Status, Gaps, and Opportunities in Earth Observing Systems: Oceans

Mark R. AbbottCollege of Oceanic and Atmospheric Sciences

Oregon State University

Future Directions

• Programs such as CLIVAR, GODAE, and GOOS emphasize operational observation strategy

• But programs such as JGOFS have shown that much research remains, especially in ecology and physical coupling– What processes need to be included?– What scales do we need to observe?– How do we parameterize for models?– Many of these remain as challenges from 1984

• Are ocean sciences ready?– We do need long-term, carefully-calibrated series

Earth Observation Summit

• Promote the development of a comprehensive, coordinated and sustainable Earth Observation System(s) among governments and the international community in order to improve our ability to understand and address global environmental and economic challenges and meet International Treaty Obligations– Affirmed the need for timely, quality, long-term global

information as a basis for sound decision-making– Called for improved coordination of systems for observations of

the Earth and to fill data gaps– Highlighted the need to assist developing countries to sustain

their observing systems by addressing capacity building– Affirmed the exchange of data from observation systems in a

full and open manner with minimum delay and at minimum cost.

– Tasked the preparation of a 10 year Implementation Plan for this EOS with a Framework to be approved by Ministers at an EOS Summit in Tokyo in May 2004 and the Plan to be approved at an EOS Summit in Europe in Dec.2004

Uses of Ocean Observations

• State of the ocean– Heat content– Ice cover– Salinity– Carbon– Color– Sea state

• Pathways of the ocean– Circulation– Fluxes, including air/sea and ocean/land– Productivity– Food and energy resources

Observing Ecosystem

Wind forcing (QuikSCAT, SeaWinds)

Dynamic Response Thermodynamics (TOPEX/Poseidon, (AVHRR, MODIS, Jason-1) TRMM MR, AMSR)

Ocean productivity (MODIS)

GCOS List of Essential Ocean Variables

• Surface: Sea surface temperature, sea surface salinity, sea level, sea state, sea ice, currents, ocean color, CO2 partial pressure

• Sub-surface: Temperature, salinity, currents, nutrients, carbon, ocean tracers, phytoplankton

• Note that forcing fields (wind stress, etc.) are listed under Atmosphere variables in GCOS report

• These could be divided into requirements for short-term (“forecasting”) and long-term (“projections”) applications– Although the names remain the same, requirements

change significantly

Accuracy and Resolution

• These have been documented many times– Satellites

• Topography – TOPEX/Poseidon-class• Ocean vector winds – SeaWinds-class• SST – MODIS-class• Ocean Color – SeaWiFS/MODIS-class• Sea ice – AMSR-class

– In situ• CLIVAR hydro lines for nutrients, density, etc.• Carbon Cycle Science Plan for carbon processes• ARGO for profiling floats• TAO/TRITON for moorings• WOCE/CLIVAR for surface drifters• GCOS for sea level stations

Present State of Ocean Observations

• Satellite observations provide global, near-surface view– Primarily research missions such as

TOPEX/Poseidon, ADEOS-2, EOS, Envisat, etc.

– Some operational missions including DMSP and POES

• In situ networks provide surface and subsurface views– Primarily research projects– Voluntary Observing Ships (SST, XBT’s)– ARGO floats– Buoys and surface drifters– Moored arrays, such as TAO/TRITON

Are These Adequate?

• GCOS comments– Improved but variable coverage in time and

space– Quality issues– Need for coordinated process to move research

systems into operations– Some critical data sets not being measured

adequately• SST, SSS, sea ice, air/sea fluxes, ocean ecosystems

– Limited systematic sampling of sub-surface variables

– Coastal oceans and shallow seas• Including extreme sea level events

Plans for Ocean Observations• Satellites

– Visible and passive microwave radiometry• POES, DMSP evolving into NPOESS• Some capabilities of research missions evolving into

NPOESS– Exceptions – fluorescence, salinity

– Altimetry• Research missions evolving into OSTM

– Scatterometry• Continued research missions

– SAR• Continued research missions

• In situ– VOS measurements (flow-through, XBT’s)– Continued ARGO and surface drifter deployments– Limited buoy networks– Sea level gauges– Repeat hydrographic lines (research-based)

Proposed Repeat Hydro Lines

pCO2 VOS and Time Series Plans

Gaps

• Measurements– High-quality altimetry after OSTM– Continuation of ocean vector winds– Inadequate surface and subsurface networks

• Salinity, SST, air/sea fluxes• Expansion of ARGO, drifter, and buoy networks• High latitude measurements• Sea level network• Continued hydrographic sections

– Comprehensive time series stations– Chlorophyll fluorescence– Coastal zone processes

