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Add omega #125

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Dec 16, 2024
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Add omega #125

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29 changes: 29 additions & 0 deletions pydropsonde/circles.py
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Thank you @hgloeckner for including this, it looks good to me ! And sorry for not having written this myself. Assuming hydrostaticity it is also possible to deduce from the pressure velocity $\omega$ the vertical velocity $w = - \omega / (\rho g)$, some people may find it convenient

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all good :) You wrote a pretty good explanation what should be done.

I will add the vertical velocity as well - just wanted to be sure that everything is alright like this

Original file line number Diff line number Diff line change
Expand Up @@ -297,3 +297,32 @@ def add_vorticity(self):
}
self.circle_ds = ds.assign(vor=(ds.dudx.dims, vor.values, vor_attrs))
return self

def add_omega(self):
"""
Calculate vertical pressure velocity as
\int div dp

This calculates the vertical pressure velocity as described in
Bony and Stevens 2019

Returns:
self: circle object with updated circle_ds
"""
ds = self.circle_ds
alt_dim = self.alt_dim
div = ds.div.where(~np.isnan(ds.div), drop=True).sortby(alt_dim)
p = ds.mean_p.where(~np.isnan(ds.div), drop=True).sortby(alt_dim)
zero_vel = xr.DataArray(data=[0], dims=alt_dim, coords={alt_dim: [0]})
pres_diff = xr.concat([zero_vel, p.diff(dim=alt_dim)], dim=alt_dim)
del_omega = -div * pres_diff.values
omega = del_omega.cumsum(dim=alt_dim) * 0.01 * 60**2
omega_attrs = {
"standard_name": "atmosphere_vertical_velocity",
"long_name": "Area-averaged atmospheric pressure velocity",
"units": "hPa hr-1",
}
self.circle_ds = ds.assign(
dict(omega_p=(ds.div.dims, omega.values, omega_attrs))
)
return self
8 changes: 7 additions & 1 deletion pydropsonde/pipeline.py
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Original file line number Diff line number Diff line change
Expand Up @@ -603,7 +603,13 @@ def run_pipeline(pipeline: dict, config: configparser.ConfigParser):
"calculate_circle_data": {
"intake": "circles",
"apply": iterate_Circle_method_over_dict_of_Circle_objects,
"functions": ["add_density", "apply_fit2d", "add_divergence", "add_vorticity"],
"functions": [
"add_density",
"apply_fit2d",
"add_divergence",
"add_vorticity",
"add_omega",
],
"output": "circles",
"comment": "calculate circle products",
},
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