I contacted WeatherCloud support requesting what barometric pressure they desire to be uploaded to them from our pws. They stated “compensated barometric pressure”. How does this term fit into altimeter and sea level pressure? My guess is sea level pressure.

Ron.

Altimeter and barometric pressure in this case when we have atmosheric pressure sensore readings, both are sea level pressure reduction algorithms.

Barometer pressure is quite complicated. It takes not only elevation, but also temperature, humidity and dew point.

Altimeter needs only elevation.

There is more than one alghoritm for sea level reduction.

Please check here:

www.softwx.com` // formulas/algorithms`

// Sea Level Pressure reduction algorithms

TSLPAlgorithm = (

paDavisVP, // algorithm closely approximates SLP calculation used inside Davis Vantage Pro weather equipment console (http://www.davisnet.com/weather/)

paUnivie, // http://www.univie.ac.at/IMG-Wien/daquamap/Parametergencom.html

paManBar // from Manual of Barometry (1963)

);

// Altimeter algorithms

TAltimeterAlgorithm = (

aaASOS, // formula described in the ASOS training docs

aaASOS2, // metric formula that was likely used to derive the aaASOS formula

aaMADIS, // apparently the formula used by the MADIS system

aaNOAA, // essentially the same as aaSMT with any result differences caused by unit conversion rounding error and geometric vs. geopotential elevation

aaWOB, // Weather Observation Handbook (algorithm similar to aaASOS & aaASOS2 - main differences being precision of constants used)

aaSMT // Smithsonian Meteorological Tables (1963)

);

TVapAlgorithm = (

vaDavisVp, // algorithm closely approximates calculation used by Davis Vantage Pro weather stations and software

vaBuck, // this and the remaining algorithms described at http://cires.colorado.edu/~voemel/vp.html

vaBuck81,

vaBolton,

vaTetenNWS,

vaTetenMurray,

vaTeten

);

But, CWOP needs altimeter value. It has to be done.

Same problem I had on the beginning with coordinates. They use not very popular standard to describe longitude/latitude.

I hope that now WiFiLoggers will deliver proper data to CWOP.