Estimation of solar irradiance using ground-based whole sky imagers

With the spirit of reproducible research, this repository contains all the codes required to produce the results in the manuscript: S. Dev, F. M. Savoy, Y. H. Lee, S. Winkler, Estimation of solar irradiance using ground-based whole sky imagers, Proc. IEEE International Geoscience and Remote Sensing Symposium (IGARSS), 2016.

Please cite the above paper if you intend to use whole/part of the code. This code is only for academic and research purposes.

Manuscript

The author version of this manuscript is manuscript.PDF.

Code Organization

All codes are written in python.

Helper Scripts

• CalculateLuminance.py Calculates the luminance of the sky/cloud image, based on the sun location in the image and crop dimension.
• cmask.py Generates the mask of the sky/cloud image with a given center position and radius.
• findCorrelation.py Calculates the correlation value for various crop dimensions.
• findSelectedFiles.py Selects a set of images for luminance computation. In case of High Dynamic Range (HDR) mode, it selects the lowest exposure image; otherwise it selects the normal Low Dynamic Range (LDR) image.
• import_WS.py Imports the weather station data with its various meteorological sensor measurements.
• import_WS_CI.py Imports the weather station data, and also calculates the clearness index value for the location of our sky camera.
• nearest.py Finds the nearest timestamp in a presorted list of timestamps.
• normalize_array.py Normalizes a given numpy array.
• SG_model.py Calculates the clear-sky irradiance value for Singapore.
• sun_positions_day_files.py Computes the sun-position in a set of sky/cloud images.

Weather Data

The folder ./weatherData contains the weather data for the month of December 2015.

Pre-computed Files

In this repository, we also share all the pre-computed luminance files that is necessary to reproduce the results.

Generated Files

The ouput files are kept in the folder ./outputFiles.

Reproducibility

The program ./main.ipynb is the main script, that reproduces all the results. It uses different helper scripts stored in the folder ./helperScripts. It also reproduces the figures in this associated paper.