The International Pyrheliometer Comparison (IPC) is an WMO event that takes place every five years at the Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC) in Davos, Switzerland.
The IPC helps ensure the quality of solar radiation measurements worldwide through comparison of reference instruments to the World Standard Group (WSG) , a group of six instruments located at PMOD/WRC Davos and representing the World Radiometric Reference (WRR) - the world standard for solar radiation. Representatives from WMO Regional and National Radiation Centers and from National Metrology Institutes participate with their reference instruments, which are then used to calibrate field pyranometers and other radiation instruments in the countries they represent.
This ensures traceability of local solar measurements to the world standard (WRR) and thus worldwide comparability. Measuring solar radiation is important because the measurements are used for meteorology and climatology, detecting climate change, physics applications and solar energy measurements for use in solar power applications.
Parallel to the IPC the PMOD/WRC is holding two other comparisons: The International Pyrgeometer Comparison (IPgC) for instruments measuring the infrared radiation and the Filter Radiometer Comparison (FRC) for instruments measuring aerosols in the atmosphere. Science seminars were held besides the instrument comparisons where radiation experts from all over the world shared their knowledge to build capacity and to define common standards on measuring radiation throughout the world.