Weather Parametres

Group	Abbreviation/Symbol	Description
Parameter	Bh	Direct radiation on horizontal surface
	Bk	Direct radiation on inclined surface
	Bn	Direct normal radiation (beam)
	DD	Wind direction
	Dh	Diffuse radiation (horizontal)
	Dh hor	Diffuse radiation (horizontal) with raised horizon
	Dh min	Diffuse radiation on clear days
	Dk	Diffuse radiation on inclined surface
	eh	Emissivity horizontal
	ev	Emissivity vertical
	FF	Wind speed (10 m above ground)
	FFE	Wind speed in E direction
	FFN	Wind speed in N direction
	FFaE, N, W, S	Wind fraction E, N, W, S (in %)
	<G>	Average radiation intensity
	Gh	Global radiation (horizontal)
	Gh hor	global radiation (horizontal) with raised horizon
	Gh max (Gc)	Maximum global radiation (on clear days) (horizontal)
	Gk	Global radiation on inclined surface
	GvE, N, W, S	Global radiation on vertical surface in E, N, W, and S directions
	H	Radiation time integral (radiation energy)
	HDD12/20	Heating degree days (with critical temperatures 12°C outside, 20°C in- side)
	Lin	Longwave horizontal radiation impinging (longwave incoming)
	Lup	Longwave horizontal radiation emitted (longwave outgoing)
	Lv	Longwave radiation on vertical surface
	LG	Global illuminance
	LD	Diffuse illuminance
	mx	Mixing ratio
	N	Total cloud cover
	p	Atmospheric pressure
	PAR	Photosynthetically active radiation
	PV	Photovoltaic (installation/production)
	r	Albedo, reflection coefficient
	R	Radiation balance
	Rb	Ratio of direct radiation integral on inclined and horizontal surfaces
	RD	Days with precipitation ≥ 1.0 mm
	R-Faktor	Ratio of global radiation integral on inclined and horizontal surfaces
	RH	Relative humidity
	RR	Precipitation
	Ta	Air temperature
	Td	Dew point temperature
	Tp	Wet-bulb temperature (psychrometer temperature)
	Ts	Surface temperature
	PrecW	Water content of Atmosphere (precipitable water)
Earth	j	Latitude
	j'	Latitude of equivalent horizontal area
	l	Longitude
Surface	b	Surface inclination
	g	Surface azimuth (orientation of surface)
	Q	Incident angle of radiation on inclined surface
	rD	Isotropic diffuse view factor
	rR	Isotropic reflex view factor
Sun	ma	Optical air mass
	d	Declination
	gs	Solar azimuth
	hs	Solar altitude
	I0	Solar constant
	G0	Radiation at the upper edge of the atmosphere (Solar constant adjusted to distance earth-sun)
	Gex	Extraterrestrial solar radiation (horizontal)
	KT	Clearness index (month)
	Kt	Clearness index (day)
	kt	Clearness index (hour)
	So	Astronomical day (sunshine duration)
	Sd	Effective sunshine duration
	ws	Hourly (solar) angle
	wss	Hourly angles at sunrise and sunset
Time	dm	Day of month (1..28/29/30/31)
	dy	Day of year (1..365/366)
	ET	Time equation
	GMT	Greenwich mean time (=UTC)
	h	Hour of day
	hy	Hour of year
	IZRM	Internal reference time in min
	m	Month
	CET (MEZ)	Central European Time
	ST	True solar time
	t	Local time (time of day)
	ts	Time difference between local time and zonal time
	tz	Time difference between zonal time and universal time
	UTC	Universal time coordinated

     

Abbreviation	Parameter	Unit
M	Month
Gh	Global radiation horizontal	[kWh/m² month]
Dh	Diffuse radiation horizontal	[kWh/m² month]
Ta	Temperature	[°C]
RH	Relative humidity	[%]
RR	Precipitation	[mm]
Rd	Days with precipitation	[days]
FF	Wind speed	[m/s]
Tadmin	Mean daily minimum of tem- perature	[°C]
Tadmax	Mean daily maximum of temper- ature	[°C]
Tamin	Minimum hourly temperature	[°C]
Tamax	Maximum hourly temperature	[°C]

Parameter	Description	Basic unit	Further units
DD	Wind direction	[°]	-
FF	Wind speed (FFE, FFN longitudinal and latitudinal part of the wind speed)	[m/s]	[1/10 m/s], [kt], [km/h]
FX	Gust peak speed (format "sia 2028" only)	[m/s]	[1 m/s]
H	Time integrated radiation (Index refers to radiation type)	[kWh/m²]	[MJ/m²]
G	Average hourly radiation intensity: (H/Dt) (Index refers to radia- tion type)	[W/m²]	[btu/ft² h], [kJ/m² h]
<G>	Average radiation intensity: (H/Dt) (Index refers to radiation type). For daily, monthly and yearly averages	[W/m²]	[btu/ft² h], [kJ/m² h]
hs	Solar altitude, i.e. the angle between the line joining the center of the sun with the site and the horizontal plane at the site.	[rad]	[°]
KTm, Ktd kt	Clearness index: Ratio of global radiation on earth's surface and extraterrestrial radiation (Gh / G0). KT refers to monthly values, Kt to daily values and kt to hourly values.	[ ]	-
mx	Mass mixing ratio: quantity of water vapor per kg of dry air	[g/kg]	-
N	Cloud cover	[octal units]	-
LG	Global illumance	[lux]	-
LB	Direct illuminance	[lux]	-
LD	Diffuse illuminance	[lux]	-
p	Atmospheric pressure	[hPa]	[1/100 inch Hg]
RD	Days with Precipitation ≥ 1.0 mm	[d]	-
RR	Precipitation	[mm]	-
RH	Relative humidity	[%]	-
PrecW	Precipitable water	[mm]	-
dr	Driving rain
Enthalpy	Enthalpy	[kJ/kg]
snow	Snow depth	[mm]
r (rho)	Albedo	[ ]
Sd	Effective sunshine duration	[h]	-
Ta	Air temperature (ambient temperature, 2 m above ground)	[°C]	[1/10 °C], [F]
Ta min/max	Lowest/highest hourly temperature per month	[°C]	[1/10 °C], [F]
Ta dmin/dmax	Average minimum/max. daily temperature	[°C]	[1/10 °C], [F]
Td	Dew point temperature	[°C]	[1/10 °C], [F]
Tp	Wet-bulb temperature (psychrometer temperature)	[°C]	[1/10 °C], [F]
Ts	Surface temperature (5 cm above ground)	[°C]	[1/10 °C], [F]
tl	Linke turbidity factor	[ ]

Abbreviation	Parameter	Unit
m	Month
dy or dm	Day of year or day of month
h	Hour
gh	Global radiation	[W/m²]
ta	Temperature	[°C]
dh	Diffuse radiation	[W/m²]
bn	Beam radiation	[W/m²]
td	Dew point temperature	[°C]
rr	Precipitation	[mm]
ff	Wind speed	[m/s]