Vertical Velocity

This function estimate the vertical velocity from model output. It works only with models on hybrid sigma pressure coordinate.

Usage

omega(ua, va, ps, ap_full, b_full, ap_half, b_half, lon, lat, nthreads = 1)

Arguments

ua

zonal wind component [lon, lat, lev, time] on model levels (m/s).

va

meridional wind component [lon, lat, lev, time] on model levels (m/s).

ps

surface pressure [lon, lat, time] (hPa).

ap_full

vertical coordinate formula term ap(k) or a(k) [lev] at layer midpoints (hPa).

b_full

vertical coordinate formula term b(k) [lev] at layer midpoints. b(k) is dimensionless fraction.

ap_half

vertical coordinate formula term ap(k) or a(k) [lev+1] at layer interfaces (hPa).

b_half

vertical coordinate formula term b(k) [lev+1] at layer interfaces. b(k) is dimensionless fraction.

lon

longitude coordinates [lon] (degrees east).

lat

latitude coordinates [lat] (degrees north).

nthreads

an integer specifying the number of threads to use for computation (OpenMP). Default is 1.

Value

the vertical velocity [lon, lat, lev, time] in Pa/s. Lev is from the top of the atmosphere to the surface.

Note

The function handles model output organised top of the atmosphere to the surface and vice versa.

References

Schulzweida, Uwe. (2023). CDO User Guide (2.3.0). Zenodo. doi:10.5281/zenodo.10020800 .