*
Corresponding authors
a
Institute of Meteorology and Climatology, Leibniz University Hannover, Germany
b
National Institute of Water and Atmospheric Research, NIWA Lauder, Omakau, Central Otago, New Zealand
c
Instituto de Meteorologia, Lisboa, Portugal
d
School of Earth Atmospheric and Environmental Sciences, University of Manchester, UK
e
Università di Roma La Sapienza, Roma, Italy
f
Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki, Greece
g
Faculty of Natural Sciences and Technology, Trondheim, Norway
h
Laboratoire d'Optique Atmosphèrique, Université de Sciences et Technologies de Lille, France
i
Research Center Karlsruhe, Germany
j
Finnish Meteorological Institute, Helsinki, Finland
k
Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center (PMOD/WRC), Switzerland
l
National Institute for Public Health and the Environment, Bilthoven, The Netherlands
m
German Weather Service (DWD), Lindenberg, Germany