scholarly journals Impact of Density Gradients on Net Sediment Transport into the Wadden Sea

2008 ◽  
Vol 38 (3) ◽  
pp. 566-587 ◽  
Author(s):  
Hans Burchard ◽  
Götz Flöser ◽  
Joanna V. Staneva ◽  
Thomas H. Badewien ◽  
Rolf Riethmüller
Keyword(s):  
Wadden Sea ◽  
Sea Water ◽  
Model Simulation ◽  
Three Dimensional ◽  
Field Studies ◽  
Tidal Mixing ◽  
Density Gradients ◽  
Three Dimensional Model ◽  
Model Simulations ◽  
The North

Abstract This study tests the hypothesis that horizontal density gradients have the potential to significantly contribute to the accumulation of suspended particulate matter (SPM) in the Wadden Sea. It is shown by means of long-term observations at various positions in the Wadden Sea of the German Bight that the water in the inner regions of the Wadden Sea is typically about 0.5–1.0 kg m−3 less dense than the North Sea water. During winter this occurs mostly because of freshwater runoff and net precipitation; during summer it occurs mostly because of differential heating. It is demonstrated with idealized one-dimensional water column model simulations that the interaction of such small horizontal density gradients with tidal currents generates net onshore SPM fluxes. Major mechanisms for this are tidal straining, estuarine circulation, and tidal mixing asymmetries. Three-dimensional model simulations in a semienclosed Wadden Sea embayment with periodic tidal forcing show that SPM with sufficiently high settling velocity (ws = 10−3 m s−1) is accumulating in the Wadden Sea Bight because of density gradients. This is proven through a comparative model simulation in which the dynamic effects of the density gradients are switched off, with the consequence of no SPM accumulation. These numerical model results motivate future targeted field studies in different Wadden Sea regions with the aim to further support the hypothesis.

Three-dimensional model simulations for the north coast of British Columbia

1996 ◽  
Vol 16 (13) ◽  
pp. 1655-1682 ◽  
Author(s):  
V.A. Ballantyne ◽  
M.G.G. Foreman ◽  
W.R. Crawford ◽  
R. Jacques
Keyword(s):  
British Columbia ◽  
Three Dimensional ◽  
North Coast ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Model Simulations ◽  
The North

scholarly journals Modern Geodetic Measurement Techniques in Gravimetric Studies on the Example of Gypsum Karst in the Siesławice Region

2018 ◽  
Vol 35 ◽  
pp. 03002 ◽  
Author(s):  
Sławomir Porzucek ◽  
Monika Łój ◽  
Karolina Matwij ◽  
Wojciech Matwij
Keyword(s):  
Laser Scanning ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Digital Terrain Model ◽  
Field Studies ◽  
Surface Zone ◽  
Three Dimensional Model ◽  
Geodetic Measurement ◽  
Near Surface ◽  
Gypsum Karst

In the region of Siesławice (near Busko-Zdrój, Poland) there are unique phenomena of gypsum karst. Atmospheric factors caused numerous gypsum outcrops, canals and underground voids. The article presents the possibility of using non-invasive gravimetric surveys supplemented with geodetic measurements to illustrate karst changes occurring around the void. The use of modern geodetic measurement techniques including terrestrial and airborne laser scanning enables to generate a digital terrain model and a three-dimensional model of voids. Gravimetric field studies allowed to map the anomalies of the gravitational field of the near-surface zone. Geodetic measurement results have made it possible to accurately determine the terrain correction that supplemented the gravimetric anomaly information. Geophysical interpretation indicate the presence of weathered rocks in the near surface zone and fractures and loosened zones located surround the karst cave.

