calcsun
This module is defined in Classcalcsun and can estimate sunshine hours from the the incoming short-wave observation Qsi and the values QdroD, QdfoD and SunMax calculated by the module global using the HRU's latitude.
Observations
- Qsi (W/m^2) - average incident short-wave flux for time interval (optional). Used only if sunshine hours are not available.
- SunAct (h) - sunshine hours (optional). When not available the sunshine hours are estimated from Qsi, if available.
Observation Functions
- Qsitot(W/m^2*d) - daily total (cumulative) of average interval incident short-wave fluxes, Qsi.
Variables
- hru_SunAct (h) - calculated sunshine hours.
Parameters
- none
Variable Inputs
- QdfoD (global) (MJ/m^2*d)
- QdflatD (global) (MJ/m^2*d)
- SunMax (global) (h)
Notes.
When the actual sunshine hours are not available as an observation, an estimate is made from the following,
hru_SunAct = (daily sum of Qsi*WtoMJ_D/Freq - QdfoD) * (theoretical maximum sunshine hours)/(QdflatD - QdfoD) where WtoMJ_D = 86400/10^6 and Freq is intervals/day,
otherwise the observation SunAct is used.