Coastal Ocean Carbon Observations and Applications (COCOA)Janet W. Campbell,1 Carl F. Bruce Jr,2 Paul M. DiGiacomo,3 Mary-Elena Carr,4 Andrew Bingham,2 Lloyd French,2 and Robert Green2

The Coastal Ocean Carbon Observations and Analysis (COCOA) mission is focused on the goal of quantifying pools and fluxes of carbon in the coastal ocean, knowledge of which is essential for understanding the role of the global carbon cycle in climate variability and change. The COCOA mission involves the synergistic use of high-resolution spectral reflectance data from a hyperspectral imager in geostationary orbit, coupled with complementary satellite and field measurements, and integrated within a modeling framework. The mission concept was developed by a science team in collaboration with engineers at the Jet Propulsion Laboratory. This concept was submitted to the Decadal Survey and subsequently combined with other geostationary missions to form the GEO-CAPE mission.

Science Objectives and Strategy Abstract

Science Team (2003-2005)

Sampling Strategy

Robert Arnone Head Ocean Sciences Branch, Naval Research LaboratoryWilliam Balch Senior Scientist, Bigelow Laboratory for Ocean SciencesJanet Campbell Research Professor, University of New HampshireMary-Elena Carr Research Scientist, Jet Propulsion LaboratoryFrancisco Chavez Senior Scientist, Monterey Bay Aquarium Research InstitutePaul DiGiacomo Scientist, Jet Propulsion LaboratoryMark Dowell Research Professor, University of New HampshireRobert Green AVIRIS Experiment Scientist, Jet Propulsion LaboratoryNicolas Gruber Assistant Professor, University of California, Los AngelesChuanmin Hu Research Professor, University of South FloridaMarlon Lewis Professor, Dalhousie University and President, Satlantic Inc.Stephane Maritorena Research Professor, University of California, Santa BarbaraCurt Mobley Vice President and Senior Scientist, Sequoia Scientific, IncMark Moline Assoc. Professor, California Polytechnic State UniversityJohn Ryan Project Scientist, Monterey Bay Aquarium Research InstituteDariusz Stramski Professor, Scripps Institution of Oceanography, UCSDCharles Trees Research Professor, San Diego Sate UniversityKirk Waters Program Officer, NOAA Coastal Services Center

1 Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824. Email: janet.campbell@unh.edu; 2 Jet Propulsion Laboratory, Pasadena, CA; 3 NOAA-NESDIS, Camp Springs, MD; 4 Columbia University, New York, NY

• COCOA will quantify the particulate and dissolved carbon species in coastal waters.

• High temporal resolution from GEO allows for the separation of physical and biogeochemical processes that influence carbon pools and fluxes.

• By intensively focusing on North America, COCOA will quantify representative coastal processes that impact the global carbon cycle:

Eastern boundary current and coastal upwelling (California Current)

Western boundary current (Gulf Stream) Major riverine inputs (Mississippi River) Episodic features (storms, algal blooms)

Orbit:

• Numerous orbital configurations were studied: Geosynchronous with various inclinations, MEO, Elliptical – Molniya, GTO, LEO

• A geostationary orbit at 100° - 90° West longitude was selected because it provides the greatest amount of annual revisit time for the coastal U.S.

• Six scans are required to image the entire U.S. East and Gulf coasts.

• The scan regions illustrated here extend 200 km from the coast and cover the continental shelf and beyond.

• The spatial resolution ranges from < 250 m in the Gulf of Mexico to > 300 m in the Gulf of Maine.

• Four scans are required to image the key coastal zones of the eastern Pacific.

• The scan regions illustrated here extend 100 km from the coast and cover the continen tal shelf and beyond.

• The mean spatial resolution ranges from 260 m in Los Angeles to 320 m in Seattle.

Engineering teams at JPL conducted feasibility studies in the summer of 2003 and modeled the instrument end-to-end performance.

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COCOA NEdL at 200 m

COCOA NEdL at 400 m

MODIS NEdL at 1000 m

COCOA Radiance

MODIS Radiance

COCOA 10 nm spectral resolution

Water at 60° zenith IlluminationModes of Operation:

COCOA will have two modes of operation. In the default Synoptic mode the entire U.S. coastal zone will be imaged 4-6 times each day. The Experiment & Event mode will be used to intensively image regions during the focused science experiments or during significant events such as storms or harmful algal blooms.

Mode

Maximum number of

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Total scan time

Total volume

Maximum number of

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Synoptic 10 2-3 hours~30

GBytes 6

Experiment & Event

110-15 min

~2 GBytes >20

The mission strategy is to conduct a series of focused experiments with intensive in situ sampling.

Harmful algal blooms

Hurricanes and other storm events

Upwelling systems

Riverine fluxes

Sampling Scenarios:

The synoptic mode provides 4 looks per day of each coast.

The three experiment modes sample one coast more frequently for a period of time (e.g., continuously for a month during a focused experiment) or to capture an “event”.

EST 8 9 10 11 12 13 14 15 16 17 18 19CST 7 8 9 10 11 12 13 14 15 16 17 18PST 5 6 7 8 9 10 11 12 13 14 15 16

Synoptic

West Coast

Gulf of Mexico

East Coast

Time to scan entire coast

West Coast 30 minutesGulf of Mexico 90 minutesEast Coast 60 minutes

The hyperspectral observations made several times per day, together with ancillary information and models, will be used to quantify the pools and pathways of carbon in the coastal ocean.

Ancillary Information:

• Data from other satellites (SST, PAR, winds, salinity)

• In situ data from moorings, HF radar, and other assets provided by the IOOS and ORION (aerosols, temperature profiles, currents, nutrients, …)

• Bathymetry and bottom albedo

• Hydrology (river discharge, rainfall, …)

• Tides and sea-level

Models: System of models in which a regional carbon-cycle model is nested within a basin-scale ocean and atmospheric circulation model. Within the region, carbon cycle model includes the effects of the physical circulation, biology and biogeochemistry.

Observed rates of change will be modeled as sum of in situ production, losses, and changes due to advection:

dCx/dt = P – L + horizontal + vertical

Derived variables (pools):

POC: phytoplankton biomass and detritus

PIC: calcite, inorganic sediment

DOC: region-specific relationship with CDOM

DIC: surface ocean pCO2, carbonate and bicarbonate

COCOA observes carbon pools at times t1, t2, … throughout the day.

Instrument Design

The geostationary vantage point provides the sampling frequency needed to resolve dynamic processes in coastal regions which are dominated by tides and winds. It has the added advantage of mitigating losses due to cloud cover and fog.

The NASA Earth Science Enterprise roadmap for the Carbon, Ecosystems, and Biogeochemistry Theme includes a coastal carbon mission.

COCOA scans from offshore to inshorecontours show mean pixel resolution (m)

COCOA Instrument Description and Performance

OpticsF/5 Cassegrain telescope and Offner Spectrometer

Focal Plane Array Visible CMOS/CCD detector

Primary Mirror ~ 50 cm diameter

Mass / Power 71 kg / 50 W

Spatial Resolution at Nadir

200 m

Spectral Sample5 nm between 350 and 1050 nm

SNR600 to 1000 between 400 and 800 nm at 10 nmCOCOA leverages integration time to

obtain more sensitivity than MODIS at smaller spatial scales

Summary