Query about tangential and radial wind calculation

[mrinalbiswas]

Hi,
I am trying to plot the tangential and radial component of wind in a tropical cyclone environment. I am using cross section analysis as the starting point. I am assuming that the t_wind and n_wind used in the example are the tangential and radial wind respectively. However, when I am plotting them it seems that they seem to be the opposite. I will really appreciate if you can confirm (or correct) that the steps I am following is correct or not.
FYI. The first color attachment showing up is the tangential component and the second one the radial. They look exactly opposite what it usually looks like in a hurricane environment. I am attaching one from a publication for reference. The difference is the publication one is azimuthally averaged, whereas, mine is a cross-section.
.
Thanks in advance for your time and help
Biswas
RAL/NCAR

This is the code snippet I am using:

gal96=xr.open_dataset("example.nc",decode_times=True)
data = gal96.metpy.parse_cf().squeeze()

start = (23.6, 129.2)
end = (23.6, 134.2)
cross = cross_section(data, start, end).set_coords(('lat', 'lon'))
cross['t_wind'], cross['n_wind'] = mpcalc.cross_section_components(
    cross['u_wind'],
    cross['v_wind']
)

fig = plt.figure(1, figsize=(16., 9.))
ax = plt.axes()
t_contour = ax.contourf(cross['lon'], cross['plev'], cross['t_wind'],
                          levels=np.arange(-50, 50, 5), cmap='viridis', colors=None)
plt.colorbar(theta_contour,ax=ax,shrink=0.6,orientation='vertical',pad=0.1)

ax.set_yscale('linear')
ax.set_ylim(cross['plev'].max(), 10000.)
plt.savefig('Tangential_wind.png')

fig = plt.figure(1, figsize=(16., 9.))
ax = plt.axes()

n_contour = ax.contourf(cross['lon'], cross['plev'], cross['n_wind'],
                          levels=np.arange(-120, 120, 10), cmap='viridis', colors=None)
plt.colorbar(n_contour,ax=ax,shrink=0.6,orientation='vertical',pad=0.1)
n_contour = ax.contour(cross['lon'], cross['plev'], cross['n_wind'],
                          levels=np.arange(-120, 120, 20), cmap=None, colors='black',linewidths=1)
ax.clabel(n_contour, fmt='%d', inline=True, colors='black')

ax.set_yscale('linear')
ax.set_ylim(cross['plev'].max(), 10000.)
plt.savefig('Radial_wind.png')

[dcamron]

These are indeed inverted! There's a bit of a terminology headache, for sure. Please let me know if I have my understanding backwards:

In your work, are "radial" winds along the radius, or that are "inward/outward" relative to the center of the storm? In MetPy's terminology, the tangential component is along the direction of the cross section itself, and doesn't know about your storm-center reference frame. So, for how your cross sections are organized, our tangential component would line up in the same direction as your "radial" winds.

Similarly, are your "tangential" winds describing winds tangent to circles drawn around the center of your storm? If so, these would be "into/out of the page" on our cross sections, which describes our normal component, normal to the cross section itself.

I hope this clears this up! Let me know if I'm misunderstanding the terminology in your work.

[mrinalbiswas]

You are correct. In our work, both radial and tangential winds are relative to the center of the storm. Thanks for your detailed explanation.