Lidars are a key instrument for the characterization of aerosols and their impact on the Earth's environment as they are able to provide vertically resolved information of aerosols. With multiwavelength-Raman-polarization lidars, aerosol layers can be characterized in terms of types, size distribution, and concentration (Ansmann and Müller, 2005; Müller et al., 2007; Ansmann et al., 2012).

Motivated by the urgent need for robust multiwavelength-Raman-polarization lidars that are easy to operate and allow aerosol typing, a portable lidar system, called PollyXT, has been developed at the Leibniz Institute for Tropospheric Research (TROPOS) with international partners during the last decade (Althausen et al., 2009; Engelmann et al., 2015). The aim was to develop a sophisticated multiwavelength-Raman-polarization lidar for scientific purpose, but with the advantages of an easy-to-use and well-characterized instrument with same design, same automated operation, and same centralized data processing in line with the CIMEL Sun photometer of AERONET (Holben et al., 2001). These Polly systems have been developed for continuous, stand-alone operation in remote environments and were successfully deployed in the high northern latitudes of Finland (> 30 cm snow and < 20 °C, Hirsikko et al., 2014), in the rain forest of the Amazonian Basin with temperatures of > 30 °C and high relative humidity (Baars et al., 2012), and under permanent mechanical stress from motor vibrations plus rough sea aboard the research vessel Polarstern (Kanitz et al., 2013a).

As the number of Polly systems and measurement sites has increased with time, an independent, voluntary, international network of cooperating institutes, the so-called PollyNET (Althausen et al., 2013), has evolved as an additional contribution to the world wide aerosol observational efforts. Namely the Finnish Meteorological Institute (FMI), the National Institute of Environmental Research (NIER) in Korea, the Évora University in Portugal (UE-ICT), the University of Warsaw (UW) in Poland, The German Meteorological Service (DWD) and the National Observatory of Athens (NOA) in Greece contribute actively to the network by hosting Polly systems. Each group contributes with its expertise and knowledge to the network and to joint scientific projects.

Source: Baars, H. et al. (2016): An overview of the first decade of PollyNET: An emerging network of automated Raman-polarization lidars for continuous aerosol profiling. ACP, 16, 5111-5137, doi:10.5194/acp-16-5111-2016, 2016.