Total Solar Irradiance: Present status of TSI observations
Abstract
Total Solar Irradiance is measured by pyrheliometers. These instruments are either fully charac-terized and measure in absolute units or they are traceable to the World Radiometric Reference (WRR) at the World Radiation Center in Davos. The WRR in turn is so far only traceable to SI in power but not in irradiance. The added difficulty when discussing metrology of pyrheliome-ters in space is that the WRR is operated in air. Thus, so far, measurements of TSI in space rely on the full characterization of the instruments and a fully traceable TSI measurements has not yet been flown. This talk will give an overview over existing space observations of TSI and discusses the dif-ferences in the absolute and relative values between the various experiments. The challenge for future experiments is to get full traceability of the measurements in space. There are two upcoming experiments, PREMOS on PICARD and GLORY/TIM, which will yield TSI measurements which will be SI traceable.
- Publication:
-
38th COSPAR Scientific Assembly
- Pub Date:
- 2010
- Bibcode:
- 2010cosp...38.1689S