A Fourier transform spectroradiometer for ground-based remote
sensing of the atmospheric downwelling long-wave radiance

Bianchini, Giovanni; Castagnoli, F.; Natale, Gianluca Di; Palchetti, Luca

doi:10.5194/amt-2018-233

Cited by 1 publication

(4 citation statements)

References 14 publications

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“…The Radiation in Far Infrared -Prototype for Applications and Development (REFIR-PAD) (Bianchini et al, 2019) is a Fourier transform spectroradiometer (FTS) that detects the spectral radiance emitted by the atmosphere in the broad band between 100-1500 cm −1 (6-100 µm) with a spectral resolution of 0.4 cm −1 . REFIR-PAD was installed inside the PHYSICS shelter at Concordia base at Dome C, where it views the atmosphere through a 1.5 m chimney.…”

Section: Refir-pad Fourier Spectroradiometer and Tropospheric Backsca...mentioning

confidence: 99%

“…The total field of view (FOV) is equal to 115 mrad, with a internal beam divergence of about 0.00087 sr and a throughput of about 0.0035 cm 2 sr. The complete instrument specifications and description are thoroughly described in Bianchini et al (2006Bianchini et al ( , 2019 and Palchetti et al (2015).…”

Section: Refir-pad Fourier Spectroradiometer and Tropospheric Backsca...mentioning

confidence: 99%

“…is the internal solid angle of the beam divergence which determines the formulation of the instrument line shape (ILS) and it was also fitted to take into account the effect of self-apodization. Finally, β is a scale factor on the frequency grid introduced to compensate for possible drift of the REFIR-PAD laser reference and for the shift due to the internal finite aperture (Bianchini et al, 2019;Di Natale et al, 2021). SACR uses a Levenberg-Marquardt iterative algorithm to minimize the cost function (Rodgers, 2000) as follows:…”

Section: Retrieval Of the Particle Size Distributions From Refir-pad ...mentioning

confidence: 99%

“…with y and x a being vectors of the measurements and a priori parameters, respectively. S y denotes the variance-covariance matrices (VCMs) of the measurements and contains the REFIR-PAD spectral noise, which is given by the square sum of the noise equivalent to signal ratio (NESR) and the calibration error (Bianchini et al, 2019). The NESR is calculated from the standard deviation of the four uncalibrated spectra provided during each REFIR-PAD measurement; the calibration error is due to the uncertainty on the temperature of the three black bodies (hot, cold, and reference) used for the radiance calibration procedure.…”

Section: Retrieval Of the Particle Size Distributions From Refir-pad ...mentioning

confidence: 99%

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Consistency test of precipitating ice cloud retrieval properties obtained from the observations of different instruments operating at Dome C (Antarctica)

Natale

Turner²,

Bianchini³

et al. 2022

Atmos. Meas. Tech.

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Abstract. Selected case studies of precipitating ice clouds at Dome C (Antarctic Plateau) were used to test a new approach for the estimation of ice cloud reflectivity at 24 GHz (12.37 mm wavelength) using ground-based far infrared spectral measurements from the REFIR-PAD Fourier transform spectroradiometer and backscattering/depolarization lidar profiles. The resulting reflectivity was evaluated with the direct reflectivity measurements provided by a co-located micro rain radar (MRR) operating at 24 GHz, that was able to detect falling crystals with large particle size, typically above 600 µm. To obtain the 24 GHz reflectivity, we used the particle effective diameter and the cloud optical depth retrieved from the far infrared spectral radiances provided by REFIR-PAD and the tropospheric co-located backscattering lidar to calculate the modal radius and the intercept of the particle size distribution. These parameters spanned in the wide ranges between 570–2400 µm and 10−2–104 cm−5, respectively. The retrieved effective sizes and optical depths mostly varied in the ranges 70–250 µm and 0.1–5, respectively. From these parameters, the theoretical reflectivity at 24 GHz was obtained by integrating the size distribution over different cross sections for various habit crystals provided by Eriksson et al. (2018) databases. From the comparison with the radar reflectivity measurements, we found that the hexagonal column-like habits, the columnar crystal aggregates, and the 5/6 branches bullet rosettes showed the best agreement with the MRR observations. The dispersion coefficient of the crystal particle size distribution was assumed in the range 0–2 according to the temperature dependence found in previous studies. The retrieved values of the intercept and slope were found in good agreement with these studies. The presence of the inferred habits was confirmed by the crystal images taken by the ICE-CAMERA, operating in proximity of REFIR-PAD and the MRR. In particular, the occurrence of hexagonal column-like ice crystals was confirmed by the presence of 22∘ solar halos, detected by the HALO-CAMERA. The average crystal lengths obtained from the retrieved size distribution were also compared to those estimated from the ICE-CAMERA images. The agreement between the two results confirmed that the retrieved parameters of the particle size distributions correctly reproduced the observations.

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Section: Refir-pad Fourier Spectroradiometer and Tropospheric Backsca...mentioning

confidence: 99%

Section: Refir-pad Fourier Spectroradiometer and Tropospheric Backsca...mentioning

confidence: 99%

Section: Retrieval Of the Particle Size Distributions From Refir-pad ...mentioning

confidence: 99%

Section: Retrieval Of the Particle Size Distributions From Refir-pad ...mentioning

confidence: 99%

See 2 more Smart Citations

Consistency test of precipitating ice cloud retrieval properties obtained from the observations of different instruments operating at Dome C (Antarctica)

Natale

Turner²,

Bianchini³

et al. 2022

Atmos. Meas. Tech.

View full text Add to dashboard Cite

show abstract

A Fourier transform spectroradiometer for ground-based remote sensing of the atmospheric downwelling long-wave radiance

Cited by 1 publication

References 14 publications

Consistency test of precipitating ice cloud retrieval properties obtained from the observations of different instruments operating at Dome C (Antarctica)

Consistency test of precipitating ice cloud retrieval properties obtained from the observations of different instruments operating at Dome C (Antarctica)

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