Particle Size Distribution and Optical Volume Scattering Function in the Mid and Upper Water Column of Optically Deep Coastal Regions: Transport from the Bottom Boundary Layer

2002 ◽  
Author(s):  
Y. C. Agrawal
Keyword(s):  
Boundary Layer ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Water Column ◽  
Size Distribution ◽  
Bottom Boundary Layer ◽  
Scattering Function ◽  
Coastal Regions ◽  
Volume Scattering ◽  
Bottom Boundary

scholarly journals Spectral particulate attenuation and particle size distribution in the bottom boundary layer of a continental shelf

2001 ◽  
Vol 106 (C5) ◽  
pp. 9509-9516 ◽  
Author(s):  
Emmanuel Boss ◽  
W. Scott Pegau ◽  
Wilford D. Gardner ◽  
J. Ronald V. Zaneveld ◽  
Andrew H. Barnard ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Continental Shelf ◽  
Size Distribution ◽  
Bottom Boundary Layer ◽  
Bottom Boundary

Observations of the Particle Size Distribution and Concentration in a Coastal System using an In Situ Laser Analyzer

2002 ◽  
Vol 36 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Teresa Serra ◽  
Xavier Casamitjana ◽  
Jordi Colomer ◽  
Timothy C. Granata
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Water Column ◽  
Size Distribution ◽  
Posidonia Oceanica ◽  
High Energy ◽  
Suspended Particles ◽  
Energy Conditions ◽  
Coastal System

An in situ laser particle size analyzer (LISST-100, Sequoia Scientific, Inc.) has been used to study the particle size distribution and concentration of biological and non biological particles in the water column of a Mediterranean coastal system. Two field campaigns have been carried out during low and high energy conditions of the flow, caused by the passage of a storm front. For the low energy period, the water column remained stratified, whereas for the high energetic period the water column was warmer and well mixed. The first study dealt with the distribution of particles near the bottom of the coastal area. Here, two regions were taken into account. The first region was a sea-grass meadow of Posidonia oceanica and the second region was a barren sand area. The second study dealt with the determination of the vertical distribution of suspended particles in the whole water column of the system. The results showed a decrease in the vertical concentration of suspended particles in the water column with the passage of the storm front, which was associated with advection of warm water mass rather than by vertical mixing. In contrast, vertical resuspension determined the fate of suspended particles at the bottom of the water column and an increase of their concentration was found.

scholarly journals Dependency of particle size distribution at dust emission on friction velocity and atmospheric boundary-layer stability

2020 ◽  
Vol 20 (21) ◽  
pp. 12939-12953
Author(s):  
Yaping Shao ◽  
Jie Zhang ◽  
Masahide Ishizuka ◽  
Masao Mikami ◽  
John Leys ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Particle Size ◽  
Probability Distribution ◽  
Particle Size Distribution ◽  
Atmospheric Boundary Layer ◽  
Size Distribution ◽  
Turbulent Flows ◽  
Friction Velocity ◽  
Surface Shear Stress ◽  
Surface Shear

Abstract. Particle size distribution of dust at emission (dust PSD) is an essential quantity to estimate in dust studies. It has been recognized in earlier research that dust PSD is dependent on soil properties (e.g. whether soil is sand or clay) and friction velocity, u∗, which is a surrogate for surface shear stress and a descriptor for saltation-bombardment intensity. This recognition has been challenged in some recent papers, causing a debate on whether dust PSD is “invariant” and the search for its justification. In this paper, we analyse the dust PSD measured in the Japan Australian Dust Experiment and show that dust PSD is dependent on u∗ and on atmospheric boundary-layer (ABL) stability. By simple theoretical and numerical analysis, we explain the two reasons for the latter dependency, which are both related to enhanced saltation bombardment in convective turbulent flows. First, u∗ is stochastic and its probability distribution profoundly influences the magnitude of the mean saltation flux due to the non-linear relationship between saltation flux and u∗. Second, in unstable conditions, turbulence is usually stronger, which leads to higher saltation-bombardment intensity. This study confirms that dust PSD depends on u∗ and, more precisely, on the probability distribution of u∗, which in turn is dependent on ABL stability; consequently, dust PSD is also dependent on ABL. We also show that the dependency of dust PSD on u∗ and ABL stability is made complicated by soil surface conditions. In general, our analysis reinforces the basic conceptual understanding that dust PSD depends on saltation bombardment and inter-particle cohesion.

The Effect of Varying Salinity and Temperature on the Dynamics of Orimulsion in Water

2003 ◽  
Vol 2003 (1) ◽  
pp. 419-427
Author(s):  
Merv Fingas ◽  
Zhendi Wang ◽  
Mike Landriault ◽  
Jordan Noonan ◽  
Ron MacKay
Keyword(s):  
Time Series ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Water Column ◽  
Size Distribution ◽  
Brackish Water ◽  
Water Surface ◽  
Simple Equations

ABSTRACT Studies have shown that Orimulsion behaves somewhat predictably in saltwater (33 ppt NaCl) and freshwater, driven by buoyancy to rise in saltwater and sink in freshwater, but behaviour in brackish water (20 ppt NaCl) is difficult to predict. Temperature has also been indicated as having an influence on Orimulsion behaviour. The current study extended experimentation to lower temperatures and a large number of salinity values, ranging from fresh to saltwater. This study resulted in information on the behaviour of Orimulsion spills in salt, fresh, and brackish water with salinity values ranging from 0.1 to 33 °/oo at temperatures of 5 and 15 °C. Depletion rates and characteristics were determined by adding Orimulsion to a 300-L tank of water, taking a time series of samples, and determining the concentration of bitumen and the particle size distribution. Changes in bitumen concentration and particle size distribution as a function of time were also measured. Resurfaced bitumen was scraped from the top of the tank and weighed to determine the amount rising. Using these data, simple equations were developed to describe and predict the concentration of bitumen in the water column as a function of time. Similarly, nomograms showing the amount of oil on the bottom and on the water surface are presented.

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