scholarly journals Warm Spiral Streamers over Gulf Stream Warm-Core Rings

2020 ◽  
Vol 50 (11) ◽  
pp. 3331-3351
Author(s):  
Weifeng (Gordon) Zhang ◽  
Dennis J. McGillicuddy
Keyword(s):  
Surface Waters ◽  
Gulf Stream ◽  
Large Scale ◽  
Vertical Structure ◽  
Water Mass ◽  
Field Measurements ◽  
Mesoscale Dynamics ◽  
Density Anomaly ◽  
Warm Core ◽  
Spiral Structures

AbstractThis study examines the generation of warm spiral structures (referred to as spiral streamers here) over Gulf Stream warm-core rings. Satellite sea surface temperature imagery shows spiral streamers forming after warmer water from the Gulf Stream or newly formed warm-core rings impinges onto old warm-core rings and then intrudes into the old rings. Field measurements in April 2018 capture the vertical structure of a warm spiral streamer as a shallow lens of low-density water winding over an old ring. Observations also show subduction on both sides of the spiral streamer, which carries surface waters downward. Idealized numerical model simulations initialized with observed water-mass densities reproduce spiral streamers over warm-core rings and reveal that their formation is a nonlinear submesoscale process forced by mesoscale dynamics. The negative density anomaly of the intruding water causes a density front at the interface between the intruding water and surface ring water, which, through thermal wind balance, drives a local anticyclonic flow. The pressure gradient and momentum advection of the local interfacial flow push the intruding water toward the ring center. The large-scale anticyclonic flow of the ring and the radial motion of the intruding water together form the spiral streamer. The observed subduction on both sides of the spiral streamer is part of the secondary cross-streamer circulation resulting from frontogenesis on the stretching streamer edges. The surface divergence of the secondary circulation pushes the side edges of the streamer away from each other, widens the warm spiral on the surface, and thus enhances its surface signal.

scholarly journals The Gulf Stream North Wall: Ageostrophic Circulation and Frontogenesis

2019 ◽  
Vol 49 (4) ◽  
pp. 893-916 ◽  
Author(s):  
James C. McWilliams ◽  
Jonathan Gula ◽  
M. Jeroen Molemaker
Keyword(s):  
Gulf Stream ◽  
Large Scale ◽  
Vertical Structure ◽  
Large Change ◽  
Cross Wall ◽  
Western Boundary ◽  
Zonal Jets ◽  
North Wall ◽  
Ageostrophic Circulation ◽  
Northern Wall

AbstractEastward zonal jets are common in the ocean and atmosphere, for example, the Gulf Stream and jet stream. They are characterized by atypically strong horizontal velocity, baroclinic vertical structure with an upward flow intensification, large change in the density stratification meridionally across the jet, large-scale meanders around a central latitude, narrow troughs and broad crests, and a sharp and vertically sloping northern (poleward) “wall” defined by horizontal maxima in the lateral gradients of both velocity and density. Measurements and realistic oceanic simulations show these features in the Gulf Stream downstream from its western boundary separation point. A diagnostic theory based on the conservative balance equations is developed to calculate the 3D velocity field associated with the dynamic height field. When applied to an idealized representation of a meandering jet, it explains the spatial structure of the associated ageostrophic secondary circulation around the jet and the positive frontogenetic tendency along the northern wall in the meander sector located upstream from the trough. This provides a basis for understanding why submesoscale instabilities and cross-wall intrusion and streamer events are more prevalent along the sector downstream from the trough and at the crest where there is not such a frontogenetic tendency. An important attribute for this frontogenesis pattern is the 3D shape of the jet, whose idealization is summarized above.

scholarly journals Understanding physical drivers of the 2015/16 marine heatwaves in the Northwest Atlantic

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
E. Perez ◽  
S. Ryan ◽  
M. Andres ◽  
G. Gawarkiewicz ◽  
C. C. Ummenhofer ◽  
...  
Keyword(s):  
Gulf Stream ◽  
Vertical Structure ◽  
Global Ocean ◽  
Jet Stream ◽  
Temperature Structure ◽  
Northwest Atlantic ◽  
Important Species ◽  
Warm Core ◽  
Latitudinal Position ◽  
Commercially Important

AbstractThe Northwest Atlantic, which has exhibited evidence of accelerated warming compared to the global ocean, also experienced several notable marine heatwaves (MHWs) over the last decade. We analyze spatiotemporal patterns of surface and subsurface temperature structure across the Northwest Atlantic continental shelf and slope to assess the influences of atmospheric and oceanic processes on ocean temperatures. Here we focus on MHWs from 2015/16 and examine their physical drivers using observational and reanalysis products. We find that a combination of jet stream latitudinal position and ocean advection, mainly due to warm core rings shed by the Gulf Stream, plays a role in MHW development. While both atmospheric and oceanic drivers can lead to MHWs they have different temperature signatures with each affecting the vertical structure differently and horizontal spatial patterns of a MHW. Northwest Atlantic MHWs have significant socio-economic impacts and affect commercially important species such as squid and lobster.

scholarly journals Specialty of vertical water exchange of the Caspian sea on the basis of distribution of transient tracers

2019 ◽  
Vol 46 (5) ◽  
pp. 496-502
Author(s):  
V. S. Brezgunov
Keyword(s):  
Deep Water ◽  
Surface Waters ◽  
Caspian Sea ◽  
Large Scale ◽  
Water Exchange ◽  
Vertical Structure ◽  
Gravitational Convection ◽  
The Caspian Sea ◽  
Structure Of Water ◽  
Geochemical Studies

The analysis of the reliability of different scenarios for the formation of the vertical structure of the waters of the Caspian Sea, obtained from the distribution of transient tracers (CFC-11, CFC-12, 3H and 3He) at the deep-water stations of the Middle and Southern Caspian within the framework of international integrated isotope-geochemical studies during the maximum sea level rise in 1995–1996. Taking into account the available hydrometeorological data and the characteristics of water dating using transient tracers, it was concluded that after large-scale gravitational convection in the Middle Caspian caused by anomalous cooling of surface waters in the Northern Caspian at the end of the winter of 1976, a structure of water masses was formed that excluded deep water ventilation in the Middle and South Caspian Sea until the mid-90s.

