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The design and characterisation of small and cost-effective reference black-bodysources for radiometric calibration of Fourier transform spectrometers in the midand far infrared is presented. The paper describes the optimisation of the absorbingblack-coating material and the study of two types of cavity geometry, one designedfor collimated beams and one for focused beams. These two reference sources havebeen developed for the Radiation Explorer in the Far InfraRed spectrometer cov-ering the 100-1400 cm −1 spectral range. They are currently used on-board twoprototypes for ground and stratospheric balloon based atmospheric emission mea-surements. An emissivity of better than 0.9999 is obtained for both type of cavitygeometry giving a calibration error, depending only on the temperature gradientinside the blackbody, of less than 0.5 K. Keywords: Fourier transform spectra, Infrared spectroscopy, Blackbody radiation PACS: 33.20.Ea, 07.57.Ty, 44.40.+a 1 IntroductionIn emission spectroscopy, the calibration of the observed radiance requiresthe measurement of a known source of radiation, which typically is givenby the emission of a blackbody (BB) cavity described by the Planck law ofradiation. The design of a well-characterised and reliable BB source can be

A simple and compact parallelogram mirror drive based on flexure pivots suitable for intermediate resolution Fourier transform spectroscopy is presented. The system permits 12 mm of mirror translation with a residual tilt of less than ±0.4 mrad in the horizontal plane and ±0.2 mrad in the vertical plane. A system prototype was built and fully characterized for a Fourier transform spectrometer operating on a stratospheric balloon.

Polar stratospheric clouds (PSC) were observed with the multi-wavelength lidar of the MOANA project (Modelling and Observations of Aerosols in the Northern Atmosphere) during SESAME (Second European Stratospheric Arctic and Mid-latitude Experiment). The physical state, liquid or solid, of the cloud particles can be inferred from the lidar data. Using isentropic back-trajectories to obtain the thermal history of the sampled air masses, it is possible to reconcile most of the observations with current ideas on PSC formation and evolution. When the cloud particles were identified as liquid, changes in the size distribution of the droplets along the trajectory were calculated using a micro-physical box model. Backscatter ratios calculated from the size distributions are in broad agreement with the lidar data, giving confidence in current understanding of the evolution of ternary solution (H2SO4, HNO3 and H2O) droplets. Results from two soundings are shown which bear on the problem of the formation of solid particles. In the first, solid particles were detected. The air mass had cooled to the frost point 12 hours earlier. In the second no solid particles were detected although the air temperature was below the nitric acid trihydrate existence point, and had decreased by 12K in the previous 14 hours.

Measurements have been performed at eight laboratories on Raman-shifted radiation from frequency-quadrupled Nd:YAG and KrF lasers. Each of these sources is a possible candidate for making differential-absorption lidar measurements of ozone in the free troposphere. The spectral purity, efficiency and divergence of the different sources are compared and explained using a simplified model of the Raman interaction. Particular attention has been given to the use of buffer gases to optimize the Raman gain and divergence. The experimental results show that the operating conditions required to optimize the output energy of each of these types of laser source can be quite different. In the case of the KrF laser, it has been shown that high energies can be generated at low active gas pressures, and that increasing the pressure increases the beam quality, but decreases the energy. (Less)

Reliable time series of vegetation optical properties are needed to improve the modeling of the terrestrial carbon budget with remote sensing data. This paper describes the development of an automatic spectral system able to collect continuous long-term in-field spectral measurements of spectral down-welling and surface reflected irradiance. The paper addresses the development of the system, named hyperspectral irradiometer (HSI), describes its optical design, the acquisition, and processing operations. Measurements gathered on a vegetated surface by the HSI are shown, discussed and compared with experimental outcomes with independent instruments. © 2011 American Institute of Physics.

A four wavelength backscattering depolarization LIDAR designed for polar stratospheric cloud and stratospheric aerosol measurement is described. The system uses the following wavelengths: 355 nm, 532 nm, 750 nm, and 850 nm. These wavelengths, obtained by means of the third- and second-harmonic of a Nd: YAG laser and by means of a tunable Ti: Sapphire laser, are chosen in a way to better characterize the particel size of such stratospheric aerosols. They are not emitted simultaneously as the LIDAR system is designed with only two detection channels permitting to detect, in the analog and in the photon counting mode, both the direct and the depolarized backscattered signal. The system has been operational in northern Finland since the end of November 1991.

