An Operator’s View of the Ocean Observing System in the Gulf of Maine Neal R. Pettigrew and...

An Operator’s View of the Ocean Observing System in the Gulf of MaineNeal R. Pettigrew and Heather Deese

School of Marine Sciences, University of Maine, Orono, ME 04469 USA

UMAINE/NERACOOS Technical ProgramUMAINE/NERACOOS Technical Program

Weather -- surface winds, waves, atmospheric pressure, air temperature, visibility

Oceanic conditions – surface currents, subsurface Doppler current profiles, temperature & conductivity

Environmental quality – dissolved Oxygen (SeaBird, and Aanderaa Optode)

Passive Acoustics – Fish Tag Monitoring (Salmon, Sturgeon)

Ocean optics –Surface PAR, Chlorophyll fluorescence , CDOM fluorescence, light scattering and attenuation, multi-wavelength absorption, upwelling and downwelling multi-wavelength radiometry (ocean-color)

Modeling (forecast and nowcast):circulation & and hydrographic fields (POM) surfacw waves (high resolution SWAN)

Satellite Data: SST, Ocean Color, Visible, Scatterometer winds

Surface current mapping: long-range CODAR

GoMOOS GoMOOS Shelf Buoy Shelf BuoySolar PoweredSolar Powered

High StabilityHigh Stability

Economical DesignEconomical Design

Leaves no anchor behindLeaves no anchor behind

Inductive Modem systemInductive Modem system

Dual real-time telemetry Dual real-time telemetry systemssystems

Dual wind-speed and Dual wind-speed and direction sensorsdirection sensors

• Taut elastic tether for reduced pitch and roll motion and reduced watch circle

• Deep CT measure-ments (to 250 m) telemetered to buoy via inductive modem

• Long range Doppler Current profiles

• Iridium and GOES Telemetry of data

• Acoustic release, anchor left on bottom

DEEPER WATER MOORING

Near-surface instrument cages

Buoy Deployment• Buoy deployment and

recovery are major operations. A deployment shown here on the RV Cape Hatteras (~145 ft). Normally deployment and recovery is done aboard an 85 ft vessel.

• GoMOOS has built 22 buoys for 11 monitoring locations. Each buoy pair is serviced on 6 month rotation schedule as are all the sensors.

• The twin buoy systems and 6-month deployment schedule are key to the high data returns achieved.

THE SHORT SEASON

THE LONG SEASON

FUNDING HISTORY

• BUOY FUNDS– 2000 ($1.7M,ONR)– 2001 ($1.7M,ONR– 2002 ($0.9M,NOAA)– 2003 ($0.5M,NOAA)*– 2004 ($1.3M,NOOA)– 2005 ($0.7M,NOAA*– 2006 ($0.5M,NOAA*– 2007 ($0.58,NOOA)*– 2008 ($0.54,NOAA)*

*stop-gap funds from:UME, UNH, UNH

• CODAR FUNDS– 2000 ($0.3M,ONR)– 2001 ($0.3M,ONR)– 2002 ($0.1M,NOAA– 2003 ($0,NOAA)*– 2004 ($0.1M,NOAA)– 2005 ($0.1M,NOAA)– 2006 ($0,NOAA)*– 2007 ($0,NOAA)*– 2008 ($0, NOOA)*

Gulf of Maine Buoy Array (2008-20??)

BuoyLocation Water Depth

(m)Start Date End

Date% dataReturn

A Massachusetts Bay 65 7/10/2001 ongoing 94%

B Western Maine Shelf 62 7/9/2001 ongoing 96%

E Central Maine Shelf 100 7/9/2001 ongoing 93%

I Eastern Maine Shelf 100 7/24/2001 ongoing 95%

F Southwest Scotia Shelf

98 8/1/2000 ongoing 94%

M Jordan Basin 285 7/12/2003*

ongoing 92%

N Northeast Channel 225 6/3/2004 ongoing 94%

Data returns of the still-active buoys

Seasonal hydrographic variations (2001-2009)

Jan Apr Jul Oct Jan30

31

32

33

Sal

inity

(ps

u)Western shelf (B)

Jan Apr Jul Oct Jan31.5

32

32.5

33Eastern shelf (I)

1m20m50m

Jan Apr Jul Oct Jan

5

10

15

20

Tem

pera

ture

(c)

Jan Apr Jul Oct Jan

4

68

10

12

Jan Apr Jul Oct Jan22

24

26

(

kg/m

3 )

