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  • 1
    In: Journal of geophysical research. C, Oceans, Hoboken, NJ : Wiley, 1978, 114(2009), 6, 2169-9291
    In: volume:114
    In: year:2009
    In: number:6
    In: extent:19
    Description / Table of Contents: Through the analysis of observational mooring data collected at the northeastern Laptev Sea continental slope in 2004-2007, we document a hydrographic seasonal signal in the intermediate Atlantic Water (AW) layer, with generally higher temperature and salinity from December-January to May-July and lower values from May-July to December-January. At the mooring position, this seasonal signal dominates, contributing up to 75% of the total variance. Our data suggest that the entire AW layer down to at least 840 m is affected by seasonal cycling, although the strength of the seasonal signal in temperature and salinity reduces from 260 m (±0.25ʿC and ±0.025 psu) to 840 m (±0.05ʿC and ±0.005 psu). The seasonal velocity signal is substantially weaker, strongly masked by high-frequency variability, and lags the thermohaline cycle by 45-75 days. We hypothesize that our mooring record shows a time history of the along-margin propagation of the AW seasonal signal carried downstream by the AW boundary current. Our analysis suggests that the seasonal signal in the Fram Strait Branch of AW (FSBW) at 260 m is predominantly translated from Fram Strait, while the seasonality in the Barents Sea branch of AW (BSBW) domain (at 840 m) is attributed instead to the seasonal signal input from the Barents Sea. However, the characteristic signature of the BSBW seasonal dynamics observed through the entire AW layer leads us to speculate that BSBW also plays a role in seasonally modifying the properties of the FSBW.
    Type of Medium: Online Resource
    Pages: 19 , graph. Darst
    ISSN: 2169-9291
    Language: English
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  • 2
    In: Geophysical research letters, Hoboken, NJ : Wiley, 1974, 35(2008), 1944-8007
    In: volume:35
    In: year:2008
    In: extent:5
    Description / Table of Contents: The seasonal hydrographic cycle explains about 25-75% of the entire salinity variability spectrum of the Siberian shelf hydrography. Quasi-decadal variations in the seasonal salinity difference over the Laptev and East Siberian sea shelves derived from continuous summer-to-winter historical records from the 1960s-1990s are attributed to atmospheric vorticity quasi-decadal variations. Summer cyclonic vorticity results in riverine water accumulation on the shelf, increasing the salinity summer-to-winter difference. Summer anticyclonic wind pattern enhances fresh water movement from the shelf towards the Arctic Ocean that tends to weaken the seasonal salinity amplitude.
    Type of Medium: Online Resource
    Pages: 5 , graph. Darst
    ISSN: 1944-8007
    Language: English
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  • 3
    In: Journal of geophysical research. C, Oceans, Hoboken, NJ : Wiley, 1978, 113(2008), 2169-9291
    In: volume:113
    In: year:2008
    In: extent:14
    Description / Table of Contents: A time series of summer fresh water content anomalies (FWCA) over the Laptev and East Siberian sea shelves was constructed from historical hydrographic records for the period from 1920 to 2005. Results from a multiple regression between FCWA and various atmospheric and oceanic indices show that the fresh water content on the shelves is mainly controlled by atmospheric vorticity on quasi-decadal timescales. When the vorticity of the atmosphere on the shelves is antycyclonic, approximately 500 km3 of fresh water migrates from the eastern Siberian shelf to the Arctic Ocean through the northeastern Laptev Sea. When the vorticity of the atmosphere is cyclonic, this fresh water remains on the southern Laptev and East Siberian sea shelves. This FWCA represents approximately 35% of the total fresh water inflow provided by river discharge and local sea-ice melt, and is about ten times larger than the standard deviation of the Lena River summer long-term mean discharge. However, the large interannual and spatial variability in the fresh water content of the shelves, as well as the spatial coverage of the hydrographic data, makes it difficult to detect the long-term tendency of fresh water storage associated with climate change
    Type of Medium: Online Resource
    Pages: 14 , graph. Darst
    ISSN: 2169-9291
    Language: English
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  • 4
    In: Journal of geophysical research. C, Oceans, Hoboken, NJ : Wiley, 1978, 113(2008), 2169-9291
    In: volume:113
    In: year:2008
    In: extent:13
    Description / Table of Contents: We document through the analysis of 2002-2005 observational data the recent Atlantic Water (AW) warming along the Siberian continental margin due to several AW warm impulses that penetrated into the Arctic Ocean through Fram Strait in 1999-2000. The AW temperature record from our long-term monitoring site in the northern Laptev Sea shows several events of rapid AW temperature increase totaling 0.8ʿC in FebruaryAugust 2004. We hypothesize the along-margin spreading of this warmer anomaly has disrupted the downstream thermal equilibrium of the late 1990s to earlier 2000s. The anomaly mean velocity of 2.4-2.5 ± 0.2 cm/s was obtained on the basis of travel time required between the northern Laptev Sea and two anomaly fronts delineated over the Eurasian flank of the Lomonosov Ridge by comparing the 2005 snapshot along-margin data with the AW pre-1990 mean. The magnitude of delineated anomalies exceeds the level of pre-1990 mean along-margin cooling and rises above the level of noise attributed to shifting of the AW jet across the basin margins. The anomaly mean velocity estimation is confirmed by comparing mooring-derived AW temperature time series from 2002 to 2005 with the downstream along-margin AW temperature distribution from 2005. Our mooring current meter data corroborate these estimations.
