Glider and shipboard observations for underwater optical detection and communications By: LCDR Alec Cullen LCDR Brian Breshears LT Ross Hammerer Thesis Advisor: Peter C. Chu Co-Advisor: Tetyana Margolina Excellence Through Knowledge
Effect of Ocean Environment on Underwater Communication and Detection Optical communication/detection systems are an alternative to acoustics The ocean optical properties are highly variable and depend on ocean environment Scattering by seawater and particles including chlorophyll-a causes light attenuation. http://www.whoi.edu/page.do?pid=119416&tid =3622&cid=163149 Underwater Optical Transfer Equation http://www.aticourses.com 2
Objective The objective of this project: Analyze and produce two-dimensional (2-D) maps of the glider and shipboard observed hydrographic and optical data collected by NAVOCEANO in the Arabian Gulf, Gulf of Oman, Adriatic Sea, and East Asian Marginal Seas Assess which basic oceanographic parameters significantly affect underwater optical transmission Assess spatial and temporal variations in correlation between oceanographic features and optical transmission parameters Obtain insight into the potential impact of optical conditions for developing optics-based naval systems in MCM or submarine/uuv communications 3
The SEAGLIDER From SEAGLIDER Fabrication Center. seaglider.washington.edu Profiles from surface to 1500m Buoyancy engine produces slight buoyancy changes to induce pitched upward or downward gliding. Internal battery pack is shifted side to side to facilitate turning. Uses Iridium LEO system to obtain GPS fixes, upload data, and receive command and control instructions from NAVO Glider Operations Center (GOC). From Applied Physics Laboratory www.apl.washington.edu Instrumentation 1) Seabird Electronics SBE 41 CTD sensor 1 Hz sample rate T accurate to.001 degrees C Salinity accurate to.005 PSU* Pressure accurate to 2 dbar* 2) WET Labs, Inc ECO bb2fl optical sensor puck Optical Backscatter @ 470nm and 650nm* Fluorimeter: Chlorophyll-A @ 470 nm* Samples in top 300m to preserve battery life 4
Glider Data Set Western Pacific Kyushu Okinawa 10,623 profiles from 2008-2014 Primarily east of the Ryuku Islands Dynamic area encompassing portion of Kuroshio WBC Luzon Total area: ~ 435,000 km 2 5
Ship Board Observation -HIDEX-BP Environmental instrumentation includes: 1. A Sea Bird model SBE CTD Measure temperature (ºC), salinity (PSU), and depth (m). 2. A Chelsea Mk II Aquatracka fluorometer Measure chlorophyll-a fluorescence (µg/l) at wavelength 676 nanometers (nm). 3. A Sea Tech 25 cm pathlength transmissometer Measure red light (670 nm) transmission (%). From http://www.teamorca.org/cfiles/biolum_study.cfm A vertical profiler High intake flow (up to 35L/s) 4. APL (Applied Physics Laboratory) 1 m pathlength transmissometer Measure blue light (490 nm) transmission (%). Long residence time Faster profile rate, 200-meter HIDEX profiles takes 20 minutes to complete. 6
Survey locations/profile count Time Survey Locations Number of Profiles Jun 1993 Gulf of Oman 62 Jul 1993 Arabian Gulf 42 Feb 1995 Yellow Sea 58 Jan/May/Jun 1995 East China Sea 85 Mar 1996 Arabian Gulf 120 Apr 1996 Gulf of Oman 46 Apr/May 1997 East China Sea 48 Nov 1997 South China Sea 35 Mar/Apr 1998 South China Sea 54 Jul 1999 South China Sea 45 May/Jun 2000 Arabian Gulf 92 Jun 2000 Gulf of Oman 48 Sep 2000 Gulf of Oman 56 Sep 2002 Adriatic Sea 47 Jun/Jul 2001 Yellow Sea 75 Jun/Jul/Aug 2005 Philippine Sea 28 7
