It's easy to see why the pressure issue comes up all the time...

>From the VWS manual regarding the VWS database format:

Column   Parameter
Number
9        Barometric Pressure
24       Sea-level Barometric Pressure
25       Pressure Altitude 

The manual goes on to define the following in it's glossary:

Barometric Pressure. The pressure exerted by the atmosphere as a 
consequence of gravitational attraction exerted upon the "column" of air 
lying directly above the point in question. The measurement can be 
expressed in several ways. One is in millibars. Another is in inches or 
millimeters of mercury (Hg). Also known as atmospheric pressure. 

Pressure Altitude. Atmospheric or barometric pressure expressed in terms of 
altitude which corresponds to that pressure in the standard atmosphere. 

Sea Level Pressure. The atmospheric pressure at mean sea level either 
directly measured by stations at sea level or empirically determined from 
the station pressure and temperature by stations not at sea level. Used as 
a common reference for analyses of surface pressure patterns. 

I can probably make sense of it so far, in VWS speak 'Barometric Pressure' 
is what in weewx speak we call 'pressure', 'Pressure Altitude' is what we 
call 'altimeter' and 'Sea level Pressure' is what we call 'barometer'. Bu 
then the VWS tabulated daily text file includes a column titled 'Raw 
Barom', now things start to get confusing...

Gary

On Tuesday, 2 August 2016 08:31:28 UTC+10, Tom Keffer wrote:
>
> 5) any other gotchas in doing a conversion to weewx?
>>
>
> ​Please note that field 'rain' is the amount of rain that fell *during 
> that archive interval*. That is, it's the amount of rain that fell in the 
> five minute sampling window.
>
> Also, see the Wiki 
> <https://github.com/weewx/weewx/wiki/Barometer,-pressure,-and-altimeter>for 
> the differences between the three different kinds of pressure: barometer, 
> pressure, and altimeter.
>
> -tk
>

-- 
You received this message because you are subscribed to the Google Groups 
"weewx-user" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
For more options, visit https://groups.google.com/d/optout.

Reply via email to