수평면 전일사량 측정데이터 보정에 관한 실험적 연구

Abstract

A Precision Spectral Pyranometer (PSP) is mainly used as a reference to calibrate other pyranometers due to its high accuracy and sensitivity in response to the spectrum wavelength range of 0.285 µ to 2.8 µ, while the sensitivity of photovoltaic-type Li-Cor pyranometer is limited within a certain spectral range from 0.4 µ to 1.1 µ. In this study, two Eppley PSPs (PSP1 and PSP2) were first compared to the calibrated Eppley PSPs from National Renewable Energy Laboratory (NREL), resulting in two linear correction factors based on the comparison between the logger output (V) from the test PSP and the solar radiation (W/m2) from the NREL PSP. The Li-Cor pyranometer used in this study was then corrected based on the comparison of measured solar radiation (W/m2) from the corrected PSP1 and the Li-Cor pyranometer. In addition, instrument scale corrections were also performed for the PSPs and the Li-Cor from the transmitter to the data logger. From the comparisons, a linear correction factor (1.0214) with R=0.9998 was developed for the scale correction between PSP1 and PSP2, while the Li-Cor pyranometer has a scale(1.0597) and offset (32.046) with R=0.9998 against PSP1. As a result, it was identified that there were good agreements within ± 10 W/m2 between Eppley PSP1 vs. PSP2 solar radiation and within ± 20 W/m2 between PSP1 vs Li-Cor solar radiation after the empirical scale corrections developed in this study.