A high dynamic radiation measurements instrument: the Bolometric Oscillation Sensor (BOS)

Abstract

Abstract. The bolometric oscillation sensor (BOS) is a broadband radiation measurement instrument onboard the PICARD satellite that has been active between 2010 and 2014. The main detector is a thermistor attached black coated surface, which was permanently exposed to space without any optical and aperture accessories. The temperature measurements are used within a transfer function to determine variations in incoming solar irradiance as well as the terrestrial radiation. In the present article, the measurement principle of BOS and its transfer function are presented. The performance of the instrument is discussed based on laboratory experiments and space observations from the PICARD satellite. The comparison of the short term variation of Total Solar Irradiance (TSI) with absolute radiometers such as VIRGO/SOHO and TIM/SORCE over the same period of time, suggests that BOS is a relatively much simpler but very effective sensor to monitor electromagnetic radiation variations from visible to infrared wavelengths.