Dear All,
Curios me and I want to explain it to our collaboratos, who ask me about.
Why in Short Cut can not ask the average for air relative humidity?
I downloaded the latest version 3.0 to see if there is a change for this aspect, but the installation crashes in the file AM416a.mux
Thanks
Smile
Ops
the installation on another PC it worked fine.
Remains the question of the inability to obtain the avg of RH%
Thanks
Smile
Following is some information from colleagues here at CSI. My knowledge of RH is limited to loving the humid south more than the dry west. Basically, we removed this option on purpose but give you a "back door" way of doing it if you really want.
Let the regurgitation begin:
The relationship between relative humidity, vapor pressure, saturation vapor pressure, air temperature, and dew point temperature are nonlinear. If a function is non-linear, the mean output of the function is not that same as the function output using a mean input.
This means that RH_mean, found by averaging the instantaneous RH is not equal to e_mean / e_sat_mean. The magnitude of the error depends on where you are on the vapor pressure/temperature curve, e.g. how nonlinear the curve.
One proper way to find a average relative humidity with a temperature and humidity probe is ...
a) measure instantaneous air temperature and instantaneous relative humidity,
b) compute an instantaneous vapor pressure and saturation vapor pressure,
c) average the air temperature, vapor pressure, saturation vapor pressure,
d) at the end of the output period, compute mean air temperature, mean vapor pressure, mean saturation vapor pressure, and
e) finally, compute a true mean relative humidity with mean vapor pressure and mean saturation pressure and save the data to a data table.
With all of that said:
You can right click the variable name and select average from the context menu.
... maybe we should offer an "average relative humidity" calculation in ShortCut or a maybe a AverageRH datatable output option ...
Dear Sam
Many thanks, now is more clear!