Proprietà ottiche di polveri eoliche in Antartide
Funded by: Ministero dell’Istruzione, Università e Ricerca (MIUR) Calls: PNRA – PROGRAMMA NAZIONALE RICERCHE in ANTARTIDE
Start date: 2018-11-05 End date: 2020-11-04
Total Budget: EUR 284.150,00 INO share of the total budget: EUR 8.800,00
Scientific manager: Marco Potenza and for INO is: Del Guasta Massimo
Organization/Institution/Company main assignee: Università degli Studi di Milano
other Organization/Institution/Company involved:
UNIMIB Università degli Studi di Milano Bicocca
other INO’s people involved:
Abstract: OPTAIR is a multidisciplinary project aimed at determining and studying the optical properties of airborne particles at Concordia and to assess on an experimental basis the relationships among the particles suspended in air and deposited on ground.
The project goal is to install a permanent instrumentation for measuring single airborne particles overall the year (RU1) and to collect the snow on a regular frequency.
The snow will be accurately characterized in European laboratories (RU2) and put in correlation with data from airborne particles and LIDAR measurements (RU3).
The impact of the project will be to obtain on an experimental basis the optical properties of eolian dust(airborne and deposited) and to assess the impact on past and present climate.
The possibility of having real time LIDAR data from Concordia (RU3) represents a unique opportunity for this project.
OPTAIR is centred on the use of the novel Single Particle Extinction and Scattering (SPES) optical method (Potenza et al., 2014 and references therein).
The breakthrough of the method is represented by the capability of measuring both the extinction cross section and the optical thickness of each particle sensed by the instrument. Moreover, the optical layout is robust because it relies on self reference interference of the scattered and the transmitted light, and rigorously calibration free.
It demonstrated to be effective in determining properties of particles such as shape and internal structure in the case of liquid suspensions obtained from the so called “old” DomeC ice core (Lorius et al., 1979).
This recently brought clear assessments about the shape variability of dust with time, with important impact on the radiative transfer of the atmosphere in the past (Potenza et al., under revision: see in support information).
Radiative transfer is one of the key elements determining climate.
It is widely recognized to be strongly affected by aerosols (IPCC 2013), which in turn are not really very well understood nor characterized in terms of their optical properties.
This is also caused by the strong heterogeneous nature of the aerosol, consisting of mineral dust, marine aerosol, volcanic products, etc.
Knowledge of the optical properties of past and present aerosol is of importance in climate modelling for describing the current and projected climate change.
An innovative SPES device working in liquid has been recently installed at EUROCOLD with the aim of performing systematic analyses of dust archived in Antarctic ice cores (ICE-1).
Some glacial and interglacial liquid samples from the old Dome C, EPICA, Vostok, and Talos Dome ice cores have already been analyzed. Results from the old Dome C ice core are discussed in a paper under review (Nature Scientific Reports).
In 2015, a new SPES instrument has been realized (AIR-1) to measure single airborne particles.
A working prototype of AIR-1 is currently operating at RU1 and will be exploited for measurements in collaboration with the EU Joint Research Centre (Ispra) in June 2016, within the activities of the Vehicle Engine Laboratory (VELA).
This proposal aims at developing activities at Concordia Station in collaboration with, and giving support to, the existing groups measuring airborne dust and its optical properties (see proposal CO-PRE, M. Del Guasta, INO CNR, RU3).
One of the advantages of the proposed SPES method is the possibility of a true real time detection of each particle, which gives the opportunity to relate the arrival of particles to other independent optical measurements as LIDAR for example.
By including the possibility to perform very accurate measurements of dust concentration, size distribution (spherical equivalent), and optical properties on snow and ice cores at EUROCOLD (RU2), this project will allow to establish a direct link between modern dust and paleo-dust that is essential to paleoclimate models.