asbio (version 0.2-1)

radiation.heatl: Radiation-heatload algorithm

Description

The function radiation.heatl calculates annual incident solar radiation (MJ cm$^2$ yr$^-1$) and heatload (a radiation index based on the idea that highest amounts of radiation occur on southwest facing slopes in the northern hemisphere).

Usage

radiation.heatl(slope, aspect, lat)

Arguments

slope

slope (measured in degrees)

aspect

aspect (measured in degrees)

lat

latitude (measured in degrees)

Value

• radiation
  Annual incident radiation in (MJ cm$^2$ yr$^-1$)
• heatload
  A unitless measure of heatload, maximized on SW aspects.

Details

The function requires three types of data: slope (measured in degrees), aspect (measured in degrees), and northern latitude = lat (measured in degree). The function is based on equations from a paper written by McCune and Keon (2002). Note that this function ignores climatic factors including cloudiness, and is therefore is probably best for relative comparisons of radiation and heatload within a region and not for absolute measurements.

References

McCune, B., and D. Keon (2002) Equations for potential annual direct radiation and heat load. Journal of Vegetation Science, 13: 603-606.

Examples

slope<-20
asp<-25
lat<-46
radiation.heatl(slope,asp,lat)