Variability of light transmission through Arctic land-fast sea ice during spring

Abstract. The amount of solar radiation transmitted through Arctic sea ice is determined by the thickness and physical properties of snow and sea ice. Light transmittance is highly variable in space and time since thickness and physical properties of snow and sea ice are highly heterogeneous on variable time and length scales. We present field measurements of under-ice irradiance along transects under undeformed land-fast sea ice at Barrow, Alaska (March, May, and June 2010). The measurements were performed with a spectral radiometer mounted on a floating under-ice sled. The objective was to quantify the spatial variability of light transmittance through snow and sea ice, and to compare this variability along its seasonal evolution. Along with optical measurements, snow depth, sea ice thickness, and freeboard were recorded, and ice cores were analyzed for chlorophyll a and particulate matter. Our results show that snow cover variability prior to onset of snow melt causes as much relative spatial variability of light transmittance as the contrast of ponded and white ice during summer. Both before and after melt onset, measured transmittances fell in a range from one third to three times the mean value. In addition, we found a twentyfold increase of light transmittance as a result of partial snowmelt, showing the seasonal evolution of transmittance through sea ice far exceeds the spatial variability. However, prior melt onset, light transmittance was time invariant and differences in under-ice irradiance were directly related to the spatial variability of the snow cover.

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Variability of light transmission through Arctic land-fast sea ice during spring

The Cryosphere Discussions ◽

10.5194/tcd-6-4363-2012 ◽

2012 ◽

Vol 6 (5) ◽

pp. 4363-4385 ◽

Cited By ~ 6

Author(s):

M. Nicolaus ◽

C. Petrich ◽

S. R. Hudson ◽

M. A. Granskog

Keyword(s):

Sea Ice ◽

Spatial Variability ◽

Physical Properties ◽

Large Scale ◽

Light Transmission ◽

Ice Cores ◽

Arctic Sea Ice ◽

Optical Measurements ◽

Light Transmittance ◽

Seasonal Evolution

Abstract. The amount of solar radiation transmitted through Arctic sea ice is determined by the thickness and physical properties of snow and sea ice. Light transmittance is highly variable in space and time since thickness and physical properties of snow and sea ice are highly heterogeneous on variable time and length scales. We present field measurements of under-ice irradiance along repeated (March, May, June 2010) transects under un-deformed land-fast sea ice at Barrow, Alaska. The objective was to quantify seasonal evolution and spatial variability of light transmittance through snow and sea ice. Along with optical measurements, snow depth, sea ice thickness, and freeboard were recorded, and ice cores were analyzed for Chlorophyll a and particulate matter. Our results show that snow cover variability prior to onset of snow melt may cause as much spatial variability of relative light transmittance as the contrast of ponded and white ice during summer. In both instances, a spatial variability of up to three times above and below the mean was measured. In addition, we found a thirtyfold increase of light transmittance as a result of partial snowmelt. Hence, the seasonal evolution of transmittance through sea ice exceeded the spatial variability. Nevertheless, more comprehensive under-ice radiation measurements are needed for a more generalized and large-scale understanding of the under-ice energy budget for physical, biological, and geochemical applications.

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Seasonal Evolution of Light Transmission Distributions Through Arctic Sea Ice

Journal of Geophysical Research Oceans ◽

10.1029/2018jc014833 ◽

2019 ◽

Vol 124 (8) ◽

pp. 5418-5435 ◽

Cited By ~ 7

Author(s):

Christian Katlein ◽

Stefanie Arndt ◽

H. Jakob Belter ◽

Giulia Castellani ◽

Marcel Nicolaus

Keyword(s):

Sea Ice ◽

Light Transmission ◽

Arctic Sea Ice ◽

Seasonal Evolution ◽

Arctic Sea

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Seasonal cycle of solar energy fluxes through Arctic sea ice

The Cryosphere Discussions ◽

10.5194/tcd-8-2923-2014 ◽

2014 ◽

Vol 8 (3) ◽

pp. 2923-2956

Author(s):

S. Arndt ◽

M. Nicolaus

Keyword(s):

