Measurement of the specific surface area of snow using infrared reflectance in an integrating sphere at 1310 and 1550 nm

Gallet, Jean‐Charles; Dominé, Florent; Zender, C. S.; Picard, Ghislain

doi:10.5194/tc-3-167-2009

Cited by 233 publications

(414 citation statements)

References 53 publications

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“…This instrument measures the reflectance (at 1300 and 805 nm) of the snow face in drilled holes with a centimeter vertical resolution. The reflectances are converted into specific surface area (SSA) using a complex algorithm ) that was validated with independent measurements (Gallet et al, 2009). The accuracy was estimated to 12 %.…”

Section: Snow Propertiesmentioning

confidence: 99%

Influence of meter-scale wind-formed features on the variability of the microwave brightness temperature around Dome C in Antarctica

et al. 2014

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Abstract. Space-borne passive microwave radiometers are widely used to retrieve information in snowy regions by exploiting the high sensitivity of microwave emission to snow properties. For the Antarctic Plateau, many studies presenting retrieval algorithms or numerical simulations have assumed, explicitly or not, that the subpixel-scale heterogeneity is negligible and that the retrieved properties were representative of whole pixels. In this paper, we investigate the spatial variations of brightness temperature over a range of a few kilometers in the Dome C area. Using ground-based radiometers towed by a vehicle, we collected brightness temperature at 11, 19 and 37 GHz at horizontal and vertical polarizations along transects with meter resolution. The most remarkable observation was a series of regular undulations of the signal with a significant amplitude reaching 10 K at 37 GHz and a quasi-period of 30-50 m. In contrast, the variability at longer length scales seemed to be weak in the investigated area, and the mean brightness temperature was close to SSM/I and WindSat satellite observations for all the frequencies and polarizations. To establish a link between the snow characteristics and the microwave emission undulations, we collected detailed snow grain size and density profiles at two points where opposite extrema of brightness temperature were observed. Numerical simulations with the DMRT-ML microwave emission model revealed that the difference in density in the upper first meter explained most of the brightness temperature variations. In addition, we found that these variations of density near the surface were linked to snow hardness. Patches of hard snow -probably formed by wind compaction -were clearly visible and covered as much as 39 % of the investigated area. Their brightness temperature was higher than in normal areas. This result implies that the microwave emission measured by satellites over Dome C is more complex than expected and very likely depends on the year-to-year areal proportion of the two different types of snow.

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Section: Snow Propertiesmentioning

confidence: 99%

Influence of meter-scale wind-formed features on the variability of the microwave brightness temperature around Dome C in Antarctica

et al. 2014

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“…The IceCube instrument (A2 Photonic Sensors, Grenoble, France) (Fig. 3g, h) (Zuanon, 2013) is similar to DUFISSS presented by Gallet et al (2009), but it uses only 1310 nm wavelength laser for reflectance measurements. Measurement procedure includes calibration, snow sampling, measurement of the snow samples with the instrument, and conversion of measured values to SSA with software.…”

Section: Specific Surface Areamentioning

confidence: 99%

Sodankylä manual snow survey program

Leppänen

Kontu

Hannula

et al. 2016

Geosci. Instrum. Method. Data Syst.

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Abstract. The manual snow survey program of the Arctic Research Centre of the Finnish Meteorological Institute (FMI-ARC) consists of numerous observations of natural seasonal taiga snowpack in Sodankylä, northern Finland. The easily accessible measurement areas represent the typical forest and soil types in the boreal forest zone. Systematic snow measurements began in 1909 with snow depth (HS) and snow water equivalent (SWE). In 2006 the manual snow survey program expanded to cover snow macro-and microstructure from regular snow pits at several sites using both traditional and novel measurement techniques. Present-day snow pit measurements include observations of HS, SWE, temperature, density, stratigraphy, grain size, specific surface area (SSA) and liquid water content (LWC). Regular snow pit measurements are performed weekly during the snow season. Extensive time series of manual snow measurements are important for the monitoring of temporal and spatial changes in seasonal snowpack. This snow survey program is an excellent base for the future research of snow properties.

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“…A proper validation of these parameterizations is, however, still lacking. The development of new observation techniques for radiation (Nicolaus et al, 2010b;Hudson et al, 2012) and snow and ice properties (Arnaud et al, 2011;Gallet at al., 2009) has the potential to facilitate the future collection of high quality and complete data sets. There is also need for more realistic melt pond parameterizations, which, in addition to albedo, account for the latent heat, which has impact on the timing of autumn freeze-up.…”

Section: Main Advances and Remaining Challenges In Individual Researcmentioning

confidence: 99%

Advances in understanding and parameterization of small-scale physical processes in the marine Arctic climate system: a review

et al. 2014

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Abstract. The Arctic climate system includes numerous highly interactive small-scale physical processes in the atmosphere, sea ice, and ocean. During and since the International Polar Year 2007-2009, significant advances have been made in understanding these processes. Here, these recent advances are reviewed, synthesized, and discussed. In atmospheric physics, the primary advances have been in cloud physics, radiative transfer, mesoscale cyclones, coastal, and fjordic processes as well as in boundary layer processes and surface fluxes. In sea ice and its snow cover, advances have been made in understanding of the surface albedo and its relationships with snow properties, the internal structure of sea ice, the heat and salt transfer in ice, the formation of superimposed ice and snow ice, and the small-scale dynamics of sea ice. For the ocean, significant advances have been related to exchange processes at the ice-ocean interface, diapycnal mixing, double-diffusive convection, tidal currents and diurnal resonance. Despite this recent progress, some of these small-scale physical processes are still not sufficiently understood: these include wave-turbulence interactions in the atmosphere and ocean, the exchange of heat and salt at the ice-ocean interface, and the mechanical weakening of sea ice. Many other processes are reasonably well understood as stand-alone processes but the challenge is to understand their interactions with and impacts and feedbacks on other processes. Uncertainty in the parameterization of small-scale processes continues to be among the greatest challenges facing climate modelling, particularly in high latitudes. Further improvements in parameterization require new year-round field campaigns on the Arctic sea ice, closely combined with satellite remote sensing studies and numerical model experiments.

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Measurement of the specific surface area of snow using infrared reflectance in an integrating sphere at 1310 and 1550 nm

Cited by 233 publications

References 53 publications

Influence of meter-scale wind-formed features on the variability of the microwave brightness temperature around Dome C in Antarctica

Influence of meter-scale wind-formed features on the variability of the microwave brightness temperature around Dome C in Antarctica

Sodankylä manual snow survey program

Advances in understanding and parameterization of small-scale physical processes in the marine Arctic climate system: a review

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