Shear dispersion from near-inertial internal Poincaré waves in large lakes

2015 ◽  
Vol 60 (6) ◽  
pp. 2222-2235 ◽  
Author(s):  
Jun M. Choi ◽  
Cary D. Troy ◽  
Nathan Hawley
Keyword(s):  
Large Lakes ◽  
Shear Dispersion ◽  
Poincare Waves

A weakly nonlinear evolution model for long internal waves in a large lake

2010 ◽  
Vol 656 ◽  
pp. 260-297 ◽  
Author(s):  
TAKAHIRO SAKAI ◽  
L. G. REDEKOPP
Keyword(s):  
Internal Waves ◽  
Environmental Parameters ◽  
Wave Mode ◽  
Evolution Model ◽  
Field Energy ◽  
Kelvin Wave ◽  
Large Lakes ◽  
Weakly Nonlinear ◽  
Poincare Waves ◽  
Wave Modes

A wind-forced weakly nonlinear weakly dispersive evolution model is derived for a continuously stratified circular lake of slowly varying depth under the effect of the Earth's rotation. The model was numerically integrated to investigate the evolution of long internal waves of vertical mode one for various sets of environmental parameters. It is demonstrated that the Kelvin wave steepens as it propagates, and the steepened front subsequently generates a train of oscillatory waves. It is demonstrated that Poincaré waves do not steepen, but their amplitude is modulated in an oscillatory manner with time, exhibiting a pseudo recurrence character. The model was applied to the wind forced problem, confirming that Kelvin and Poincaré waves are the dominant response. Energy partition among Kelvin and Poincaré wave modes is estimated as a function of wind-forcing parameters. For large lakes, the most significant wave amplitude is found in the Kelvin wave mode, but the gross field energy is most significantly contained in Poincaré wave modes.

The genus Synura (Synurales, Synurophyceae) in small urban rivers of Nizhniy Novgorod

2017 ◽  
Vol 51 ◽  
pp. 57-70 ◽  
Author(s):  
E. S. Gusev ◽  
O. S. Perminova ◽  
N. A. Startseva ◽  
A. G. Okhapkin
Keyword(s):  
Taxonomic Composition ◽  
Morphological Data ◽  
Small Rivers ◽  
Urban Rivers ◽  
Large Lakes ◽  
Volga River ◽  
Volga River Basin ◽  
Means Of Transmission ◽  
Special Studies ◽  
The City

The latest special studies of the genus Synura in Russia were conducted in the 1970s. In the last decade, 14 new species of the genus were described based on molecular and morphological data. The total number of valid taxa of the genus has increased to 49. Only 18 taxa of Synura are known in Russia up to date, and the diver sity of the genus on this huge territory is strongly underestimated. Previous studies of the genus were focused mainly on large lakes or reservoirs. To reveal a more complete flora, it is necessary to include other habitats into account. Small urban rivers can be prospective habitats for interesting taxa including synuralean algae. Our study focuses on the taxonomic composition of the genus Synura in four small rivers in Nizhniy Novgorod (European Russia): Chyornaya, Levinka, Borzovka and Rzhavka. All the rivers flow in the city and fall under strong anthropogenic impact. The genus Synura was studied by means of transmission and scanning electron microscopy during 2011, 2012, 2014, 2015. In total, eight species and one form of Synura have been found: S. conopea, S. curtispina, S. echinulata, S. glabra, S. macropora, S. petersenii, S. spinosa f. spinosa, S. spinosa f. longispina, S. uvella. All nine taxa were observed in the river Chyornaya. Five taxa were found in the rivers Levinka, Borzovka and Rzhavka. One species (Synura conopea) is a new record to the flora of Russia. It was found in all studied rivers. Four taxa (S. conopea, S. glabra, S. macropora, S. spinosa f. longispina) are new records to the Middle Volga river basin.

