scholarly journals Mesoscale Atlantic water eddy off the Laptev Sea continental slope carries the signature of upstream interaction

2008 ◽  
Vol 113 (C7) ◽  
Author(s):  
I. A. Dmitrenko ◽  
S. A. Kirillov ◽  
V. V. Ivanov ◽  
R. A. Woodgate
Keyword(s):  
Continental Slope ◽  
Atlantic Water ◽  
Laptev Sea ◽  
The Laptev Sea

Seasonal variability of Atlantic water on the continental slope of the Laptev Sea during 2002–2004

2006 ◽  
Vol 244 (3-4) ◽  
pp. 735-743 ◽  
Author(s):  
Igor A. Dmitrenko ◽  
Igor V. Polyakov ◽  
Sergey A. Kirillov ◽  
Leonid A. Timokhov ◽  
Harper L. Simmons ◽  
...  
Keyword(s):  
Continental Slope ◽  
Seasonal Variability ◽  
Atlantic Water ◽  
Laptev Sea ◽  
The Laptev Sea

scholarly journals Structure and dynamics of mesoscale eddies over the Laptev Sea continental slope in the Arctic Ocean

2018 ◽  
Author(s):  
Andrey Pnyushkov ◽  
Igor V. Polyakov ◽  
Laurie Padman ◽  
An T. Nguyen
Keyword(s):  
Arctic Ocean ◽  
Continental Slope ◽  
Mesoscale Eddies ◽  
The Arctic ◽  
Laptev Sea ◽  
Surface Mixed Layer ◽  
Fram Strait ◽  
Structure And Dynamics ◽  
The Arctic Ocean ◽  
The Laptev Sea

Abstract. Heat fluxes steered by mesoscale eddies may be a significant (but still not quantified) source of heat to the surface mixed layer and sea ice cover in the Arctic Ocean, as well as a source of nutrients for enhancing seasonal productivity in the near-surface layers. Here we use four years (2007–2011) of velocity and hydrography records from a moored profiler over the Laptev Sea slope, and 15 months (2008–2009) of acoustic Doppler current profiler data from a nearby mooring, to investigate the structure and dynamics of eddies at the continental margin of the eastern Eurasian Basin. Typical eddy scales are radii of order of 10 km, heights of six hundred meters, and maximum velocities of ~ 0.1 m s −1. Eddies are approximately equally divided between cyclonic and anticyclonic polarizations, contrary to prior observations from the deep basins and along the Lomonosov Ridge. Eddies are present in the mooring records about 20–25 % of the time, taking about one week to pass through the mooring at an average frequency of about one eddy per month. We found the eddies observed are formed in two distinct regions–near Fram Strait, where the western branch of Atlantic Water (AW) enters the Arctic Ocean, and near Severnaya Zemlya, where the Fram Strait and Barents Sea branches of the AW inflow merge. These eddies, embedded in the Arctic Circumpolar Boundary Current, carry anomalous water properties along the eastern Arctic continental slope. The enhanced diapycnal mixing that we found within EB eddies suggests a potentially important role for eddies in the vertical redistribution of heat in the Arctic Ocean interior.

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.

scholarly journals Spatial variability of primary production and chlorophyll in the Laptev sea in august–september

2019 ◽  
Vol 59 (5) ◽  
pp. 755-770
Author(s):  
A. B. Demidov ◽  
V. I. Gagarin ◽  
E. G. Arashkevich ◽  
P. N. Makkaveev ◽  
I. V. Konyukhov ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Spatial Variability ◽  
Primary Production ◽  
Continental Slope ◽  
Incident Radiation ◽  
Laptev Sea ◽  
Phytoplankton Primary Production ◽  
Average Value ◽  
Nutrients Concentration ◽  
The Laptev Sea

Spatial distribution of phytoplankton primary production and chlorophyll was studied based on the data of three cruises carried out in AugustSeptember of 2015, 2017 and 2018. The average value of water column primary production (IPP) along the transect from Lena`s mouth to the continental slope was 2.8 fold higher than that one along the transect from Khatanga`s mouth, which was explained by the level of incident radiation and nutrients concentration. Along the cross-slope transects increasing of photosynthetically layer integrated chlorophyll (Chlph) occurred due to developing of deep maxima. IPP and Chlph increasing was registered in the vicinity of the continental slope. In AugustSeptember the averaged IPP value was 100 mgC m-2 d-1 that is the evidence of oligotrophy of the Laptev Sea at the end of summer and at the beginning of autumn.

