The Physical Oceanography of the Arctic Mediterranean Sea

2022 ◽  
ZooKeys ◽  
2018 ◽  
Vol 771 ◽  
pp. 15-40 ◽  
Author(s):  
Hiroshi Yamasaki ◽  
Katarzyna Grzelak ◽  
Martin V. Sørensen ◽  
Birger Neuhaus ◽  
Kai Horst George

Kinorhynchs rarely show a wide distribution pattern, due to their putatively low dispersal capabilities and/or limited sampling efforts. In this study, a new kinorhynch species is described,Echinoderespterussp. n., which shows a geographically and bathymetrically wide distribution, occurring on the Karasik Seamount and off the Svalbard Islands (Arctic Ocean), on the Sedlo Seamount (northeast Atlantic Ocean), and on the deep-sea floor off Crete and on the Anaximenes Seamount (Mediterranean Sea), at a depth range of 675–4,403 m. The new species is characterized by a combination of middorsal acicular spines on segments 4–8, laterodorsal tubes on segment 10, lateroventral tubes on segment 5, lateroventral acicular spines on segments 6–9, tufts of long hairs rising from slits in a laterodorsal position on segment 9, truncated tergal extensions on segment 11, and the absence of any type-2 gland cell outlet. The specimens belonging to the populations from the Arctic Ocean, the Sedlo Seamount, and the Mediterranean Sea show morphological variation in the thickness and length of the spines as well as in the presence/absence of ventromedial sensory spots on segment 7. The different populations are regarded as belonging to a single species because of their overlapping variable characters.


2015 ◽  
Vol 28 (10) ◽  
pp. 4015-4026 ◽  
Author(s):  
Jinqing Zuo ◽  
Hong-Li Ren ◽  
Weijing Li

Abstract In the boreal winter, the Arctic Oscillation (AO) evidently acts to influence surface air temperature (SAT) anomalies in China. This study reveals a large intraseasonal variation in the relationship between the winter AO and southern China SAT anomalies. Specifically, a weak in-phase relationship occurs in December, but a significant out-of-phase relationship occurs in January and February. The authors show that the linkage between the AO and southern China SAT anomalies strongly depends on the AO-associated changes in the Middle East jet stream (MEJS) and that such an AO–MEJS relationship is characterized by a significant difference between early and middle-to-late winter. In middle-to-late winter, the Azores center of high pressure anomalies in the positive AO phase usually extends eastward and yields a significantly anomalous upper-level convergence over the Mediterranean Sea, which can excite a Rossby wave train spanning the Arabian Sea and intensify the MEJS. In early winter, however, the Azores center of the AO is apparently shifted westward and is mainly confined to the Atlantic Ocean; in this case, the associated change in the MEJS is relatively weak. Both observational diagnoses and experiments based on a linearized barotropic model suggest that the MEJS is closely linked to the AO only when the latter generates considerable upper-level convergence anomalies over the Mediterranean Sea. Therefore, the different impacts of the AO on the MEJS and the southern China SAT anomalies between early and middle-to-late winter are primarily attributed to the large intraseasonal zonal migrations of the Azores center of the AO.


2017 ◽  
Author(s):  
Axel Behrendt ◽  
Hiroshi Sumata ◽  
Benjamin Rabe ◽  
Ursula Schauer

Abstract. UDASH is a unified and high-quality temperature and salinity data set for the Arctic Ocean and the subpolar seas north of 65° N for the period 1980–2015. The archive aims at including all publicly available data and so far consists of 288 532 oceanographic profiles measured mainly with conductivity/temperature/depth (CTD) probes, bottles, mechanical thermographs and expendable thermographs. The data were collected by ships, ice-tethered profilers, profiling floats and other platforms. To achieve a uniform quality level, suitable for a wide range of oceanographic analyses, approximately 74 million single measurements of temperature and salinity were thoroughly quality-checked. A large number of duplicate and erroneous profiles were detected and not included into the archive. Data outliers, suspicious gradients and other suspect data were flagged for quick identification. The final archive provides a unique and simple way of accessing most of the available temperature and salinity data for the Arctic Mediterranean Sea and can be downloaded from https://doi.org/10.1594/PANGAEA.872931.


2021 ◽  
Author(s):  
Shun Yang ◽  
Haibin Song ◽  
Kun Zhang

<p>The eddies are ubiquitous in the ocean and play an important role in the transportation and redistribution of heat, salt, carbon, nutrients and other materials in the global ocean, thus can regulate global climate and affect the distribution of marine organism. Compared with mesoscale eddies, submesoscale vortices (SVs) have smaller spatial and temporal scales, which impose higher requirements on observation and simulation. The oceanic SVs have a strong vertical velocity, which provides an important supply of nutrients in the upper ocean.</p><p>Many researchers have studied the SVs in the Arctic Ocean by physical oceanography methods (e.g., <em>in-situ </em>measurements and satellite observations). Here, we found a perfect bowl-like SV using a new method named seismic oceanography (SO). SO can use multichannel seismic (MCS) reflection data to produce surprisingly detailed images of water column. Compared with the traditional physical oceanography methods, SO has the advantages of high acquisition efficiency, high lateral resolution (~10 m) and full depth imaging of seawater.</p><p>We used MCS data to image the water column in the in autumn Northeast Chukchi Sea, and captured a perfect bowl-like structure with a depth range of ~200-620m. The structure is almost bilaterally symmetric and has dip angles of 4.8° and 5.5° on the left and on the right, respectively. And it has a horizontal scale of about 12 km at the top and 4.5 km at the bottom, and both the top and bottom of it are near horizontal. The reflections are almost blank in its interior, but are intense and very narrow (~30 m thick) at the lateral boundaries. This indicated that the interior water is homogeneous and quite different from that around it. Fortunately, there is an XBT station near the seismic line and collected almost simultaneously (only one day apart) with the seismic line. The XBT station shows obvious high temperature anomaly over 2°C at the depth of 210-700 m. Therefore, we concluded the structure is a subsurface warm SV, i.e. anticyclonic warm eddy, and may be a submesoscale coherent vortex (SCV). The anomalies from the surrounding water masses indicate that the SV was created at the edge of the Arctic Ocean and then advected here.</p><p>In addition, we used Rossby number (Ro) and Okubo-Weiss (OW) parameter calculated from daily-averaged re-analysis hydrographic data (~3.5 km of grid spacing at 75°N ) from Copernicus Marine Environment Monitoring Service (CMEMS) to analyze the SV. Result shows that the values of the Ro and OW parameter in the area of the SV are both negative. This also suggests that this SV is an anticyclone. This submesoscale anticyclonic vortex may be generated from the friction effect between the warm inflow from the North Pacific and the right wall of Barrow Canyon after passing through the Bering Strait, and then transported to the Northeast of Chukchi Sea by the Beaufort Gyre.</p>


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Tatiana Talipova ◽  
Efim Pelinovsky ◽  
Oxana Kurkina ◽  
Andrey Kurkin

Numerical modeling of dispersive shock waves called solibore in a stratified fluid is conducted. The theoretical model is based on extended version of the Korteweg-de Vries equation which takes into account the effects of cubic nonlinearity and Earth rotation. This model is now very popular in the physical oceanography. Initial conditions for simulations correspond to the real observed internal waves of shock-like shape in the Pechora Sea, the Arctic. It is shown that a sharp drop (like kink in the soliton theory) in the depth of the thermocline is conserved at a distance of one–three kilometers, and then it is transformed into dispersive shock waves (shock wave with undulations).


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