GeostrophicWind function

Calculate geostrophic winds

Geostrophic wind from a geopotential height field.

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

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

Returns

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

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.

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()

See Also

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