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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: 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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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Polar research 18 (1999), S. 0 
    ISSN: 1751-8369
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Geosciences
    Notes: Recently observed changes in the Arctic have highlighted the need for a better understanding of Arctic dynamics. This research addresses that need and is also motivated by the recent finding of two regimes of Arctic ice - ocean wind-driven circulation. In this paper, we demonstrate that during 1946-1997 the Arctic environmental parameters have oscillated with a period of 10-15 years. Our results reveal significant differences among atmosphere, ice, and ocean processes during the anticyclonic and cyclonic regimes in the Arctic Ocean and its marginal seas. The oscillating behaviour of the Arctic Ocean we call the Arctic Ocean Oscillation (AOO). Based on existing data and results of numerical experiments, we conclude that during the anticyclonic circulation regime the prevailing processes lead to increases in atmospheric pressure, in ice concentration and ice thickness, river runoff, and surface water salinity - as well as to decreases in air temperature, wind speed, number of storms, precipitation, permafrost temperatures, coastal sea level, and surface water temperature. During the cyclonic circulation regime the prevailing processes lead to increased air and water temperatures, wind speed, number of storms,open water periods, and to decreases in ice thickness and ice concentration, river runoff, atmospheric pressure, and water salinity. The two-climate regime theory may help answer questions related to observed decadal variability of the Arctic Ocean and to reconcile the different conclusions among scientists who have analysed Arctic data obtained during different climate states.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Polar research 18 (1999), S. 0 
    ISSN: 1751-8369
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Geosciences
    Notes: Diagnostic computations of density-driven circulation for seven winters from 1973 through 1979 were carried out. The only forcing was provided by observed temperature and salinity data collected during onsite Russian winter surveys in 1973–79. Computed circulations from 1973 through 1978 were close to the mean circulation obtained earlier by averaging observed 1973–79 temperature and salinity (Polyakov & Timokhov 1994). The computed 1979 density-driven circulation flowed counter-clockwise to the north of the Laptev Sea. This circulation pattern was caused by an anomalous salinity distribution associated with changes in the atmospheric circulation regime in 1979. Prevailing offshore winds blew fresh water from the Laptev and East Siberian shelves toward Fram Strait. Fresh water was exchanged for saltier intermediate water that upwelled to the surface along the slope. The observed surface salinity anomalies at the continental slope of the Laptev Sea in 1979 increased by several salinity units. One may speculate that the same process may have caused the observed salinification of the Eurasian Basin in the 1990s.
    Type of Medium: Electronic Resource
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  • 5
    Publication Date: 2023-03-16
    Description: Underway (U)CTD data were collected during an August-September 2018 expedition to the Arctic Ocean aboard the RV Akademik Tryoshnikov, and was a joint expedition between the German-Russian project CATS (Changing Arctic Transpolar System) and the US-Russian project NABOS (Nansen and Amundsen Basin Observing System). The UCTD was operated mostly in yoyo-mode during selected transects between the shelf and the basin across the continental slope of the Eurasian Basin while the ship was transiting with 8 - 14 knots. The UCTD probe records the start time of the measurements and stores 16 samples each second internally. The exact location of each profile was subsequently found based on the time stamp from the cruise track. The unpumped conductivity sensor has a slower response time than the temperature sensor, which makes the computation of salinity from conductivity and temperature potentially spiky, especially in the pycnocline or in frontal regions. We followed the recommendation of the manufacturer to calculate salinity with Seabird processing software. In shallower waters (〈200m), the water column was profiled all the way to the seafloor, while in deeper waters, only the upper 200-350m were sampled. Shipboard echo soundings were not available, actual water depths at the profile locations need to be extracted from bathymetric charts (for instance IBCAO ). The UCTD was calibrated against a Seabird 911 CTD during the cruise. Temperature measurements were comparable to the ship's CTD and remained uncorrected, the processed salinities include a salinity correction based on a deviation from the ship's CTD.
