airmasscoef: Calculates the airmass coefficient

Description Usage Arguments Value Examples

View source: R/solartools.R

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

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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

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# 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 Dec. 14, 2018, 3:10 p.m.