Three-Dimensional Modeling of MVT Lead-Zinc Deposit in Western Hunan and its Application

2014 ◽  
Vol 644-650 ◽  
pp. 2674-2677
Author(s):  
Kun Wang ◽  
Ke Yan Xiao
Keyword(s):  
Regional Scale ◽  
Three Dimensional ◽  
Hunan Province ◽  
Three Dimensional Model ◽  
Three Dimensional Modeling ◽  
The North ◽  
Dimensional Modeling ◽  
North Part ◽  
Lead Zinc ◽  
Fault Belt

In order to study the evolution and metallogenic regularity of MVT lead-zinc deposits in western portion of Hunan province (China), two sets of three-dimensional model are established by Minexplorer software: 3D model in typical deposit and 3Dmodel on regional scale. On the basis of synthetic analyses of two sets of models, the further prospecting should be focused on the north part of ore-bearing layer along the Huayuan-Zhangjiajie fault belt. It is effective to observe occurrence and distribution characteristics from the 3D geological model, and to provide the basis for further exploration prospecting of the concealed deposits.

Eclectic modelling of the North Atlantic. II. Transient tracers and the ventilation of the Eastern Basin thermocline

1988 ◽  
Vol 325 (1583) ◽  
pp. 201-236 ◽  
Keyword(s):  
North Atlantic ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Ekman Pumping ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Oxygen Utilization ◽  
The North ◽  
Time Histories ◽  
Weak Constraints

Renewal rates of the waters of the thermocline in the eastern North Atlantic are estimated by combining linear quasi-geostrophic dynamics with steady and transient tracers into a unified eclectic, reservoir model. The two-dimensional model first employed is finally rejected when it is found that it generates oxygen-utilization rates (OUR) that are, by conventional biological wisdom, too high. The three-dimensional model that replaces the two-dimensional one shows that the our is indeterminate, with possible ranges from zero to unacceptably high values. The region is flushed primarily from the north and east. The problem of using transient tracers is mathematically equivalent to that of distributed-system boundary-control theory, the open-ocean boundary conditions playing the role of the unknown control variables. The missing time histories of this new set of unknowns means that tritium and helium-3 distributions are only comparatively weak constraints on the flow field, but do set upper bounds on the vertical exchange with surface waters. Surface Ekman pumping is adequate to explain the interior distributions without additional buoyancy ventilation, although this latter process is possible. Some speculation is made about conditions under which transient tracers might play a more definitive role.

scholarly journals RAS-NAAD: 40-yr High-Resolution North Atlantic Atmospheric Hindcast for Multipurpose Applications (New Dataset for the Regional Mesoscale Studies in the Atmosphere and the Ocean)

2020 ◽  
Vol 59 (5) ◽  
pp. 793-817 ◽  
Author(s):  
Alexander Gavrikov ◽  
Sergey K. Gulev ◽  
Margarita Markina ◽  
Natalia Tilinina ◽  
Polina Verezemskaya ◽  
...  
Keyword(s):  
High Resolution ◽  
Ocean Circulation ◽  
North Atlantic ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Lateral Boundary Condition ◽  
Three Dimensional Model ◽  
Free Atmosphere ◽  
The North ◽  
The North Atlantic

AbstractWe present in this paper the results of the Russian Academy of Sciences North Atlantic Atmospheric Downscaling (RAS-NAAD) project, which provides a 40-yr 3D hindcast of the North Atlantic (10°–80°N) atmosphere at 14-km spatial resolution with 50 levels in the vertical direction (up to 50 hPa), performed with a regional setting of the WRF-ARW 3.8.1 model for the period 1979–2018 and forced by ERA-Interim as a lateral boundary condition. The dataset provides a variety of surface and free-atmosphere parameters at sigma model levels and meets many demands of meteorologists, climate scientists, and oceanographers working in both research and operational domains. Three-dimensional model output at 3-hourly time resolution is freely available to the users. Our evaluation demonstrates a realistic representation of most characteristics in both datasets and also identifies biases mostly in the ice-covered regions. High-resolution and nonhydrostatic model settings in NAAD resolve mesoscale dynamics first of all in the subpolar latitudes. NAAD also provides a new view of the North Atlantic extratropical cyclone activity with a much larger number of cyclones as compared with most reanalyses. It also effectively captures highly localized mechanisms of atmospheric moisture transports. Applications of NAAD to ocean circulation and wave modeling are demonstrated.

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