A possible application of hyperspectral remote sensing regards the assessment of light pollution due to cities and industries. In this paper we introduce the results from a remote sensing campaign performed in September 2001 at night time. For the first time nocturnal light pollution was measured at high spatial and spectral resolution us- ing two airborne hyperspectral sensors, namely the Multispectral Infrared and Visible Imaging Spectrometer (MIVIS) and the Visible InfraRed Scanner (VIRS-200). These imagers, generally employed for day-time Earth remote sensing, were flown over the Tuscany coast (Italy) on board of a Casa 212/200 airplane from an altitude of 1.5-2.0 km. We describe the experimental activities which preceded the remote sensing campaign, the opti- mization of sensor configuration, and the images as far acquired. The obtained results point out the novelty of the performed measurements and highlight the need to employ advanced remote sensing techniques as a spec- troscopic tool for light pollution monitoring.

In this paper we describe a new instrument named ALISEO (Aerospace Leap-frog Imaging Stationary Interferometer for Earth Observation), which belongs to the class of the “stationary interferometers”. ALISEO has been selected as the main payload for a novel Italian Space Agency (ASI) optical mission based on a micro-satellite (MIOSat) with steering capability. The mission is constituted by a micro-satellite equipped with advanced payloads, among which there are an extensible telescope, a MEMS Mach-Zehnder non-imaging interferometer, and ALISEO. MIOSat is expected to provide the scientific community with the technological demonstration of this new remote sensing technology.

ALISEO (Aerospace Leap-frog Imaging Stationary Interferometer for Earth Observation) belongs to the stationary interferometers representing a promising architecture for future Earth Observation (EO) sensors due to their simple optical layout. ALISEO has been selected by the Italian Space Agency as the principal payload for a new optical mission based on a micro-satellite (MIOsat). Payloads planned for MIOsat are an extensible telescope, a high-resolution panchromatic camera, a Mach-Zehnder MEMS interferometer, and ALISEO. MIOsat is expected to provide a platform with pointing capability for those advanced sensors. ALISEO operates in the common-path Sagnac configuration, and it does not employ any moving part to generate phase delay between the two rays. The sensor acquires the target images modulated by a pattern of autocorrelation functions: a fringe pattern that is fixed with respect to the instrument's field of view. The complete interferogram of each target location is retrieved introducing relative source-observer motion, which allows any image pixels to be observed under different phase delays. Recent laboratory measurements performed with ALISEO are described and discussed in this paper. In order to calibrate the optical path difference (OPD) of raw interferograms, a set of measurements have been carried out using a double planar diffuser system and several coloured He-Ne lasers. Standard reflectance tiles together doped with Holmium and Rare Earths have been used for validating the wavelength calibration of the instrument and proving the reliability of the reflectance retrieving procedure.

An old-fashioned technology such as the "searchlight profiler", which was used in the 1960s for the early profiling of atmospheric backscatter, recently modified for its use with lasers and CCD cams1, has been revisited in the telemetric-LIDAR described here. The instrument is intended for the low-cost monitoring of urban aerosols, with a limited useful range of 100-200 meters. A modulated CW laser beam is used to probe the atmosphere, and a refractive telescope is used to collect the backscattered light on a photodiode array. Like in a telemetric system, the distance between the laser beam and the telescope axis determines the range resolution and the distance of the measurement volume corresponding to each pixel of the array. The system was used in conjunction with in-situ PM10 instruments for several months of continuous operation in Prato and Florence (Italy). The comparison between LIDAR-derived and conventional PM10 measurements is shown.

The spectrally-resolved characterization of the atmospheric emission has a fundamental role in the study of the Earth radiation balance, and only a measurement performed in a wide spectral range enables us to separate the contributions to the radiative balance due to the different altitudes, constituents and physical phases. The REFIR-PAD (Radiation Explorer in the Far InfraRed-Prototype for Application and Development) Fourier transform spectroradiometer can perform a characterization of the broadband radiative signature of clouds and aerosols, with the only limitation of the need of low levels of water vapour like those that are obtainable in high altitude stations during winter. The capabilities of this kind of measurement have been assessed in a series of test campaign performed in Tuscany during the winter of 2006/2007 when atmospheric emission spectra have been acquired in various transparency conditions and the evidence of transparency in the far-infrared region below 600 cm -1 has been demonstrated. REFIR-PAD operates in the spectral range extending from 100 to 1400 cm -1 with a resolution of 0.5 cm -1 , using room-temperature detectors and optics and a compact, misalignment-compensated design. The instrument, developed at IFAC-CNR, Florence, has been successfully deployed in several campaigns, both in the ground based zenith-looking geometry and in the nadir-looking balloon borne configuration. The operating spectral range of the REFIR-PAD spectroradiometer encompasses great part of the atmospheric emission spectrum, from the relatively unexplored far-infrared region below 400 cm -1 , dominated by water vapour rotational band, to the atmospheric transparency window, where a number of atmospheric instruments are already operating and can provide intercomparison data.

