ALT    * POT TEMP *  DEW PNT *    DD    *    FF
>                    *   (MB)   *  (DEG F) *  (DEG F) *   (DEG)  *   (KNT)
> 21-APR-2007 1320  *1018.(-0.4)*  51(7.92)*  49(8.49)*111.(13.7)*3.48(-1.7)
> 21-APR-2007 1335  *1018.(-0.4)*  51(7.92)*  49(8.49)*108.(16.7)*3.48(-1.7)
> 21-APR-2007 1350  *1018.(-0.5)*  51(7.92)*  49(8.49)*120.(4.68)*2.61(-0.9)
> 21-APR-2007 1405  *1018.(0.06)*  52( 9.5)*  50(9.86)*113.(9.36)*2.61(1.25)
> 21-APR-2007 1420  *1018.(-0.2)*  53( 8.5)*  51(8.87)*141.(-18.)*2.61(1.25)
> 21-APR-2007 1435  *1018.(-0.2)*  54( 7.5)*  52(7.88)*131.(-8.6)*3.48(0.38)
> 21-APR-2007 Errs  *   0/96   *  10/96   *  10/96   *   0/96   *   0/96
> 21-APR-2007 Smry  *0.02(0.26)*3.64(2.59)*3.92(2.06)*17.7(49.4)*0.94(1.56)
>
> There's not much wrong with my instrument, although it's heading in for 
> a firmware update and new sensor module as it's a test unit from Vaisala...
>
> gerry
>
> Gerry Creager -- gerry.creager at tamu.edu
> Texas Mesonet -- AATLT, Texas A&M University	
> Cell: 979.229.5301 Office: 979.458.4020  FAX 979.862.3983
> MAIL:  AATLT, 3139 TAMU
> Physical: 1700 Research Parkway, Suite 160,
> College Station, TX 77843-3139
>
> ----
>
> From: "Tim Crummel" <tim5719 at chartermi.net>
> Date: Sun, 22 Apr 2007 14:39:59 -0400
> Subject: Re: [wxqc] Balancing Daytime and Night Temperature Readings
>
> I get errors quite frequently And I know my system is correct. So I tend to
> disregard a lot of the messages. My system is a Heathkit and I use certified
> instruments to calibrate it. If I should place the temp probe in water and
> then freeze it then expose the incased probe to air until it starts to melt
> It is adjusted so that it reads 32.1 degrees. High end is done by a
> certified thermometer that is stated to be with in .5 degrees at 120
> degrees. Tim CW0241 Kalamazoo Michigan 
>
> ----