scholarly journals Snow depth on Arctic sea ice from historical in situ data

2018 ◽  
Vol 12 (6) ◽  
pp. 1867-1886 ◽  
Author(s):  
Elena V. Shalina ◽  
Stein Sandven
Keyword(s):  
Standard Deviation ◽  
Snow Depth ◽  
North Pole ◽  
The Arctic ◽  
Laptev Sea ◽  
Average Depth ◽  
Detailed Data ◽  
Marginal Seas ◽  
East Siberian Sea ◽  
Level Ice

Abstract. The snow data from the Soviet airborne expeditions Sever in the Arctic collected over several decades in March, April and May have been analyzed in this study. The Sever data included more measurements and covered a much wider area, particularly in the Eurasian marginal seas (Kara Sea, Laptev Sea, East Siberian Sea and Chukchi Sea), compared to the Soviet North Pole drifting stations. The latter collected data mainly in the central part of the Arctic Basin. The following snow parameters have been analyzed: average snow depth on the level ice (undisturbed snow) height and area of sastrugi, depth of snow dunes attached to ice ridges and depth of snow on hummocks. In the 1970s–1980s, in the central Arctic, the average depth of undisturbed snow was 21.2 cm, the depth of sastrugi (that occupied about 30 % of the ice surface) was 36.2 cm and the average depth of snow near hummocks and ridges was about 65 cm. For the marginal seas, the average depth of undisturbed snow on the level ice varied from 9.8 cm in the Laptev Sea to 15.3 cm in the East Siberian Sea, which had a larger fraction of multiyear ice. In the marginal seas the spatial variability of snow depth was characterized by standard deviation varying between 66 and 100 %. The average height of sastrugi varied from 23 cm to about 32 cm with standard deviation between 50 and 56 %. The average area covered by sastrugi in the marginal seas was estimated to be 36.5 % of the total ice area where sastrugi were observed. The main result of the study is a new snow depth climatology for the late winter using data from both the Sever expeditions and the North Pole drifting stations. The snow load on the ice observed by Sever expeditions has been described as a combination of the depth of undisturbed snow on the level ice and snow depth of sastrugi weighted in proportion to the sastrugi area. The height of snow accumulated near the ice ridges was not included in the calculations because there are no estimates of the area covered by those features from the Sever expeditions. The effect of not including that data can lead to some underestimation of the average snow depth. The new climatology refines the description of snow depth in the central Arctic compared to the results by Warren et al. (1999) and provides additional detailed data in the marginal seas. The snow depth climatology is based on 94 % Sever data and 6 % North Pole data. The new climatology shows lower snow depth in the central Arctic comparing to Warren climatology and more detailed data in the Eurasian seas.

scholarly journals Snow depth on Arctic sea ice from historical in situ data

2017 ◽  
Author(s):  
Elena V. Shalina ◽  
Stein Sandven
Keyword(s):  
Standard Deviation ◽  
Snow Depth ◽  
Arctic Sea Ice ◽  
North Pole ◽  
The Arctic ◽  
Average Height ◽  
Data Set ◽  
Marginal Seas ◽  
East Siberian Sea ◽  
Level Ice

Abstract. In this paper we analyze snow data from Soviet airborne expeditions Sever that was collected in the Arctic around places of landings in March, April and May and cover much wider area than the region of observations of Soviet North Pole drifting stations. Particularly, there were a lot of Sever observations in the Eurasian seas. We investigate the following snow parameters: average snow depth on the level ice, height and area of sastrugi, depth of snow dunes attached to ice ridges and depth of snow on hummocks. We have built new snow depth climatology for the late winter that was calculated using both Sever expedition and North Pole drifting station observations. Our result refines the description of snow depth in the central Arctic and provides detailed information on snow depth in the marginal seas. In the 1970s–80s the snow cover in the central Arctic had the following characteristics: the snow depth of the undisturbed snow was 21.2 cm, the depth of sastrugi (that occupied about 36 % of the ice surface) was 36.2 cm and the depth of snow assembled near the hummocks and ridges was about 65 cm. For the marginal seas Sever observations revealed that the average depth of undisturbed snow on the level ice changed from 9.8 cm in the Laptev Sea to 15.3 cm in the East Siberian Sea, the topmost value in the East Siberian Sea is explained by the highest proportion of multiyear ice there. Observations demonstrated a very high spatial variability of snow depth in the marginal seas characterized by standard deviation changing from 66 to 100 %. The average height of sastrugi in the Eurasian seas varied from 23 cm to about 32 cm with standard deviation from 50 to 56 %. Average area covered by sastrugi in the marginal seas was estimated as 36.5 % of the area of the ice floe where those features have been observed. The snow map introduced here as a new climatology is built from Sever and North Pole data, with the latter amounted to 6.1 % of the whole data set. On the whole, our snow depth map reveals lower values comparing to Warren climatology in the central Arctic and shows refined information for the Eurasian seas.

