Publication

Detection of bioparticles by synergy of depolarisation-LIF lidars supported by in situ measurements at the high alpine station of Helmos, Greece, during the CHOPIN campaign 2024

2025

Abstract

The Cleancloud Helmos OrograPhic site experimeNt (CHOPIN) campaign took place in autumn 2024 at a unique high-altitude location at Mount Helmos, Greece (38.0oN, 22.2oE) ideal for targeted studies of aerosol-cloud interactions (ACI) due to its strategic location, serving as a crossroad for different aerosol transport paths. This unique position allows the detection of a wide range of particles like wildfire smoke, continental polluted, marine and mineral dust from Sahara, as well as bioparticles (pollen, bacteria, fungal spores) from near- and long-range sources. State-of-the-art laser remote sensing and in situ instrumentation was implemented at Mount Helmos at two level heights: 1700 m (remote sensing instrumentation) and 2314 m a.s.l. (in situ instrumentation) to characterize the incoming air masses in terms of their bioparticle content and study the role of bioparticles in cloud formation. In this study we will focus on data obtained by two lidar systems: the two-wavelength (532 -parallel and cross depolarization and 1064 nm) depolarization aerosol lidar system (AIAS), and the NTUA/EPFL/FORTH 4-wavelength elastic-Raman-laser induced fluorescence (LIF) lidar system (ATLAS-NEF) to provide vertical profiles of aerosol optical properties (extinction and backscatter coefficients and lidar ratio at 355 nm, backscatter Ångström exponents at 355/532nm, 532/1064 nm, particle depolarisation lidar ratio at 532 nm), water vapor mixing ratio, fluorescence capacity and fluorescence backscatter coefficients at 470 nm. We present cases of Saharan dust intrusions with increased values of the aerosol backscatter coefficient and high particle depolarization ratios (δ532 ~~0.20-0.25) and increased values of lidar ratios (LR~~40-55 sr), high numbers of ice-nucleation particles (INPs) obtained with a PINE instrument and strong signals obtained at the 3 channels of the Wideband Integrated Bioparticles Sensor (WIBS) operating at the (HAC)2 station indicate the presence of bioparticles able to enhance cloud formation.

Official source

https://infoscience.epfl.ch/entities/publication/90030fc3-9db2-4fbc-8107-53be8ebbe7cf

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2025

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/90030fc3-9db2-4fbc-8107-53be8ebbe7cf

About this result

Related concepts (32)

Lidar

Lidar (ˈlaɪdɑːr, also LIDAR, LiDAR or LADAR, an acronym of "light detection and ranging" or "laser imaging, detection, and ranging") is a method for determining ranges by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. LIDAR may operate in a fixed direction (e.g., vertical) or it may scan multiple directions, in which case it is known as LIDAR scanning or 3D laser scanning, a special combination of 3-D scanning and laser scanning.

Cloud

In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may compose the droplets and crystals. On Earth, clouds are formed as a result of saturation of the air when it is cooled to its dew point, or when it gains sufficient moisture (usually in the form of water vapor) from an adjacent source to raise the dew point to the ambient temperature.

Water vapor

Water vapor, water vapour or aqueous vapor is the gaseous phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Water vapor is transparent, like most constituents of the atmosphere. Under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation. It is less dense than most of the other constituents of air and triggers convection currents that can lead to clouds and fog.

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Detection of bioparticles by synergy of depolarisation-LIF lidars supported by in situ measurements at the high alpine station of Helmos, Greece, during the CHOPIN campaign 2024

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