    Type of Medium: Online Resource
    Pages: 13 , graph. Darst
    ISSN: 2169-9291
    Language: English
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  • 5
    In: Geophysical research letters, Hoboken, NJ : Wiley, 1974, 36(2009), 1944-8007
    In: volume:36
    In: year:2009
    In: extent:4
    Description / Table of Contents: The winter net sea-ice production (NSIP) over the Laptev Sea shelf is inferred from continuous summer-to-winter historical salinity records of 1960s-1990s. While the NSIP strongly depends on the assumed salinity of newly formed ice, the NSIP quasi-decadal variability can be linked to the wind-driven circulation anomalies in the Laptev Sea region. The increased wind-driven advection of ice away from the Laptev Sea coast when the Arctic Oscillation (AO) is positive implies enhanced coastal polynya sea-ice production and brine release in the shelf water. When the AO is negative, the NSIP and seasonal salinity amplitude tends to weaken. These results are in reasonable agreement with sea-ice observations and modeling.
    Type of Medium: Online Resource
    Pages: 4 , graph. Darst
    ISSN: 1944-8007
    Language: English
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  • 6
    In: Deep-sea research. Part 1, Oceanographic research papers, Amsterdam [u.a.] : Elsevier Science, 1993, 56(2009), 4, Seite 513-527, 1879-0119
    In: volume:56
    In: year:2009
    In: number:4
    In: pages:513-527
    Description / Table of Contents: Inflow of Atlantic water (AW) from Fram Strait and the Barents Sea into the Arctic Ocean conditions the intermediate (100-1000 m) waters of the Arctic Ocean Eurasian margins. While over the Siberian margin the Fram Strait AW branch (FSBW) has exhibited continuous dramatic warming beginning in 2004, the tendency of the Barents Sea AW branch (BSBW) has remained poorly known. Here we document the contrary cooling tendency of the BSBW through the analysis of observational data collected from the icebreaker Kapitan Dranitsyn over the continental slope of the Eurasian Basin in 2005 and 2006. The CTD data from the R.V. Polarstern cruise in 1995 were used as a reference point for evaluating external atmospheric and sea-ice forcing and oxygen isotope analysis. Our data show that in 2006 the BSBW core was saltier (by ~0.037), cooler (~0.41 ʿC), denser (by ~0.04 kg/m3), deeper (by 150-200 m), and relatively better ventilated (by 78 mymol/kg of dissolved oxygen, or by 1.11.7% of saturation) compared with 2005. We hypothesize that the shift of the meridional wind from off-shore to on-shore direction during the BSBW translation through the Barents and northern Kara seas results in longer surface residence time for the BSBW sampled in 2006 compared with samples from 2005. The cooler, more saline, and better-ventilated BSBW sampled in 2006 may result from longer upstream translation through the Barents and northern Kara seas where the BSBW was modified by sea-ice formation and interaction with atmosphere. The data for stable oxygen isotopes from 1995 and 2006 reveals amplified brine modification of the BSBW core sampled downstream in 2006, which supports the assumption of an increased upstream residence time as indicated by wind patterns and dissolved oxygen values.
