PRANA

Atmospheric Physics at Dome Concordia 75°S 123°E

PRANA – Radiative Properties of Atmospheric Water vapour and clouds in Antarctica (IFAC-CNR, Firenze)

Contacts: Luca Palchetti, Giovanni Bianchini Istituto Fisica Applicata (IFAC-CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino (I) Tel. +39.055.522.6311, Fax. +39.055.522.6348

PRANA experiment

The PRANA (Proprieta’ Radiative del vapore Acqueo e delle nubi in Antartide – Radiative Properties of Atmospheric Water vapour and clouds in Antarctica) research programme regards the monitoring and the spectral characterisation of the downwelling longwave radiation (DLR) from 100 to 1400 cm-1 emitted by the atmosphere in different sky conditions. This measurement will allow to improve the knowledge in the under-explored far infrared (FIR) spectral region of the emission spectrum from 100 to 400 cm-1. In particular, the modelling of the pure rotational water vapour band and the radiative properties of high altitude ice clouds, such as cirrus and polar stratospheric clouds (PSC), will be studied in depth. As the modelling capabilities is validated, the measurement can be used for the estimation of the total precipitable water vapour content (PWV) and the PSC coverage.
The spectral measurement of the downwelling radiance will be performed by a spectroradiometer called REFIR-PAD (Radiation Explorer in the Far InfraRed – Prototype for Applicattions and Development, http://refir.ifac.cnr.it), which is a prototype developed at IFAC for field applications. Cloud characterisation will be performed by a LIDAR system ICECAMERA, which is already operative on the site. Both instruments are installed in the Physics shelter devoted to atmospheric physics.

REFIR-PAD products

REFIR-PAD will supply the following products:

Raw measurement data (level 0);
Non apodized calibrated spectra of the down-welling radiance (level 1). In the range of 100-400 cm-1 these measurements are unique;
Geophysical products (level 2): water vapour and temperature vertical profiles and total precipitable water vapour (PWV).

Expected uncertainties are for Brightness temperature error about 0.1K (@ 280K),and for PWV about 5%.