A polarization lidar operating at 532 nm was converted into an automatic, polarimetric lidar capable of measuring the entire Stokes vector of backscattered light and its derived quantities. Among these quantities, circular and linear depolarizations were studied as tools for investigating the presence of anisotropic scattering media. Isotropic scatterers show a simple relationship between linear and circular depolarization, a relation that we confirm theoretically and experimentally. Deviations from this relation, which are possible in the presence of anisotropic scatterers such as horizontally oriented ice plates when they are observed with a slant lidar, were studied both numerically and experimentally.

In recent years the Italian Space Agency funded a feasibility study for an aerospace imaging interferometer for Earth Observation. The instrument, named ALISEO (Aerospace Leap-frog Imaging Stationary Interferometer for Earth Observation), belongs to the class of the so called "stationary interferometers," and it operates in the common path Sagnac configuration not employing any moving parts to generate phase delay. ALISEO acquires the target image as modulated by a pattern of autocorrelation functions of the energy coming from each target's location. The complete interferogram is retrieved introducing relative source-observer motion. In order to calibrate the optical-path-difference (OPD) axis of the raw interferograms, a set of measurements have been carried out illuminating a double planar diffuser system by He-Ne lasers operating at different wavelengths. Standard reflectance tiles together with diffusers doped with Holmium and Rare Earths have been used to verify the wavelength calibration of the instrument. Finally, a procedure for raw data pre-processing aimed at retrieving at-sensor radiance spectra is developed taking into account the issues of dark signal subtraction, spectral instrument response compensation, effects of vignetting, and Fourier back-transform algorithm.

In preparation for a possible space mission, a breadboard version named REFIR-BB of the Radiation Explorer in the Far Infrared (REFIR) instrument has been built. The REFIR is a Fourier-transform spectrometer with a new optical layout operating in the spectral range 100-1100 cm(-1) with a resolution of 0.5 cm(-1), a 7-s acquisition time, and a signal-to-noise ratio of better than 100. Its mission is the spectral measurement in the far infrared of the Earth's outgoing emission, with particular attention to the long-wavelength spectral region, which is not covered by either current or planned space missions. This measurement is of great importance for deriving an accurate estimate of the radiation budget in both clear and cloudy conditions. The REFIR-BB permits the trade-off among all instrument parameters to be studied, the optical layout to be tested, and the data-acquisition strategy to be optimized. The breadboard could be used for high-altitude ground-based campaigns or could be flown for test flights on aircraft or balloon stratospheric platforms. The breadboard's design and the experimental results are described, with particular attention to the acquisition strategy and characterization of the interferometer. Tests were performed both in laboratory conditions and in vacuum. Notwithstanding a loss of efficiency above 700 cm(-1) caused by the poor performance of the photolithographic polarizers used as beam splitters, the results demonstrate the feasibility of using the spectrometer for space applications.

In this paper, mid-infrared spectrometer based on a liquid nitrogen cooled lead-salt diode laser, emitting at 2190 cm/sup -1/ for the in-situ measurement of stratospheric nitrous oxide is developed. The system operates unattended for several hours under changing ambient conditions: during flight, the pressure is ranging from 1000 down to 30 mbar, temperature ranges from +70/spl deg/C to -90/spl deg/C. Typical flight measurements are performed between 10000 and 22000 m of altitude and at an aircraft speed of 160-190 m/s.

In this paper, compact near-infrared distributed feedback diode-laser, emitting at 1.651 micron for the measurement of atmospheric methane profiles on an airborne platform is developed. The detection technique is based on two-tone frequency modulation spectroscopy. The calibration procedure for the analyser with respect to pressure changes during the flight mission is also discussed.