scholarly journals A combined approach of remote sensing and airborne electromagnetics to determine the volume of polynya sea ice in the Laptev Sea

2013 ◽  
Vol 7 (1) ◽  
pp. 441-473 ◽  
Author(s):  
L. Rabenstein ◽  
T. Krumpen ◽  
S. Hendricks ◽  
C. Koeberle ◽  
C. Haas ◽  
...  
Keyword(s):  
Sea Ice ◽  
Thickness Distribution ◽  
Growth Conditions ◽  
Ice Age ◽  
The Arctic ◽  
Ice Thickness ◽  
Laptev Sea ◽  
Volume Estimate ◽  
Sea Ice Thickness ◽  
Level Ice

Abstract. A combined interpretation of synthetic aperture radar (SAR) satellite images and helicopter electromagnetic (HEM) sea-ice thickness data has provided an estimate of sea-ice volume formed in Laptev Sea polynyas during the winter of 2007/08. The evolution of the surveyed sea-ice areas, which were formed between late December 2007 and middle April 2008, was tracked using a series of SAR images with a sampling interval of 2–3 days. Approximately 160 km of HEM data recorded in April 2008 provided sea-ice thicknesses along profiles that transected sea-ice varying in age from 1–116 days. For the volume estimates, thickness information along the HEM profiles was extrapolated to zones of the same age. The error of areal mean thickness information was estimated to be between 0.2 m for younger ice and up to 1.55 m for older ice, with the primary error source being the spatially limited HEM coverage. Our results have demonstrated that the modal thicknesses and mean thicknesses of level ice correlated with the sea-ice age, but that varying dynamic and thermodynamic sea-ice growth conditions resulted in a rather heterogeneous sea-ice thickness distribution on scales of tens of kilometers. Taking all uncertainties into account, total sea-ice area and volume produced within the entire surveyed area were 52 650 km2 and 93.6 ± 26.6 km3. The surveyed polynya contributed 2.0 ± 0.5% of the sea-ice produced throughout the Arctic during the 2007/08 winter. The SAR-HEM volume estimate compares well with the 112 km3 ice production calculated with a high resolution ocean sea-ice model. Measured modal and mean-level ice thicknesses correlate with calculated freezing-degree-day thicknesses with a factor of 0.87–0.89, which was too low to justify the assumption of homogeneous thermodynamic growth conditions in the area, or indicates a strong dynamic thickening of level ice by rafting of even thicker ice.

Variability in Sea Ice Melt Onset in the Arctic Northeast Passage: Seesaw of the Laptev Sea vs. the East Siberian Sea

2021 ◽  
Author(s):  
Hongjie Liang ◽  
Jie Su
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Sensible Heat Flux ◽  
Storm Tracks ◽  
The Arctic ◽  
Laptev Sea ◽  
Easterly Wind ◽  
East Siberian Sea ◽  
Atmospheric Circulation Indices ◽  
The Laptev Sea

<p>The ice/snow melt onset (MO) is a critical triggering signal for ice-albedo positive feedback in the Arctic. Concerning the Northeast Passage (NEP), for 1979-1998, the MO in the East Siberian Sea (ESS) occurred generally earlier than that in the Laptev Sea (LS). However, for 1999-2018, the LS experienced significantly earlier MO than did the ESS in several years. This phenomenon is identified as the MO Seesaw (MOS), i.e., the MO difference between the LS and ESS. For the positive MOS, storm tracks in May tend to cover the ESS rather than the LS and easterly wind prevails and shifts slightly to a northerly wind in the ESS, resulting in higher surface air temperature (SAT) and total-column water vapor (TWV) and earlier MO in the ESS. For the negative MOS, storm tracks are much stronger in the LS than in the ESS and prominent southerly/southwesterly wind brings warm air from coastal land towards the LS. The effect of the Barents Oscillation (BO) on the MOS could be dated back to April. When the Barents Sea is centered with a low SLP in April, sea ice in the LS would be driven away from the coasts, leading to a lower sea ice area (SIA), which increases the surface latent heat flux and humidifies the overlying atmosphere. Along with an enhanced downward sensible heat flux, earlier regional average MO occurs in the LS. For 1999-2018, the MOS was more closely related to both the local variables and the large-scale atmospheric circulation indices.</p>