Heat Flux ◽

Sea Ice ◽

Light Transmission ◽

Reanalysis Data ◽

Arctic Sea Ice ◽

Light Transmittance ◽

The Arctic ◽

Energy Fluxes ◽

Solar Heat ◽

Arctic Sea

Abstract. Arctic sea ice has not only decreased considerably during the last decades, but also changed its physical properties towards a thinner and more seasonal cover. These changes strongly impact the energy budget and might affect the ice-associated ecosystem of the Arctic. But until now, it is not possible to quantify shortwave energy fluxes through sea ice sufficiently well over large regions and during different seasons. Here, we present a new parameterization of light transmittance through sea ice for all seasons as a function of variable sea ice properties. The annual maximum solar heat flux of 30 × 105 J m−2 occurs in June, then also matching the under ice ocean heat flux. Furthermore, our results suggest that 96% of the total annual solar heat input occurs from May to August, during four months only. Applying the new parameterization on remote sensing and reanalysis data from 1979 to 2011, we find an increase in light transmission of 1.5% a−1 for all regions. Sensitivity studies reveal that the results strongly depend on the timing of melt onset and the correct classification of ice types. Hence, these parameters are of great importance for quantifying under-ice radiation fluxes and the uncertainty of this parameterization. Assuming a two weeks earlier melt onset, the annual budget increases by 20%. Continuing the observed transition from Arctic multi- to first year sea ice could increase light transmittance by another 18%. Furthermore, the increase in light transmission directly contributes to an increase in internal and bottom melt of sea ice, resulting in a positive transmittance-melt feedback process.

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Seasonal variations in the properties and structural composition of sea ice and snow cover in the Bellingshausen and Amundsen Seas, Antarctica

Journal of Glaciology ◽

10.3189/s0022143000002902 ◽

1997 ◽

Vol 43 (143) ◽

pp. 138-151 ◽

Cited By ~ 2

Author(s):

M. O. Jeffries ◽

K. Morris ◽

W.F. Weeks ◽

A. P. Worby

Keyword(s):

Sea Ice ◽

Isotopic Composition ◽

Snow Cover ◽

Sea Water ◽

Ice Cores ◽

Ice Cover ◽

Snow Accumulation ◽

Ice Formation ◽

Frazil Ice ◽

Core Sets

AbstractSixty-three ice cores were collected in the Bellingshausen and Amundsen Seas in August and September 1993 during a cruise of the R.V. Nathaniel B. Palmer. The structure and stable-isotopic composition (18O/16O) of the cores were investigated in order to understand the growth conditions and to identify the key growth processes, particularly the contribution of snow to sea-ice formation. The structure and isotopic composition of a set of 12 cores that was collected for the same purpose in the Bellingshausen Sea in March 1992 are reassessed. Frazil ice and congelation ice contribute 44% and 26%, respectively, to the composition of both the winter and summer ice-core sets, evidence that the relatively calm conditions that favour congelation-ice formation are neither as common nor as prolonged as the more turbulent conditions that favour frazil-ice growth and pancake-ice formation. Both frazil- and congelation-ice layers have an av erage thickness of 0.12 m in winter, evidence that congelation ice and pancake ice thicken primarily by dynamic processes. The thermodynamic development of the ice cover relies heavily on the formation of snow ice at the surface of floes after sea water has flooded the snow cover. Snow-ice layers have a mean thickness of 0.20 and 0.28 m in the winter and summer cores, respectively, and the contribution of snow ice to the winter (24%) and summer (16%) core sets exceeds most quantities that have been reported previously in other Antarctic pack-ice zones. The thickness and quantity of snow ice may be due to a combination of high snow-accumulation rates and snow loads, environmental conditions that favour a warm ice cover in which brine convection between the bottom and top of the ice introduces sea water to the snow/ice interface, and bottom melting losses being compensated by snow-ice formation. Layers of superimposed ice at the top of each of the summer cores make up 4.6% of the ice that was examined and they increase by a factor of 3 the quantity of snow entrained in the ice. The accumulation of superimposed ice is evidence that melting in the snow cover on Antarctic sea-ice floes ran reach an advanced stage and contribute a significant amount of snow to the total ice mass.

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

Journal of Geophysical Research Biogeosciences ◽

10.1002/2016jg003626 ◽

2017 ◽

Vol 122 (6) ◽

pp. 1486-1505 ◽

Cited By ~ 25

Author(s):

Hanna M. Kauko ◽

Torbjørn Taskjelle ◽

Philipp Assmy ◽

Alexey K. Pavlov ◽

C. J. Mundy ◽

...

