Esperimento di chiusura nel lontano infrarosso per le nubi antartiche


Funded by: Ministero dell’Istruzione, Università e Ricerca (MIUR)  
Start date: 2017-03-01  End date: 2019-02-28
Total Budget: EUR 152.500,00  INO share of the total budget: EUR 135.000,00
Scientific manager: Di Natale Gianluca   and for INO is: Di Natale Gianluca

Organization/Institution/Company main assignee: CNR – Istituto Nazionale di Ottica (INO)

other Organization/Institution/Company involved:
Università di Bologna – Dipartimento di Fisica e Astronomia
Università di Firenze

other INO’s people involved:
Palchetti Luca

Abstract: Most uncertainties that are present in the characterization of the longwave emission of cirrus clouds come from the lack of spectrally resolved measurements in the far-infrared (FIR) spectral region from 100 to 667 cm −1 (100–15 μm).
The Antarctic Plateau represents one of best place where these measurements can be performed because the high-altitude and the very dry conditions allow to sound efficiently the infrared spectrum down to the FIR regions.
The main objective of this project is a complete spectral characterization of cirrus and mixed phase clouds in order to evaluate the radiative models in the FIR regime, where the clouds effect is very strong, and systematic spectral measurements are scarcely available.
In some selected cases of precipitating or close to the surface cirrus clouds, we propose to perform a radiative closure experiment with the aim to simultaneously improve the single-scattering models for ice and mixed-phase clouds, and to retrieve the optical and
micro-physical properties of clouds, such as effective diameters, ice and liquid water path and optical depths. The required spectral radiance measurements in the range 100-1000 cm-1 will be acquired by the Fourier spectroradiometer REFIR-PAD, already operative at Dome-C, whereas the atmospheric cloud fields will be constrained with the support of other instruments, such as a backscattering/depolarization lidar, also operative in Antarctica, for the estimation of the clouds position, phase,and the extinction profile (limited to some case studies), an ice and halo imager cameras for the determination of the clouds micro-physics in some cases, and a radar for the evaluation of the cloud ice content in the cases of precipitating clouds.
Furthermore daily radiosondes and standard meteo station data, available at the base, will allow to independently characterise the atmospheric state.
The observations of the underexplored FIR spectral region, performed in this project, are expected to provide new information on the radiative properties of clouds and their role in Earth Radiation Budget (ERB) and to improve our ability to model and assess cloud processes in climate models.