Exploring the aerosoL-cloud interaction in the atmosPheric column by Improved remote Sensing methods. (ELPIS)

clouds

  • Ref. PID2020-120015RB-I00
  • Funding Agency: Ministerio de Ciencia e Innovación. MICINN
  • Realization: 01/09/2021 a 31/08/2024
  • PIs: Lucas Alados Arboledas, Francisco José Olmo Reyes
  • Researchers: Inmaculada Foyo Moreno, Arturo Gabriel Quirantes Sierra

Abstract

Aerosol effects on global and regional climate and human health depend on amount, composition, size and absorption properties of the aerosol as well as on the vertical distribution, and proximity to clouds. The interaction of aerosol particles with clouds and the related climatic effects have been in the focus of atmospheric research for several decades. Aerosols can act as cloud condensation nuclei (CCN)in liquid water clouds and as ice nucleating particles (INPs) in mixed-phase and ice clouds. Changes in their concentration affect cloud extent, lifetime, cloud droplet size and radiative properties. Unreliability about these interactions is the source of the highest uncertainty in assessing the anthropogenic climate change. Aerosol characterization is feasible using a variety of remote sensing techniques, including multispectral elastic and Raman scattering, absorption and depolarization. In this project we propose to extend the information to the induced fluorescence. The use of these approaches in lidar remote sensing is not new, but some of them, particularly fluorescence and depolarization require additional effort to provide quantitative information that could be useful for characterizing the atmospheric aerosol and follow their atmospheric processes by remote sensing.

The general objective of ELPIS is improving our knowledge of the aerosol-cloud interaction by improved remote sensing tools that allow a better characterization of different aerosol types along the atmosphere ic column, focus on disentangle the role of the ample variety of atmospheric aerosols in the cloud properties with special emphasis on their role as Cloud Condensation Nuclei, CCN, and Ice Nuclei, IN. To achieve this ambitious goal, this proposal will tackle the problem both from the instrumental and methodological sides. In the frame of ELPIS we will complete the setup of a LIDAR with extended multi-wavelength Raman and depolarization capabilities adding the capability for sounding the induced fluorescence in the atmospheric column. This instrumental effort will be combined with the development of improved methodologies for calibration and data processing. From this setup retrieval of the contribution of different particles will be derived together with estimates of INP and CCN.

The new LIDAR capabilities will be complemented with those of a Doppler cloud RADAR and wind Doppler LIDAR, operated at AGORA for studying the aerosol and cloud interactions in the atmospheric column. All this work will be complemented with the work at the laboratory characterizing physicochemical features of single and ensembles of particles that will help us to improve the algorithms used in remote sensing for retrieving microphysical aerosol properties. The developed methodologies will be applied in our AGORA experimental site, combining remote sensing and in-situ approaches and exploiting our proximity to the high mountain station SNS that will allow some validations and provide complementary information to be used in the study. The new setup ofthe lidar, including fluorescence capabilities will allow us a better classification of bioaerosol and other aerosol components, contributing in his way to disentangle issues like the role of bioaerosol in the hydrological cycle. The special location of AGORA and the LIDAR-RADAR combination will allow the experimental study of cloud formation during Saharan dust outbreaks to elucidate the behavior of mineral particles as INP