rad_angle¶

rad_angle(aspect, slope, latitude, declination=0.0)[source]¶

Return the cosine of the “radiation angle” according to Herbsta, et al 2006 [1].

Parameters:

aspect – direction of the gradient in XY plane in radians in clockwise direction with respect to north
slope – inclination of the gradient in radians
latitude – point latitude in radians
declination – sun declination angle in radians

All input arguments must be of the same shape or scalar.

The formula is taken from Herbsta, et al. 2006 [1]. They cite Moore, et al. 1988 [2] as source - which doesn’t seem to mention the formula anywhere.

[1] (2006 Geostatistical co-regionalization of soil hydraulic properties in a microscale catchment using terrain attributes [Herbsta, et al.])

[2] Moore, I.D., Burch, G.J., Mackenzie, D.H., 1988. Topographic: effects on the distribution of surface soil water and the location of ephemeral gullies. American Society of Agricultural Engi- neers 31 (4), 1098 – 1107.

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