High-frequency streamflow acquisition and bed level/flow angle estimates in a mountainous river using shallow-water acoustic tomography

2016 ◽  
Vol 30 (13) ◽  
pp. 2247-2254 ◽  
Author(s):  
Kiyosi Kawanisi ◽  
Masoud Bahrainimotlagh ◽  
Mohamad Basel Al Sawaf ◽  
Mahdi Razaz
Keyword(s):  
Shallow Water ◽  
High Frequency ◽  
Acoustic Tomography ◽  
Flow Angle ◽  
Mountainous River

Scaling characteristics of mountainous river flow fluctuations determined using a shallow-water acoustic tomography system

2017 ◽  
Vol 484 ◽  
pp. 11-20 ◽  
Author(s):  
Mohamad Basel Al Sawaf ◽  
Kiyosi Kawanisi ◽  
Junya Kagami ◽  
Masoud Bahreinimotlagh ◽  
Mochammad Meddy Danial
Keyword(s):  
Shallow Water ◽  
River Flow ◽  
Acoustic Tomography ◽  
Tomography System ◽  
Flow Fluctuations ◽  
Mountainous River

MAPPING TIDAL CURRENTS AND RESIDUAL CURRENTS BY USE OF COASTAL ACOUSTIC TOMOGRAPHY

2017 ◽  
Author(s):  
Xiao-Hua Zhu ◽  
Xiao-Hua Zhu ◽  
Ze-Nan Zhu ◽  
Ze-Nan Zhu ◽  
Xinyu Guo ◽  
...  
Keyword(s):  
Shallow Water ◽  
Shallow Water Equations ◽  
Mean Amplitude ◽  
Momentum Equation ◽  
Tidal Currents ◽  
Acoustic Tomography ◽  
Mean Values ◽  
Residual Currents ◽  
Water Depths ◽  
Deep Area

A coastal acoustic tomography (CAT) experiment for mapping the tidal currents in the Zhitouyang Bay was successfully carried out with seven acoustic stations during July 12 to 13, 2009. The horizontal distributions of tidal current in the tomography domain are calculated by the inverse analysis in which the travel time differences for sound traveling reciprocally are used as data. Spatial mean amplitude ratios M2 : M4 : M6 are 1.00 : 0.15 : 0.11. The shallow-water equations are used to analyze the generation mechanisms of M4 and M6. In the deep area, velocity amplitudes of M4 measured by CAT agree well with those of M4 predicted by the advection terms in the shallow water equations, indicating that M4 in the deep area where water depths are larger than 60 m is predominantly generated by the advection terms. M6 measured by CAT and M6 predicted by the nonlinear quadratic bottom friction terms agree well in the area where water depths are less than 20 m, indicating that friction mechanisms are predominant for generating M6 in the shallow area. Dynamic analysis of the residual currents using the tidally averaged momentum equation shows that spatial mean values of the horizontal pressure gradient due to residual sea level and of the advection of residual currents together contribute about 75% of the spatial mean values of the advection by the tidal currents, indicating that residual currents in this bay are induced mainly by the nonlinear effects of tidal currents.

Polychaete palaeoecology in an early Late Ordovician marine astrobleme of Sweden

2010 ◽  
Vol 148 (2) ◽  
pp. 269-287 ◽  
Author(s):  
MATS E. ERIKSSON ◽  
ÅSA M. FRISK
Keyword(s):  
Shallow Water ◽  
High Frequency ◽  
Relative Frequency ◽  
Late Ordovician ◽  
Crater Floor ◽  
Drill Core ◽  
Upper Ordovician ◽  
Composition Characteristic ◽  
Post Impact ◽  
Early Late

AbstractThe post-impact Dalby Limestone (Kukruse; Upper Ordovician) of the Tvären crater, southeastern Sweden, has been analysed with regards to polychaetes, as represented by scolecodonts. A palaeoecological succession is observed in the Tvären-2 drill core sequence, as the vacant ecospace was successively filled by a range of benthonic, nektonic and planktonic organisms. Scolecodonts belong to the first non-planktonic groups to appear and constitute one of the most abundant fossil elements. The polychaete assemblage recorded has an overall composition characteristic of that of the Upper Ordovician of Baltoscandia. Oenonites, Vistulella, Mochtyella and the enigmatic ‘Xanioprion’ represent the most common genera, whereas Pteropelta, Protarabellites?, Atraktoprion and Xanioprion are considerably more rare. The assemblage differs from coeval ones particularly in its poorly represented ramphoprionid fauna and the relatively high frequency of ‘Xanioprion’. A taxonomic succession and changes in abundance and relative frequency of different taxa is observed from the deepest part of the crater and upwards towards more shallow water environments. The initial post-impact assemblage does not, however, necessarily represent a benthonic colonization of the crater floor. Instead it seems to be a taphocoenosis, as indicated by its taxonomic correspondence to the rim facies fauna recovered from Dalby Limestone erratics of the Ringsön island. The Tvären succession has yielded considerably richer scolecodont assemblages than hitherto recorded from the approximately coeval Lockne crater, possibly as a consequence of shallower water settings in the former area.

Measurements of high-frequency shallow-water acoustic phase fluctuations

2000 ◽  
Vol 25 (4) ◽  
pp. 507-515 ◽  
Author(s):  
S.J. Stanic ◽  
R.R. Goodman ◽  
R.W. Meredith ◽  
E. Kennedy
Keyword(s):  
Shallow Water ◽  
High Frequency ◽  
Phase Fluctuations ◽  
Acoustic Phase

Shallow water sediment properties derived from high-frequency shear and interface waves

1992 ◽  
Vol 97 (B4) ◽  
pp. 4739 ◽  
Author(s):  
John Ewing ◽  
Jerry A. Carter ◽  
George H. Sutton ◽  
Noel Barstow
Keyword(s):  
Shallow Water ◽  
High Frequency ◽  
Sediment Properties ◽  
Interface Waves ◽  
Shallow Water Sediment
Sign in / Sign up

Export Citation Format

Share Document