OOI Science Drivers and Design I: Observing the Dynamic...

Science Community Workshop IBaltimore, Nov 11-12, 2009

Ocean Observatories Initiative

OOI Science Drivers and Design I: Observing the Dynamic

Coastal Ocean

Schofield, Barth, Plueddemann

Science Community Workshop 1 2

Community Input• Pre-ORION and observatory-related workshops

– DEOS, SCOTS, ALPS, RECONN, Profiler, …

• ORION-era workshops– San Juan, Salt Lake City

• RFA process• Advisory committees

– STAC, PAC

• Review committees– Blue Ribbon Panels, CDR, PDR, FDR, …


Program Documents

• Science Prospectus

• Science Plan

• Final Network Design


OOI Coastal Arrays• Prototypical eastern boundary system

(wind-driven upwelling)• Links to climate forcing (PDO, ENSO)

• Prototypical shelfbreak system (buoyancy-driven current)

• Links to climate forcing (NAO)

Plueddemann and Cook (WHOI)


Middle Atlantic Bight• Persistent advection

of cold, fresh water from the north

• Fresh water input from a series of rivers along the coast

• Influence of Gulf Stream rings and meanders from the south

• Complex frontal zone at the shelf-break

Plueddemann, Trowbridge, and Sosik (WHOI)


Shelf Break Processes


Frontal Dynamics• The front is distinguished by the transition from

cold, fresh shelf water to warmer, saltier slope water

Linder and Gawarkiewicz (1998)

• Surface- intensified jet, near the 150 m isobath

• Mechanisms of cross-front exchange are largely unknown


Frontal Dynamics

• Upwelling at base of front due to bottom boundary layer convergence

• Filamentation and turbulent stirring over slope

Houghton (1997)


Ecosystem Dynamics• The shelfbreak front is a biological as well as a

physical property boundary

Chlorophyll (H. Sosik)SST (APL/Johns Hopkins)


Ecosystem Dynamics• Slope nutrient input

important to primary production on shelf

• Shelfbreak exhibits a spring chlorophyll maximum via local nutrient enrichment

• Process(es) of nutrient exchange among shelf, front, and slope are not understood

chlorophyll 18-20 June 2001 (H. Sosik)


Marine Habitats

• The shelfbreak and coastal zone are the most important marine habitats in the MAB

• The shelfbreak has highest diversity of marine mammals in the U.S. Mid-Atlantic EEZ

Natural Resources Defense Council (2001)


Climate Connections

• NAO state modifies storm tracks, circulation and stratification in the North Atlantic

Heidi and Cook (WHOI)


Climate Connections

Irminger SeaArrayIrminger SeaArray

Pioneer ArrayPioneer Array70°W70°W

40°N40°N

• North Atlantic variability linked to MABCEV (UW)


Climate Connections

• High-latitude source waters

• Climate variability drives water property changes

• Altered circulation and stratification patterns

• MAB ecosystems experience regime shifts

Green and Pershing, Science (2007)


Coastal CO2 Flux

• Coastal ocean adds complexity to oceanic CO2 balance

• Global analyses do not adequately resolve the coastal zones

• MAB CO2 monitoring recommended by North Am Carbon Program

Sabine et al. (2004)


Pioneer Infrastructure• A Multi-Element, Multi-Scale Array

– Moored Array resolving frontal scale at shelfbreak

– Glider Array resolving mesoscale features from outer shelf to slope sea

– AUVs with docking stations allowing adaptive sampling at intermediate scales

– Sensors for interdisciplinary observations– Expandability for science user experiments


Observing Infrastructure

Plueddemann and Trowbridge (WHOI)


Pioneer Array• Multi-platform, multi-scale• Fixed and mobile assets• Integrated with regional

observing assets

glidersmooringsPlueddemann and Trowbridge (WHOI)


