scholarly journals Modified Halocline Water over the Laptev Sea Continental Margin: Historical Data Analysis

2012 ◽  
Vol 25 (16) ◽  
pp. 5556-5565 ◽  
Author(s):  
Igor A. Dmitrenko ◽  
Sergey A. Kirillov ◽  
Vladimir V. Ivanov ◽  
Bert Rudels ◽  
Nuno Serra ◽  
...  
Keyword(s):  
Continental Margin ◽  
North Atlantic Ocean ◽  
Source Region ◽  
Vertical Mixing ◽  
Atlantic Water ◽  
Laptev Sea ◽  
Boundary Current ◽  
Salinity Stratification ◽  
The North ◽  
The Laptev Sea

Abstract Historical hydrographic data (1940s–2010) show a distinct cross-slope difference of the lower halocline water (LHW) over the Laptev Sea continental margins. Over the slope, the LHW is on average warmer and saltier by 0.2°C and 0.5 psu, respectively, relative to the off-slope LHW. The LHW temperature time series constructed from the on-slope historical records are related to the temperature of the Atlantic Water (AW) boundary current transporting warm water from the North Atlantic Ocean. In contrast, the on-slope LHW salinity is linked to the sea ice and wind forcing over the potential upstream source region in the Barents and northern Kara Seas, as also indicated by hydrodynamic model results. Over the Laptev Sea continental margin, saltier LHW favors weaker salinity stratification that, in turn, contributes to enhanced vertical mixing with underlying AW.

A volcanic passive continental margin between the Laptev Sea Shelf and the Eurasia Basin?

2021 ◽  
Author(s):  
Anatoly Nikishin ◽  
Vasily Savin ◽  
Sierd Cloetingh ◽  
Carmen Gaina ◽  
Nikolay Malyshev ◽  
...  
Keyword(s):  
Continental Slope ◽  
Continental Margin ◽  
Gravity Data ◽  
Laptev Sea ◽  
The North ◽  
Rfbr Grant ◽  
Break Up ◽  
Seismic Lines ◽  
Eurasia Basin ◽  
The Laptev Sea

<p>New seismic, magnetic and gravity data of the continental margin of the Laptev Sea shelf indicate: (<strong>1</strong>) Absence of the Lomonosov-Khatanga transform fault between the Eurasia Basin and Laptev Sea shelf. On a number of new seismic lines we do not observe evidence for transtension or transpressional deformation along this lineament whereas some typical deformation for the continental slopes is recognized. Recent seisimicity is absent along the lineament. (<strong>2</strong>) The pull-apart Laptev-Gakkel continental basin along the Laptev Sea continental slope is in an orthogonal position to the Gakkel Ridge axial rift. This pull-apart basin was tectonically active during Eocene-Oligocene times. (<strong>3</strong>) Evidence exists for number possible intrusions just below the rift/postrift (break-up) unconformity (56 Ma) on some seismic lines in the area between the Taimyr Shelf and the continental slope of the Eurasia Basin. Evidence is also found for the existence of possible volcanics just below the break-up unconformity in this area. (<strong>4</strong>) Intrusions might also be present just below the 56 Ma break-up unconformity recognized on some seismic lines in the area between the Lomonosov Ridge and the continental slope of the Eurasia Basin. Buried volcanoes are likely present as well. These two magmatic provinces are symmetric to each other on both sides of the Eurasia Basin and well expressed on the new magnetic anomaly map.(<strong>5</strong>) The Eurasia Basin has a conical shape in its Southern near-Laptev domain. Opening of the basin appears to be controlled by propagation of oceanic crust spreading to the south. (<strong>6</strong>) We assume that the continental margin between the Laptev Sea Shelf and the Eurasian Basin could be a passive volcanic margin. This margin is characterized by a structure that is very similar to the North Atlantic margin of almost the same age. This study was supported by RFBR grant (18-05-70011).</p>

scholarly journals Changes in the paleohydrological conditions in the Laptev Sea during the late Pleistocene and Holocene based on a study of aquatic palynomorphs

2019 ◽  
Vol 59 (3) ◽  
pp. 433-448
Author(s):  
T. S. Klyuvitkina ◽  
Ye. I. Polyakova
Keyword(s):  
Environmental Change ◽  
Sea Level ◽  
Continental Margin ◽  
Cold Water ◽  
Sediment Cores ◽  
Atlantic Water ◽  
Time Interval ◽  
Laptev Sea ◽  
Global Sea Level ◽  
The Laptev Sea

