scholarly journals The spatial and interannual dynamics of the surface water carbonate system and air–sea CO<sub>2</sub> fluxes in the outer shelf and slope of the Eurasian Arctic Ocean

Ocean Science ◽  
2017 ◽  
Vol 13 (6) ◽  
pp. 997-1016 ◽  
Author(s):  
Irina I. Pipko ◽  
Svetlana P. Pugach ◽  
Igor P. Semiletov ◽  
Leif G. Anderson ◽  
Natalia E. Shakhova ◽  
...  
Keyword(s):  
Time Series ◽  
Surface Water ◽  
High Resolution ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Outer Shelf ◽  
The Arctic ◽  
Arctic Seas ◽  
Carbonate System ◽  
The Arctic Ocean

Abstract. The Arctic is undergoing dramatic changes which cover the entire range of natural processes, from extreme increases in the temperatures of air, soil, and water, to changes in the cryosphere, the biodiversity of Arctic waters, and land vegetation. Small changes in the largest marine carbon pool, the dissolved inorganic carbon pool, can have a profound impact on the carbon dioxide (CO2) flux between the ocean and the atmosphere, and the feedback of this flux to climate. Knowledge of relevant processes in the Arctic seas improves the evaluation and projection of carbon cycle dynamics under current conditions of rapid climate change. Investigation of the CO2 system in the outer shelf and continental slope waters of the Eurasian Arctic seas (the Barents, Kara, Laptev, and East Siberian seas) during 2006, 2007, and 2009 revealed a general trend in the surface water partial pressure of CO2 (pCO2) distribution, which manifested as an increase in pCO2 values eastward. The existence of this trend was defined by different oceanographic and biogeochemical regimes in the western and eastern parts of the study area; the trend is likely increasing due to a combination of factors determined by contemporary change in the Arctic climate, each change in turn evoking a series of synergistic effects. A high-resolution in situ investigation of the carbonate system parameters of the four Arctic seas was carried out in the warm season of 2007; this year was characterized by the next-to-lowest historic sea-ice extent in the Arctic Ocean, on satellite record, to that date. The study showed the different responses of the seawater carbonate system to the environment changes in the western vs. the eastern Eurasian Arctic seas. The large, open, highly productive water area in the northern Barents Sea enhances atmospheric CO2 uptake. In contrast, the uptake of CO2 was strongly weakened in the outer shelf and slope waters of the East Siberian Arctic seas under the 2007 environmental conditions. The surface seawater appears in equilibrium or slightly supersaturated by CO2 relative to atmosphere because of the increasing influence of river runoff and its input of terrestrial organic matter that mineralizes, in combination with the high surface water temperature during sea-ice-free conditions. This investigation shows the importance of processes that vary on small scales, both in time and space, for estimating the air–sea exchange of CO2. It stresses the need for high-resolution coverage of ocean observations as well as time series. Furthermore, time series must include multi-year studies in the dynamic regions of the Arctic Ocean during these times of environmental change.

scholarly journals The dynamics of the carbon dioxide system in the outer shelf and slope of the Eurasian Arctic Ocean

2017 ◽  
Author(s):  
Irina I. Pipko ◽  
Svetlana P. Pugach ◽  
Igor P. Semiletov ◽  
Leif G. Anderson ◽  
Natalia E. Shakhova ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Time Series ◽  
Surface Water ◽  
High Resolution ◽  
Arctic Ocean ◽  
Outer Shelf ◽  
The Arctic ◽  
Arctic Seas ◽  
Carbonate System ◽  
The Arctic Ocean

