Journal cover Journal topic
Annales Geophysicae Sun, Earth, planets, and planetary systems An interactive open-access journal of the European Geosciences Union
Ann. Geophys., 36, 213-229, 2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Regular paper
14 Feb 2018
Relative humidity vertical profiling using lidar-based synergistic methods in the framework of the Hygra-CD campaign
Lev D. Labzovskii1, Alexandros Papayannis2, Ioannis Binietoglou3,4, Robert F. Banks5,6, Jose M. Baldasano5,7, Florica Toanca3, Chris G. Tzanis8, and John Christodoulakis8 1School of Environmental Science and Engineering, South University of Science and Technology of China, Shenzhen 518055, China
2Laser Remote Sensing Laboratory, Physics Department, National Technical University of Athens, Athens, Zografou, 15780, Greece
3Laser Remote Sensing Laboratory, National Institute of R&D for Optoelectronics, Magurele (Ilfov), 07712, Romania
4Raymterics S.A., Spartis 32, Metamorfosi Attikis, 14452, Greece
5Earth Sciences Department, Barcelona Supercomputing Center-Centro Nacional de Supercomutación (BSC-CNS), Barcelona, 08034, Spain
6Department of Geoscience and Remote Sensing, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, 2628 CN, the Netherlands
7Environmental Modelling Laboratory, Technical University of Catalonia (UPC), Barcelona, 08028, Spain
8Section of Environmental Physics and Meteorology, Department of Physics, National and Kapodistrian University of Athens, Athens, 15784, Greece
Abstract. Accurate continuous measurements of relative humidity (RH) vertical profiles in the lower troposphere have become a significant scientific challenge. In recent years a synergy of various ground-based remote sensing instruments have been successfully used for RH vertical profiling, which has resulted in the improvement of spatial resolution and, in some cases, of the accuracy of the measurement. Some studies have also suggested the use of high-resolution model simulations as input datasets into RH vertical profiling techniques. In this paper we apply two synergetic methods for RH profiling, including the synergy of lidar with a microwave radiometer and high-resolution atmospheric modeling. The two methods are employed for RH retrieval between 100 and 6000 m with increased spatial resolution, based on datasets from the HygrA-CD (Hygroscopic Aerosols to Cloud Droplets) campaign conducted in Athens, Greece from May to June 2014. RH profiles from synergetic methods are then compared with those retrieved using single instruments or as simulated by high-resolution models. Our proposed technique for RH profiling provides improved statistical agreement with reference to radiosoundings by 27 % when the lidar–radiometer (in comparison with radiometer measurements) approach is used and by 15 % when a lidar model is used (in comparison with WRF-model simulations). Mean uncertainty of RH due to temperature bias in RH profiling was  ∼ 4.34 % for the lidar–radiometer and  ∼ 1.22 % for the lidar–model methods. However, maximum uncertainty in RH retrievals due to temperature bias showed that lidar-model method is more reliable at heights greater than 2000 m. Overall, our results have demonstrated the capability of both combined methods for daytime measurements in heights between 100 and 6000 m when lidar–radiometer or lidar–WRF combined datasets are available.

Citation: Labzovskii, L. D., Papayannis, A., Binietoglou, I., Banks, R. F., Baldasano, J. M., Toanca, F., Tzanis, C. G., and Christodoulakis, J.: Relative humidity vertical profiling using lidar-based synergistic methods in the framework of the Hygra-CD campaign, Ann. Geophys., 36, 213-229,, 2018.
Publications Copernicus
Short summary
This study aims to evaluate synergetic methods for relative humidity vertical profiling based on lidar–radiometer and lidar–simulation combinations. We demonstrate the effectiveness of combined lidar-based methods for relative humidity profiling in comparison with radiometer observations or WRF simulations and assess temperature-related uncertainties in resulting relative humidity profiles. All results are acquired during the HygrA-CD campaign in Athens (Greece) in 2014.
This study aims to evaluate synergetic methods for relative humidity vertical profiling based on...