In this paper we present some laboratory measurements obtained by a new imaging interferometer. This instrument has been derived from the so called “stationary interferometers,” which do not employ any moving part to optically scan the instrument field-of-view. The device acquires the image of an object superimposed to a fixed (stationary) pattern of autocorrelation functions of the energy coming from each pixel. The interference pattern, constituted by a system of vertical fringes, is scanned by moving the observed target with respect to the imaging device. In order to calibrate the optical-path-difference axis of the raw interferograms, we have executed a set of measurements employing a He-Ne laser source spread by a pair of planar diffusers. The dependence of the optical-path-difference values on the source spectral content has been addressed performing a set of measurements after filtering a 600W halogen lamp with interference filters of 10nm bandwidth. We have described the procedure of pre-processing of the acquired data to retrieve the spectrum of at-sensor radiance (dark signal subtraction, spectral instrument response compensation, effects of vignetting and Fourier transform algorithm). Some hints are given about the use of this instrument from airborne platforms for remote sensing of the Earth.

A new solar spectral irradiometer that operates in the visible and near-infrared spectral ranges has been developed. This instrument takes advantage of a new concept optical head that collects the light that impinges on a hemispheric surface, thus improving the instrument angular response with respect to traditional devices. The technical characteristics of the instrument are investigated and detailed, and its radiometric calibration, performed by means of a Langley-like method, is discussed. A new simplified theoretical model that accounts for the diffuse irradiance observed in an optically thin plane-parallel atmosphere has been developed to improve the fit of the irradiance diurnal evolution. An alternative polynomial parametric representation of monochromatic diffuse irradiance evolution has been attempted, but satisfactory results were not obtained from the fitting of experimental data. The new instrument could be useful to carry out remote-sensing validation campaigns.

The fundamental component of a stationary interferometer is a beam-splitter semi-transparent plate that provides phase-delay between the two interfering rays. The phase-delay changes with varying the incident angle of the entering ray, thus producing the entire interference pattern while moving the device over the surface of the observed target. Due to their technical characteristics these interferometers can reliably be adapted for aerospace remote sensing applications. Their ability to produce the interference of the incoming radiation over a broad spectrum of optical wavelength together with the possibility to accommodate the spectral resolution by changing its optical aperture and the sampling step make these instruments interesting for Earth remote sensing. This paper describes the results coming from laboratory experiments and numerical simulations carried out in order to investigate the use of the static interferometers for remote sensing purposes.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A statistically significant data set of backscattering LIDAR and ground-based information has been obtained for the planetary boundary layer (PBL) of Florence (I). The summer LIDAR backscattering data at 532 and 1064 nm have been used to estimate both the size and the number concentration of the urban aerosols in the accumulation mode. This technique seems to be relatively insensitive to the aerosol composition. The time-height evolution of the PBL [mainly the stable (SL) and the mixed (ML) layers] has been plotted, together with the meteorological and ground-based pollution data for the 200 measurement days. The ground-based hourly pollution data (NOx, CO) have been compared with the hourly-averaged 1064 nm backscattering at 25 meters above the ground. A correlation, R equals 0.65, was obtained between NOx and 1064 nm backscattering during the summer period when the traffic aerosols do not grow considerably after their production. The correlation is not significant during winter, when the growth of the particles is much faster. During winter, the RH variations are more important than aerosol number variations to determine the backscattering evolution.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The depolarization-backscatter lidar reported here is developed for application in the polar stratospheric and high- tropospheric studies. That includes the following operations: detection of the stratospheric background aerosol, detection of high-altitude cirrus clouds and polar stratospheric clouds (PSC), detection of Rayleigh backscatter signal for subsequent stratospheric temperature retrieval algorithm application. The lidar is stationed in Sodankyla, Finland (67N) and intended for a 2-year operation at that site. It operates with one Nd:YAG laser with second and third harmonics conversion. The detection of the backscatter atmospheric signal is performed at the fundamental, second and the third harmonics of the laser (1 micrometer, 532 nm and 355 nm), as well as the vibrational Raman backscatter from the nitrogen pumped by the third harmonic at 387 nm. The backscatter signal at 532 nm is detected separately in (p) and (s) polarization.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Ground based LIDAR systems have been operated in Florence (Italy) and in Lauder (New Zealand) during the Lidar In space Technological Experiment (LITE). A very good agreement was found for all the cases of stratospheric aerosol measurements. Only a few correlative cloud measurements are available. For these cases no correlation was found between LITE and ground based lidar data. Our observations seem to indicate that a space borne lidar system could be a powerful tool for a global scale stratospheric aerosol survey. Time and spatial variability of tropospheric clouds make far more critical the use of a space-borne lidar for tropospheric cloud monitoring.