A New Large Scale Technic for Quantitative Recovery of Enteroviruses by Adsorption on Suspended Glass Powder. Application to Surface and Drinking Waters of the Paris Area

1982 ◽  
Vol 14 (4-5) ◽  
pp. 281-290
Author(s):  
Ph Vilaginès ◽  
B Sarrette ◽  
C Danglot ◽  
R Vilaginès
Keyword(s):  
River Water ◽  
Surface Waters ◽  
Large Scale ◽  
Glass Powder ◽  
Virus Concentration ◽  
Drinking Waters ◽  
Paris Area ◽  
New Apparatus ◽  
Quantitative Recovery

The aim of this work is to describe a new and inexpensive glass powder apparatus allowing virus concentration from 500 1 sample of water (10). Its efficiency was determined by analysis of drinking and surface waters preinoculated by Poliovirus. The detection of viruses from river water is compared when 500 1 (new apparatus) or 10 1 (preceeding apparatus) (7) are processed. The proposed new 500 1 apparatus allowed the recuperation of viruses in 100 % of the analysed samples the 10 1 one allowing their recuperation in only 50 % samples. This method was applied to the virus determination in the surface and drinking waters of the Paris area.

Phosphorus Leaching Under Cut Grassland

1999 ◽  
Vol 39 (12) ◽  
pp. 63-67 ◽  
Author(s):  
B. L. Turner ◽  
P. M. Haygarth
Keyword(s):  
Surface Waters ◽  
Large Scale ◽  
Agricultural Land ◽  
Algal Growth ◽  
Soil Types ◽  
P Fractions ◽  
Inorganic P ◽  
Potential Source ◽  
Significant Mechanism ◽  
Total P

Phosphorus (P) transfer from agricultural land to surface waters can contribute to eutrophication, excess algal growth and associated water quality problems. Grasslands have a high potential for P transfer, as they receive P inputs as mineral fertiliser and concentrates cycled through livestock manures. The transfer of P can occur through surface and subsurface pathways, although the capacity of most soils to fix inorganic P has meant that subsurface P transfer by leaching mechanisms has often been perceived as negligible. We investigated this using large-scale monolith lysimeters (135 cm deep, 80 cm diameter) to monitor leachate P under four grassland soil types. Leachate was collected during the 1997–98 drainage year and analysed for a range of P fractions. Mean concentrations of total P routinely exceeded 100 μg l−1 from all soil types and, therefore, exceeded P concentrations above which eutrophication and algal growth can occur. The majority of the leachate P was in algal-available Mo-reactive (inorganic) forms, although a large proportion occurred in unreactive (organic) forms. We suggest that subsurface transfer by leaching can represent a significant mechanism for agricultural P transfer from some soils and must be given greater consideration as a potential source of diffuse P pollution to surface waters.

scholarly journals Combined Block Adjustment for Optical Satellite Stereo Imagery Assisted by Spaceborne SAR and Laser Altimetry Data

2021 ◽  
Vol 13 (16) ◽  
pp. 3062
Author(s):  
Guo Zhang ◽  
Boyang Jiang ◽  
Taoyang Wang ◽  
Yuanxin Ye ◽  
Xin Li
Keyword(s):  
Large Scale ◽  
Satellite Image ◽  
Field Measurements ◽  
High Elevation ◽  
Global Scale ◽  
Stereo Image ◽  
Image Process ◽  
Control Points ◽  
Altimetry Data ◽  
Laser Altimetry

To ensure the accuracy of large-scale optical stereo image bundle block adjustment, it is necessary to provide well-distributed ground control points (GCPs) with high accuracy. However, it is difficult to acquire control points through field measurements outside the country. Considering the high planimetric accuracy of spaceborne synthetic aperture radar (SAR) images and the high elevation accuracy of satellite-based laser altimetry data, this paper proposes an adjustment method that combines both as control sources, which can be independent from GCPs. Firstly, the SAR digital orthophoto map (DOM)-based planar control points (PCPs) acquisition is realized by multimodal matching, then the laser altimetry data are filtered to obtain laser altimetry points (LAPs), and finally the optical stereo images’ combined adjustment is conducted. The experimental results of Ziyuan-3 (ZY-3) images prove that this method can achieve an accuracy of 7 m in plane and 3 m in elevation after adjustment without relying on GCPs, which lays the technical foundation for a global-scale satellite image process.

Copper complexation in sargasso sea and gulf stream warm-core ring waters

1988 ◽  
Vol 23 (1-2) ◽  
pp. 181-203 ◽  
Author(s):  
Alfred K Hanson ◽  
Carole M Sakamoto-Arnold ◽  
Douglas L Huizenga ◽  
Dana R Kester
Keyword(s):  
Gulf Stream ◽  
Sargasso Sea ◽  
Warm Core ◽  
Warm Core Ring ◽  
Copper Complexation
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