Baseline Surface Radiation Network (BSRN) quality control of solar radiation data on the Gangneung-Wonju National University radiation station

Abstract

Gangneung-Wonju National University (GWNU) radiation station has been collecting data on global, direct, and diffuse solar radiation since 2011. We conducted a quality control (QC) assessment of GWNU data collected between 2012 and 2014, using procedures outlined by the Baseline Surface Radiation Network (BSRN). The QC process involved the comparison of observations, the correction of observational equipment, the examination of physically possible limits, and the comparative testing of observations and model calculations. Furthermore, we performed a shading check of the observational environment around the GWNU solar station. For each solar radiation element (observed every minute), we performed a QC check and investigated any flagged problems. 98.31% of the data were classified as good quality, while the remaining 1.69% were flagged as bad quality based on the shading check and comparison tests. We then compared the good-quality data to the global solar radiation data observed at the Gangwon Regional Office of Meteorology (GROM). After performing this comparison, the determination coefficient (R2; 0.98) and standard deviation (SD; 0.92 MJ m−2) increased compared to those computed before the QC check (0.97 and 1.09 MJ m−2). Even considering the geographical differences and weather effects between the two stations, these results are statistically significant. However, we also confirmed that the quality of the GROM data deteriorated in relation to weather conditions because of poor maintenance. Hence, we conclude that good-quality observational data rely on the maintenance of both observational equipment and the surrounding environment under optimal conditions.