What happened:

The xarray.ufuncs.angle is broken. From the help docstring one may use option deg=True to have the result in degrees instead of radians (which is consistent with numpy.angle function). Yet results show that this is not the case. Moreover specifying deg=True or deg=False leads to the same result with the values in radians.

What you expected to happen:

To have the result of xarray.ufuncs.angle converted to degrees when option deg=True is specified.

Minimal Complete Verifiable Example:

```python

Put your MCVE code here

import numpy as np import xarray as xr

ds = xr.Dataset(coords={'wd': ('wd', np.arange(0, 360, 30, dtype=float))})

Z = xr.ufuncs.exp(1j * xr.ufuncs.radians(ds.wd)) D = xr.ufuncs.angle(Z, deg=True) # YIELDS INCORRECT RESULTS if not np.allclose(ds.wd, (D % 360)): print(f"Issue with angle operation: {D.values%360} instead of {ds.wd.values}" \ + f"\n\tERROR xr.ufuncs.angle(Z, deg=True) gives incorrect results !!!")

D = xr.ufuncs.degrees(xr.ufuncs.angle(Z)) # Works OK if not np.allclose(ds.wd, (D % 360)): print(f"Issue with angle operation: {D%360} instead of {ds.wd}" \ + f"\n\tERROR xr.ufuncs.degrees(xr.ufuncs.angle(Z)) gives incorrect results!!!")

D = xr.apply_ufunc(np.angle, Z, kwargs={'deg': True}) # Works OK if not np.allclose(ds.wd, (D % 360)): print(f"Issue with angle operation: {D%360} instead of {ds.wd}" \ + f"\n\tERROR xr.apply_ufunc(np.angle, Z, kwargs={{'deg': True}}) gives incorrect results!!!") ```

Anything else we need to know?:

Though xarray.ufuncs has a deprecated warning stating that the numpy equivalent may be used, this is not true for numpy.angle. Example:

```python import numpy as np import xarray as xr

ds = xr.Dataset(coords={'wd': ('wd', np.arange(0, 360, 30, dtype=float))})

Z = np.exp(1j * np.radians(ds.wd)) print(Z) print(f"Is Z an XArray? {isinstance(Z, xr.DataArray)}")

D = np.angle(ds.wd, deg=True) print(D) print(f"Is D an XArray? {isinstance(D, xr.DataArray)}") `` If this code is run, the result ofnumpy.angle(xarray.DataArray)is not a DataArray object, contrary to other numpy operations (for all versions of xarray I've used). Hence thexarray.ufuncs.angle` is a great option, if it was not for the current problem.

Environment:

No issues with xarray versions 0.16.2 and 0.17.0. This error happens from 0.18.0 onwards, up to 0.19.0 (recentmost).

Output of <tt>xr.show_versions()</tt>

INSTALLED VERSIONS ------------------ commit: None python: 3.7.10 (default, Feb 26 2021, 18:47:35) [GCC 7.3.0] python-bits: 64 OS: Linux OS-release: 4.19.0-18-amd64 machine: x86_64 processor: byteorder: little LC_ALL: en_US.utf8 LANG: C.UTF-8 LOCALE: ('en_US', 'UTF-8') libhdf5: None libnetcdf: None xarray: 0.19.0 pandas: 1.2.3 numpy: 1.20.2 scipy: 1.5.3 netCDF4: None pydap: None h5netcdf: None h5py: None Nio: None zarr: None cftime: None nc_time_axis: None PseudoNetCDF: None rasterio: None cfgrib: None iris: None bottleneck: None dask: None distributed: None matplotlib: None cartopy: None seaborn: None numbagg: None pint: None setuptools: 58.2.0 pip: 21.3 conda: 4.10.3 pytest: None IPython: None sphinx: None