The Pyranometer Responsivity INTERpolator (PRINTER) interpolates pyranometer incidence angle dependent calibration factors, or responsivities (µV/W/m2), into an accurate and easy to use single polynomial function. The polynomials can be of very low or high degree, are extrapolated to 0° and 90°, and are calculated using robust techniques to avoid oscillations and overshoots, which can occur when using other regression methods.
The program input is a text file in the format of a Broadband Outdoor Radiometer CALibration (BORCAL) file. The program outputs are plots of the responsivities and associated uncertainties and coefficients for the polynomial regression fits of both the responsivities and the upper prediction interval of the associated standard uncertainties. These calculated coefficients for the single polynomial functions can then be easily copied and implemented in spreadsheet software or a programming environment.
Sample Spreadsheet: Coeff Template.xlsm