metR (version 0.15.0)

GeostrophicWind: Calculate geostrophic winds

Description

Geostrophic wind from a geopotential height field.

Usage

GeostrophicWind(gh, lon, lat, cyclical = "guess", g = 9.81, a = 6371000)

Value

A named list with vectors for the zonal and meridional component of geostrophic wind.

Arguments

gh

geopotential height

lon

longitude in degrees

lat

latitude in degrees

cyclical

boundary condition for longitude (see details)

g

acceleration of gravity

a

Earth's radius

Details

If cyclical = "guess" (the default) the function will try to guess if lon covers the whole globe and set cyclical conditions accordingly. For more predictable results, set the boundary condition explicitly.

See Also

Other meteorology functions: Derivate(), EOF(), WaveFlux(), thermodynamics, waves

Examples

data(geopotential)
geopotential <- data.table::copy(geopotential)
geopotential[date == date[1], c("u", "v") := GeostrophicWind(gh, lon, lat)]
library(ggplot2)
ggplot(geopotential[date == date[1]], aes(lon, lat)) +
    geom_contour(aes(z = gh)) +
    geom_vector(aes(dx = u, dy = v), skip = 2) +
    scale_mag()