Keyword(s):

Sea Ice ◽

Light Transmission ◽

Arctic Sea Ice ◽

Ice Algae ◽

Arctic Sea

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Multi-frequency polarimetric microwave observations of snow cover on first-year Arctic sea ice

2015 IEEE International Geoscience and Remote Sensing Symposium (IGARSS) ◽

10.1109/igarss.2015.7327015 ◽

2015 ◽

Author(s):

Vishnu Nandan ◽

John J. Yackel ◽

Jagvijay P. S. Gill ◽

Torsten Geldsetzer ◽

Mark C. Fuller

Keyword(s):

Sea Ice ◽

Snow Cover ◽

Arctic Sea Ice ◽

First Year ◽

Arctic Sea

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Dissolved Neodymium Isotopes Trace Origin and Spatiotemporal Evolution of Modern Arctic Sea Ice

10.5194/egusphere-egu2020-7782 ◽

2020 ◽

Author(s):

Georgi Laukert ◽

Dorothea Bauch ◽

Ilka Peeken ◽

Thomas Krumpen ◽

Kirstin Werner ◽

...

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Surface Waters ◽

Ice Cores ◽

Arctic Sea Ice ◽

The Arctic ◽

Spatiotemporal Evolution ◽

Arctic Sea ◽

The Arctic Ocean ◽

Ice Floes

The lifetime and thickness of Arctic sea ice have markedly decreased in the recent past. This affects Arctic marine ecosystems and the biological pump, given that sea ice acts as platform and transport medium of marine and atmospheric nutrients. At the same time sea ice reduces light penetration to the Arctic Ocean and restricts ocean/atmosphere exchange. In order to understand the ongoing changes and their implications, reconstructions of source regions and drift trajectories of Arctic sea ice are imperative. Automated ice tracking approaches based on satellite-derived sea-ice motion products (e.g. ICETrack) currently perform well in dense ice fields, but provide limited information at the ice edge or in poorly ice-covered areas. Radiogenic neodymium (Nd) isotopes (&#949;Nd) have the potential to serve as a chemical tracer of sea-ice provenance and thus may provide information beyond what can be expected from satellite-based assessments. This potential results from pronounced &#949;Nd differences between the distinct marine and riverine sources, which feed the surface waters of the different sea-ice formation regions. We present the first dissolved (< 0.45 &#181;m) Nd isotope and concentration data obtained from optically clean Arctic first- and multi-year sea ice (ice cores) collected from different ice floes across the Fram Strait during the RV POLARSTERN cruise PS85 in 2014. Our data confirm the preservation of the seawater &#949;Ndsignatures in sea ice despite low Nd concentrations (on average ~ 6 pmol/kg) resulting from efficient brine rejection. The large range in &#949;Nd signatures (~ -10 to -30) mirrors that of surface waters in various parts of the Arctic Ocean, indicating that differences between ice floes but also between various sections in an individual ice core reflect the origin and evolution of the sea ice over time. Most ice cores have &#949;Nd signatures of around -10, suggesting that the sea ice was formed in well-mixed waters in the central Arctic Ocean and transported directly to the Fram Strait via the Transpolar Drift. Some ice cores, however, also revealed highly unradiogenic signatures (&#949;Nd < ~ -15) in their youngest (bottom) sections, which we attribute to incorporation of meltwater from Greenland into newly grown sea ice layers. Our new approach facilitates the reconstruction of the origin and spatiotemporal evolution of isolated sea-ice floes in the future Arctic.

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Structural characteristics and development of sea ice in the western Ross Sea

Antarctic Science ◽

10.1017/s0954102093000094 ◽

1993 ◽

Vol 5 (1) ◽

pp. 63-75 ◽

Cited By ~ 31

Author(s):

M. O. Jeffries ◽

W. F. Weeks

Keyword(s):

Sea Ice ◽

Internal Structure ◽

Ross Sea ◽

Ice Cores ◽

Arctic Sea Ice ◽

Weddell Sea ◽

The Arctic ◽

Ice Thickness ◽

Pack Ice ◽

Western Ross Sea

The internal structure of ice cores from western Ross Sea pack ice floes showed considerable diversity. Snow-ice formation made a small, but significant contribution to ice growth. Frazil ice was common and its growth clearly occurred during both the pancake cycle and deformation events. Congelation ice was also common, in both its crystallographically aligned and non-aligned varieties. Platelet ice was found in only one core next to the Drygalski Ice Tongue, an observation adding to the increasing evidence that this unusual ice type occurs primarily in coastal pack ice near ice tongues and ice shelves. The diverse internal structure of the floes indicates that sea ice development in the Ross Sea is as complex as that in the Weddell Sea and more complex than in the Arctic. The mean ice thickness at the ice core sites varied between 0.71 m and 1.52 m. The thinnest ice generally occurred in the outer pack ice zone. Regardless of latitude, the ice thickness data are further evidence that Antarctic sea ice is thinner than Arctic sea ice.

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