Error with using PVGIS weather data (zenith conversion in airmass?)

[expeon07]

Describe the bug
Hi, I'm trying to run a ModelChain model using a weather file obtained through get_pvgis_tmy() function. However I am getting an error with the weather data

To Reproduce
Steps to reproduce the behavior:

weather, months, inputs, metadata = pvlib.iotools.get_pvgis_tmy(latitude, longitude, outputformat='epw', coerce_year=2023)

system_loss = 0.1
times = weather.index
solar_position = pvlib.solarposition.get_solarposition(times, latitude, longitude)

system = pvlib.pvsystem.PVSystem(
    surface_tilt=30,
    surface_azimuth=150,
    module_parameters=sandia_modules["Canadian_Solar_CS6X_300M__2013_"],
    inverter_parameters=cec_inverters["ABB__MICRO_0_25_I_OUTD_US_208__208V_"],
    temperature_model_parameters=pvlib.temperature.TEMPERATURE_MODEL_PARAMETERS["sapm"]["open_rack_glass_glass"],

)

mc = pvlib.modelchain.ModelChain(system, location=location)
mc.prepare_inputs(weather)

Error

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
AttributeError: 'float' object has no attribute 'radians'

The above exception was the direct cause of the following exception:

TypeError                                 Traceback (most recent call last)
Cell In[6], line 23
     21 mc = pvlib.modelchain.ModelChain(system, location=location)
     22 print(mc)
---> 23 mc.prepare_inputs(weather)
     24 # # mc.run_model(weather)
     25 
     26 # ac_power = mc.ac * (1 - system_loss)
     27 # dc_power = mc.dc['p_mp']  # Maximum power point (Pmp)
     28 
     29 # print(dc_power)

File ~/.local/share/virtualenvs/Lowfield-Green-CSxyL99o/lib/python3.10/site-packages/pvlib/modelchain.py:1424, in ModelChain.prepare_inputs(self, weather)
   1421 self._assign_weather(weather)
   1423 self._prep_inputs_solar_pos(weather)
-> 1424 self._prep_inputs_airmass()
   1425 self._prep_inputs_albedo(weather)
   1426 self._prep_inputs_fixed()

File ~/.local/share/virtualenvs/Lowfield-Green-CSxyL99o/lib/python3.10/site-packages/pvlib/modelchain.py:1255, in ModelChain._prep_inputs_airmass(self)
   1251 def _prep_inputs_airmass(self):
   1252     """
   1253     Assign airmass
   1254     """
-> 1255     self.results.airmass = self.location.get_airmass(
   1256         solar_position=self.results.solar_position,
   1257         model=self.airmass_model)
   1258     return self

File ~/.local/share/virtualenvs/Lowfield-Green-CSxyL99o/lib/python3.10/site-packages/pvlib/location.py:319, in Location.get_airmass(self, times, solar_position, model)
    316 else:
    317     raise ValueError(f'{model} is not a valid airmass model')
--> 319 airmass_relative = atmosphere.get_relative_airmass(zenith, model)
    321 pressure = atmosphere.alt2pres(self.altitude)
    322 airmass_absolute = atmosphere.get_absolute_airmass(airmass_relative,
    323                                                    pressure)

File ~/.local/share/virtualenvs/Lowfield-Green-CSxyL99o/lib/python3.10/site-packages/pvlib/atmosphere.py:219, in get_relative_airmass(zenith, model)
    217 # set zenith values greater than 90 to nans
    218 z = np.where(zenith > 90, np.nan, zenith)
--> 219 zenith_rad = np.radians(z)
    221 model = model.lower()
    223 if 'kastenyoung1989' == model:

TypeError: loop of ufunc does not support argument 0 of type float which has no callable radians method

Would anyone know if there's something wrong with the code or if it's a bug? Thank you!!

[cwhanse]

The error tells you that zenith is a single value, with float type. Somehow you aren't getting a time series of weather data. What does times look like?

[cwhanse]

@expeon07 happy to help you diagnose this problem here. For questions like "is there something wrong" we prefer a post to the pvlib-python google group, or stackoverflow. If we find a bug, then a GH issue is welcome.

[expeon07]

times is a DateTimeIndex in UTC

DatetimeIndex(['2023-01-01 00:00:00+00:00', '2023-01-01 01:00:00+00:00',
               '2023-01-01 02:00:00+00:00', '2023-01-01 03:00:00+00:00',
               '2023-01-01 04:00:00+00:00', '2023-01-01 05:00:00+00:00',
               '2023-01-01 06:00:00+00:00', '2023-01-01 07:00:00+00:00',
               '2023-01-01 08:00:00+00:00', '2023-01-01 09:00:00+00:00',
               ...
               '2023-12-31 14:00:00+00:00', '2023-12-31 15:00:00+00:00',
               '2023-12-31 16:00:00+00:00', '2023-12-31 17:00:00+00:00',
               '2023-12-31 18:00:00+00:00', '2023-12-31 19:00:00+00:00',
               '2023-12-31 20:00:00+00:00', '2023-12-31 21:00:00+00:00',
               '2023-12-31 22:00:00+00:00', '2023-12-31 23:00:00+00:00'],
              dtype='datetime64[ns, UTC]', name='time(UTC)', length=8760, freq=None)

Thanks for the info about where to post questions! Can also transfer this question on stackoverflow if it takes long

[cwhanse]

transfer this question on stackoverflow

Let's do that. Please link your SO post here.

[expeon07]

Sure, question is still on staging-ground. But it has the same title. Will update later when it gets published.
Thank you!!