Abstract. The Arctic now is undergoing dramatic changes, which cover the entire range of natural processes; from extreme increases in the temperatures of air, soil, and water, to changes in the cryosphere, the biodiversity of Arctic waters, and land vegetation. Small changes in the largest marine carbon pool, the dissolved inorganic carbon pool, can have profound impact on the carbon dioxide (CO2) flux between the ocean and the atmosphere, and the feedback of this flux to climate. Knowledge of relevant processes in the Arctic seas improves the evaluation and projection of the carbon cycle dynamics under conditions of rapid climate change. Investigation of the CO2 system in the outer shelf and continental slope waters of the Eurasian Arctic seas (the Barents, Kara, Laptev, and East Siberian seas) during 2006, 2007, and 2009 revealed a general trend in the surface water pCO2 distribution, which manifested as an increase in pCO2 values eastward. Existence of this trend was determined by different oceanographic and biogeochemical regimes in the western and eastern parts of the study area; the trend is likely increasing due to a combination of factors determined by contemporary change in the Arctic climate, each change in turn evoked a series of synergistic effects. A high-resolution in situ investigation of the carbonate system parameters of the four Arctic seas was carried out in the warm season of 2007, which was characterized by the next-to-lowest historic sea ice extent in the Arctic Ocean to that date. The study showed the different responses of the seawater carbonate system to the environment changes in the western vs. the eastern Eurasian Arctic seas. The large open, highly-productive water area in the northern Barents Sea enhances atmospheric CO2 uptake. In contrast, a growing CO2 evasion occurs in the outer shelf and slope waters of the East Siberian Arctic seas as a result of the increasing influence of river runoff and degradation of terrestrial organic matter, in combination with the high surface-water temperature due to the warm air temperature and decreasing albedo during sea ice free conditions. This investigation shows the importance of processes that vary on small scales, both in time and space, for estimating the air-sea exchange of CO2. It stresses the need for high-resolution coverage of ocean observations as well as time series. Furthermore, time series must include multi-year studies in the dynamic regions of the Arctic Ocean during these times of environmental change.

scholarly journals Dynamics in the Deep Canada Basin, Arctic Ocean, Inferred by Thermistor Chain Time Series

2007 ◽  
Vol 37 (4) ◽  
pp. 1066-1076 ◽  
Author(s):  
M-L. Timmermans ◽  
H. Melling ◽  
L. Rainville
Keyword(s):  
Time Series ◽  
High Resolution ◽  
Internal Wave ◽  
Arctic Ocean ◽  
Temperature Fluctuations ◽  
Canada Basin ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Vertical Displacements ◽  
Wave Energy Flux

Abstract A 50-day time series of high-resolution temperature in the deepest layers of the Canada Basin in the Arctic Ocean indicates that the deep Canada Basin is a dynamically active environment, not the quiet, stable basin often assumed. Vertical motions at the near-inertial (tidal) frequency have amplitudes of 10– 20 m. These vertical displacements are surprisingly large considering the downward near-inertial internal wave energy flux typically observed in the Canada Basin. In addition to motion in the internal-wave frequency band, the measurements indicate distinctive subinertial temperature fluctuations, possibly due to intrusions of new water masses.

scholarly journals On the future navigability of Arctic sea routes: High-resolution projections of the Arctic Ocean and sea ice

Marine Policy ◽  
2017 ◽  
Vol 75 ◽  
pp. 300-317 ◽  
Author(s):  
Yevgeny Aksenov ◽  
Ekaterina E. Popova ◽  
Andrew Yool ◽  
A.J. George Nurser ◽  
Timothy D. Williams ◽  
...  
Keyword(s):  
High Resolution ◽  
Sea Ice ◽  
Arctic Ocean ◽  
The Arctic ◽  
Arctic Sea ◽  
The Arctic Ocean ◽  
The Future

scholarly journals Marine Heatwaves in Siberian Arctic Seas and Adjacent Region

2021 ◽  
Vol 13 (21) ◽  
pp. 4436
Author(s):  
Elena Golubeva ◽  
Marina Kraineva ◽  
Gennady Platov ◽  
Dina Iakshina ◽  
Marina Tarkhanova
Keyword(s):  
Numerical Modeling ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Northern Region ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Arctic Seas ◽  
Siberian Arctic ◽  
The Arctic Ocean ◽  
The Impact

