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EURAMET Traceability Project on traceability of passive remote sensing of aerosol optical properties to the SI


A new EURAMET Traceability Project Opens external link in new window“Traceability of the GAW-PFR reference Precision Filter Radiometers to the SI” was started in collaboration between PTB, Working Group 4.11 “Spectroradiometry” and PMOD/WRC. PMOD/WRC is designated by the World Meteorological Organisation (WMO) to operate the World aerosol Optical depth Research and Calibration Center (WORCC). WORCC is responsible for hosting the world reference for Aerosol Optical Depth (AOD), formed as a set of Precision Filter Radiometers (PFR). Furthermore, it operates the AOD monitoring network established within the frame of the Global Atmospheric Watch (GAW) program (GAW-PFR network). The WORCC mandate also encompasses to provide AOD traceability from its GAWPFR reference to other global and regional AOD monitoring networks. This is achieved through the Filter Radiometer comparison campaign held a PMOD/WRC every five years, and by collocating PFR travel standards at other network calibration sites (e.g. ACTRIS CARS). The collaboration between PTB and PMOD/WRC with respect to the SI-traceability of spectral solar irradiance of the PFR started in 2019 and continued in the framework of the EMPIR project Opens external link in new window19ENV04 MAPP, “Metrology for aerosol optical properties”. The proposed project aims at providing SI-traceability to the global AOD monitoring community through comparisons with the GAWPFR reference, which is made up of a set of PFR instruments, of which one or more instruments will be annually calibrated at PTB.

Left: A GAW-PFR radiometer installed for the calibration at the tuneable laser setup TULIP at PTB 

Right: GAW-PFR radiometers installed for the solar measurements at PMOD/WRC

Further Information:


Contact Person:
Saulius Nevas, E-
Mail: saulius.nevas(at)ptb.de, Tel. 0531-592-4115


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Dr. Dr. Jens Simon

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