Consideration is given to a novel inversion algorithm to determine the aerosol size distribution from lidar signals obtained at several wavelengths. This algorithm is based on a nonlinear fit of the backscattered measurements using a set of predetermined functions. Size distribution profiles of tropospheric aerosols in different meteorological conditions - clear, hazy, and cloudy atmosphere - are determined on the basis of lidar measurements made in central Switzerland, which is characterized by a specific microclimate. Measurements of stratospheric clouds and aerosols created by the Pinatubo eruption were measured above Berlin and Sodankyla, Finland. These measurements are used to characterize the size distribution of these volcanic aerosols in order to estimate their influence on radiative transfer.

Since January 1988 an Italian backscattering Lidar has been operating in Antarctica, at the Italian base of Terra Nova Bay during the summer 1988 and now at the French base of Dumont d’Urville. The system was built by the research group of IROE of CNR, within a broad research program on atmospheric studies carried out by the Italian National Program for Antarctic Research. Among the principal objectives of this program are to contribute understanding of the Ozone Hole problem and to characterize the radiative properties of clouds by means of Lidar, IR radiometry, local meteorological data and satellite data, in order to better understand the role of clouds in the radiative budget of the planet. A complex DIAL system, to carry out ozone concentration measurements in the Ozone Hole, is presently being built under the Italian-French cooperative program for Antarctica, while an automated Nd-YAG diode pumped Lidar is being designed to operate semiautomatically in an Antarctic winter base, maybe at Dome C, which will be located on the Antarctic Plateau, at 3250 meters altitude.

In the present paper a Lidar (light detection and ranging) system is described. It allows high-speed data acquisition of Lidar signals and meteorological parameters by means of standard instrumentation. The Lidar, controlled by a computer, utilized two laser sources (Nd: Yag and ruby), a modified Ricthey-Chretien telescope and signal detection, storage and real-time monitoring equipment. The whole system was installed in a container for field experiments.

An elastic backscattering lidar and initial results are described. The lidar system has been designed to operate in Antarctica for the Italian National Programme for Antarctic Research. The first field trials were held during the period from 31 December 1987 to 10 February 1988. Data were collected for both tropospheric and stratospheric atmospheric parameters. Tropospheric measurements included the cloud base, optical depth, extinction and backscattering coefficients for clouds, whereas aerosols and the molecular atmosphere were monitored in the stratosphere. The lidar system was also tested for the determination of temperature and density in ranges up to 40 km. Preliminary results of the lidar measurements carried out at Terra Nova Bay are presented. The lidar system is composed of a Nd−YAG laser, a Newtonian telescope and two receiving channels with computer-controlled data acquisition and display equipment. The system is operated in a mobile container specifically designed for the Antarctic environment.

The ability of an infra-red scanner to detect oil spills over the sea surface is discussed on the basis of the first results of the Archimedes experiment 1983. During this experiment an infra-red scanner was flown over two oil spills and a real-time detection was achieved. The IR images were also recorded and processed in order to improve the film-thickness evaluation. An infra-red visible package was then developed which allows a real-time remote sensing of oil spills, eventually from small aircrafts.

Lidar stratospheric aerosol measurements have been carried out at IROE since April 1982, just after the eruption of the Mexican volcano El Chichon. Over two years evolution in stratospheric aerosol loading has been monitored and compared with data collected by other stations. Since the Lidar system can perform an average signature, every minute, also short-time fluctuations in Lidar signatures have been analysed in order to obtain information on stratospheric air turbulence and on the possible presence of gravity waves

