Reverts speed and direction to U and V components.

Description

This function calculates U (i.e. zonal or east/west) and V (i.e. meridional or north/south) components from a specified speed and direction.

Usage

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NCEP.uv.revert(spd, dir, radians=FALSE)

Arguments

spd

A numeric value indicating speed.

dir

A numeric value indicating direction in degrees from north or radians if radians is TRUE.

radians

A logical indicating whether dir is given in degrees from north (FALSE) or radians (TRUE).

Details

This function calculates U (i.e. zonal or east/west) and V (i.e. meridional or north/south) components from a specified speed and direction. U and V components describe the direction into which movement occurs with east and north being positive, respectively. If directions are given in radians, radians must be set to TRUE.

Value

A data.frame containing U and V components given in the same units as speed.

Author(s)

Michael U. Kemp mukemp+RNCEP@gmail.com

References

To cite package 'RNCEP' in publications use:

Kemp, M. U., van Loon, E. E., Shamoun-Baranes, J., and Bouten, W. 2011. RNCEP:global weather and climate data at your fingertips. – Methods in Ecology and Evolution. DOI:10.1111/j.2041-210X.2011.00138.x.

Examples

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library(RNCEP)
## Using NCEP.uv.revert ##
NCEP.uv.revert(spd=12, dir=225, radians=FALSE)