    Type of Medium: Online Resource
    Pages: graph. Darst
    ISSN: 1879-0119
    Language: English
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  • 7
    Publication Date: 2015-03-10
    Description: This study was motivated by a strong warming signal seen in mooring-based and oceanographic survey data collected in 2004 in the Eurasian Basin of the Arctic Ocean. The source of this and earlier Arctic Ocean changes lies in interactions between polar and sub-polar basins. Evidence suggests such changes are abrupt, or pulse-like, taking the form of propagating anomalies that can be traced to higher-latitudes. For example, an anomaly found in 2004 in the eastern Eurasian Basin took ∼1.5 years to propagate from the Norwegian Sea to the Fram Strait region, and additional ∼4.5–5 years to reach the Laptev Sea slope. While the causes of the observed changes will require further investigation, our conclusions are consistent with prevailing ideas suggesting the Arctic Ocean is in transition towards a new, warmer state.
    Type: Article , PeerReviewed
    Format: text
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  • 8
    Publication Date: 2018-12-31
    Description: The thermohaline structure of the Arctic Basin (AB) of the Arctic Ocean (AO) is determined to a great extent by an intermediate water layer existing under ice at a depth varying from 100 to 700–1000 m. The water layer is formed by warm North Atlantic Water (AW), which enters the AB by two ways: through Fram Strait and the Barents Sea (Fig. 1). The AW arriving to the AB via Fram Strait extends further eastward along the continental slope of the Eurasian Arctic region and forms the Fram Branch (FBAW). The Barents Branch of the AW (BBAW) was formed by the North Atlantic Water entering the Barents Sea between the Spitsbergen Archipelago and the Scandinavian Peninsula. Both branches merge in the northern Kara Sea.
    Type: Article , PeerReviewed
    Format: text
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  • 9
    Publication Date: 2018-12-31
    Description: Recent observations show dramatic changes of the Arctic atmosphere–ice–ocean system. Here the authors demonstrate, through the analysis of a vast collection of previously unsynthesized observational data, that over the twentieth century the central Arctic Ocean became increasingly saltier with a rate of freshwater loss of 239 ± 270 km3 decade−1. In contrast, long-term (1920–2003) freshwater content (FWC) trends over the Siberian shelf show a general freshening tendency with a rate of 29 ± 50 km3 decade−1. These FWC trends are modulated by strong multidecadal variability with sustained and widespread patterns. Associated with this variability, the FWC record shows two periods in the 1920s–30s and in recent decades when the central Arctic Ocean was saltier, and two periods in the earlier century and in the 1940s–70s when it was fresher. The current analysis of potential causes for the recent central Arctic Ocean salinification suggests that the FWC anomalies generated on Arctic shelves (including anomalies resulting from river discharge inputs) and those caused by net atmospheric precipitation were too small to trigger long-term FWC variations in the central Arctic Ocean; to the contrary, they tend to moderate the observed long-term central-basin FWC changes. Variability of the intermediate Atlantic Water did not have apparent impact on changes of the upper–Arctic Ocean water masses. The authors’ estimates suggest that ice production and sustained draining of freshwater from the Arctic Ocean in response to winds are the key contributors to the salinification of the upper Arctic Ocean over recent decades. Strength of the export of Arctic ice and water controls the supply of Arctic freshwater to subpolar basins while the intensity of the Arctic Ocean FWC anomalies is of less importance. Observational data demonstrate striking coherent long-term variations of the key Arctic climate parameters and strong coupling of long-term changes in the Arctic–North Atlantic climate system. Finally, since the high-latitude freshwater plays a crucial role in establishing and regulating global thermohaline circulation, the long-term variations of the freshwater content discussed here should be considered when assessing climate change and variability.
    Type: Article , PeerReviewed
    Format: text
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  • 10
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    In:  [Talk] In: SCAR/IASC IPY Open Science Conference "Polar Research - Arctic and Antarctic Perspectives in the International Polar Year", 08.07.-11.07.2008, St. Petersburg, Russia .
    Publication Date: 2019-09-23
    Type: Conference or Workshop Item , NonPeerReviewed
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