scholarly journals Surface signature of Mediterranean water eddies in the North-East Atlantic: effect of the upper ocean stratification

2012 ◽  
Vol 9 (4) ◽  
pp. 2457-2491 ◽  
Author(s):  
I. Bashmachnikov ◽  
X. Carton
Keyword(s):  
Initial Period ◽  
Sea Surface ◽  
Upper Ocean ◽  
Buoyancy Frequency ◽  
Coriolis Parameter ◽  
Ocean Stratification ◽  
North East ◽  
The North ◽  
Surface Signature ◽  
Mediterranean Water

Abstract. Meddies, intra-thermocline eddies of Mediterranean water, are often visible at the sea surface as positive sea-level anomalies. Here we study the surface signature of several meddies tracked with RAFOS floats and AVISO altimetry. Then, theoretical estimates of the surface signature of a meddy are derived, based on geostrophy and potential vorticity balance. The intensity of the surface signature is proportional to the meddy core radius and to the Coriolis parameter, and inversely proportional to the core depth and buoyancy frequency. This indicates that surface signature of a meddy may be strongly reduced by the upper ocean stratification. Estimates suggest that the southernmost limit for detection in altimetry of small meddies (with radii on the order of 15 km) should lie in the northern subtropics, while large meddies (with radii of 25–30 km) could be detected as far south as the northern tropics. During the initial period of meddy acceleration after meddy formation or a stagnation stage, a cyclonic signal also is generated at the sea-surface, but mostly the anticyclonic surface signal follows the meddy.

scholarly journals Surface signature of Mediterranean water eddies in the Northeastern Atlantic: effect of the upper ocean stratification

Ocean Science ◽  
2012 ◽  
Vol 8 (6) ◽  
pp. 931-943 ◽  
Author(s):  
I. Bashmachnikov ◽  
X. Carton
Keyword(s):  
Potential Vorticity ◽  
Initial Period ◽  
Relative Vorticity ◽  
Sea Surface ◽  
Upper Ocean ◽  
Buoyancy Frequency ◽  
Coriolis Parameter ◽  
Ocean Stratification ◽  
Surface Signature ◽  
Mediterranean Water

Abstract. Meddies, intra-thermocline eddies of Mediterranean water, can often be detected at the sea surface as positive sea-level anomalies. Here we study the surface signature of several meddies tracked with RAFOS floats and AVISO altimetry. While pushing its way through the water column, a meddy raises isopycnals above. As a consequence of potential vorticity conservation, negative relative vorticity is generated in the upper layer. During the initial period of meddy acceleration after meddy formation or after a stagnation stage, a cyclonic signal is also generated at the sea-surface, but mostly the anticyclonic surface signal follows the meddy. Based on geostrophy and potential vorticity balance, we present theoretical estimates of the intensity of the surface signature. It appears to be proportional to the meddy core radius and to the Coriolis parameter, and inversely proportional to the core depth and buoyancy frequency. This indicates that surface signature of a meddy may be strongly reduced by the upper ocean stratification. Using climatic distribution of the stratification intensity, we claim that the southernmost limit for detection in altimetry of small meddies (with radii on the order of 10–15 km) should lie in the subtropics (35–45° N), while large meddies (with radii of 25–30 km) could be detected as far south as the northern tropics (25–35° N). Those results agree with observations.

scholarly journals Energetic Submesoscales Maintain Strong Mixed Layer Stratification during an Autumn Storm

2017 ◽  
Vol 47 (10) ◽  
pp. 2419-2427 ◽  
Author(s):  
Daniel B. Whitt ◽  
John R. Taylor
Keyword(s):  
Mixed Layer ◽  
North Atlantic ◽  
Small Scale ◽  
Upper Ocean ◽  
Ocean Mixed Layer ◽  
Ocean Stratification ◽  
The North ◽  
Large Eddy ◽  
The Mean ◽  
Scale Turbulence

AbstractAtmospheric storms are an important driver of changes in upper-ocean stratification and small-scale (1–100 m) turbulence. Yet, the modifying effects of submesoscale (0.1–10 km) motions in the ocean mixed layer on stratification and small-scale turbulence during a storm are not well understood. Here, large-eddy simulations are used to study the coupled response of submesoscale and small-scale turbulence to the passage of an idealized autumn storm, with a wind stress representative of a storm observed in the North Atlantic above the Porcupine Abyssal Plain. Because of a relatively shallow mixed layer and a strong downfront wind, existing scaling theory predicts that submesoscales should be unable to restratify the mixed layer during the storm. In contrast, the simulations reveal a persistent and strong mean stratification in the mixed layer both during and after the storm. In addition, the mean dissipation rate remains elevated throughout the mixed layer during the storm, despite the strong mean stratification. These results are attributed to strong spatial variability in stratification and small-scale turbulence at the submesoscale and have important implications for sampling and modeling submesoscales and their effects on stratification and turbulence in the upper ocean.

scholarly journals Role of the Atlantic multidecadal variability in modulating East Asian climate

2020 ◽  
Author(s):  
Paul-Arthur Monerie ◽  
Jon Robson ◽  
Buwen Dong ◽  
Dan Hodson
Keyword(s):  
Pacific Ocean ◽  
Surface Temperature ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Sea Surface ◽  
Western Pacific Ocean ◽  
North East ◽  
The North ◽  
Circumglobal Teleconnection ◽  
The North Atlantic

