scholarly journals Sediment Supply Explains Long‐Term and Large‐Scale Patterns in Salt Marsh Lateral Expansion and Erosion

2019 ◽  
Vol 46 (20) ◽  
pp. 11178-11187 ◽  
Author(s):  
Cai J.T. Ladd ◽  
Mollie F. Duggan‐Edwards ◽  
Tjeerd J. Bouma ◽  
Jordi F. Pagès ◽  
Martin W. Skov
Keyword(s):  
Salt Marsh ◽  
Large Scale ◽  
Sediment Supply ◽  
Lateral Expansion

Influence of river pattern and sediment input on estuary morphology

2020 ◽  
Author(s):  
Anne Baar ◽  
Elena Bastianon ◽  
Lisanne Braat ◽  
Daniel Parsons
Keyword(s):  
River Discharge ◽  
Large Scale ◽  
Numerical Models ◽  
Sediment Supply ◽  
Tidal Amplitude ◽  
Model Studies ◽  
Braiding Index ◽  
Sediment Input ◽  
River Pattern

<p>Alluvial estuaries are dynamic landscapes that are very sensitive to changes in boundary conditions such as river discharge and sediment supply. A better understanding of the influence of upstream river discharge and sediment input on the development of estuaries under various scenarios requires long-term morphodynamic models, to both predict future changes and improve geological interpretations by storing the stratigraphy. Past 1D model studies have shown that upstream river discharge has a significant effect on the equilibrium bed profile of estuaries, but these studies ignore the effect of 2D bar and channel formation. Using 2D numerical models to predict the development of these systems on the scale of millennia proved to be difficult, since the modelled morphology is very sensitive to the choice in e.g. sediment transport predictor and bed slope effect. In this study, we use the knowledge of previous research that determined best parameter settings for realistic river and bar patterns to model long-term and large-scale estuary morphodynamics in Delft3D. Our objective is to quantify the effects of river discharge and sediment supply on the shape of estuaries and its deposits. Firstly, we systematically varied upstream river width and tidal amplitude to examine the relation between upstream river pattern and estuary dimensions. We quantified e.g. braiding index, bar dimensions, and tidal excursion length. Results show that flood flow velocities and tidal prism are less influenced by river discharge than suggested by 1D models, and are significantly influenced by the braiding index of the river. With relatively high tides, estuary bar patterns depend on tidal amplitude, while with lower tides estuary depth and braiding index are related to upstream river width and discharge. Next steps will include varying discharge to study the effect on the rate of adaptation of the river and estuary, and varying the grain size of the sediment input at the upstream boundary. We will input coarse sediment to explore differences between fluvial deposits and tidal currents, and fine sediment to use the model for research related to biofilm.</p>

Long-term salt marsh vertical accretion in a tidal bay with reduced sediment supply

2014 ◽  
Vol 146 ◽  
pp. 14-23 ◽  
Author(s):  
Zhigang Ma ◽  
Tom Ysebaert ◽  
Daphne van der Wal ◽  
Dick J. de Jong ◽  
Xiuzhen Li ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Sediment Supply ◽  
Vertical Accretion

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

Computer Analyses in Preventive Health Research

1967 ◽  
Vol 06 (01) ◽  
pp. 8-14 ◽  
Author(s):  
M. F. Collen
Keyword(s):  
Medical Research ◽  
Preventive Medicine ◽  
Health Research ◽  
Large Scale ◽  
Preventive Health ◽  
New Era ◽  
Large Numbers ◽  
Normal Test ◽  
Computer Analyses

The utilization of an automated multitest laboratory as a data acquisition center and of a computer for trie data processing and analysis permits large scale preventive medical research previously not feasible. Normal test values are easily generated for the particular population studied. Long-term epidemiological research on large numbers of persons becomes practical. It is our belief that the advent of automation and computers has introduced a new era of preventive medicine.

(A review) Atlas of especially protected natural areas of Saint Petersburg / Ed. in chief V. N. Khramtsov, T. V. Kovaleva, N. Yu. Natsvaladze. St. Petersburg, 2013. 176 p.

2014 ◽  
pp. 124-129
Author(s):  
Z. V. Karamysheva
Keyword(s):  
Protected Areas ◽  
Large Scale ◽  
Natural Areas ◽  
Natural Protected Areas ◽  
Saint Petersburg ◽  
Natural Processes ◽  
Original Illustrations ◽  
Vegetation Maps ◽  
Protected Natural Areas

The review contains detailed description of the «Atlas of especially protected natural areas of Saint Petersburg» published in 2013. This publication presents the results of long-term studies of 12 natural protected areas made by a large research team in the years from 2002 to 2013 (see References). The Atlas contains a large number of the historical maps, new satellite images, the original illustrations, detailed texts on the nature of protected areas, summary tables of rare species of vascular plants, fungi and vertebrates recorded in these areas. Special attention is paid to the principles of thematic large-scale mapping. The landscape maps, the vegetation maps as well as the maps of natural processes in landscapes are included. Reviewed Atlas deserves the highest praise.

