# Functions to calculate ICAO standard atmospheric properties: temperature, density, and pressure.

Source:`R/atmos_properties.R`

`atmosprops.Rd`

Functions to calculate ICAO standard atmospheric properties: temperature, density, and pressure.

## Usage

```
atmtemp(alt = NULL, units = NULL, ret_units = FALSE)
atmpres(alt = NULL, units = NULL, ret_units = FALSE)
atmdens(alt = NULL, units = NULL, ret_units = FALSE)
```

## Arguments

- alt
the altitude (above mean sea level). If excluded, sea level is assumed [\(m\) or \(ft\)]

- units
character vector that contains the system of units [options are

`SI`

for International System of Units and`Eng`

for English (US customary) units.- ret_units
If set to TRUE the value(s) returned are of class

`units`

with units attached to the value. [Default is FALSE]

## Value

the temperature of air for the standard atmosphere for the atmtemp function [\(^{\circ}C\) or \(^{\circ}F\)]

the absolute pressure of air for the standard atmosphere for the atmpres function [\(N m^{-2}\) or \(lbf ft^{-2}\)]

the density of air for the standard atmosphere for the atmdens function [\({kg}\,{m^{-3}}\) or \({slug}\,{ft^{-3}}\)]

## Examples

```
#Find standard atmospheric temperature at altitude 8000 m
atmtemp(alt = 8000, units = 'SI')
#> [1] -36.93477
#Find standard atmospheric pressure assuming default altitude of zero (sea-level)
atmpres(units = 'Eng', ret_units = TRUE)
#>
#> Altitude not given.
#> Assuming alt = 0 ft
#> 2116.216 [lbf/ft^2]
#Find standard atmospheric density at altitude 15000 ft
atmdens(alt = 15000, units = 'Eng')
#> [1] 0.00149495
```