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REFIR-PAD @ Dome C

Current and past research projects at Concordia Station

Contact: Giovanni Bianchini, Istituto Nazionale di Ottica (INO-CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino (I) Tel. +39.055.522.6309, Fax. +39.055.522.6348

The DOCTOR project (2016-present)

The Dome C Tropospheric Observer (DOCTOR) project aims to exploit the specific observation point provided by the East Antarctic Plateau to perform a long-term monitoring of the Antarctic troposphere in terms of its radiative and thermal properties and its composition.

The polar regions have a fundamental role in climate, being the main radiative sink of the Earth System thanks to their high visible-UV albedo and high thermal emissivity. Even CO2, which is globally responsible for a positive greenhouse effect, in polar regions, due to very low ground temperatures can have a negative contribution.
The East-Antarctic plateau is a rather isolated system due to its atmospheric circulation, and is also relatively simple in terms of orography, so it qualifies as an optimal system for the study of the mechanisms of climate.

The instrumental setup included in the DOCTOR project allows a measurement repetition rate which is high enough to capture not only the slow trends but also some fast evolving phenomena, like rapid warming events, which often are at the base of the observed trends.
The project makes use of the REFIR-PAD Fourier transform spectroradiometer, which provides a spectrally-resolved measurement of the atmospheric downwelling radiance in the 7-100 mm spectral range, covering the most part of the atmospheric emission.
These spectroscopic measurements are complemented by an infrared laser profiler, which provides the vertical structure of clouds, and by several other auxiliary sensors providing atmospheric parameters at ground level and integrated radiometric measurements
The data acquired by the projects observing system is analyzed by a specifically developed code which integrates all the information and produces vertical profiles of water vapor and temperature, columnar amounts for water and N2O and cloud optical thickness. Time series for these parameters have been obtained tracing back to December 2011, while development is ongoing to provide as a new product the columnar amount of O3.

The COMPASS project (2014-2015)

The CoMPASs (Concordia Multi-Process Atmospheric Studies) project has been developed in order to identify and characterize these feedbacks and interactions between processes, spanning across three different atmospheric regions: the boundary layer, the troposphere and the stratosphere.
The main research themes follow the vertical structure of the atmosphere:

  • Characterization of the atmospheric boundary layer (ABL) in terms of dynamics, turbulence and radiation, especially during the winter period, in which the ABL has peculiar properties in terms of reduced thickness and extreme sensitivity to external forcing.
  • Study of the clouds in the free troposphere, which, in the region of Dome C, shows a remarkable variability, both daily and seasonal, and therefore requires continuous monitoring to quantify its interactions with the neighboring atmospheric layers.
  • Study of the stratospheric processes within the Antarctic polar vortex, as ozone chemistry and polar stratospheric clouds, carried out throughout the year in order to constantly follow the evolution of the vortex itself.

CoMPASs makes use of a strong observational component, deploying an array of different instruments all characterized by the vertical remote sensing measurement technique: stratospheric and tropospheric lidars, UV and middle/far-infrared spectroradiometers, and a high-resolution mini-sodar.
The study involves different spatial and temporal scales. The prevalent use of remote sensing instrumentation from the ground allows the characterization of a large part of the atmosphere. The instrumentation is expected to operate continuously, automatically or semi-automatically through the intervention of personnel present even during the winter season, thus obtaining a characterization of processes with temporal coverage on different scales (daily, seasonal, annual).

The PRANA project (2012-2013)

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.fi.ino.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.

The STRAAP-B project (2014-2015)

The STRRAP-b (STudy of the Radiative Regimes over the Antarctic Plateau and beyond) project aims to deepen the knowledge on the Antarctic Plateau radiative regime and its regulating processes, through in situ radiometric measurements coupled with remote sensing techniques, using broadband and hyperspectral instrumentation.

Specifically, the project aims to define accurately the effects of cloud cover, ozone and water vapor, and surface reflectance properties on the radiative balance over the East antarctic Plateau. For the different conditions of cloud coverage, the downwelling and upwelling solar radiation will be spectrally and geometrically characterized.

Information provided by the BSRN station and new instrument implementations will be exploited to calibrate/validate satellite retrieval products related to the surface reflectivity, and provide validated measures of the components of solar and infrared irradiance incident and reflected by the surface. The use of satellite information properly configured over the Antarctic in conjunction with the data provided by the other three BSRN stations operated in Antarctica (SPO, SYO, GVN), will allow researchers to expand definitions of the radiative regimes to a regional scale and possibly up along the coast. Atmospheric corrections will be taken into account by ground based remote sensing of columnar ozone, measurements of UV spectral radiation, while water vapor will be measured by various platforms including radiosonde, REFIR-PAD IR radiometer and HAMSTRAD MW radiometer.

Past campaigns performed by REFIR-PAD (not involving Concordia Station)

Radiative Heating in the Underexplored Bands Campaign 2 - RHUBC2 (2009)

Cerro Toco site, Chilean Andes

The second RHUBC campaign took place from August to October 2009 from the Cerro Toco site in the Chilean Andes (5383 m a.s.l.) under the U.S. ARM (Atmospheric Radiation Monitoring) program.

Earth COoling by WAter vapor Radiation - ECOWAR (2007)

Testa Grigia site, Italian-Swiss Alps

The ECOWAR campaign took place from 3 to 16 of March, 2007 from the Testa Grigia scientific station near Plateau Rosa, at 3480 meters a.s.l. on the Italian-Swiss Alps. Here are some papers describing the ECOWAR campaign and the results obtained through it.