Calculate wave-activity flux

Usage

WaveFlux(gh, u, v, lon, lat, lev, g = 9.81, a = 6371000)

Arguments

gh: Geopotential Height Anomaly (unit: gpm or m). The deviation of the geopotential height from the climatological mean (\(z' = z - \bar{z}\)). It is used to compute the perturbation geostrophic streamfunction: \(\psi' = \frac{g}{f}z'\).
u: Mean Zonal Wind (unit: m/s). The background basic flow (\(\bar{u}\)), usually representing the long-term climatological mean zonal velocity.
v: Mean Meridional Wind (unit: m/s). The background basic flow (\(\bar{v}\)), usually representing the long-term climatological mean meridional velocity.
lon: Numeric vector of longitudes (unit: degrees).
lat: Numeric vector of latitudes (unit: degrees).
lev: The pressure level of the data (unit: hPa). Used for the vertical scaling factor \(p/1000\) in the T-N flux formula.
g: Standard gravity acceleration (default: \(9.81 m/s^2\)).
a: Earth's mean radius (default: 6,371,000 m).

Value

A data.table containing the calculated wave activity flux components:

w.x: Zonal component of the Wave Activity Flux.
w.y: Meridional component of the Wave Activity Flux.

Details

The function computes the horizontal components (\(W_x, W_y\)) of the phase-independent wave activity flux.

Note on Units: Ensure that gh is provided as Geopotential Height (in meters or gpm). If your input data is Geopotential (\(\Phi\), in \(m^2/s^2\), common in ERA5 raw data), you must divide it by gravity (g) before passing it to this function.

References

Takaya, K. and H. Nakamura, 2001: A Formulation of a Phase-Independent Wave-Activity Flux for Stationary and Migratory Quasigeostrophic Eddies on a Zonally Varying Basic Flow. J. Atmos. Sci., 58, 608–627, doi:10.1175/1520-0469(2001)058<0608:AFOAPI>2.0.CO;2
Adapted from https://github.com/marisolosman/Reunion_Clima/blob/master/WAF/Calculo_WAF.ipynb