humidity: Converting Humidity Measures into Each Other

In IDPmisc: 'Utilities of Institute of Data Analyses and Process Design (www.zhaw.ch/idp)'

Description

Converting dew point (of water in air) into vapor pressure or relative humidity and vice versa.

Usage

hr(T, Td, warn = TRUE)
pw(Td, warn = TRUE)
pw.ai(Td, warn = TRUE)
pw.aw(Td, warn = TRUE)
Td(pw = NULL, T = NULL, hr = NULL, warn = TRUE)
Td.aw(pw = NULL, T = NULL, hr = NULL, warn = TRUE)
Tf.ai(pw = NULL, T = NULL, hr = NULL, warn = TRUE)

Arguments

hr	Relative humidity in [\textnormal{\%}].
T	Temperature of air in [^\circ \textnormal{C}].
Td	Dew point of air in [^\circ \textnormal{C}].
pw	Saturation vapour pressure in [\textnormal{hPa}].
warn	When TRUE and arguments are out of range, a warning is thrown.

Details

All vapour pressures correspond to pure water vapour and are not adjusted to water vapour in air.

Value

hr transforms dew point above ice / water at a certain temperature into relative humidity (-65^\circ\textnormal{C} <= T <= 60^\circ\textnormal{C}).
pw transforms dew point into saturation vapour pressure above ice (-65^\circ\textnormal{C} <= T <= 0^\circ\textnormal{C}) and above water (0^\circ\textnormal{C} < T <= 60^\circ\textnormal{C}) respectively.
pw.ai transforms dew point into saturation vapour pressure above ice (-65^\circ\textnormal{C} <= T <= 0^\circ\textnormal{C}).
pw.aw transforms dew point into saturation vapour pressure above liquid water (-45^\circ\textnormal{C} <= T <= 60^\circ\textnormal{C}).
Td transforms vapour pressure or relative humidity and temperature into frost point above ice (-65^\circ\textnormal{C} <= T <= 0^\circ\textnormal{C}) and dew point above water (0^\circ\textnormal{C} < T <= 60^\circ\textnormal{C}) respectively.
Td.aw transforms vapour pressure or relative humidity and temperature into dew point above water (-45^\circ\textnormal{C} <= T <= 60^\circ\textnormal{C}).
Tf.ai transforms vapour pressure or relative humidity and temperature into frost point above ice (-65^\circ\textnormal{C} <= T <= 0^\circ\textnormal{C}).

Author(s)

Rene Locher

References

Guide to Meteorological Instruments and Methods of Observation, WMO, WMO-No. 8, Seventh edition, 2008, updated 2010, 1.4-29 Annex 4.B

Examples

 pw(Td = c(-65, -45, 0, 30, 60))
 Td(pw = pw(c(-20, 0, 20)))

 hr(T = c(20, 30, 40), Td = c(0, 20, 30))
 ## [1] 26.20257 55.09561 57.46519

 hr(T = seq(0, 60, 5), Td = 0)

Example output

[1] 5.400077e-03 7.207549e-02 6.112000e+00 4.233724e+01 1.999329e+02
[1] -20   0  20
[1] 26.20257 55.09561 57.46519
 [1] 100.000000  70.112427  49.851953  35.917615  26.202565  19.341424
 [7]  14.436463  10.889315   8.295941   6.380152   4.950929   3.874690
[13]   3.057026

IDPmisc documentation built on Jan. 21, 2020, 5:06 p.m.