In situ measurements of compressional and shear wave properties during gravity coring operations

2019 ◽  
Vol 146 (4) ◽  
pp. 2748-2748
Author(s):  
Megan S. Ballard ◽  
Kevin M. Lee ◽  
Andrew R. McNeese ◽  
Preston S. Wilson
Keyword(s):  
Shear Wave ◽  
In Situ Measurements ◽  
Wave Properties

In situ measurements of sediment compressional and shear wave properties in Currituck Sound

2015 ◽  
Vol 137 (4) ◽  
pp. 2282-2282 ◽  
Author(s):  
Megan S. Ballard ◽  
Kevin M. Lee ◽  
Andrew R. McNeese ◽  
Preston S. Wilson ◽  
Thomas G. Muir ◽  
...  
Keyword(s):  
Shear Wave ◽  
In Situ Measurements ◽  
Currituck Sound ◽  
Wave Properties

In situ measurements of compressional and shear wave propagation in marine sediments and comparison to geoacoustic models

2018 ◽  
Vol 144 (3) ◽  
pp. 1960-1960
Author(s):  
Kevin M. Lee ◽  
Megan S. Ballard ◽  
Andrew R. McNeese ◽  
Gabriel R. Venegas ◽  
Preston S. Wilson
Keyword(s):  
Wave Propagation ◽  
Shear Wave ◽  
Marine Sediments ◽  
In Situ Measurements

The Carbon:²³⁴Thorium ratios of sinking particles in the California Current Ecosystem 2: Examination of a thorium sorption, desorption, and particle transport model

2019 ◽  
Author(s):  
Michael Stukel ◽  
Thomas Kelly
Keyword(s):  
Organic Carbon ◽  
Water Column ◽  
Particulate Organic Carbon ◽  
Transport Model ◽  
California Current ◽  
In Situ Measurements ◽  
Power Law Distribution ◽  
Sinking Particles ◽  
Organic Carbon Concentration

Thorium-234 (234Th) is a powerful tracer of particle dynamics and the biological pump in the surface ocean; however, variability in carbon:thorium ratios of sinking particles adds substantial uncertainty to estimates of organic carbon export. We coupled a mechanistic thorium sorption and desorption model to a one-dimensional particle sinking model that uses realistic particle settling velocity spectra. The model generates estimates of 238U-234Th disequilibrium, particulate organic carbon concentration, and the C:234Th ratio of sinking particles, which are then compared to in situ measurements from quasi-Lagrangian studies conducted on six cruises in the California Current Ecosystem. Broad patterns observed in in situ measurements, including decreasing C:234Th ratios with depth and a strong correlation between sinking C:234Th and the ratio of vertically-integrated particulate organic carbon (POC) to vertically-integrated total water column 234Th, were accurately recovered by models assuming either a power law distribution of sinking speeds or a double log normal distribution of sinking speeds. Simulations suggested that the observed decrease in C:234Th with depth may be driven by preferential remineralization of carbon by particle-attached microbes. However, an alternate model structure featuring complete consumption and/or disaggregation of particles by mesozooplankton (e.g. no preferential remineralization of carbon) was also able to simulate decreasing C:234Th with depth (although the decrease was weaker), driven by 234Th adsorption onto slowly sinking particles. Model results also suggest that during bloom decays C:234Th ratios of sinking particles should be higher than expected (based on contemporaneous water column POC), because high settling velocities minimize carbon remineralization during sinking.

Evaluation of reanalysis and satellite-based sea surface winds using in situ measurements from Chinese Antarctic Expeditions

2013 ◽  
Vol 24 (3) ◽  
pp. 147
Author(s):  
Ming LI ◽  
Qinghua YANG ◽  
Jiechen ZHAO ◽  
Lin ZHANG ◽  
Chunhua LI ◽  
...  
Keyword(s):  
In Situ Measurements ◽  
Sea Surface ◽  
Surface Winds ◽  
Sea Surface Winds
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