/Fast-SZA-and-SAA-computation

The implementation of the fast algorithm for computation of the Solar Zenith Angle (aka SZA) and Solar Azimut Angle (aka SAA) based on the logic proposed by Roberto Grena in 2012 (https://doi.org/10.1016/j.solener.2012.01.024). The precision of the algorithm is 0.3 degrees for the SZA and 0.5 degrees for the SAA (mean-average error).

Primary LanguagePythonMIT LicenseMIT

Fast algorithm for the computation of the SZA and SAA

Author: David Salac https://github.com/david-salac/

The implementation of the fast algorithm for computation of the Solar Zenith Angle (aka SZA) and Solar Azimut Angle (aka SAA) based on the logic proposed by Roberto Grena in 2012 (https://doi.org/10.1016/j.solener.2012.01.024). The precision of the algorithm is 0.3 degrees for the SZA and 0.5 degrees for the SAA (mean-average error).

Implementation is available in two languages:

  • Python (for versions 3.x only)
  • Go language (located in the folder 'GO_version')
  • C++ version (located in the folder 'CPP_version')

Testing of the algorithm

Algorithm has been tested using PVLIB implementation of the SZA and SAA computation which is precise up to 0.2 degrees (maximal error for both).

The PVLIB version is unfortunately much slower (which is the motivation for writing of this algorithm).

Usage

Algorithm requires the Pandas DatetimeIndex time array in the UTC. Algorithm also requires longitude and latitude of the place (in degrees).

You can run algorithm for testing purposes:

from sza_saa_grena import solar_zenith_and_azimuth_angle
# ...
# Some random time series:
time_array = pd.date_range("2020/1/1", periods=87_600, freq="10T", tz="UTC")
sza, saa = solar_zenith_and_azimuth_angle(longitude=-0.12435,  # London longitude
                                          latitude=51.48728,   # London latitude
                                          time_utc=time_array)

Source

Five new algorithms for the computation of sun position from 2010 to 2110, Roberto Grena, 2012, online: https://doi.org/10.1016/j.solener.2012.01.024

License

MIT License

Copyright (c) 2020 David Salac

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.