Tracing terrestrial organic matter in surface sediments in Laptev Sea and East Siberian Sea: a Rock-Eval pyrolysis approach

2020 ◽  
Author(s):  
Elena Gershelis ◽  
Roman Kashapov ◽  
Alexey Ruban ◽  
Andrey Grin'ko ◽  
Oleg Dudarev ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Surface Sediments ◽  
The Arctic ◽  
Laptev Sea ◽  
Residual Carbon ◽  
Terrestrial Organic Matter ◽  
East Siberian Sea ◽  
Carbon Compounds ◽  
Rock Eval

<p>The East Siberian Arctic shelf (ESAS), the world’s largest continental shelf, receives substantial input of terrestrial organic carbon (TerrOC) both from increasing river discharge and from amplifying coastal erosion. Increasing TerrOC supply directly affects the Arctic marine carbon cycle, and, therefore, the fate of TerrOC upon its translocation to the Arctic continental margin has been the subject of growing interest in recent decades. Previous studies reported a strong decrease in sedimentary bulk TerrOC and terrestrial biomarkers with increasing distance from the coast during cross-shelf transport with much higher extent of degradation in the ESAS nearshore zone. Despite major progress has been made in estimating TerrOC inputs and quantifying its degradation rates in the Arctic land-shelf system, there are still important pieces insufficiently understood. Rock-Eval (RE) pyrolysis contributes to the traditional geochemical interpretations, based on elemental, isotopic and biomarker analyses and provides additional insight into the distribution, source and degradation state of organic carbon compounds of sedimentary organic matter.</p><p>In this study, the analytical approach included the characterization of marine and terrestrial carbon compounds using RE data coupled with organic carbon stable isotope composition. Rock-Eval analyses was performed on over 80 surface sediments samples from the Laptev Sea and western part of the East Siberian Sea collected during Arctic expeditions in 2011-2019. A track of rapidly degrading terrOC in shallow deposits may be traced using the ratios between hydrogen and oxygen indices and from the distribution of labile organic carbon fraction. Our results indicated high content of heavily degraded material with low hydrogen index, high oxygen index and a high content of residual carbon in sediments on the outer shelf of the western Laptev Sea and on the continental slope. Sharp decreasing of oxygen content in the eastern part of Laptev Sea and the western East Siberian Sea marked intensive dilution of degraded carbon with fresher material exported from New Siberian Islands. Furthermore, the RE data indicated a relatively high content of residual carbon (up to 87 %) stored in the studied surface sediments.</p><p>This research is supported by Russian Science Foundation, project # 19-77-00067.</p>

Multi-proxy evaluation of terrestrial organic matter degradation across the East Siberian Arctic Seas

2021 ◽  
Author(s):  
Felipe Matsubara ◽  
Birgit Wild ◽  
Jannik Martens ◽  
Rickard Wennström ◽  
Oleg Dudarev ◽  
...  
Keyword(s):  
Organic Matter ◽  
Coastal Erosion ◽  
River Discharge ◽  
The Arctic ◽  
Laptev Sea ◽  
Terrestrial Organic Matter ◽  
Arctic Seas ◽  
Transport Pathway ◽  
East Siberian Sea ◽  
Siberian Arctic