• Chlorophyll in optically-complex waters• High resolution sampling

– Continuation of SAR

More Gaps

• Infrastructure– Calibration/validation strategies, especially

for ocean color– Coordinated analysis and reprocessing

• Multiple data sets to sort out ambiguities

– Technology development and infusion• pCO2 observing technology

– Data management and distribution– Recovery of historical data sets– Development and refinement of model

parameterizations

Specific Issues

• Sampling and impacts on field estimates– Ocean vector winds– Ocean topography– SST and clouds

• Unexpected linkages– Impacts of SST on wind fields

• Coastal dynamics– Fluorescence and chlorophyll

• Emerging technologies– Fluorescence line height

• Calibration and validation

QSCAT vs. ECMWF Curl

QSCAT vs. ECMWF Divergence

Sampling Characteristics of Altimeters

Fu et al.

Wide-Swath Ocean Altimeter

• RMS error for 10-day cycle

• Geostrophic velocity

Fu et al.

MODIS SST

Day

Night

SeaWiFS Sampling at the Polar Front

Future Research Mission Concepts

• Wide Swath Ocean Altimeter as proof of concept on OSTM

• Test flight of ocean salinity mission• Ocean vector winds as part of operational

constellation– Further research on high-resolution fields– Improved capability to retrieve vector winds under

extreme conditions

• Advanced ocean color sensor to study absorbing aerosols and variations in fluorescence efficiency– Optically complex conditions, both ocean and

atmosphere

• Expanded calibration and validation activities in support of CDRs

NASA Today

What is NASA’s 20-Year Vision?

The Earth Science Vision Team addressed five The Earth Science Vision Team addressed five future Earth sciences research and development future Earth sciences research and development topics:topics:

• The genesis and development of extreme weather

• Seasonal climate change and predictability

• Sea level change

• Earthquake prediction

• Biosphere, climate and human interactions

Additional topics are to be identified in the future

Satellite Transition ScheduleSatellite Transition Schedule

NPOESS

CY 99 00 11 12 13 14 15 16 17 1803 08 09 1001 02 0704 05 06

0530

1330

DMSP

POES

POES

EOS-Aqua

NPP

EOS-Terra

DMSP

METOP

WindSat/Coriolis

0730 - 1030

Local Eq

uato

rial C

rossin

g T

ime

NPOESS

NPOESS

NPOESS

Earliest Availability

Projected End of Life based on MMDs

Advantages of an Operations Approach

• Provides continuous coverage• Real-time data 24 hours a day, 7 days a

week• Bridges gap between civilian and military

missions• Continuity with existing systems/planned

systems• Commitment to support long-term data

continuity for environmental monitoring and global change assessment– Here’s the challenge!

The NPOESS Approach• Environmental Data Records (EDR’s)

– “Threshold” often not sufficient for climate research– “Objective” often required– Climate-quality time series will not be a collection of

standard EDRs• Who will support the necessary data access, algorithm

development, and reprocessing?

• New EDR requirements– Many specific improvements– Added stability requirements

• Calibration/validation– Still being defined

• Mission operations– What constitutes failure for replacement launch?– What about overlap and residual assets in orbit?

What is a Climate Data Record?

• Need for long, consistent time series– Subtle, and often ambiguous, climate

signals– Detection and attribution

• Identify and quantify biases and errors

– Beyond the “LG” class of statistics– More than just match-ups to in situ data– Understand impacts of sampling errors– Includes sensor and algorithms

Calibration/Validation Strategies

• NPOESS Integrated Program Office beginning to plan calibration/validation strategies

• Initial focus on aircraft-based approaches• But validation for climate data products will

require continuing campaigns and reprocessing– SeaWiFS data have been reprocessed several times

since 1997 launch

• Many data products will require expensive in situ programs– MOBY bio-optical mooring

• How does one validate measurement “stability?”

Challenges in Integrating Research and Operations for Climate Studies

• Division of responsibilities and roles• Adequacy of operational data for climate

research• Development of sustainable instrumentation,

but also evolvable• Ensuring long-term records with NASA

missions• Prioritizing and establishing an observing

strategy• Open, enduring mechanisms for science input

and oversight

How do these link to science themes?

• Ocean forcing and response to atmosphere– Circulation and heat transport– Eddy processes– Upper ocean mixing, upwelling/downwelling

• Ocean biogeochemical cycling– Shifts in ecosystem structure– Uptake and sequestration

• Coastal dynamics– Response to changes in terrestrial processes– Role in the carbon cycle– Fisheries and energy resources

• Long-term monitoring and attribution– Inherent time and space scales of ocean processes