1 / 12

OASIS 2006 meeting, February 2 nd , WHOI

OASIS 2006 meeting, February 2 nd , WHOI. MISC lab report Emmanuel Boss & Wayne Slade. Processed data (available on our FTP site) includes O(12days) of 1min averages of: C-side ac-9. LISST-FLOC. LISST-B. BBRT ( b (117)) Nortek ADV (3D velocity. Acoustic backscattering).

jett
Download Presentation

OASIS 2006 meeting, February 2 nd , WHOI

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. OASIS 2006 meeting, February 2nd, WHOI MISC lab report Emmanuel Boss & Wayne Slade • Processed data (available on our FTP site) includes O(12days) of 1min averages of: • C-side ac-9. • LISST-FLOC. • LISST-B. • BBRT (b(117)) • Nortek ADV (3D velocity. Acoustic backscattering). Signs of biofouling are evident in LISST’s data towards the end of the deployment.

  2. Ac-9 data: Cp: Trend towards smaller g Suggests filtration system worked well for 12 days. Large and rapid changes in beam attenuation.

  3. Ac-9 data: Cp: Change of relationship in time (disaggregation ?).

  4. Ac-9 data: Colored dissolved organic material: • Suggests filtration system worked well for 12 days. • 676nm absorption increases as function of time (Organic coating of windows/ instrumental drift). Removal of red signal removes much of the increase. • Influence of particulate resuspension events is not observed.

  5. Combine LISST-B and Floc data: LISST-F 3 random 1min averages samples Black-floc Red-B Petzold, LISST-B Ac-9 Matching LISST-FLOC and LISST-B to obtain the phase function (and ultimately the VSF) in the near forward. How do the beam attenuation’s compare?

  6. LISST-B&FLOC data: Order of beam-c is consistent with acceptance angles (0.02, 0.1, 0.7). High frequency changes in beam attenuation (changes 2-7 fold in < 6 hrs). Drift in LISST relative to ac-9 (t>12) and relative to each other (t>15).

  7. Ac-9, LISST-B&FLOC data: Trend towards higher R • Ratio to cLISST-B varies from 0.35 to 1.0 (Rmedian=0.63, to LISST-F Rmedian=0.57). • Petzold: between 1535% of scattering is between 0.10.8. • Diver visibility ~ 4/c. Which c?

  8. ADV-backscattering, BBRT and cp,ac-9: • bbp/cp ~0.025 throughout. • Acoustic scattering behave differently.

  9. Interesting puzzles: • Size distribution changes as turbidity increase are towards: • Larger particles based on cp spectrum inversion. • Smaller particles, based on LISST inversion & ratio of cac9/cLISST D Single grain Micro floc Macro floc Possible explanation: Resuspended single-grain particles are larger as bottom stress increases. Macro floc break at higher shears becoming smaller. Particulate properties cycle is ~12hr. If shear due to tidal current dominated the stress cycle would be ~6hr. Possible explanation: cycle is driven by interaction of directional waves with the tides.

  10. Still to process: ABS (AQUAScat) Sontek ADV BB-9 A-side ac9 • Issues to discuss: • Calibration of acoustics devices. • Depth resolution of optical properties in future deployments. Papers: Submitted: Optics Express: Calibrating the LISST to obtain VSF. Synthesis: Particle dynamics –floculation, setling and breakup.

More Related