Pyrgi, cittadina etrusca e colonia romana, posta sulle coste del Tirreno fra Roma e Civitavecchia, fu visitata e descritta da molti archeologi e topografi del secolo scorso, ma non é stata oggetto di studi topografici recenti. Queste brevi note vogliono illustrare con maggior precisione alcuni punti fondamentali della sua topografia. La ricerca é stata molto facilitata dall'uso delle fotografie aeree esistenti nella Scuola Britannica, una delle quali ripresa nel maggio 1944 é qui riprodotta (pl. III; cfr. fig. 1, dove indichiamo gli elementi ricavati dalla fotografia o accertati sul terreno e, a trattini, le linee fondamentali della topografia moderna).Sul luogo di Pyrgi esiste oggi il castello di Santa Severa (pl. IV, a) al quale conduce una breve strada che si distacca dall'Aurelia al chilometro 52,550. Un recinto medievale di fortificazione con piccole torri sporgenti, costruito in blocchetti quadrangolari di arenaria, fa capo ad un'alta rocca quadrilatera con torri ai quattro angoli. Separate da essa e collegato solamente con un aereo ponte di legno é il torrione maestro cilindrico, in posizione dominante sulla riva del mare.Una memoria del martirio di Santa Severa si legge negli Acta Sanctorum 29 gennaio vol. ii, p. 946 sg. dove si hanno le seguenti determinazioni topografiche: Centumcellae, milliario XXXV ab urbe iuxta mare … in loco qui dicitur Pignus.

The FLIDAR-2 is the result of the researches carried out at IROE-CNR on the remote sensing of the environment by lidar fluorosensors and passive optical sensors.

Chlorophyll plays a fundamental role in the photosynthetic process of living plants, it is therefore obvious that each phenomenon related to chlorophyll may also be related to the photosynthetic process. Since chlorophyll a shows a strong fluorescence emission in the wavelength region between 67 0 nm and 740 nm it is attractive to analyze the potential of laser fluorosensors in the remote sensing of living plants. While a quite large number of papers were devoted to the lidar remote sensing of chlorophyll fluorescence in phytoplancton only few papers has been devoted to the remote sensing of chlorophyll fluorescence in living plants. A research program in this field was started as a part of a national program on agriculture improvement (IPRA Project), the analysis was carried out in the laboratory by means of a lidar simulator and in fields by means of the lidar fluorosensor FLIDAR-2.

Lidar measurements in fog were carried out in the years 1978 and 1980 as a part of the Air Traffic Control Program of the CNR. The aim of these experiments was the measurement of the atmospheric extinction coefficient and the determination of the multiple-scattering effect on this kind of measurements.

This paper describes two different activities carried out at the IROE- CNR on the remote sensing of the sea. The first activity deals with the analysis of the potential of infrared scanners in the real-time monitoring of oil spills over the sea surface and of thermal discontinuities of the sea, particularly in coastal waters. The IROE participated to some field experiments in the last years in the North Sea (Archimedes 83), in the Marano lagoon (November 83, May 85), and in the Northern Adriatic Sea (Adria 84) successfuly testing the ability of small I.R. scanners in the real-time identification of oil spills and thermal discontinuities (1,2,3). The most suitable image processing techniques were also investigated. The second activity concerns the design and construction of an high-resolution spectrometer for the remote sensing of the sea surface in the visible region of the spectrum. The first test of this spectrometer was done during the Adria 84 (3) experiment.

Two years evolution of the stratospheric aerosol loading are presented; this study started after the eruption of the volcano El Chichon. Measurements were carried out in Florence, Italy, from the end of April 1982 to today. The increase of stratospheric aerosols at our latitude up to December 1982-January 1983 and the following decay has been monitored. Scattering Ratio and Integrated Backscattering, from the tropopause to 28 Km height has been corn puted. Due to the characteristics of the IROE Lidar system short time fluctuations in the lidar signatures could be observed, obtaining information on stratospheric inhomogeneities and structures.

A room-temperature broadband FTS was designed for the characterization of the Earth outgoing flux in the FIR spectral range with a resolution of half wavenumber. Laboratory characterization and field measurements (ground-based and balloon) are shown.

International audience; The first spectral measurement of Earth's emitted radiation to space in the wideband range from 100 to 1400 cm-1 with 0.5 cm-1 spectral resolution is presented. The measurement was performed from a stratospheric balloon in tropical region using a Fourier transform spectrometer, during a field campaign held in Brazil in June 2005. The instrument, which has uncooled components including the detector module, is a prototype developed as part of the study for the REFIR (Radiation Explorer in the Far InfraRed) space mission. This paper shows the results of the field campaign with particular attention to the measurement capabilities of the prototype. The results are compared with measurements taken by IASI-balloon (Infrared Atmospheric Sounding Interferometer – Balloon version), aboard the same platform, and with forward model estimations. The infrared signature of clouds is observed in the measurements.