Etude de l'aménagement d'une forêt classée au Mali avec la participation des populations riveraines - Données du problème et éléments de méthodologie | A Study of the Management of a State-Owned Forest in Mali with the Participation of the Population Living nearby - Issue under Investigation and Elements of Methodology

2000 ◽  
Vol 151 (3) ◽  
pp. 80-83
Author(s):  
Pascal Schneider ◽  
Jean-Pierre Sorg
Keyword(s):  
Natural Resources ◽  
Research Methodology ◽  
Large Scale ◽  
Environmental Context ◽  
Forest Resources ◽  
The State ◽  
Commercial Use ◽  
Economic Context ◽  
The People

In and around the state-owned forest of Farako in the region of Sikasso, Mali, a large-scale study focused on finding a compromise allowing the existential and legitimate needs of the population to be met and at the same time conserving the forest resources in the long term. The first step in research was to sketch out the rural socio-economic context and determine the needs for natural resources for autoconsumption and commercial use as well as the demand for non-material forest services. Simultaneously, the environmental context of the forest and the resources available were evaluated by means of inventories with regard to quality and quantity. According to an in-depth comparison between demand and potential, there is a differentiated view of the suitability of the forest to meet the needs of the people living nearby. Propositions for a multipurpose management of the forest were drawn up. This contribution deals with some basic elements of research methodology as well as with results of the study.

Investigations on the filtration of natural aquatic suspensions supported by dosing small amounts of Fe(III)-salts (βFe ≤ 0.1 mg.L-1): mode of action and basic design criteria

2002 ◽  
Vol 2 (2) ◽  
pp. 91-98
Author(s):  
R. Winzenbacher ◽  
R. Schick ◽  
H.-H. Stabel ◽  
M. Jekel
Keyword(s):  
Large Scale ◽  
Suspended Solids ◽  
Iron Hydroxides ◽  
Essential Step ◽  
Iron Salts ◽  
Alkaline Earths ◽  
Co Precipitation ◽  
Solid Liquid ◽  
Solid Liquid Separation

Improved removal of particles during the treatment of natural aquatic suspensions has been achieved by pre-ozonation and the addition of small quantities of iron salts (βFe ≤ 0.1 mg.L-1; “Fe(III)-assisted filtration”) followed by rapid filtration. As shown by investigations on a large-scale installation at Lake Constance Water Supply, this procedure reliably reduces suspended solids by at least 2-3 powers of ten in long-term use. However, the high efficacy of Fe(III)-assisted filtration cannot be explained on the basis of known coagulation mechanisms (like adsorption-charge neutralization, co-precipitation). Instead, the essential step was found to be the conditioning of the filter medium by coating it with colloids containing Fe(OH)3, and this “Fe coating” process occurs only in the presence of alkaline earths (especially Ca2+). According to further experiments, the enhanced solid-liquid separation was ultimately traced to chemical interactions such as the formation of calcium-organic association structures between the iron hydroxides and other solids. For design of Fe(III)-assisted filtration steps, finally, a βCa/DOC ratio above 40 mg.mg-1 and pre-oxidation with ozone dosages not exceeding 2 mg O3/mg DOC was recommended.

A Perspective On The Impact of COVID-19 Pandemic in Basic Science Research and its Future implications

Coronaviruses ◽  
2020 ◽  
Vol 01 ◽  
Author(s):  
Yam Nath Paudel ◽  
Efthalia Angelopoulou ◽  
Bhupendra Raj Giri ◽  
Christina Piperi ◽  
Iekhsan Othman ◽  
...  
Keyword(s):  
Basic Science ◽  
Large Scale ◽  
Preventive Measure ◽  
Science Research ◽  
Research Institutes ◽  
Basic Science Research ◽  
Long Term Consequences ◽  
Long Term Impact ◽  
The Impact

: COVID-19 has emerged as a devastating pandemic of the century that the current generations have ever experienced. The COVID-19 pandemic has infected more than 12 million people around the globe and 0.5 million people have succumbed to death. Due to the lack of effective vaccines against the COVID-19, several nations throughout the globe has imposed a lock-down as a preventive measure to lower the spread of COVID-19 infection. As a result of lock-down most of the universities and research institutes has witnessed a long pause in basic science research ever. Much has been talked about the long-term impact of COVID-19 in economy, tourism, public health, small and large-scale business of several kind. However, the long-term implication of these research lab shutdown and its impact in the basic science research has not been much focused. Herein, we provide a perspective that portrays a common problem of all the basic science researchers throughout the globe and its long-term consequences.

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