# Conversions: Conversions between relative humidity, vapour pressure... In plantecophys: Modelling and Analysis of Leaf Gas Exchange Data

## Description

A collection of functions to convert between relative humidity (RH) (%), vapour pressure deficit (VPD) (kPa), dew point temperature, and leaf- or air temperature-based VPD or RH. To convert from relative humidity to VPD, use the `RHtoVPD` function, use `VPDtoRH` for the other way around. The water vapor saturation pressure is calculated with `esat`. Use `DewtoVPD` to convert from dewpoint temperature to VPD. The functions `VPDleafToAir` and `VPDairToLeaf` convert VPD from a leaf temperature to an air-temperature basis and vice versa. The functions `RHleafToAir` a `RHairToLeaf` do the same for relative humidity.

## Usage

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17``` ```RHtoVPD(RH, TdegC, Pa = 101) VPDtoRH(VPD, TdegC, Pa = 101) esat(TdegC, Pa = 101) VPDtoDew(VPD, TdegC, Pa = 101) DewtoVPD(Tdew, TdegC, Pa = 101) VPDleafToAir(VPD, Tleaf, Tair, Pa = 101) VPDairToLeaf(VPD, Tair, Tleaf, Pa = 101) RHleafToAir(RH, Tleaf, Tair, Pa = 101) RHairToLeaf(RH, Tair, Tleaf, Pa = 101) ```

## Arguments

 `RH` Relative humidity (%) `TdegC` Temperature (degrees C) (either leaf or air) `Pa` Atmospheric pressure (kPa) `VPD` Vapour pressure deficit (kPa) `Tdew` Dewpoint temperature (degrees C) `Tleaf` Leaf temperature (degrees C) `Tair` Air temperature (degrees C)

## Details

The function describing saturated vapor pressure with temperature is taken from Jones (1992). All other calculations follow directly from the standard definitions, for which Jones (1992) may also be consulted.

Remko Duursma

## References

Jones, H.G. 1992. Plants and microclimate: a quantitative approach to environmental plant physiology. 2nd Edition., 2nd Edn. Cambridge University Press, Cambridge. 428 p.

plantecophys documentation built on April 1, 2021, 1:06 a.m.