def run_nwp(forecast, model, run_time, issue_time):
"""
Calculate benchmark irradiance and power forecasts for a Forecast or
ProbabilisticForecast.
Forecasts may be run operationally or retrospectively. For
operational forecasts, *run_time* is typically set to now. For
retrospective forecasts, *run_time* is the time by which the
forecast should be run so that it could have been be delivered for
the *issue_time*. Forecasts will only use data with timestamps
before *run_time*.
Parameters
----------
forecast : datamodel.Forecast or datamodel.ProbabilisticForecast
The metadata of the desired forecast.
model : function
NWP model loading and processing function.
See :py:mod:`solarforecastarbiter.reference_forecasts.models`
for options.
run_time : pd.Timestamp
Run time of the forecast.
issue_time : pd.Timestamp
Issue time of the forecast run.
Returns
-------
ghi : pd.Series or pd.DataFrame
dni : pd.Series or pd.DataFrame
dhi : pd.Series or pd.DataFrame
air_temperature : pd.Series or pd.DataFrame
wind_speed : pd.Series or pd.DataFrame
ac_power : pd.Series or pd.DataFrame
Series are returned for deterministic forecasts, DataFrames are
returned for probabilisic forecasts.
Examples
--------
The following code would return hourly average forecasts derived
from the subhourly HRRR model.
.. testsetup::
import datetime
from solarforecastarbiter import datamodel
from solarforecastarbiter.reference_forecasts import models
from solarforecastarbiter.reference_forecasts.main import *
>>> run_time = pd.Timestamp('20190515T0200Z')
>>> issue_time = pd.Timestamp('20190515T0000Z')
>>> modeling_parameters = datamodel.FixedTiltModelingParameters(
... surface_tilt=30, surface_azimuth=180,
... ac_capacity=10, dc_capacity=15,
... temperature_coefficient=-0.4, dc_loss_factor=0,
... ac_loss_factor=0)
>>> power_plant = datamodel.SolarPowerPlant(
... name='Test plant', latitude=32.2, longitude=-110.9,
... elevation=715, timezone='America/Phoenix',
... modeling_parameters=modeling_parameters)
>>> forecast = datamodel.Forecast(
... name='Test plant fx',
... site=power_plant,
... variable='ac_power',
... interval_label='ending',
... interval_value_type='mean',
... interval_length='1h',
... issue_time_of_day=datetime.time(hour=0),
... run_length=pd.Timedelta('24h'),
... lead_time_to_start=pd.Timedelta('0h'))
>>> ghi, dni, dhi, temp_air, wind_speed, ac_power = run_nwp(
... forecast, models.hrrr_subhourly_to_hourly_mean,
... run_time, issue_time)
"""
fetch_metadata = fetch_nwp.model_map[models.get_nwp_model(model)]
# absolute date and time for model run most recently available
# as of run_time
init_time = utils.get_init_time(run_time, fetch_metadata)
# absolute start and end times. interval_label still controls
# inclusive/exclusive
start, end = utils.get_forecast_start_end(forecast, issue_time)
site = forecast.site
logger.info(
'Calculating forecast for model %s starting at %s from %s to %s',
model, init_time, start, end)
# model will account for interval_label
*forecasts, resampler, solar_position_calculator = model(
site.latitude, site.longitude, site.elevation, init_time, start, end,
forecast.interval_label)
if isinstance(site, datamodel.SolarPowerPlant):
solar_position = solar_position_calculator()
if isinstance(forecasts[0], pd.DataFrame):
# must iterate over columns because pvmodel.irradiance_to_power
# calls operations that do not properly broadcast Series along
# a DataFrame time index. pvlib.irradiance.haydavies operation
# (AI = dni_ens / dni_extra) is the known culprit, though there
# may be more.
ac_power = {}
for col in forecasts[0].columns:
member_fx = [fx.get(col) for fx in forecasts]
member_ac_power = pvmodel.irradiance_to_power(
site.modeling_parameters,
solar_position['apparent_zenith'],
solar_position['azimuth'], *member_fx)
ac_power[col] = member_ac_power
ac_power = pd.DataFrame(ac_power)
else:
ac_power = pvmodel.irradiance_to_power(
site.modeling_parameters, solar_position['apparent_zenith'],
solar_position['azimuth'], *forecasts)
else:
ac_power = None
# resample data after power calculation
resampled = list(map(resampler, (*forecasts, ac_power)))
nwpoutput = namedtuple(
'NWPOutput',
['ghi', 'dni', 'dhi', 'air_temperature', 'wind_speed', 'ac_power'])
return nwpoutput(*resampled)
def test_get_nwp_model(model, exp):
assert models.get_nwp_model(model) == exp