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== Insolation statistics == | == Insolation statistics == | ||
[[File:Insolation statistics.jpg|thumb|right|Insolation statistics per year]] | [[File:Insolation statistics.jpg|thumb|right|Insolation statistics per year]] | ||
For an explanation of this chart it is necessary to explain the insolation first. | |||
We measure [https://en.wikipedia.org/wiki/Solar_irradiance Solar Irradiance] as the power per unit area received from the Sun in the form of electromagnetic radiation as measured in the wavelength range of the measuring instrument (your solar sensor of your weather station). ''CumulusMX'' stores this in [[Standard_log_files|the monthly logs]] as the value of the ''Solar Radiation'' (field nr 19) at that moment. It is the momentary solar power in W/m<sup>2</sup>. | |||
== Using Numerical Integration == | |||
The Solar Insolation for a given time period is the integration of the measured Solar Radiation values. Or as the wiki says: | |||
''Solar irradiance is often integrated over a given time period in order to report the radiant energy emitted into the surrounding environment (joule per square metre, J/m2) during that time period. This integrated solar irradiance is called solar irradiation, solar exposure, solar insolation, or insolation.'' | |||
So if we take R for Radiation (which we sample in field 19) we get for a time period of a day: | |||
<math>\int\limits_{0}^{24}{R} \, dt</math> | |||
But because we do not have continuous measurement we have to approximate this by taking the samples of the ''Solar Radiation'' we do have for the sampling interval we use (1, 5, 10 etc... minutes). Assuming equal distance between the samples and a not too disruptive radiation function we get an approximation for the integral as: | |||
<math>\sum_{t=0}^{24} field19</math> | |||
for all samples, assuming the measured value is the midpoint of | |||
<math>t + \frac{1}{2}*interval</math> and <math>t - \frac{1}{2}*interval</math>. | |||
However this interval appears not to be constant in the reality of ''CumulusMX''. | |||
== Solving the variability of the interval == | |||
== Monthly Insolation statistics per year == | == Monthly Insolation statistics per year == | ||