Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
"The correlation uses three parameters for ground temperature at the surface to define a correlation for undisturbed ground temperatures as a function of depth and time. If one thinks of the ground temperature for a given depth as a sinusoid, the average ground temperature, amplitude (average difference between maximum ground temperature and minimum ground temperature), and the phase shift (day of minimum surface temperature) are all required to define the correlation.
If the parameters are left blank they can be autocalculated by including soil surface temperatures in the input using the Site:GroundTemperature:Shallow object. They can also be calculated by using the CalcSoilSurfTemp preprocessor."
https://bigladdersoftware.com/epx/docs/25-1/input-output-reference/group-location-climate-weather-file-access.html#sitegroundtemperatureundisturbedkusudaachenbach