We used a satellite-derived global daily sea surface temperature (SST) dataset with resolution 0.25 × 0.25∘ to analyze interannual changes in the Arctic Shelf seas from 2000 to 2020 and to reveal extreme events in SST distribution. Results show that the second decade of the 21st century for the Siberian Arctic seas turned significantly warmer than the first decade, and the increase in SST in the Arctic seas could be considered in terms of marine heatwaves. Analyzing the spatial distribution of heatwaves and their characteristics, we showed that from 2018 to 2020, the surface warming extended to the northern deep-water region of the Laptev Sea 75∘ to 81∘N. To reveal the most important forcing for the northward extension of the marine heatwaves, we used three-dimensional numerical modeling of the Arctic Ocean based on a sea-ice and ocean model forced by the NCEP/NCAR Reanalysis. The simulation of the Arctic Ocean variability from 2000 to 2020 showed marine heatwaves and their increasing intensity in the northern region of the Kara and Laptev seas, closely connected to the disappearance of ice cover. A series of numerical experiments on the sensitivity of the model showed that the main factors affecting the Arctic sea-ice loss and the formation of anomalous temperature north of the Siberian Arctic seas are equally the thermal and dynamic effects of the atmosphere. Numerical modeling allows us to examine the impact of other physical mechanisms as well. Among them were the state of the ocean and winter sea ice, the formation of fast ice polynias and riverine heat influx.

Understanding eddy field in the Arctic Ocean from high-resolution satellite observations

2020 ◽  
Author(s):  
Igor Kozlov ◽  
Anastasia Artamonova ◽  
Larisa Petrenko ◽  
Evgeny Plotnikov ◽  
Georgy Manucharyan ◽  
...  
Keyword(s):  
High Resolution ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Ocean Circulation ◽  
The Arctic ◽  
Special Focus ◽  
Deep Basin ◽  
Eddy Characteristics ◽  
Ice Concentration ◽  
The Arctic Ocean

&lt;p&gt;The Arctic Ocean is a host to major ocean circulation systems, many of which generate eddies that can transport water masses and corresponding tracers over long distances from their formation sites. However, comprehensive observations of critical eddy characteristics are currently not available and are limited to spatially and temporally sparse in situ observations.&lt;/p&gt;&lt;p&gt;Here we use multi-mission high&amp;#8208;resolution spaceborne synthetic aperture radar (SAR) measurements to detect eddies over open ocean and marginal ice zones (MIZ) of Fram Strait and Beaufort Gyre regions. We provide the first estimate of eddy properties, including their locations, size, vorticity sign and monthly distribution during summer period (from June to October). The results of historical Envisat ASAR observations for 2007 and 2011 are then compared to Sentinel-1 and ALOS-2 PALSAR-2 measurements acquired in 2016 and 2018, to infer the possible changes in the intensity and locations of eddy generation over the last decade.&lt;/p&gt;&lt;p&gt;The most prominent feature of the obtained results is that cyclonic eddies strongly dominate over anticyclones. Eddies range in size between 0.5 and 100 km and are frequently found over the shelf and near continental slopes but also present in the deep basin. For MIZ eddies, the number of eddies clearly depends on sea ice concentration with more eddies detected at the ice edge and over low ice concentration regions. The obtained results clearly show that eddies are ubiquitous in the Arctic Ocean even in the presence of sea ice and emphasize the need for improved ocean observations and modeling at eddy scales.&lt;/p&gt;&lt;p&gt;A special focus is also given to infer eddy dynamics over the Arctic marginal ice zones. The use of sequential Sentinel-1 SAR images enables to retrieve high-resolution velocity field over MIZ on a daily basis and observe eddy-driven MIZ dynamics down to submesoscales. The obtained eddy orbital velocities are in agreement with historical observations and may reach up to 0.5-0.7 m/s. We believe that this information is critical for better understanding of the key dynamical processes governing the MIZ state, as well as for improving and validation of sea ice and coupled ice-ocean models.&lt;/p&gt;&lt;p&gt;The analysis of eddies in this work was supported by RFBR grant 18&amp;#8208;35&amp;#8208;20078. Processing and analysis of Sentinel&amp;#8208;1 and ALOS&amp;#8208;2 Palsar&amp;#8208;2 data were done within RSF grant 18&amp;#8208;77&amp;#8208;00082. Software development for data analysis in this work was made under the Ministry of Science and Higher Education of the Russian Federation contract 0555&amp;#8208;2019&amp;#8208;0001.&lt;/p&gt;

