1. Joint Research Centre (JRC) European Commission Via Fermi 2749 Ispra (VA) I‐21027 Italy
2. AIT—Austrian Institute of Technology Giefinggasse 4 Vienna 1201 Austria
3. Physikalisch‐Meteorologisches Observatorium Davos, World Radiation Center (PMOD/WRC) Dorfstrasse 33 Davos 7260 Switzerland
4. EKO Instruments Europe B.V. Lulofsstraat 55 Den Haag 2521 AL The Netherlands
5. European Space Agency, ESTEC Keplerplaan 1 Noordwijk ZH 2200 AG The Netherlands
6. Physikalisch‐Technische Bundesanstalt (PTB) Bundesallee 100 Braunschweig 38116 Germany
7. Radboud University Nijmegen Heyendaalseweg 135 Nijmegen 6525 HZ The Netherlands
8. RSE Milano Via Rubattino 54 Milan Italy
9. SERIS National University of Singapore 7 Engineering Drive 1, #06‐01, Block E3A Singapore
10. SUPSI Scuola Universitaria Professionale Svizzera Italiana, Campus Trevano Canobbio CH‐6952 Switzerland
11. ENEA, Centro Ricerche di Portici Portici IT‐80055 Italy