xoa.dyn.flow2d#

xoa.dyn.flow2d(u, v, xy0, duration, step, date=None)[source]#

Integrate gridded 2D velocities from initial positions

Uses a 4th-order Runge-Kutta scheme to advect particles in a 2D velocity field.

Parameters:

u (xarray.DataArray) – Gridded zonal velocity (must be 2D after squeezing).
v (xarray.DataArray) – Gridded meridional velocity (must be 2D after squeezing).
xy0 (tuple, int, xarray.Dataset) –
Initial positions. Either:
- a (x_array, y_array) tuple of longitudes and latitudes,
- an int for randomly placed particles,
- a xarray.Dataset with longitude and latitude coordinates.
duration (int, numpy.timedelta64) – Total integration time in seconds.
step (int, numpy.timedelta64) – Integration time step in seconds.
date (None, numpy.datetime64) – A reference date for the output time coordinate.

Returns:

xarray.Dataset – Output positions with lon and lat coordinates varying along time and particles dimensions.

Example

Advect two particles for 3 hours with a 2-hour time step:

ff = flow2d(u, v, ([1., 2.], [1., 1.5]),
            np.timedelta64(3, "h"), np.timedelta64(2, "h"),
            date="2000-01-01")

xoa.dyn.flow2d