Jan Apr Jul Oct Jan24

25

26

Seasonal Cycles and Interannual Variability (Buoy I)

Seasonal Cycles and Interannual Variability (Buoy B)

Deep inflow through the Northeast Channel

Jul04 Jan05 Jul05 Jan06 Jul06 Jan07 Jul07 Jan08

-200

-180

-160

-140

-120

-100

-80

-60

-40

-20

Velocity (monthly avg) at Buoy N 2004 - 2008

-6

-6

-6-6

-6

-3

-3-3

-3

-3

-3

-3

-3

-3

-3-3

0

00

0

0

00

0

0

0

0

00

0

000

0

0

0

0

0

3

33

33

3

3

3

3

3

3

-3-3

6

6

66

6

00

3

33

3

3

3

3

3

9

9

9

9

66

6

6

6

6

6

6

6

6

12

12

12

3

3

9

99

3

3

9

9

9

9

15

15 6

-6

96

6

-3-3

-612

9

12-6

3

1212

6

9

-9-6 -3-6

-3 0

15-3 S=32.5

S=34

Jan01 Jul01 Jan02 Jul02 Jan03 Jul03 Jan04 Jul04 Jan05 Jul05 Jan06 Jul06 Jan07 Jul07

A

B

E

I

M

L

N

-0.79

-0.71

-0.76

-0.66

-0.8

-1.17

-0.75

Monthly Anomaly of Daily Salinity (50m) relative to 2001:2007, [y-offset = 1PSU]

Jan01 Jul01 Jan02 Jul02 Jan03 Jul03 Jan04 Jul04 Jan05 Jul05 Jan06 Jul06 Jan07 Jul07

A

B

E

I

M

L

N

-2.25

-2.31

-1.83

-0.65

-0.87

-1.11

-0.51

Monthly Anomaly of Daily Salinity (1m) relative to 2001:2007, [y-offset = 2PSU]

Data and Methods• Prince 5 station (44˚55.02'N, 66˚49.98'W) is the only

long-term, deep water time series in GoM• Monthly (or more frequent) observations 1924-2006• Data binned by depth: 0-5m, 20-25m, 50-55m, 90-95m• Analysis• Calculate monthly anomaly time series: subtract long-

term monthly mean (climatology) from monthly average time series

• Remove outliers (abs >= 2*std) for each month• (Calculate annual average of monthly anomalies)• Least-squares regression to fit trend to de-meaned time

series (monthly anomaly or annual average)• Calculate 95% probability window using standard error

for trend line and t-test with effective degree of freedom estimated from first zero-crossing for each time series.

Retrospective look at GoM Observing• Over the first 7 years the data return of GoMOOS was

90% or greater. • The GoMOOS buoy design was novel in 2001, but no

funds have been available for upgrades and innovations. After 7+ years, buoys and sensors have deteriorated, and the array coverage has decreased due to funding shortages.

• Funding shortages and fluctuations have prevented technological and operational improvements.

• Never-the-less the array has provided unprecedented information about seasonal and interannual variability in circulation, physical properties, and optical properties in the GoM. Flow and property anomalies may be an early indication of a regime shift toward fresher, low nutrient conditions.

Looking forward: GoM Observing

• Mid-term: Much has been learned about operating in real-time throughout the years in the GoM and significant technical improvements are feasible.– Assuming a positive change in the funding

climate:• autonomous mobile platforms in operation.• Vertical profiling capabilities on surface

moorings in high wave climates• Real-time in-water control of sensors

• Long-term: Decadal and climate change signals measured in the GoM.– New sensor technologies including toxic

metals, HABs, bacteria, inorganic nutrients.

Prospective Glider lines as part of the Northeast RCOOS

Unmanned Surface Sail Vessels (USSVs)

• Early prototype autonomous sail vessel by NAVOCEAN LLC and the University of Maine.

• Initial sensors: T, wind.• Planned sensors: CT,

Accelerometer, DO optode, fluorometer, Doppler Profiler.

• Anticipated mission duration: Year at 2-3 knots.

• New hull designs in the works

Summary• The Gulf of Maine Observing system in

retrospect (2001-2008)– Simple designs and strategies for a harsh

environment– Data returns routinely in the 90%(+)– Greatest difficulties were fiscal rather than physical

• Prospects of the Gulf of Maine Observing system (2009-?)– New platforms and sensors are needed to realize

potential of the regional system– Profiling on surface moorings will be a major step

forward, but 12-15m winter waves are an obstacle – Stable and predictable funding required to realize

potential.