| cal_relativeHumidity {simET} | R Documentation |
Calculating relative humidity
Description
The relative humidity (RH) expresses the degree of saturation of the air as a ratio of the actual (ea) to the saturation (eo(T)) vapour pressure at the same temperature (T).
Usage
cal_relativeHumidity(ea, e0)
Arguments
ea |
actual saturation vapour pressure. From cal_ActualVapourPressure_for_* |
e0 |
saturation vapour pressure. From cal_saturationVapourPressure() |
Details
Relative humidity is the ratio between the amount of water the ambient air actually holds and the amount it could hold at the same temperature. It is dimensionless and is commonly given as a percentage. Although the actual vapour pressure might be relatively constant throughout the day, the relative humidity fluctuates between a maximum near sunrise and a minimum around early afternoon (Figure 12). The variation of the relative humidity is the result of the fact that the saturation vapour pressure is determined by the air temperature. As the temperature changes during the day, the relative humidity also changes substantially.
Value
A vector for relative humidity %
References
Allen, R. G., Pereira, L. S., Raes, D., & Smith, M. FAO Irrigation and drainage paper No. 56. Rome: Food and Agriculture Organization of the United Nations, 1998.