The impact of shallow stratification on air-sea CO2 flux in the summer Arctic Ocean

2021 ◽  
Author(s):  
Yuanxu Dong ◽  
Dorothee Bakker ◽  
Thomas Bell ◽  
Peter Liss ◽  
Ian Brown ◽  
...  
Keyword(s):  
Surface Water ◽  
Wind Speed ◽  
Sea Ice ◽  
Surface Temperature ◽  
Arctic Ocean ◽  
The Arctic ◽  
Near Surface ◽  
Ice Melt ◽  
The Arctic Ocean ◽  
The Impact

&lt;p&gt;Air-sea carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) flux is often indirectly estimated by the bulk method using the i&lt;em&gt;n-situ&lt;/em&gt; air-sea difference in CO&lt;sub&gt;2&lt;/sub&gt; fugacity and a wind speed dependent parameterisation of the gas transfer velocity (&lt;em&gt;K&lt;/em&gt;). In the summer, sea-ice melt in the Arctic Ocean generates strong shallow stratification with significant gradients in temperature, salinity, dissolved inorganic carbon (DIC) and alkalinity (TA), and thus a near-surface CO&lt;sub&gt;2&lt;/sub&gt; fugacity &amp;#160;(&lt;em&gt;f&lt;/em&gt;CO&lt;sub&gt;2w&lt;/sub&gt;) gradient. This gradient can cause an error in bulk air-sea CO&lt;sub&gt;2&lt;/sub&gt; flux estimates when the &lt;em&gt;f&lt;/em&gt;CO&lt;sub&gt;2w&lt;/sub&gt; is measured by the ship&amp;#8217;s underway system at ~5 m depth. Direct air-sea CO&lt;sub&gt;2&lt;/sub&gt; flux measurement by eddy covariance (EC) is free from the impact of shallow stratification because the EC CO&lt;sub&gt;2&lt;/sub&gt; flux does not rely on a &lt;em&gt;f&lt;/em&gt;CO&lt;sub&gt;2w&lt;/sub&gt; measurement. In this study, we use summertime EC flux measurements from the Arctic Ocean to back-calculate the sea surface &lt;em&gt;f&lt;/em&gt;CO&lt;sub&gt;2w&lt;/sub&gt; and temperature and compare them with the underway measurements. We show that the EC air-sea CO&lt;sub&gt;2&lt;/sub&gt; flux agrees well with the bulk flux in areas less likely to be influenced by ice melt (salinity &gt; 32). However, in regions with salinity less than 32, the underway &lt;em&gt;f&lt;/em&gt;CO&lt;sub&gt;2w&lt;/sub&gt; is higher than the EC estimate of surface &lt;em&gt;f&lt;/em&gt;CO&lt;sub&gt;2w&lt;/sub&gt; and thus the bulk estimate of ocean CO&lt;sub&gt;2&lt;/sub&gt; uptake is underestimated. The &lt;em&gt;f&lt;/em&gt;CO&lt;sub&gt;2w&lt;/sub&gt; difference can be partly explained by the surface to sub-surface temperature difference. The EC estimate of surface temperature is lower than the sub-surface water temperature and this difference is wind speed-dependent. Upper-ocean salinity gradients from CTD profiles suggest likely difference in DIC and TA concentrations between the surface and sub-surface water. These DIC and TA gradients likely explain much of the near-surface &lt;em&gt;f&lt;/em&gt;CO&lt;sub&gt;2w&lt;/sub&gt; gradient. Accelerating summertime loss of sea ice results in additional meltwater, which enhances near-surface stratification and increases the uncertainty of bulk air-sea CO&lt;sub&gt;2&lt;/sub&gt; flux estimates in polar regions.&lt;/p&gt;

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