<p>    Ongoing global warming is expected to accelerate the thaw of permafrost on land and to increase the input of terrigenous organic matter (terrOM) into the Arctic Ocean through coastal erosion and river discharge. Large remobilization of terrOM into the East Siberian Arctic Shelf (ESAS) dominates the organic matter in surface sediments over large parts of the shelf and its degradation contributes to ocean acidification. Previous studies have focused on the source apportionment of terrOM and the releases of CO<sub>2</sub> and CH<sub>4</sub> to the atmosphere from terrOM degradation; this study focuses on its diagenetic state during cross-shelf transport, since degradation is the link between permafrost thawing and greenhouse gases emissions. This study probes the degradation status of different terrOM components across the ESAS using various molecular and isotopic proxies and hence evaluates their differences to infer degradation.</p><p>    High-molecular weight (HMW) lipid compounds and lignin phenols are exclusively produced by terrestrial plants, providing protection, strength and rigidity to the plant structure. Owing to diagenesis, microbial degradation leads to <strong>1)</strong> <strong>loss of functional groups</strong>, thus the ratios of HMW n-alkanoic acids, HMW n-alkanols and sterols relative to HMW n-alkanes decrease; <strong>2)</strong> <strong>reduction of unsaturated to saturated carbons</strong>, so ratios of stanols relative to stenols increase; <strong>3) a higher formation of carboxylic acids in the lignin polymer</strong> and hence<strong> </strong>ratios of acids to aldehydes of vanillyl (Vd and Vl) and syringyl (Sd and Sl) increase.</p><p>    The concentrations of lipid- and lignin-derived products per sediment specific surface area decreased with offshore distance of the samples. During cross-shelf transport, the biomarker degradation proxies showed an increasing degradation for Sd/Sl, Vd/Vl, the “tannin-like” compound 3,5-dihydrobenzoic acid to vanillyl (3,5-Bd/V), β-sitostanol/ β-sitostenol and Carbon Preference Index (CPI) of HMW n-alkanes. Some other proxies showed no clear trend from inner to outer shelf and such inconsistent patterns are currently being investigated to better understand both the usefulness/response of different proxies and of the lability of terrOM in the ESAS. While β-sitostanol/β-sitostenol and CPI HMW n-alkane did not show strong differences between the East Siberian Sea and the Laptev Sea, Vd/Vl and Sd/Sl ratios indicated stronger degradation on the outer Laptev Sea and 3,5-Bd/V ratios indicated stronger degradation in the outer eastern East Siberian Sea. Such differences could reflect source properties of terrOM entering the ESAS, such as differences in source vegetation or transport pathway, i.e. coastal erosion or river discharge.</p>

Methane oxidation processes in sediment of the Laptev and East Siberian Seas indicated from microbial lipids and carbon isotope composition

2021 ◽  
Author(s):  
Weichao Wu ◽  
Henry Holmstrand ◽  
Birgit Wild ◽  
Natalia Shakhova ◽  
Denis Kosmach ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Arctic Ocean ◽  
Water Column ◽  
Marine Sediment ◽  
The Arctic ◽  
Laptev Sea ◽  
Microbial Lipids ◽  
East Siberian Sea ◽  
Siberian Arctic ◽  
The Laptev Sea

<p>The East Siberian Arctic Shelf is an integrated coastal sea system with complex biogeochemical processes influenced by underlying subsea permafrost, hydrates and thermogenic compartments. Methane is released from the marine sediments to the water column, which serves as an interphase between the lithosphere and the atmosphere. Before escaping into water column and atmosphere, methane has potentially experienced extensive aerobic and anaerobic oxidation by microbes in the marine sediment. In particular, the aerobic process is assumed to be dominant in the surface oxic/suboxic marine sediment (upper 1cm) after anaerobic processes in deeper zones. However, these processes are insufficiently understood in sediments of the Arctic Ocean. To probe these, we investigated the microbial lipids and their stable carbon composition in surface marine sediment (upper 1 cm) from two active methane seep areas in the Laptev Sea and the East Siberian Sea.</p><p>The microbial fatty acids (C12 to C18 fatty acids) were relatively enriched in <sup>13</sup>C (δ<sup>13</sup>C -18.8 to -31.2‰) compared to that of dissolved CH<sub>4</sub> in nearby bottom water (-54.6 to -29.7‰). This contrasts to previous reports of strongly depleted δ<sup>13</sup>C signals in microbial lipids (e.g., -100‰) at active marine mid-ocean ridges and mud volcanoes, from quite different ocean areas. The absence of a depleted δ<sup>13</sup>C signal in these general microbial biomarkers suggest that these reflect substrates other than methane such as other parts of the sediment organic matter, indicated by the stronger correlation of δ<sup>13</sup>C between fatty acids and bulk organic carbon than that between fatty acid and CH<sub>4</sub>. However, the putatively more specific biomarkers for aerobic methanotrophic bacteria (mono-unsaturated C16 and C18 fatty acids) show a distinct pattern in the Laptev Sea and East Siberian Sea: C16:1 and C18:1 were enriched in <sup>13</sup>C (up to 4.5 ‰) relative to their saturated analogs in the Laptev Sea; whereas, C18:1 was depleted in <sup>13</sup>C (up to 4.5 ‰) compared to C18 in the East Siberian Sea. This could be because the relative populations of Type I and II methanotrophs were different in the two areas with different carbon assimilation pathways. Our results cannot exclude a slowly active aerobic methanotrophs at methane seeps in the East Siberian Arctic Ocean and thus call for more information from molecular microbiology.</p>

scholarly journals A combined approach of remote sensing and airborne electromagnetics to determine the volume of polynya sea ice in the Laptev Sea

2013 ◽  
Vol 7 (3) ◽  
pp. 947-959 ◽  
Author(s):  
L. Rabenstein ◽  
T. Krumpen ◽  
S. Hendricks ◽  
C. Koeberle ◽  
C. Haas ◽  
...  
Keyword(s):  
Sea Ice ◽  
Thickness Distribution ◽  
Growth Conditions ◽  
Ice Age ◽  
The Arctic ◽  
Ice Thickness ◽  
Laptev Sea ◽  
Volume Estimate ◽  
Sea Ice Thickness ◽  
Level Ice

Abstract. A combined interpretation of synthetic aperture radar (SAR) satellite images and helicopter electromagnetic (HEM) sea-ice thickness data has provided an estimate of sea-ice volume formed in Laptev Sea polynyas during the winter of 2007/08. The evolution of the surveyed sea-ice areas, which were formed between late December 2007 and middle April 2008, was tracked using a series of SAR images with a sampling interval of 2–3 days. Approximately 160 km of HEM data recorded in April 2008 provided sea-ice thicknesses along profiles that transected sea ice varying in age from 1 to 116 days. For the volume estimates, thickness information along the HEM profiles was extrapolated to zones of the same age. The error of areal mean thickness information was estimated to be between 0.2 m for younger ice and up to 1.55 m for older ice, with the primary error source being the spatially limited HEM coverage. Our results have demonstrated that the modal thicknesses and mean thicknesses of level ice correlated with the sea-ice age, but that varying dynamic and thermodynamic sea-ice growth conditions resulted in a rather heterogeneous sea-ice thickness distribution on scales of tens of kilometers. Taking all uncertainties into account, total sea-ice area and volume produced within the entire surveyed area were 52 650 km2 and 93.6 ± 26.6 km3. The surveyed polynya contributed 2.0 ± 0.5% of the sea-ice produced throughout the Arctic during the 2007/08 winter. The SAR-HEM volume estimate compares well with the 112 km3 ice production calculated with a~high-resolution ocean sea-ice model. Measured modal and mean-level ice thicknesses correlate with calculated freezing-degree-day thicknesses with a factor of 0.87–0.89, which was too low to justify the assumption of homogeneous thermodynamic growth conditions in the area, or indicates a strong dynamic thickening of level ice by rafting of even thicker ice.

scholarly journals Change in the time of stable ice formation in the Russian Eastern Arctic seas at the beginning of 21st century

2019 ◽  
Vol 65 (4) ◽  
pp. 389-404
Author(s):  
A. G. Egorov ◽  
E. A. Pavlova
Keyword(s):  
21St Century ◽  
Chukchi Sea ◽  
The Arctic ◽  
Ice Formation ◽  
Laptev Sea ◽  
Late Time ◽  
Arctic Seas ◽  
East Siberian Sea ◽  
Arctic Area ◽  
The Laptev Sea

The purpose of the paper is to analyze the spatial-temporal variability of the time of stable ice formation in the Russian Eastern Arctic seas (the Laptev Sea, the East-Siberian Sea, the Chukchi Sea) in autumn period during 1942–2018, as well as the climatic changes for the last 20 years. The specialized information archive containing the dates of stable ice formation in the elements of regular grid (5 degrees along the parallel and 1 degree along the meridian) based on the AARI observations and satellite imagery was developed. The archive covers 2.2 million km2 of the Arctic area.  During the period from 1942 to 2018 one can reveal 4 consecutive climatic periods: mean dates of ice formation (1942–1953), anomaly early dates of ice formation (1954–1988), mean dates of ice formation (1989–2002) and anomaly late dates of ice formation (2003–2018). Notice that the ice formation regime in the 21st century, by its abnormality, differs radically from that in the 20th one. For the total area of three seas, the mean date of ice formation in the 21st century became 21 days later than in the 20th one. The most significant changes (up to 45 days) take place in the Chukchi Sea. The transformation of the ice formation regime typical for the 1942–2002 to the regime of 2003–2018 happened rather quickly — approximately within 5 years. The anomaly late time of ice formation began in the Chukchi Sea in 2003, and then this anomaly propagated to the East-Siberian Sea (in 2005) and to the Laptev Sea (in 2009). The 16-year period of anomaly late ice formation consists of three 5–6-year periods depending on location of the maximum anomalies: 2003–2008 (the Chukchi Sea), 2009–2013 (the Laptev Sea), and 2014–2018 (the Chukchi Sea again). As a consequence, the period of autumn warming, which has begun in 2003, is going on till present, and the latest date of ice formation in the eastern Arctic seas for the entire 77-year period was registered just in 2018. 

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