Lecture 22 : Deployment strategies for different optical sampling platforms: mobile platforms (AKA “ALPS). What are mobile platforms? Why use them? Some case studies! ALPS report, Rudnick and Perry (2003), http://www.geo-prose.com/ALPS/alps_rpt_12.16.03.pdf
What are mobile platforms?
Why use them?
Some case studies!
ALPS report, Rudnick and Perry (2003), http://www.geo-prose.com/ALPS/alps_rpt_12.16.03.pdf
Special Issue of L&O (2008) on science from mobile platforms
What are mobile platforms?*Autonomous, mobile platforms without tether to ship or land; include surface drifters, profiling floats, AUVs, gliders* Sensors – small, robust, often low-power – measure water column physics, optics, biology, chemistry and sea floor properties* Wireless communication – two-way* Networks of sensing systemsWhy use them?* Sampling is the central observational problem in oceanography* Wide range of scales requires “scalable”observational systems * Global questions require observational systems to be “long-lived”* Intermittent and regional questions require observational systems to be “portable”
Biofouling; Abbott ratio 683/555 as indicator of biofouling; why?
No optics in Surface Velocity Drifter Programme –lost opportunity?
Succession of sensors (plastic pouch & bolt cutting)?
Mitchell, Solo float
spring bloom, Sea of Japan, 3-channel Ed –> Kd 490
How would biofouling affect Kd?
How would you verifythat c ~ POC?
~ 100 m – 10 mm
large cells, zooplankton, flocs
very different particle size structure on float vs. CTD mounted
––> role of aggregates in ocean dynamics
Gliders – lowest payload but long duration (to 7 months); add more sensors, increase drag, decrease mission length; goes slowly (neither Eulerian nor Langragian)
deep chl max
New Jersey coast: beam c and bb
to identify nephloid layers
Moline: Repeat transects of bioluminescence potential off
California with three time scales: A) months B) week C) day
Floats + gliders – multiple spatial scales, redundancy of sensors Floats – Ed, Lu, ISUS nitrate, beam c, bb, chl F, T, S, O2 Gliders – T, S, O2, chl F, 2 bb
Future needs* New platforms - hybrid glider/AUV, large recoverable floats, small water-following floats* New and smaller sensors – more variables (turbulence, nutrients, trace metals, dissolved gases, molecular sensing, zooplankton) – redundancy of variables – ability to go deeper (avoid biofoul; deep water “val”)* Adaptive sampling and control; multiple platforms* Improved communications – cheaper* Biofouling and internal calibration* Water sampling – for unique samples and validation* Greater accessibility