status, gaps, and opportunities in earth observing systems: oceans mark r. abbott college of oceanic...
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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