airmasscoef: Calculates the airmass coefficient

In ilyamaclean/microclima: microclimate modelling with R

Calculates the airmass coefficient

Description

airmasscoef is used to calculate, for a given location and time, the direct optical path length of a solar beam through the atmosphere of the Earth, expressed as a ratio relative to the path length vertically upwards.

Usage

airmasscoef(
  localtime,
  lat,
  long,
  julian,
  merid = round(long/15, 0) * 15,
  dst = 0
)

Arguments

localtime	local time (decimal hour, 24 hour clock).
lat	latitude of the location for which the airmass coefficient is required (decimal degrees, -ve south of equator).
long	longitude of the location for which the airmass coefficient is required (decimal degrees, -ve west of Greenwich meridian).
julian	a numeric value representing the Julian day as returned by julday().
merid	an optional numeric value representing the longitude (decimal degrees) of the local time zone meridian (0 for GMT). Default is round(long / 15, 0) * 15
dst	an optional numeric value representing the time difference from the timezone meridian (hours, e.g. +1 for BST if merid = 0).

Value

the airmass coefficient, i.e. the direct optical path length of a solar beam through the Earth’s atmosphere, expressed as a ratio relative to the path length vertically upwards for a given location and time.

Examples

# airmass coefficient at noon on 21 June 2010, Porthleven, Cornwall
jd <- julday (2010, 6, 21) # Julian day
airmasscoef(12, 50.08, -5.31, jd)

ilyamaclean/microclima documentation built on Sept. 5, 2024, 8:37 p.m.