Pioneer SitesPlatform Site Location Depth Comments

EOM mooring, AUV dock, winched profiler with ADCP inshore

40o 14’ N 70o 45’ W 110 m

Typical inshore extent of shelf break front and jet

Moored profiler with ADCP central inshore40o 08’ N 70o 45’ W 130 m

10 km horizontal separation, resolves frontal correlation scale

EOM mooring, MFN, winched profiler with ADCP central

40o 03’ N 70o 45’ W 150 m

At climatological shelf break front, MFN for science user instruments

Moored profiler with ADCP central offshore39o 57’ N 70o 45’ W 300 m

10 km horizontal separation, resolves frontal correlation scale

EOM mooring, AUV dock, moored profiler with ADCP offshore

39o 52’ N 70o 45’ W 500 m

Typical offshore extent of shelf break front and jet

Moored profiler with ADCPupstream inshore

40o 14’ N 70o 38’ W 110 m

15 km horizontal separation, resolves along-stream correlation scale

Moored profiler with ADCPupstream offshore

39o 52’ N 70o 38’ W 500 m

15 km horizontal separation, resolves along-stream correlation scale

AUVsshelfbreak region various various

~80 km transects along and across shelf, centered on shelf break

glidersouter shelf & slope sea various various

~150 km transects from outer shelf to slope sea


Pioneer Array• Full water

column• Cross-front

resolution• Power-

generating buoys

• Multi- function nodes

• AUV docks

Plueddemann and Cook (WHOI)


Pioneer Array• Surface mooring/profiler pair• EOM mooring

– Satellite communications– Power generation at buoy– Meteorology– Sensor breakout at 5 m– EOM connection to seafloor– MFN at base, AUV docks

• Profilers– Wire crawler, to 20 m depth– Winched, surface piercing– ADCPs at base


Pioneer Array• Wire crawler profilers

– Surface expression– Iridium telemetry – 20 m minimum depth– Inductive link to surface– ADCP at base


Pioneer Infrastructure

Moored Array40 x 15 km

Site spacing10 km cross15 km along

AUV Region80 x 80 km

Glider Region150 x 130 km

Plueddemann (WHOI)



Typical AUV mission

220 km along- track

(80 km transect in 12 hr)

35 hr mission7 day repeat

Plueddemann (WHOI)



Typical glider mission

2000 km along- track

(150 km transect in 1 week)

3 mo endurance

Plueddemann (WHOI)


NE Pacific Coast• North Pacific High

dominates regional meteorology

Huyer (1983)

• California Current and coastal upwelling dominate along the coast


Coastal Dynamics

• Wind forcing, coastal currents, upwelling and topography interact to create complex flow fields

Barth (2007), Drawing by Barth and Reinert

COAS (OSU)


Ecosystem Dynamics• Coastal upwelling fuels primary production

chlorophyll temperature• Increased carbon fixation

• Increased POC flux

• Localized in time and space

Barth (2007), Drawing by Barth and Reinert, data courtesy of T. Strub


Columbia River Outflow• Primary production• CO2 exchange• Stratification• Marine habitats

Chlorophyll (R. Kudela, UCSC)summer winter


Hypoxia• Local

response to increased primary production at the surface

• Results in increased POC, decreased O2 in the BBL

Dissolved Oxygen

Particulate Org. Carbon

Velocity (N-S)

Hales et al. (2006)

hypoxic


Hypoxia• Advection

subarctic water along the Oregon coast

• Source waters are nutrient rich, oxygen poor

• Associated fish and crab mortality

125 124.8 124.6 124.4 124.243.9

44.1

44.3

44.5

44.7

Longitude (°W)

Latit

ude

(°N

)

50

Heceta Bank

Stonewall Bank

HH-Line

NH-Line

0% 1-25% 26-50% 51-75%76-100%

SH-Line

70100200300400

Newport

100

500

B

Florence

A

124

Crab Mortality Classes

Percentage of Pots0 50 100

Grantham et al. (2004)


Acidification• Upwelling brings

low pH waters to the coastal zone

• Aragonite compensation depth may be <100 m

Feely et al. (2008)


Coastal CO2 Flux• Coastal zone is

both a source and sink

• Riverine inflow with low pCO2 creates an ocean sink

• Strong coastal upwelling of high CO2 water results in ocean source

Chavez, Takahashi et al. (2007)


