Variables and style rules

variable	description	comment
tz	timezone
lat or latitude	latitude
lon or long or longitude	longitude
dni	direct normal irradiance
dni_et	direct normal irradiance at top of atmosphere (extraterrestrial)	uvchik: Is 'et' obvious? Or better something like 'extra' oder 'extrat'?
dhi	diffuse horizontal irradiance
ghi	global horizontal irradiance
aoi	angle of incidence
aoi_projection	cos(aoi)
airmass	airmass
airmass_relative or relative_airmass	relative airmass
airmass_relative or relative_airmass	absolute airmass
ground_diffuse or e_ground_diffuse	in plane ground reflected irradiation
e_direct	direct/beam irradiation in plane
e_diffuse	total diffuse irradiation in plane. sum of ground and sky diffuse.
e or e_global	global irradiation in plane. sum of diffuse and beam projection.	wholmgren: or irrad_* or *_irrad, uvchik: I thought it would be consistent using the 'e' or irrad_diffuse and irrad_direct
sky_diffuse or e_sky_diffuse	diffuse irradiation in plane without ground reflected irradiation
surf_tilt or surface_tilt	tilt angle of the surface
surf_az or surf_azimuth or surface_azimuth	azimuth angle of the surface
sun_zen or sun_zenith or solar_zenith	zenith angle of the sun
sun_az or sun_azimuth or solar_azimuth	azimuth angle of the sun
temp_cell	temperature of the cell in Kelvin
voltage_mpp	module voltage at the maximum power point	likewise: ampere, power