Operational Model and its Validation with Drift Tests in Water Areas Around the Baltic Sea

1994 ◽  
Vol 29 (2-3) ◽  
pp. 293-308
Author(s):  
J. Koponen ◽  
M. Virtanen ◽  
H. Vepsä ◽  
E. Alasaarela
Keyword(s):  
Three Dimensional ◽  
Fast Response ◽  
Velocity Measurements ◽  
Short Term ◽  
Large Lakes ◽  
Operational Model ◽  
Water Currents ◽  
Emergency Situations ◽  
Sensitivity Tests ◽  
The Baltic

Abstract Three-dimensional (3-D) mathematical models of water currents, transport, mixing, reaction kinetic, and interactions with bottom and air have been used in Finland regularly since 1982 and applied to about 40 cases in large lakes, inland seas and their coastal waters. In each case, model validity has been carefully tested with available flow velocity measurements, tracer studies and water quality observations. For operational use, i.e., for spill combatting and sea rescue, the models need fast response, proven validity and illustrative visualization. In 1987-90, validated models were implemented for operational use at five sea areas along the Finnish coast. Further validation was obtained in model applications from nine documented or arranged cases and from seven emergency situations. Sensitivity tests supplement short-term validation. In the Bothnian Sea, it was nescessary to start the calculation of water currents three days prior to the start of the experiment to reduce initial inaccuracies and to make the coastal transport estimates meaningful.

Four-decade dynamics of the water color in 61 large lakes on the Yangtze Plain and the impacts of reclaimed aquaculture zones

2021 ◽  
Vol 781 ◽  
pp. 146688
Author(s):  
Yang Xu ◽  
Lian Feng ◽  
Xuejiao Hou ◽  
Junjian Wang ◽  
Jing Tang
Keyword(s):  
Water Color ◽  
Large Lakes

scholarly journals Extension of the Upper Yellow River into the Tibet Plateau: Review and New Data

Quaternary ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 14
Author(s):  
Zhengchen Li ◽  
Xianyan Wang ◽  
Jef Vandenberghe ◽  
Huayu Lu
Keyword(s):  
Tibetan Plateau ◽  
Yellow River ◽  
Google Earth ◽  
Tibet Plateau ◽  
The Yellow River ◽  
Published Data ◽  
The Tibetan Plateau ◽  
Large Lakes ◽  
River Terraces ◽  
The Tibet Plateau

The Wufo Basin at the margin of the northeastern Tibet Plateau connects the upstream reaches of the Yellow River with the lowland catchment downstream, and the fluvial terrace sequence in this basin provides crucial clues to understand the evolution history of the Yellow River drainage system in relation to the uplift and outgrowth of the Tibetan Plateau. Using field survey and analysis of Digital Elevation Model/Google Earth imagery, we found at least eight Yellow River terraces in this area. The overlying loess of the highest terrace was dated at 1.2 Ma based on paleomagnetic stratigraphy (two normal and two reversal polarities) and the loess-paleosol sequence (12 loess-paleosol cycles). This terrace shows the connections of drainage parts in and outside the Tibetan Plateau through its NE margin. In addition, we review the previously published data on the Yellow River terraces and ancient large lakes in the basins. Based on our new data and previous researches, we conclude that the modern Yellow River, with headwaters in the Tibet Plateau and debouching in the Bohai Sea, should date from at least 1.2 Ma. Ancient large lakes (such as the Hetao and Sanmen Lakes) developed as exorheic systems and flowed through the modern Yellow River at that time.

scholarly journals Critical behaviour of hydrodynamic series

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
M. Asadi ◽  
H. Soltanpanahi ◽  
F. Taghinavaz
Keyword(s):  
Chemical Potential ◽  
Transport Coefficients ◽  
Hydrodynamic Modes ◽  
Third Order ◽  
Hydrodynamic Mode ◽  
Strongly Coupled ◽  
Conformal Theory ◽  
Shear Dispersion ◽  
Type Iib String Theory ◽  
Hydrodynamic Transport

Abstract We investigate the time-dependent perturbations of strongly coupled $$ \mathcal{N} $$ N = 4 SYM theory at finite temperature and finite chemical potential with a second order phase transition. This theory is modelled by a top-down Einstein-Maxwell-dilaton description which is a consistent truncation of the dimensional reduction of type IIB string theory on AdS5×S5. We focus on spin-1 and spin-2 sectors of perturbations and compute the linearized hydrodynamic transport coefficients up to the third order in gradient expansion. We also determine the radius of convergence of the hydrodynamic mode in spin-1 sector and the lowest non-hydrodynamic modes in spin-2 sector. Analytically, we find that all the hydrodynamic quantities have the same critical exponent near the critical point θ = $$ \frac{1}{2} $$ 1 2 . Moreover, we propose a relation between symmetry enhancement of the underlying theory and vanishing of the only third order hydrodynamic transport coefficient θ1, which appears in the shear dispersion relation of a conformal theory on a flat background.

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