Abstract We assess the effects of the North Atlantic Ocean Sea Surface Temperature (NASST) on North East Asian (NEA) surface temperature. We use a set of sensitivity experiments, performed with MetUM-GOML2, an atmospheric general circulation model coupled to a multi-level ocean mixed layer model, to mimic warming and cooling over the North Atlantic Ocean. Results show that a warming of the NASST is associated with a significant warming over NEA. Two mechanisms are pointed out to explain the NASST—North East Asia surface temperature relationship. First, the warming of the NASST is associated with a modulation of the northern hemisphere circulation, due to the propagation of a Rossby wave (i.e. the circumglobal teleconnection). The change in the atmosphere circulation is associated with advections of heat from the Pacific Ocean to NEA and with an increase in net surface shortwave radiation over NEA, both acting to increase NEA surface temperature. Second, the warming of the NASST is associated with a cooling (warming) over the eastern (western) Pacific Ocean, which modulates the circulation over the western Pacific Ocean and NEA. Additional simulations, in which Pacific Ocean sea surface temperatures are kept constant, show that the modulation of the circumglobal teleconnection is key to explaining impacts of the NASST on NEA surface temperature.

scholarly journals Sea surface height variability in the North East Atlantic from satellite altimetry

2015 ◽  
Vol 47 (3-4) ◽  
pp. 1285-1302 ◽  
Author(s):  
Paul Sterlini ◽  
Hylke de Vries ◽  
Caroline Katsman
Keyword(s):  
Satellite Altimetry ◽  
Sea Surface Height ◽  
Sea Surface ◽  
East Atlantic ◽  
North East ◽  
The North

scholarly journals Deglacial development of (sub) sea surface temperature and salinity in the subarctic northwest Pacific: Implications for upper-ocean stratification

2013 ◽  
Vol 28 (1) ◽  
pp. 91-104 ◽  
Author(s):  
Jan-Rainer Riethdorf ◽  
Lars Max ◽  
Dirk Nürnberg ◽  
Lester Lembke-Jene ◽  
Ralf Tiedemann
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Sea Surface ◽  
Upper Ocean ◽  
Northwest Pacific ◽  
Ocean Stratification

AGROENERGY AND ECONOMIC EFFICIENCY OF CREATION OF GRASS AND LEGUME-GRASS PASTURES IN THE NORTH-EAST OF THE NON-CHERNOZEM ZONE

2020 ◽  
Author(s):  
Maria Shchannikova ◽  
Dalhat Teberdiev
Keyword(s):  
Russian Federation ◽  
Initial Period ◽  
Economic Assessment ◽  
Total Expenditure ◽  
North East ◽  
The North ◽  
Fodder Production ◽  
The Russian Federation ◽  
Energy Coefficient ◽  
The Cost

In the article presents the agro-energy and economic assessment of the creation and use of grass and legume-grass herbages in the initial period of the organization of cultural pastures in the North-East of the Non-chernozem zone of the Russian Federation. Fodder production was 53–61 GJ/ha on grass pastures and 56–75 GJ/ha on legume-grass pastures. The total expenditure of anthropogenic energy was 43.1–46.8 GJ/ha on grass herbages and 23.4–25.0 GJ/ha on legume-grass herbages. The agro-energy coefficient on legume-grass herbages (239–300 %) was higher than on grass herbages (123–132 %). The cost of produced feed was 35.9–43.5 thousand rubles / ha on grass pastures and 39.8–54.5 thousand rubles/ha on legume-grass pastures. Total expenditures were 40.5–42.5 thousand rubles/ha on grass pastures and 30.2–32.5 thousand rubles/ha on legume-grass pastures. The cost of producing 100 fodder units legume-grass pastures was in 1.4–1.7 times lower than grass pastures ones.

scholarly journals Upper-Ocean Mixed Layer and Wintertime Sea Surface Temperature Anomalies in the North Pacific

2006 ◽  
Vol 19 (2) ◽  
pp. 300-307 ◽  
Author(s):  
Tomohiko Tomita ◽  
Masami Nonaka
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Mixed Layer ◽  
North Pacific ◽  
Sea Surface ◽  
Upper Ocean ◽  
Ocean Mixed Layer ◽  
The North ◽  
The Impact ◽  
The North Pacific

Abstract In the North Pacific, the wintertime sea surface temperature anomaly (SSTA), which is represented by March (SSTAMar), when the upper-ocean mixed layer depth (hMar) reaches its maximum, is formed by the anomalous surface forcing from fall to winter (S′). As a parameter of volume, hMar has a potential to modify the impact of S′ on SSTAMar. Introducing an upper-ocean heat budget equation, the present study identifies the physical relationship among the spatial distributions of hMar, S′, and SSTAMar. The long-term mean of hMar adjusts the spatial distribution of SSTAMar. Without the adjustment, the impact of S′ on SSTAMar is overestimated where the hMar mean is deep. Since hMar is partially due to seawater temperature, it leads to nonlinearity between the S′ and the SSTAMar. When the SSTAMar is negative (positive), the sensitivity to S′ is impervious (responsive) with the deepening (shoaling) of the hMar compared to the linear sensitivity. The thermal impacts from the ocean to the atmosphere might be underestimated under the assumption of the linear relationship.

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