Dataset Snapshot Data are binned into 1m increments. Profiles range from 2m to 200m 8
East Asian Marginal Seas profiles 455 total profiles spanning from 2-200m of water depth Cross-Correlation plots created on arbitrarily defined water masses Yellow Sea Latitude 33-40N Longitude 115-128E East China Sea Latitude 24-33N Longitude 120-130E Philippine Sea Latitude 18-24N Longitude 121-128E South China Sea Latitude 12-24N Longitude 104-121E 9
Cross-Correlation Values (α= 0.05) SCS PS ECS YS B/F B/S B/TB B/T B/TR F/TB F/TR S/F S/TB S/TR T/F T/S T/TB T/TR TR/TB FEB 1995 0.570-0.530-0.680-0.740-0.800-0.760 0.900 JUN 2001-0.720-0.850 0.560-0.950-0.520 0.530 0.970 JUL 2001 0.560-0.940 0.960 0.590 0.960 0.590 0.970 B/F B/S B/TB B/T B/TR F/TB F/TR S/F S/TB S/TR T/F T/S T/TB T/TR TR/TB JAN 1995 0.790 0.660-0.620 0.900 FEB 1995 0.820 0.840 0.810 0.800 0.980 0.980 0.990 0.970 0.970 0.970 MAY 1995 0.540-0.520 0.550 0.860 JUN 1995 0.890 0.940 Jun/Jul Aug 2005 B/F B/S B/TB B/T B/TR F/TB F/TR S/F S/TB S/TR T/F T/S T/TB T/TR TR/TB -0.570 0.950 B/F B/S B/TB B/T B/TR F/TB F/TR S/F S/TB S/TR T/F T/S T/TB T/TR TR/TB APR 1997 0.740-0.660 0.900 MAY 1997 0.980 0.970 NOV 1997 0.150 0.660 0.540 0.650 MAR 1998-0.810-0.770-0.700 0.660-0.860 0.960 APR 1998 0.960 OCT 1998 0.920 0.980 JUL 1999-0.640-0.650 0.950 0.800 Only statistically significant values > 0.5 shown Red = + correlated Blue = - correlated B = Bioluminescence [Photons/L/s ] T = Temperature [ºC] S = Salinity [PSU] F = Fluorescence [µg/l] TR = T Red [%] TB = T Blue [%] 10
Adriatic Sea Data Depth(m) 11
Adriatic Sea 12
Arabian Gulf Data Collection 13
Correlation Values in Vertical Domain Jun 1993 AG Jun 1993 GOO Mar 1996 AG Mar 1996 GOO Jun 2000 AG Jun 2000 GOO Sep 2000 AG Sep 2000 GOO Temp Salinity -0.73 0.76-0.73 0.73-0.71 0.81-0.92 0.81 Temp Biolum 0.52 0.64 0.61 0.73 0.58 Temp Fluor -0.55 0.63 Temp %RTr -0.68-0.52-0.71-0.67 Temp %BTr -0.63-0.56-0.72-0.71 Biolum Fluor 0.57 0.71 0.73 0.73 0.56 0.74 Biolum %RTr -0.8-0.75-0.83-0.5-0.75 Biolum %Btr -0.82-0.73-0.86-0.54-0.75 Fluor %RTr -0.68-0.82-0.79-0.85-0.61-0.79 Fluor %Btr -0.66-0.82-0.77-0.85-0.49-0.78 14
Correlation of Derived Parameters Jun 1993 AG Jun 1993 GOO Mar 1996 AG Mar 1996 GOO Jun 2000 AG Jun 2000 GOO Sep 2000 AG Sep 2000 GOO FluorPeak BiolPeak 0.61 0.79 0.74 FluorPeak Fluor50% 0.88 0.78 0.53 0.66 FluorPeak Fluor90% 0.8 FluorPeak Biol50% 0.69 0.87 0.57 0.95 FluorPeak Biol90% 0.69 0.68 FluorPeak RedBA peak 0.78 0.63 FluorPeak BlueBA peak 0.79 0.65 FluorPeak EZD 0.69 0.53 0.72 15
Future Work Glider data analysis 10,000+ profiles over a 6 year period Different optical sensor Ability to get scaling value from backscatter (Glider) to transmission (HIDEX) High resolution classified data analysis Global data set enroute from NAVOCEANO 16
Thesis Plans Effects of Varying Oceanographic Conditions in the Arabian Gulf on Underwater Optical Communications and Detection by LT Ross Hammerer, Mar 2016 Effects of Varying Oceanographic Conditions in the Adriatic Sea on Underwater Optical Communications and Detection by LCDR Alec Cullen, June 2016 Effects of Varying Oceanographic Conditions in the East Asian Marginal Seas on Underwater Optical Communications and Detection by LCDR Brian Breshears, June 2016 17
Questions? Excellence Through Knowledge