Example of a wind retrieval in a tornado over Sydney#
This shows an example of how to retrieve winds from 4 radars over Sydney.
We use smoothing to decrease the magnitude of the updraft in the region of the mesocyclone. The reduction of noise also helps the solution converge much faster since the cost function is smoother and therefore less susecptible to find a local minimum that is in noise.
The observational constraint is reduced to 0.01 from the usual 1 because we are factoring in many more data points as we are using 4 radars instead of the two in the Darwin example.
This example uses pooch to download the data files.
import pydda
import matplotlib.pyplot as plt
import numpy as np
grid1_path = pydda.tests.get_sample_file("grid1_sydney.nc")
grid2_path = pydda.tests.get_sample_file("grid2_sydney.nc")
grid3_path = pydda.tests.get_sample_file("grid3_sydney.nc")
grid4_path = pydda.tests.get_sample_file("grid4_sydney.nc")
grid1 = pydda.io.read_grid(grid1_path)
grid2 = pydda.io.read_grid(grid2_path)
grid3 = pydda.io.read_grid(grid3_path)
grid4 = pydda.io.read_grid(grid4_path)
# Set initialization and do retrieval
grid1 = pydda.initialization.make_constant_wind_field(grid1, vel_field="VRADH_corr")
new_grids, _ = pydda.retrieval.get_dd_wind_field(
[grid1, grid2, grid3, grid4],
Co=1e-2,
Cm=256.0,
Cx=10,
Cy=10,
Cz=10,
vel_name="VRADH_corr",
refl_field="DBZH",
mask_outside_opt=True,
wind_tol=0.5,
max_iterations=200,
engine="scipy",
)
# Make a neat plot
fig = plt.figure(figsize=(10, 7))
ax = pydda.vis.plot_horiz_xsection_quiver_map(
new_grids,
background_field="DBZH",
level=3,
show_lobes=False,
bg_grid_no=3,
vmin=0,
vmax=60,
quiverkey_len=20.0,
w_vel_contours=[1.0, 3.0, 5.0, 10.0, 20.0],
quiver_spacing_x_km=2.0,
quiver_spacing_y_km=2.0,
quiverkey_loc="top",
colorbar_contour_flag=True,
cmap="ChaseSpectral",
)
ax.set_xticks(np.arange(150.5, 153, 0.1))
ax.set_yticks(np.arange(-36, -32.0, 0.1))
ax.set_xlim([151.0, 151.35])
ax.set_ylim([-34.15, -33.9])
plt.show()
## You are using the Python ARM Radar Toolkit (Py-ART), an open source
## library for working with weather radar data. Py-ART is partly supported
## by the U.S. Department of Energy Office of Science as part of
## the Atmospheric Radiation Measurement (ARM) User Facility.
##
## If you use this software to prepare a publication, please cite:
##
## JJ Helmus and SM Collis, JORS 2016, doi: 10.5334/jors.119
Welcome to PyDDA 2.5.0
If you are using PyDDA in your publications, please cite:
Jackson et al. (2020) Journal of Open Research Science
Detecting Jax...
Jax/JaxOpt are not installed on your system, unable to use Jax engine.
Detecting TensorFlow...
Unable to load both TensorFlow and tensorflow-probability. TensorFlow engine disabled.
No module named 'tensorflow'
False
Calculating weights for radars 0 and 1
Calculating weights for radars 0 and 2
Calculating weights for radars 0 and 3
Calculating weights for radars 1 and 0
Calculating weights for radars 1 and 2
Calculating weights for radars 1 and 3
Calculating weights for radars 2 and 0
Calculating weights for radars 2 and 1
Calculating weights for radars 2 and 3
Calculating weights for radars 3 and 0
Calculating weights for radars 3 and 1
Calculating weights for radars 3 and 2
Calculating weights for models...