Climate Connections• PDO, ecosystem

changes documented

• Neither physical mechanisms nor biogeochemical consequences well understood

Peterson and Schwing (2003)


Endurance Infrastructure• A Multi-Element, Multi-Scale Array

– Two mooring lines spanning key shelf regions and contrasting along-shore regimes

– Glider Array resolving mesoscale features from inner shelf to slope

– Seafloor Cable providing high power and bandwidth

– Sensors for interdisciplinary observations– Expandability for science user experiments


Endurance Array• Multi-platform,

multi-scale• Fixed and mobile

assets• Cross-shelf arrays

at Newport and Grays Harbor

• Oregon Line Cabled to RSN

COAS (OSU)


Endurance SitesLocation

descriptionLatitude

°NLongitude

°WDepth

mComments

OregonOffshore

44.65 124.90 500 Offshore site, cabled, shared infrastructure with RSN

OregonShelf

44.64 124.30 80 Mid-shelf site cabled, shared infrastructure with RSN

OregonInshore

44.65 124.10 25 Inshore site, uncabled

WashingtonOffshore

46.91 124.95 500 Offshore site, un-cabled

WashingtonShelf

47.00 124.27 80 Mid-shelf site un-cabled

WashingtonInshore

47.00 124.162 25 Inshore site, un-cabled


Endurance Oregon Line• Full water

column • Key cross-

shelf sites• High power

& bandwidth via RSN cable

• Benthic experiment nodes

Inner shelfMid

shelf

Slope COAS (OSU), Illustration by Cook (WHOI)


Oregon Inner Shelf• Surface mooring

– Iridium communications– Hardened, battery power– Upper ocean sensors – EM to seafloor– MFN platform at base

• Winched profiler– Stand-alone, battery powered– Surface piercing


Oregon Mid-Shelf• Surface EM mooring

– Satellite comm’s– Power generation

(wind/solar)– Meteorology– Sensor breakout at 5 m

• Winched profiler– Cabled to RSN

• Benthic Exp Platform– Cabled to RSN


Oregon Slope• Surface mooring

– (as before)• Hybrid profiler mooring

– Winched above– Mid-water platform– Wire crawler below– Cabled to RSN

• Benthic Exp Platform– Cabled to RSN


Endurance Washington Line• Full water

column • Key cross-

shelf sites• Power-

generating buoys

• Multi- function nodes

COAS (OSU), Illustration by Cook (WHOI)


CGSN Core Sensors• Derived from community input (RFIs), Advisory Groups

(iOSC, BRP), Trace Matrices and SUR• 32 CGSN Sensor Types in 18 Measurement Classes• 237 sensors in Endurance Array, 150 sensors in Pioneer

Air-sea fluxes (3) Turbulent velocity (1) Nitrate (1)CO2 flux (2) Dissolved oxygen (2) Nutrient 4 Chan (1)Surface waves (1) pH (1) ZP sonar (2)Temp/cond/press (5) PAR (1) Digital still camera (1)Pressure (1) Spectral irradiance (1) Hydrophone (1)Mean currents (point and profile) (5)

Optical attenuation and absorption (1)

Chl-a, CDOM, and turbidity (2)

(x) = number of sensor types in measurement class


Sampling Rates• Fixed sensors

– Baseline sampling: hourly– Capable of: >=1 Hz depending on sensor

• Profilers– Baseline sampling: Uncabled: 4x/day, Cabled: 8x/day– Sub-meter vertical resolution– Capable of: 150 m vertical profile in 20 min

• Gliders, AUVs– 1 m along-track resolution– Horizontal resolution 10x profile depth– Capable of: defined or adaptive mission control


Coastal Core Sensors• Details by measurement type and platform

– Air-Sea interface• On all EM and EOM buoys

– Surface boundary layer• EM & EOM 5 m breakouts, winched profilers

– Water column• Profilers, gliders, AUVs

– Benthic boundary layer• MFN, BEP, winched profilers


Summary• Overarching science drivers

– Process focused, interdisciplinary, climate related

• East and west coast arrays with– Common elements (platforms, sensors)– Unique features

• Real-time data flow• Command and control• Extensible, expandable


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