Radiometer Measurement Intercomparison using Absolute Cavity Radiometer in Regional Radiometer Center at Tsukuba, Japan

Abstract

Solar radiation measuring instruments are generally more sensitive than other meteorological instruments. The standard reference for solar radiation measurements is maintained by the WRC (World Radiation Center) in Davos, Switzerland. The world radiometric standard reference was determined from the weighted mean of the measurements of group of 15 absolute cavity radiometers every 5 years. The reference instruments of the RRC (Regional Radiation Center) were calibrated through the WRC standards reference. Recently, intercomparison observations were performed using the standard instruments at Mt. Tsukuba in Japan in January, 2012. Several standard instruments (absolute cavity radiometer: PMO6 and AHF, pyranometer: CMP22) of KMA (Korea Meteorological Administration) participated in this program and were calibrated from the reference instruments of WRC and RRC. The errors of PMO6, AHF, and CMP22 were reported to be 0.02%, 0.3%, and 1.87%, respectively, compared to reference instruments. RRC is smaller in scale than WRC, using only five pieces of standard equipment and having only a 10-day observation period. Therefore, direct participation in IPC of WRC is needed to secure the technology related to domestic solar radiation observations.