wetbulb.temp {bigleaf} | R Documentation |

## Wet-Bulb Temperature

### Description

calculates the wet bulb temperature, i.e. the temperature that the air would have if it was saturated.

### Usage

```
wetbulb.temp(
Tair,
pressure,
VPD,
accuracy = 0.001,
Esat.formula = c("Sonntag_1990", "Alduchov_1996", "Allen_1998"),
constants = bigleaf.constants()
)
```

### Arguments

`Tair` |
Air temperature (deg C) |

`pressure` |
Atmospheric pressure (kPa) |

`VPD` |
Vapor pressure deficit (kPa) |

`accuracy` |
Accuracy of the result (deg C) |

`Esat.formula` |
Optional: formula to be used for the calculation of esat and the slope of esat.
One of |

`constants` |
cp - specific heat of air for constant pressure (J K-1 kg-1) |

### Details

Wet-bulb temperature (Tw) is calculated from the following expression:

`e = Esat(Tw) - Le067 * gamma * (Tair - Tw)`

The equation is solved for Tw using `optimize`

.
Actual vapor pressure e (kPa) is calculated from VPD using the function `VPD.to.e`

.
The psychrometric constant gamma (kPa K-1) is calculated from `psychrometric.constant`

.
Le067 is the Lewis number for water vapor to the power of 0.67 and represents the ratio of
aerodynamic resistance to water vapor and heat. Le067 * gamma is sometimes referred to as the
'modified psychrometric constant (gamma*).

### Value

`Tw -` |
wet-bulb temperature (degC) |

### References

Monteith J.L., Unsworth M.H., 2013: Principles of Environmental Physics. Plants, Animals, and the Atmosphere. 4th edition. Academic Press.

### Examples

```
wetbulb.temp(Tair=c(20,25),pressure=100,VPD=c(1,1.6))
```

*bigleaf*version 0.8.2 Index]