Modeling of radiation transport in coupled atmosphere-snow-ice-ocean systems

Stamnes, Knut; Hamre, Børge; Stamnes, Jakob J.; Ryzhikov, G.; Biryulina, M.; Mahoney, Robert; Hauss, B.; Sei, Alain

doi:10.1016/j.jqsrt.2010.06.006

Cited by 38 publications

(39 citation statements)

References 19 publications

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“…As for the snow, IOPs are obtained using the parameterizations defined by Stamnes et al . [] based on the size and volume fraction of the inclusions. Absorption coefficients corresponding to the measured absorption by particulate and dissolved matter (Figure h) were added to the ice.…”

Section: Methodsmentioning

confidence: 99%

Windows in Arctic sea ice: Light transmission and ice algae in a refrozen lead

et al. 2017

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The Arctic Ocean is rapidly changing from thicker multiyear to thinner first‐year ice cover, with significant consequences for radiative transfer through the ice pack and light availability for algal growth. A thinner, more dynamic ice cover will possibly result in more frequent leads, covered by newly formed ice with little snow cover. We studied a refrozen lead (≤0.27 m ice) in drifting pack ice north of Svalbard (80.5–81.8°N) in May–June 2015 during the Norwegian young sea ICE expedition (N‐ICE2015). We measured downwelling incident and ice‐transmitted spectral irradiance, and colored dissolved organic matter (CDOM), particle absorption, ultraviolet (UV)‐protecting mycosporine‐like amino acids (MAAs), and chlorophyll a (Chl a) in melted sea ice samples. We found occasionally very high MAA concentrations (up to 39 mg m−3, mean 4.5 ± 7.8 mg m−3) and MAA to Chl a ratios (up to 6.3, mean 1.2 ± 1.3). Disagreement in modeled and observed transmittance in the UV range let us conclude that MAA signatures in CDOM absorption spectra may be artifacts due to osmotic shock during ice melting. Although observed PAR (photosynthetically active radiation) transmittance through the thin ice was significantly higher than that of the adjacent thicker ice with deep snow cover, ice algal standing stocks were low (≤2.31 mg Chl a m−2) and similar to the adjacent ice. Ice algal accumulation in the lead was possibly delayed by the low inoculum and the time needed for photoacclimation to the high‐light environment. However, leads are important for phytoplankton growth by acting like windows into the water column.

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Section: Methodsmentioning

confidence: 99%

Windows in Arctic sea ice: Light transmission and ice algae in a refrozen lead

et al. 2017

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“…Brine pockets are represented by spheres of pure sea water with a given radius and volume fraction, and air pockets are likewise represented by spheres of air. Their inherent optical properties are calculated using a parameterization based on Mie calculations (Stamnes et al, 2011).…”

Section: Softwarementioning

confidence: 99%

Modelling radiative transfer through ponded first-year Arctic sea ice with a plane-parallel model

et al. 2017

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Abstract. Under-ice irradiance measurements were done on ponded first-year pack ice along three transects during the ICE12 expedition north of Svalbard. Bulk transmittances (400-900 nm) were found to be on average 0.15-0.20 under bare ice, and 0.39-0.46 under ponded ice. Radiative transfer modelling was done with a plane-parallel model. While simulated transmittances deviate significantly from measured transmittances close to the edge of ponds, spatially averaged bulk transmittances agree well. That is, transect-average bulk transmittances, calculated using typical simulated transmittances for ponded and bare ice weighted by the fractional coverage of the two surface types, are in good agreement with the measured values. Radiative heating rates calculated from model output indicates that about 20 % of the incident solar energy is absorbed in bare ice, and 50 % in ponded ice (35 % in pond itself, 15 % in the underlying ice). This large difference is due to the highly scattering surface scattering layer (SSL) increasing the albedo of the bare ice.

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“…For instance, the retrieval of grain size and surface temperature leads to information that can be used to map the snow melting state, valuable to understand the mass balance of the ice sheets Lyapustin et al, 2009). Passive optical sensors are employed in this regard to evince the optical and microphysical properties of snow grains from measurements of snow reflectance, and advanced algorithms have been applied to data collected by the MODerate-resolution Imaging Spectroradiometer (MODIS) and sensors with similar capabilities Aoki et al, 2007;Jin et al, 2008;Stamnes et al, 2011). However, the limited information content of such measurements translates into uniqueness problems during the retrieval process, with the result that operational snow products are still limited to snow covered area and albedo (with the exception of the recent addition to MODIS of the dust radiative forcing product as described in Painter et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Photopolarimetric retrievals of snow properties

2015

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Abstract. Polarimetric observations of snow surfaces, obtained in the 410-2264 nm range with the Research Scanning Polarimeter onboard the NASA ER-2 high-altitude aircraft, are analyzed and presented. These novel measurements are of interest to the remote sensing community because the overwhelming brightness of snow plagues aerosol and cloud retrievals based on airborne and spaceborne total reflection measurements. The spectral signatures of the polarized reflectance of snow are therefore worthwhile investigating in order to provide guidance for the adaptation of algorithms currently employed for the retrieval of aerosol properties over soil and vegetated surfaces. At the same time, the increased information content of polarimetric measurements allows for a meaningful characterization of the snow medium. In our case, the grains are modeled as hexagonal prisms of variable aspect ratios and microscale roughness, yielding retrievals of the grains' scattering asymmetry parameter, shape and size. The results agree with our previous findings based on a more limited data set, with the majority of retrievals leading to moderately rough crystals of extreme aspect ratios, for each scene corresponding to a single value of the asymmetry parameter.

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Modeling of radiation transport in coupled atmosphere-snow-ice-ocean systems

Cited by 38 publications

References 19 publications

Windows in Arctic sea ice: Light transmission and ice algae in a refrozen lead

Windows in Arctic sea ice: Light transmission and ice algae in a refrozen lead

Modelling radiative transfer through ponded first-year Arctic sea ice with a plane-parallel model

Photopolarimetric retrievals of snow properties

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