A development of a calibration method for field pyranometers using satellite image data

Abstract

In this work, a calibration method for deriving a sensitivity of field pyranometers using Himawari satellite image data was developed. The purposed method representing a relation between 10–bit digital counts ranging between 0–1023 from satellite data and global solar irradiance of a standard pyranometer measured at Nakhon Pathom (13.82 °N, 100.04 °E) was investigated and it was found to be an exponential relation. Afterward, this model was applied to estimate the sensitivity of field pyranometers installed at three meteorological monitoring stations located in the main regions of Thailand namely, Chaing Mai in the North (18.78 °N, 98.98 °E), Ubon Ratchathani in the Northeast (15.52 °N, 104.87 °E) and Songkhla in the South (7.20 °N, 100.60 °E) for the validation. The results showed that the sensitivity of field pyranometers derived from satellite data and that obtained from the standard outdoor calibration method of ISO9847 was in a very good agreement with a discrepancy between both datasets of about 1%.