    Keywords: 1; 10; 100; 101; 102; 103; 104; 105; 106; 107; 108; 109; 11; 110; 111; 112; 113; 114; 115; 116; 117; 118; 119; 12; 120; 121; 122; 123; 124; 125; 126; 127; 128; 129; 13; 130; 131; 132; 133; 134; 135; 136; 137; 138; 139; 14; 140; 141; 142; 143; 144; 145; 146; 147; 148; 149; 15; 150; 151; 152; 153; 154; 155; 156; 157; 158; 159; 16; 160; 161; 162; 163; 164; 165; 166; 167; 168; 169; 17; 170; 171; 172; 173; 174; 175; 176; 177; 178; 179; 18; 180; 181; 182; 183; 184; 185; 19; 2; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 3; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 4; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 5; 50; 51; 52; 53; 54; 55; 56; 57; 58; 59; 6; 60; 61; 62; 63; 64; 65; 66; 67; 68; 69; 7; 70; 71; 72; 73; 74; 75; 76; 77; 78; 79; 8; 80; 81; 82; 83; 84; 85; 86; 87; 88; 89; 9; 90; 91; 92; 93; 94; 95; 96; 97; 98; 99; Akademik Tryoshnikov; Arctic Ocean; AT18_005-1; AT18_005-10; AT18_005-11; AT18_005-12; AT18_005-13; AT18_005-16; AT18_005-17; AT18_005-18; AT18_005-19; AT18_005-2; AT18_005-20; AT18_005-25; AT18_005-26; AT18_005-3; AT18_005-4; AT18_005-5; AT18_005-6; AT18_005-7; AT18_005-8; AT18_005-9; AT18_010-1; AT18_010-10; AT18_010-11; AT18_010-12; AT18_010-13; AT18_010-14; AT18_010-15; AT18_010-16; AT18_010-17; AT18_010-18; AT18_010-19; AT18_010-2; AT18_010-20; AT18_010-21; AT18_010-22; AT18_010-23; AT18_010-24; AT18_010-25; AT18_010-26; AT18_010-27; AT18_010-28; AT18_010-29; AT18_010-3; AT18_010-30; AT18_010-31; AT18_010-32; AT18_010-33; AT18_010-34; AT18_010-35; AT18_010-36; AT18_010-37; AT18_010-38; AT18_010-39; AT18_010-4; AT18_010-40; AT18_010-41; AT18_010-42; AT18_010-43; AT18_010-44; AT18_010-45; AT18_010-46; AT18_010-47; AT18_010-48; AT18_010-49; AT18_010-5; AT18_010-51; AT18_010-52; AT18_010-54; AT18_010-55; AT18_010-6; AT18_010-7; AT18_010-8; AT18_010-9; AT18_015-1; AT18_015-10; AT18_015-11; AT18_015-12; AT18_015-13; AT18_015-14; AT18_015-15; AT18_015-16; AT18_015-17; AT18_015-18; AT18_015-19; AT18_015-2; AT18_015-20; AT18_015-21; AT18_015-22; AT18_015-3; AT18_015-4; AT18_015-5; AT18_015-6; AT18_015-7; AT18_015-8; AT18_015-9; AT18_019_4-1; AT18_019_4-10; AT18_019_4-11; AT18_019_4-12; AT18_019_4-13; AT18_019_4-14; AT18_019_4-15; AT18_019_4-2; AT18_019_4-3; AT18_019_4-4; AT18_019_4-5; AT18_019_4-6; AT18_019_4-7; AT18_019_4-8; AT18_019_4-9; AT18_027-1; AT18_027-10; AT18_027-11; AT18_027-12; AT18_027-13; AT18_027-14; AT18_027-15; AT18_027-16; AT18_027-17; AT18_027-18; AT18_027-19; AT18_027-2; AT18_027-20; AT18_027-21; AT18_027-22; AT18_027-23; AT18_027-24; AT18_027-25; AT18_027-26; AT18_027-27; AT18_027-28; AT18_027-29; AT18_027-3; AT18_027-30; AT18_027-31; AT18_027-32; AT18_027-33; AT18_027-34; AT18_027-35; AT18_027-36; AT18_027-37; AT18_027-4; AT18_027-5; AT18_027-6; AT18_027-7; AT18_027-8; AT18_027-9; AT18_101-1; AT18_101-10; AT18_101-11; AT18_101-12; AT18_101-13; AT18_101-14; AT18_101-15; AT18_101-16; AT18_101-17; AT18_101-18; AT18_101-19; AT18_101-2; AT18_101-20; AT18_101-21; AT18_101-22; AT18_101-23; AT18_101-24; AT18_101-25; AT18_101-26; AT18_101-27; AT18_101-28; AT18_101-29; AT18_101-3; AT18_101-30; AT18_101-31; AT18_101-32; AT18_101-33; AT18_101-34; AT18_101-35; AT18_101-36; AT18_101-37; AT18_101-38; AT18_101-4; AT18_101-5; AT18_101-6; AT18_101-7; AT18_101-8; AT18_101-9; AT2018, TICE, NABOS; AWI_PhyOce; Campaign of event; CATS; CATS - The Changing Arctic Transpolar System; CTD, underway; CTD-UW; Date/Time of event; DEPTH, water; East Siberian Sea; Event label; Laptev Sea; Latitude of event; Longitude of event; Optional event label; Physical Oceanography @ AWI; Pressure, water; Salinity; shelf-basin transects; Temperature, water; Transdrift-XXIV; underway CTD; UnderwayCTD (UCTD), Oceanscience
    Type: Dataset
    Format: text/tab-separated-values, 84081 data points
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  • 6
    Publication Date: 2024-04-20
    Description: Shipboard loosely-tethered free-falling microstructure (MSS) measurements were carried out during expedition Transdrift-XXIV to the eastern Arctic Ocean onboard the Akademik Tryoshnikov (AT2018). The expedition was jointly organized between the US-Russian NABOS (Nansen and Amundsen Basin Observational System), the German-Russian CATS (Changing Arctic Transpolar System, funded by BMBF), and the TICE-project funded by the Alfred-Wegener-Institute. 236 stations were carried out between 25 August and 23 September 2018. The profiler MSS90L manufactured by Sea and Sun Technology samples at 1024 Hz and was equipped with temperature, salinity, shear, and fluorescence sensors. Details on data processing can be found in Schulz et al. (2021). Additional parameters and metadata are provided in the attached netcdf file.
