[aprssig] [wxqc] Weather station questions...

[Geoffrey Dick]

Date: Fri, 21 Jan 2011 00:03:09 -0500
From: Ted Lum <gladstonefamily45.net at tedlum.com>
Subject: Re: [wxqc] Weather station questions...

Ted,

Thank you for your quick answer, but you have oversimplified a very
serious problem that can be handled only by the software writers
and manufacturers of weather equipment.

Let me digress.   Peet Bros. weather stations produce value sets
every second.  Weather Text Software, to be run with a computer via
a serial port updates maximum wind speed every minute.  CWOP data
updates are recommended to be no faster than once every 5 minutes. 
There is good reason for this, in that many CWOP reporting stations
are on a common APRS radio frequency limited to 1200 baud.  To report
any faster would clog the networks and bring many complaints.  Hence,
4 maximum 1-minute wind values will be ignored, and only the last value 
will be reported in a 5 minute period to be used as GUST wind speed.  
That last value has only a 1 in 5 chance of being the highest value 
measured in the 5 minute period.

Amateur Radio Weather Stations using PIC control firmware devices
such as WxTRAK or OpenTrack devices in place of the computer, do
not have any user controls I know of, allow capture of all the 
wind values output from the Weather Stations, i.e. every 
second, or every minute, and select a maximum value of all data to CWOP.   

I do not believe standards exist in Weather Stations across Manufacturers,
or software packages written for interface to the internet are set 
up to handle the 5 minute limitation of reporting GUST values properly.  

Once again, Ted, I do not see a USER method "to force brain dead" software 
or station firmware to capture maximum wind speeds in a coordinated 
reporting time.  Hence, I would like to see Mr. Creager bring up the
subject of reporting correct GUST Values at his Meteorological Society Meeting. 

Kind regards,

Geoffrey Dick, WA4IKQ (AS140), and N4APD-1 (AS659) 

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> Date: Fri, 21 Jan 2011 00:03:09 -0500
> From: Ted Lum <gladstonefamily45.net at tedlum.com>
> Subject: Re: [wxqc] Weather station questions...
>
> That's actually a software issue. The station captures it correctly. Its 
> up to the post processing software to do the right thing with the 
> archive data.

On 1/20/2011 11:52 PM, Geoffrey Dick wrote:
> On Date: Thu, 20 Jan 2011 17:27:35 -0600, Gerald Creager<gerry.creager at tamu.edu>
> 	Organization: AATLT, Texas A&M University
> 	Subject: [wxqc] Weather station questions...
>
> 	I'm headed to the American Meteorological Society meeting and will have
> 	an opportunity to talk to several of the consumer weather station
> 	vendors while there. If anyone has questions for a particular vendor, of
> 	a technical nature (not price breaks, etc) feel free to send them to me
> 	via PRIVATE e-mail (mail-to: gerry.creager at tamu.edu) with a subject line
> 	of "AMS Weather Station" so I can filter and make sure I get the stuff down.
>
> Gerry,
>
> I have often felt that CWOP reporting stations are not reporting the correct
> maximum wind speeds measured as GUST values.   The phenomenon I am seeing is
> the internal GUST values are reset multiple times, say for example, every minute,
> internal to the weather station, and 4 values are thrown out, before a CWOP station
> report is transmitted for the desired temporal frequency of every 5 minutes.
> Hence, the maximum wind speed experienced at a location may never be reported.
>
> I would like to see weather station manufacturers redefine GUST wind speed,
> coordinated to the station reporting time, so that maximum wind speeds are
> reported.   If a station temporal frequency of reporting data is every 5
> minutes, then GUST should defined as maximum wind speed measured over a
> five minute period.
>
> Geoffrey Dick
> WA4IKQ (AS140)
> N4APD-1 (AS659)

----
> Date: Fri, 21 Jan 2011 00:12:39 -0500
> From: Ted Lum <gladstonefamily45.net at tedlum.com>
> ISubject: Re: [wxqc] Weather station questions...
>
> ...and, even if the software is brain dead you can usually force it to 
> be correct by setting your archive interval to be the same as the 
> transmission frequency.

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