scholarly journals Impact of increasing inflow of warm Atlantic water on the sea‐air exchange of carbon dioxide and methane in the Laptev Sea

2016 ◽  
Vol 121 (7) ◽  
pp. 1867-1883
Author(s):  
Iréne Wåhlström ◽  
Christian Dieterich ◽  
Per Pemberton ◽  
H. E. Markus Meier
Keyword(s):  
Carbon Dioxide ◽  
Atlantic Water ◽  
Laptev Sea ◽  
The Laptev Sea ◽  
Air Exchange

scholarly journals Halocline water modification and along-slope advection at the Laptev Sea continental margin

Ocean Science ◽  
2014 ◽  
Vol 10 (1) ◽  
pp. 141-154 ◽  
Author(s):  
D. Bauch ◽  
S. Torres-Valdes ◽  
I. Polyakov ◽  
A. Novikhin ◽  
I. Dmitrenko ◽  
...  
Keyword(s):  
Sea Ice ◽  
Water Column ◽  
Continental Slope ◽  
Shelf Break ◽  
Laptev Sea ◽  
Frontal System ◽  
Ice Melt ◽  
Sea Bottom ◽  
Bottom Waters ◽  
The Laptev Sea

Abstract. A general pattern in water mass distribution and potential shelf–basin exchange is revealed at the Laptev Sea continental slope based on hydrochemical and stable oxygen isotope data from the summers 2005–2009. Despite considerable interannual variations, a frontal system can be inferred between shelf, continental slope and central Eurasian Basin waters in the upper 100 m of the water column along the continental slope. Net sea-ice melt is consistently found at the continental slope. However, the sea-ice meltwater signal is independent from the local retreat of the ice cover and appears to be advected from upwind locations. In addition to the along-slope frontal system at the continental shelf break, a strong gradient is identified on the Laptev Sea shelf between 122° E and 126° E with an eastward increase of riverine and sea-ice related brine water contents. These waters cross the shelf break at ~ 140° E and feed the low-salinity halocline water (LSHW, salinity S < 33) in the upper 50 m of the water column. High silicate concentrations in Laptev Sea bottom waters may lead to speculation about a link to the local silicate maximum found within the salinity range of ~ 33 to 34.5, typical for the Lower Halocline Water (LHW) at the continental slope. However brine signatures and nutrient ratios from the central Laptev Sea differ from those observed at the continental slope. Thus a significant contribution of Laptev Sea bottom waters to the LHW at the continental slope can be excluded. The silicate maximum within the LHW at the continental slope may be formed locally or at the outer Laptev Sea shelf. Similar to the advection of the sea-ice melt signal along the Laptev Sea continental slope, the nutrient signal at 50–70 m water depth within the LHW might also be fed by advection parallel to the slope. Thus, our analyses suggest that advective processes from upstream locations play a significant role in the halocline formation in the northern Laptev Sea.

scholarly journals Observations of Tidally Induced Currents over the Continental Slope of the Laptev Sea, Arctic Ocean

2012 ◽  
Vol 42 (1) ◽  
pp. 78-94 ◽  
Author(s):  
A. V. Pnyushkov ◽  
I. V. Polyakov
Keyword(s):  
Arctic Ocean ◽  
Continental Slope ◽  
Bottom Topography ◽  
Resonant Interaction ◽  
Tidal Currents ◽  
Laptev Sea ◽  
Sea Level Changes ◽  
Sea Ice Concentration ◽  
Ocean Layer ◽  
The Laptev Sea

Abstract Two year-long (2004–05 and 2005–06) records of currents from two moorings deployed at the continental slope of the Laptev Sea (78°26′N, 125°40′E) are used in order to define the properties of tidal currents in the upper ~200-m ocean layer. Harmonic and spectral analyses of currents showed that the semidiurnal tidal constituent S2 dominates over the semidiurnal M2 and diurnal constituents. This dominance of the S2 constituent in the tidal currents is due to resonant interaction of the superinertial wave with sloping bottom topography. In contrast to the tidal currents, sea level changes are dominated by the M2 constituent, as seen from a tidal model by L. Padman and S. Erofeeva, using assimilation of observational data. Strong anticorrelation (−0.73 ± 0.05) was found between the upper 50-m S2 current amplitudes and local sea ice concentration, with fourfold (from ~2.0 to 8.5 cm s−1) amplification of tidal currents under ice-free conditions. This is probably due to a change of local resonance conditions for the S2 tidal current. These findings may be important for understanding the increasing role of tides in a seasonally ice-free Arctic Ocean.

Sign in / Sign up

Export Citation Format

Share Document