    Keywords: Akademik Tryoshnikov; Arctic Ocean; AT18_009_2; AT18_009_5; AT18_016_2; AT18_017_1; AT18_018_2; AT18_019_2; AT18_020_2; AT18_022_4; AT18_023_2; AT18_024_2; AT18_025_4; AT18_044_2; AT18_045_2; AT18_046_2; AT18_047_3; AT18_048_2; AT18_049_2; AT18_050_2; AT18_060_3; AT18_061_2; AT18_062_2; AT18_063_2; AT18_085_4; AT18_093_2; AT18_094_2; AT18_095_2; AT18_102; AT18_103; AT18_116_2; AT18_117_2; AT18_118_2; AT18_119_2; AT18_120_2; AT18_122_2; AT2018, TICE, NABOS; AWI_PhyOce; Cast number; DATE/TIME; DEPTH, water; Dissipation rate; Event label; Laptev Sea; LATITUDE; LONGITUDE; microstructure; Micro structure probe; MSS; ocean heat flux; Physical Oceanography @ AWI; Pressure, water; Profile; Salinity; System Laptev-Sea: Transdrift; Temperature, water, potential; TRANSDRIFT; Transdrift-XXIV; turbulence; Turbulence probe MSS90L, Sea and Sun Technology
    Type: Dataset
    Format: text/tab-separated-values, 447242 data points
    Location Call Number Limitation Availability
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  • 7
    Publication Date: 2024-04-20
    Description: Shipboard loosely-tethered free-falling microstructure (MSS) measurements were carried out during expedition Transdrift-XXIV to the eastern Arctic Ocean onboard the Akademik Tryoshnikov (AT2018). The expedition was jointly organized between the US-Russian NABOS (Nansen and Amundsen Basin Observational System), the German-Russian CATS (Changing Arctic Transpolar System, funded by BMBF), and the TICE-project funded by the Alfred-Wegener-Institute. 236 stations were carried out between 25 August and 23 September 2018. The profiler MSS90L manufactured by Sea and Sun Technology samples at 1024 Hz and was equipped with temperature, salinity, shear, and fluorescence sensors.
    Keywords: Akademik Tryoshnikov; Arctic Ocean; AT18_009_2; AT18_009_5; AT18_016_2; AT18_017_1; AT18_018_2; AT18_019_2; AT18_020_2; AT18_022_4; AT18_023_2; AT18_024_2; AT18_025_4; AT18_044_2; AT18_045_2; AT18_046_2; AT18_047_3; AT18_048_2; AT18_049_2; AT18_050_2; AT18_060_3; AT18_061_2; AT18_062_2; AT18_063_2; AT18_085_4; AT18_093_2; AT18_094_2; AT18_095_2; AT18_102; AT18_103; AT18_116_2; AT18_117_2; AT18_118_2; AT18_119_2; AT18_120_2; AT18_122_2; AT2018, TICE, NABOS; AWI_PhyOce; Binary Object; Binary Object (File Size); Binary Object (Media Type); Date/Time of event; Date/Time of event 2; Event label; Laptev Sea; Latitude of event; Latitude of event 2; Longitude of event; Longitude of event 2; microstructure; Micro structure probe; MSS; ocean heat flux; Physical Oceanography @ AWI; System Laptev-Sea: Transdrift; TRANSDRIFT; Transdrift-XXIV; turbulence
    Type: Dataset
    Format: text/tab-separated-values, 232 data points
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  • 8
    Publication Date: 2021-06-16
    Description: Changes in Arctic sea ice thickness are the result of complex interactions of the dynamic and variable ice cover with atmosphere and ocean. Most of the sea ice exiting the Arctic Ocean does so through Fram Strait, which is why long-term measurements of ice thickness at the end of the Transpolar Drift provide insight into the integrated signals of thermodynamic and dynamic influences along the pathways of Arctic sea ice. We present an updated summer (July–August) time series of extensive ice thickness surveys carried out at the end of the Transpolar Drift between 2001 and 2020. Overall, we see a more than 20 % thinning of modal ice thickness since 2001. A comparison of this time series with first preliminary results from the international Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) shows that the modal summer thickness of the MOSAiC floe and its wider vicinity are consistent with measurements from previous years at the end of the Transpolar Drift. By combining this unique time series with the Lagrangian sea ice tracking tool, ICETrack, and a simple thermodynamic sea ice growth model, we link the observed interannual ice thickness variability north of Fram Strait to increased drift speeds along the Transpolar Drift and the consequential variations in sea ice age. We also show that the increased influence of upward-directed ocean heat flux in the eastern marginal ice zones, termed Atlantification, is not only responsible for sea ice thinning in and around the Laptev Sea but also that the induced thickness anomalies persist beyond the Russian shelves and are potentially still measurable at the end of the Transpolar Drift after more than a year. With a tendency towards an even faster Transpolar Drift, winter sea ice growth will have less time to compensate for the impact processes, such as Atlantification, have on sea ice thickness in the eastern marginal ice zone, which will increasingly be felt in other parts of the sea-ice-covered Arctic.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Format: application/pdf
