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Mean grain size mapping with single-beam echo sounders
| Content Provider | Semantic Scholar |
|---|---|
| Author | Walree, Paul A. Van Ainslie, Michael A. Simons, Dick G. |
| Copyright Year | 2006 |
| Abstract | Echo energies of single-beam echo sounders are inverted for the sediment mean grain size via a combination of theoretical and empirical relationships. In situ measurements of the seafloor mass density have revealed the presence of a thin transition layer between the water and the sediment. Within this layer, which has a thickness of order 1 cm, the density continuously changes from the water value to the sediment bulk value. The associated impedance gradient affects the normal-incidence reflection coefficient at high frequencies, when the product of wave number and layer thickness is of order unity or higher. A mapping algorithm recognizing this gradient is applied to echo sounder data acquired in three different areas, and for five sounder frequencies between 12 and 200?kHz. Compared with a scheme that relies on the Rayleigh reflection coefficient of a discrete interface, an overall improvement of several phi units in the grain size mapping is achieved by taking the gradient into account. A necessary condition to reach agreement between the acoustic and the ground truth grain size is that the thickness of the transition layer increases with a decreasing grain size. |
| Starting Page | 2555 |
| Ending Page | 2566 |
| Page Count | 12 |
| File Format | PDF HTM / HTML |
| DOI | 10.1121/1.2345907 |
| Alternate Webpage(s) | https://repository.tudelft.nl/islandora/object/uuid:91967a57-b6fb-4d74-a0a0-456df401d788/datastream/OBJ |
| Alternate Webpage(s) | http://mixing.coas.oregonstate.edu/Oc679/Walree%20et%20al%202006.pdf |
| Alternate Webpage(s) | https://doi.org/10.1121/1.2345907 |
| Volume Number | 120 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
