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| Titel |
Evaluation of ADCP backscatter inversion to suspended sediment concentration in estuarine environments |
| VerfasserIn |
Guan-hong Lee, Hyo-Bong Park |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250113941
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| Publikation (Nr.) |
 EGU/EGU2015-14186.pdf |
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| Zusammenfassung |
| Acoustic Doppler Current Profiler (ADCP), designed for measuring velocity profile, is now
widely used for the estimation of suspended sediment concentration from acoustic
backscatter strength, but its application to estuarine environments has still room for
improvement. In this study, we examinedthe inversion capability of two ADCPs with 600 and
1200 kHz at three Korean estuaries: macrotidalHan river estuary (HRE), microtidalNakdong
river estuary (NRE), and anthropogenically altered macrotidalYeongsan river estuary (YRE).
In particular, we examined the relative importance of the sound attenuations due to
water (αw) and sediment (αs) in response to sediment characteristics (size and
concentration) as well as changing salinity and temperature. The inverted concentration was
compared with reference concentrations obtained either water samples or Optical
Backscatter Sensors. In NRE and YRE, where suspended sediment concentrations were
smaller than 0.2 g/l, the acoustic inversion performed poorly only with αs (r =
0.20and 0.38for NRE and YRE, respectively), but well with αw (r = 0.66and 0.42
for NREand YRE, respectively). Thus, it is important to accurately constrain αw
in low-concentration estuarine environments. However, we did not find that the
varying αw performed considerably better than the constant αw. On the other hand,
the acoustic inversion was poorest at HRE regardless of αw and αs (r = 0.71 and
mean relative error =45%). The large discrepancy appears to result from the poorly
constrained, spatially and temporally varying sediment characteristics (grain size,
density and concentration) due to non-local sediment transport at macrotidal HRE. |
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