Starting solver
rmsVR = 7.359750110231316
Total points: 399749
The max of w_init is 0.0
Total number of model points: 0
Nfeval | Jvel | Jmass | Jsmooth | Jbg | Jvort | Jmodel | Jpoint | Max w
0|4080.4252| 0.0000| 0.0000| 0.0000| 0.0000| 0.0000| 0.0000| 0.0000
The gradient of the cost functions is 0.12208368625662412
Nfeval | Jvel | Jmass | Jsmooth | Jbg | Jvort | Jmodel | Jpoint | Max w
10| 91.8283| 22.9782| 0.0001| 0.0000| 0.0000| 0.0000| 0.0000| 80.8833
Max change in w: nan
The gradient of the cost functions is 0.11469278158162828
Nfeval | Jvel | Jmass | Jsmooth | Jbg | Jvort | Jmodel | Jpoint | Max w
20| 85.8892| 20.6679| 0.0001| 0.0000| 0.0000| 0.0000| 0.0000| 94.1776
The gradient of the cost functions is 0.07331884235808792
Nfeval | Jvel | Jmass | Jsmooth | Jbg | Jvort | Jmodel | Jpoint | Max w
30| 84.9256| 21.3641| 0.0001| 0.0000| 0.0000| 0.0000| 0.0000| 96.2424
---------------------------------------------------------------------------
KeyboardInterrupt Traceback (most recent call last)
Cell In[1], line 17
13 grid4 = pydda.io.read_grid(grid4_path)
14
15 # Set initialization and do retrieval
16 grid1 = pydda.initialization.make_constant_wind_field(grid1, vel_field="VRADH_corr")
---> 17 new_grids, _ = pydda.retrieval.get_dd_wind_field(
18 [grid1, grid2, grid3, grid4],
19 Co=1e-2,
20 Cm=256.0,
File ~/work/PyDDA/PyDDA/pydda/retrieval/wind_retrieve.py:1746, in get_dd_wind_field(Grids, u_init, v_init, w_init, engine, **kwargs)
1739 w_init = new_grids[0]["w"].values.squeeze()
1741 if (
1742 engine.lower() == "scipy"
1743 or engine.lower() == "jax"
1744 or engine.lower() == "auglag"
1745 ):
-> 1746 return _get_dd_wind_field_scipy(
1747 new_grids, u_init, v_init, w_init, engine, **kwargs
1748 )
1749 elif engine.lower() == "tensorflow":
1750 if kwargs.get("Cterrain", 0.0) > 0:
File ~/work/PyDDA/PyDDA/pydda/retrieval/wind_retrieve.py:788, in _get_dd_wind_field_scipy(Grids, u_init, v_init, w_init, engine, points, vel_name, refl_field, u_back, v_back, z_back, frz, Co, Cm, Cx, Cy, Cz, Cb, Cv, Cmod, Cpoint, Cterrain, terrain, Cvad, cvtol, gtol, Jveltol, Ut, Vt, low_pass_filter, mask_outside_opt, weights_obs, weights_model, weights_bg, max_iterations, mask_w_outside_opt, filter_type, filter_window, filter_order, leise_nstep, min_bca, max_bca, upper_bc, lower_bc, above, model_fields, output_cost_functions, roi, wind_tol, tolerance, const_boundary_cond, max_wind_mag, parallel)
786 parameters.print_out = False
787 if engine.lower() == "scipy":
--> 788 winds = fmin_l_bfgs_b(
789 J_and_grad,
790 winds,
791 args=(parameters,),
792 maxiter=max_iterations,
793 pgtol=tolerance,
794 bounds=bounds,
795 callback=_vert_velocity_callback,
796 )
797 else:
799 def loss_and_gradient(x):
File /usr/share/miniconda/envs/pydda-docs/lib/python3.14/site-packages/scipy/optimize/_lbfgsb_py.py:259, in fmin_l_bfgs_b(func, x0, fprime, args, approx_grad, bounds, m, factr, pgtol, epsilon, maxfun, maxiter, callback, maxls)
249 callback = _wrap_callback(callback)
250 opts = {'maxcor': m,
251 'ftol': factr * np.finfo(float).eps,
252 'gtol': pgtol,
(...) 256 'callback': callback,
257 'maxls': maxls}
--> 259 res = _minimize_lbfgsb(fun, x0, args=args, jac=jac, bounds=bounds,
260 **opts)
261 d = {'grad': res['jac'],
262 'task': res['message'],
263 'funcalls': res['nfev'],
264 'nit': res['nit'],
265 'warnflag': res['status']}
266 f = res['fun']
File /usr/share/miniconda/envs/pydda-docs/lib/python3.14/site-packages/scipy/optimize/_lbfgsb_py.py:412, in _minimize_lbfgsb(fun, x0, args, jac, bounds, maxcor, ftol, gtol, eps, maxfun, maxiter, callback, maxls, finite_diff_rel_step, workers, **unknown_options)
410 g = g.astype(np.float64)
411 # x, f, g, wa, iwa, task, csave, lsave, isave, dsave = \
--> 412 _lbfgsb.setulb(m, x, low_bnd, upper_bnd, nbd, f, g, factr, pgtol, wa,
413 iwa, task, lsave, isave, dsave, maxls, ln_task)
415 if task[0] == 3:
416 # The minimization routine wants f and g at the current x.
417 # Note that interruptions due to maxfun are postponed
418 # until the completion of the current minimization iteration.
419 # Overwrite f and g:
420 f, g = func_and_grad(x)
KeyboardInterrupt: