The MOSAiC ice floe: sediment-laden survivor from the Siberian shelf

Krumpen, Thomas; Birrien, Florent; Kauker, Frank; Rackow, Thomas; Albedyll, Luisa von; Angelopoulos, Michael; Belter, Hans Jakob; Bessonov, Vladimir; Damm, Ellen; Dethloff, Klaus; Haapala, Jari; Haas, Christian; Harris, Carolynn; Hendricks, Stefan; Hoelemann, Jens; Hoppmann, Mario; Kaleschke, Lars; Kärcher, Michael; Kolabutin, Nikolai; Lei, Ruibo; Lenz, Josefine; Morgenstern, Anne; Nicolaus, Marcel; Nixdorf, Uwe; Petrovsky, Tomash; Rabe, Benjamin; Rabenstein, Lasse; Rex, Markus; Ricker, Robert; Rohde, Jan; Shimanchuk, Egor; Singha, Suman; Smolyanitsky, Vasily; Sokolov, Vladimir; Stanton, Tim; Timofeeva, Anna; Tsamados, Michel; Watkins, Daniel

doi:10.5194/tc-14-2173-2020

Cited by 71 publications

(59 citation statements)

References 27 publications

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“…The southern Laptev Sea features extensive landfast ice regions, although the landfast ice season is getting progressively shorter (Selyuzhenok et al, 2015). Sea ice thickness of the mobile ice cover decreases (Belter et al, 2020) and late winter ice export increases (Krumpen et al, 2013), which preconditions for early spring sea ice anomalies and overall results in longer open water seasons (Itkin and Krumpen, 2017;Krumpen et al, 2020). In summary, the Siberian shelves provide a non-uniform image regarding their sea ice conditions and retreat, which however play an important role in determining how wind can affect the fate and pathways of river runoff.…”

Section: Introductionmentioning

confidence: 99%

On the Variability of Stratification in the Freshwater-Influenced Laptev Sea Region

et al. 2020

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In this paper, we investigate the seasonal and spatial variability of stratification on the Siberian shelves with a case study from the Laptev Sea based on shipboard hydrographic measurements, year-round oceanographic mooring records from 2013 to 2014 and chemical tracer-based water mass analyses. In summer 2013, weak onshore-directed winds caused spreading of riverine waters throughout much of the eastern and central shelf. In contrast, strong southerly winds in summer 2014 diverted much of the freshwater to the northeast, which resulted in 50% less river water and significantly weaker stratification on the central shelf compared with the previous year. Our year-long records additionally emphasize the regional differences in water column structure and stratification, where the northwest location was well-mixed for 6 months and the central and northeast locations remained stratified into spring due to the lower initial surface salinities of the river-influenced water. A 26 year record of ocean reanalysis highlights the region’s interannual variability of stratification and its dependence on winds and sea ice. Prior the mid-2000s, river runoff to the perennially ice-covered central Laptev Sea shelf experienced little surface forcing and river water was maintained on the shelf. The transition toward less summer sea ice after the mid-2000s increased the ROFI’s (region of freshwater influence) exposure to summer winds. This greatly enhanced the variability in mixed layer depth, resulting in several years with well-mixed water columns as opposed to the often year-round shallow mixed layers before. The extent of the Lena River plume is critical for the region since it modulates nutrient fluxes and primary production, and further controls intermediate heat storage induced by lateral density gradients, which has implications for autumnal freeze-up and the eastern Arctic sea ice volume.MAIN POINTS1.CTD surveys and moorings highlight the regional and temporal variations in water column stratification on the Laptev Sea shelf.2.Summer winds increasingly control the extent of the region of freshwater influence under decreasing sea ice.3.Further reductions in sea ice increases surface warming, heat storage, and the interannual variability in mixed layer depth.

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Section: Introductionmentioning

confidence: 99%

On the Variability of Stratification in the Freshwater-Influenced Laptev Sea Region

et al. 2020

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“…We use SIT retrievals generated at the full resolution of the altimeter with an approximate point spacing of 300 m and swath width of 1650 m along the ground-track of the satellite. The method of the SIT retrieval for each radar waveform is based on Ricker et al (2014) with updates described in Hendricks et al (2020).…”

Section: Sea-ice Thicknessmentioning

confidence: 99%

The MOSAiC Drift: Ice conditions from space and comparison with previous years

Krumpen

Albedyll

Goessling

et al. 2021

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Abstract. We combine satellite data products to provide a first and general overview of the sea-ice conditions along the MOSAiC drift and a comparison with previous years. We find that the MOSAiC drift was around 25 % faster than the climatological mean drift, as a consequence of large-scale low-pressure anomalies prevailing around the Barents-Kara-Laptev Sea region between January and March. In winter (October–April), satellite observations show that the sea-ice in the vicinity of the Central Observatory (CO) was rather thin compared to the previous years along the same trajectory. Unlike ice thickness, satellite-derived sea-ice concentration, lead frequency, and snow thickness during winter month were close to the long-term mean with little variability. With the onset of spring and decreasing distance to Fram Strait, variability in ice concentration and lead activity increased. In addition, frequency and strength of deformation events (divergence and shear) were higher during summer than during winter. Overall, we find that sea-ice conditions observed close (~ 5 km) to the CO are representative for the wider (50 km and 100 km) surroundings. An exception is the ice thickness: Here we find that sea-ice near the CO (50 km radius) was 4 % thinner than sea-ice within a 100 km radius. Moreover, satellite acquisitions indicate that the formation of large melt ponds began earlier on the MOSAiC floe than on neighbouring floes.

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“…All data used for evaluations in the following was collected during the MOSAiC campaign (Krumpen et al, 2020) from the beginning of leg 1 (24 October 2019) until the end of leg 3 (7 May 2020) (Fig. 1).…”

Section: Methodsmentioning

confidence: 99%

Snowfall and snow accumulation processes during the MOSAiC winter and spring season

Wagner

Shupe

Persson

et al. 2021

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Abstract. Data from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition allowed us to investigate the temporal dynamics of snowfall, snow accumulation, and erosion in great detail for almost the whole accumulation season (November 2019 to May 2020). We computed cumulative snow water equivalent (SWE) over the sea ice based on snow depth (HS) and density retrievals from a SnowMicroPen (SMP) and approximately weekly-measured snow depths along fixed transect paths. Hence, the computed SWE considers surface heterogeneities over an average path length of 1469 m. We used the SWE from the snow cover to compare with precipitation sensors installed during MOSAiC. The data were compared with ERA5 reanalysis snowfall rates for the drift track. Our study shows that the simple fitted HS-SWE function can well be used to compute SWE along a transect path based on SMP SWE retrievals and snow-depth measurements. We found an accumulated snow mass of 34 mm SWE until 26 April 2020. Further, we found that the Vaisala Present Weather Detector 22 (PWD22), installed on a railing on the top deck of research vessel Polarstern was least affected by blowing snow and showed good agreements with SWE retrievals along the transect, however, it also systematically underestimated snowfall. The OTT Pluvio2 and the OTT Parsivel2 were largely affected by wind and blowing snow, leading to higher measured precipitation rates, but when eliminating drifting snow periods, especially the OTT Pluvio2 shows good agreements with ground measurements. A comparison with ERA5 snowfall data reveals a good timing of the snowfall events and good agreement with ground measurements but also a tendency towards overestimation. Retrieved snowfall from the ship-based Ka-band ARM Zenith Radar (KAZR) shows good agreements with SWE of the snow cover and comparable differences as ERA5. Assuming the KAZR derived snowfall as an upper limit and PWD22 as a lower limit of a cumulative snowfall range, we estimate 72 to 107 mm measured between 31 October 2019 and 26 April 2020. For the same period, we estimate the precipitation mass loss along the transect due to erosion and sublimation as between 53 and 68 %. Until 7 May 2020, we suggest a cumulative snowfall of 98–114 mm.

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The MOSAiC ice floe: sediment-laden survivor from the Siberian shelf

Cited by 71 publications

References 27 publications

On the Variability of Stratification in the Freshwater-Influenced Laptev Sea Region

On the Variability of Stratification in the Freshwater-Influenced Laptev Sea Region

The MOSAiC Drift: Ice conditions from space and comparison with previous years

Snowfall and snow accumulation processes during the MOSAiC winter and spring season

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