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  • 9
    Publication Date: 2020-07-07
    Description: Rapid Arctic warming drives profound change in the marine environment that have significant socio-economic impacts within the Arctic and beyond, including climate and weather hazards, food security, transportation, infrastructure planning and resource extraction. These concerns drive efforts to understand and predict Arctic environmental change and motivate development of an Arctic Region Component of the Global Ocean Observing System (ARCGOOS) capable of collecting the broad, sustained observations needed to support these endeavors. This paper provides a roadmap for establishing the ARCGOOS. ARCGOOS development must be underpinned by a broadly endorsed framework grounded in high-level policy drivers and the scientific and operational objectives that stem from them. This should be guided by a transparent, internationally accepted governance structure with recognized authority and organizational relationships with the national agencies that ultimately execute network plans. A governance model for ARCGOOS must guide selection of objectives, assess performance and fitness-to-purpose, and advocate for resources. A requirements-based framework for an ARCGOOS begins with the Societal Benefit Areas (SBAs) that underpin the system. SBAs motivate investments and define the system�s science and operational objectives. Objectives can then be used to identify key observables and their scope. The domains of planning/policy, strategy, and tactics define scope ranging from decades and basins to focused observing with near real time data delivery. Patterns emerge when this analysis is integrated across an appropriate set of SBAs and science/operational objectives, identifying impactful variables and the scope of the measurements. When weighted for technological readiness and logistical feasibility, this can be used to select Essential ARCGOOS Variables, analogous to Essential Ocean Variables of the Global Ocean Observing System. The Arctic presents distinct needs and challenges, demanding novel observing strategies. Cost, traceability and ability to integrate region-specific knowledge have to be balanced, in an approach that builds on existing and new observing infrastructure. ARCGOOS should benefit from established data infrastructures following the Findable, Accessible, Interoperable, Reuseable Principles to ensure preservation and sharing of data and derived products. Linking to the Sustaining Arctic Observing Networks (SAON) process and involving Arctic stakeholders, for example through liaison with the International Arctic Science Committee (IASC), can help ensure success.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 10
    Publication Date: 2015-12-02
    Description: The Atlantic Water flow from the Barents and Kara seas to the Arctic Ocean through the St. Anna Trough (SAT) is conditioned by interaction between Fram Strait branch water circulating in the SAT and Barents Sea branch water—both of Atlantic origin. Here we present data from an oceanographic mooring deployed on the eastern flank of the SAT from September 2009 to September 2010 as well as CTD (conductivity-temperature-depth) sections across the SAT. A distinct vertical density front over the SAT eastern slope deeper than ∼50 m is attributed to the outflow of Barents Sea branch water to the Arctic Ocean. In turn, the Barents Sea branch water flow to the Arctic Ocean is conditioned by two water masses defined by relative low and high fractions of the Atlantic Water. They are also traceable in the Nansen Basin downstream of the SAT entrance. A persistent northward current was recorded in the subsurface layer along the SAT eastern slope with a mean velocity of 18 cm s−1 at 134–218 m and 23 cm s−1 at 376–468 m. Observations and modeling suggest that the SAT flow has a significant density-driven component. It is therefore expected to respond to changes in the cross-trough density gradient conditioned by interaction between the Fram Strait and Barents Sea branches. Further modeling efforts are necessary to investigate hydrodynamic instability and eddy generation caused by the interaction between the SAT flow and the Arctic Ocean Fram Strait branch water boundary current.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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