On the basis of aquatic palynomorph assemblages in sediment cores obtained from the eastern Laptev Sea shelf, major phases of environmental change associated with the last postglacial global sea-level rise can be recognized for the time since 17.5 calendar years BP (cal. ka). It is shown that in the time interval of 17.5–13.0 cal. ka in the western part of the sea there was a very cold-water sea basin with permanent sea-ice cover, 12.3–11.2 cal. ka the outer shelf were characterized by increased precipitation of river-loaded matter in a river-proximal environment of Anabara and Khatanga rivers, and the period of 11.2–7.0 cal ka was marked by enhanced influence of Atlantic water at the Laptev Sea continental margin. Modern-like environments were established in this part of the sea approximately 7.0 cal. ka.

scholarly journals Satellite-based sea ice thickness changes in the Laptev Sea from 2002 to 2017: comparison to mooring observations

2020 ◽  
Vol 14 (7) ◽  
pp. 2189-2203
Author(s):  
H. Jakob Belter ◽  
Thomas Krumpen ◽  
Stefan Hendricks ◽  
Jens Hoelemann ◽  
Markus A. Janout ◽  
...  
Keyword(s):  
Sea Ice ◽  
Source Region ◽  
European Space Agency ◽  
The Arctic ◽  
Ice Thickness ◽  
Laptev Sea ◽  
Validation Data ◽  
Data Set ◽  
Sea Ice Thickness ◽  
The Laptev Sea

Abstract. The gridded sea ice thickness (SIT) climate data record (CDR) produced by the European Space Agency (ESA) Sea Ice Climate Change Initiative Phase 2 (CCI-2) is the longest available, Arctic-wide SIT record covering the period from 2002 to 2017. SIT data are based on radar altimetry measurements of sea ice freeboard from the Environmental Satellite (ENVISAT) and CryoSat-2 (CS2). The CCI-2 SIT has previously been validated with in situ observations from drilling, airborne remote sensing, electromagnetic (EM) measurements and upward-looking sonars (ULSs) from multiple ice-covered regions of the Arctic. Here we present the Laptev Sea CCI-2 SIT record from 2002 to 2017 and use newly acquired ULS and upward-looking acoustic Doppler current profiler (ADCP) sea ice draft (VAL) data for validation of the gridded CCI-2 and additional satellite SIT products. The ULS and ADCP time series provide the first long-term satellite SIT validation data set from this important source region of sea ice in the Transpolar Drift. The comparison of VAL sea ice draft data with gridded monthly mean and orbit trajectory CCI-2 data, as well as merged CryoSat-2–SMOS (CS2SMOS) sea ice draft, shows that the agreement between the satellite and VAL draft data strongly depends on the thickness of the sampled ice. Rather than providing mean sea ice draft, the considered satellite products provide modal sea ice draft in the Laptev Sea. Ice drafts thinner than 0.7 m are overestimated, while drafts thicker than approximately 1.3 m are increasingly underestimated by all satellite products investigated for this study. The tendency of the satellite SIT products to better agree with modal sea ice draft and underestimate thicker ice needs to be considered for all past and future investigations into SIT changes in this important region. The performance of the CCI-2 SIT CDR is considered stable over time; however, observed trends in gridded CCI-2 SIT are strongly influenced by the uncertainties of ENVISAT and CS2 and the comparably short investigation period.

scholarly journals Mooring-Based Observations of Double-Diffusive Staircases over the Laptev Sea Slope*

2012 ◽  
Vol 42 (1) ◽  
pp. 95-109 ◽  
Author(s):  
Igor V. Polyakov ◽  
Andrey V. Pnyushkov ◽  
Robert Rember ◽  
Vladimir V. Ivanov ◽  
Y.-D. Lenn ◽  
...  
Keyword(s):  
Double Diffusion ◽  
Atlantic Water ◽  
Arctic Sea Ice ◽  
Heat Fluxes ◽  
Laptev Sea ◽  
Depth Range ◽  
Diffusive Convection ◽  
Arctic Sea ◽  
Effective Transfer ◽  
The Laptev Sea

Abstract A yearlong time series from mooring-based high-resolution profiles of water temperature and salinity from the Laptev Sea slope (2003–04; 2686-m depth; 78°26′N, 125°37′E) shows six remarkably persistent staircase layers in the depth range of ~140–350 m encompassing the upper Atlantic Water (AW) and lower halocline. Despite frequent displacement of isopycnal surfaces by internal waves and eddies and two strong AW warming pulses that passed through the mooring location in February and late August 2004, the layers preserved their properties. Using laboratory-derived flux laws for diffusive convection, the authors estimate the time-averaged diapycnal heat fluxes across the four shallower layers overlying the AW core to be ~8 W m−2. Temporal variability of these fluxes is strong, with standard deviations of ~3–7 W m−2. These fluxes provide a means for effective transfer of AW heat upward over more than a 100-m depth range toward the upper halocline. These findings suggest that double diffusion is an important mechanism influencing the oceanic heat fluxes that help determine the state of Arctic sea ice.

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