Sustaining Ocean Observations
to Understand Future Changes
in Earth’s Climate
DIVISION OF EARTH AND LIFE STUDIES
Briefing to the Ocean Studies Board
November 14, 2017
Committee Co-chairs:
Mary M. Glackin, The Weather Company
Robert A. Weller, Woods Hole Oceanographic Institution
Study Committee
MARY M. GLACKIN, Co-Chair, The Weather Company, an IBM Business, Washington, D.C.
ROBERT A. WELLER, Co-Chair, Woods Hole Oceanographic Institution, Massachusetts
EDWARD A. BOYLE, Massachusetts Institute of Technology, Cambridge
ROBERT B. DUNBAR, Stanford University, California
ROBERT HALLBERG, NOAA’s Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey
PATRICK HEIMBACH, University of Texas at Austin
MARK MERRIFIELD, University of Hawaii at Manoa
DEAN ROEMMICH, Scripps Institution of Oceanography, La Jolla, California
LYNNE D. TALLEY, Scripps Institution of Oceanography, La Jolla, California
MARTIN VISBECK, GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany
Staff
SUSAN ROBERTS, Director, Ocean Studies Board
EMILY TWIGG, Associate Program Officer, Ocean Studies Board
APRIL MELVIN, Associate Program Officer, Board on Atmospheric Sciences and Climate
ALLIE PHILLIPS, Senior Program Assistant, Ocean Studies Board
Study Context
• The oceans play a substantial role in climate: The ocean absorbs 90% of the
surplus heat, about 30% of the CO2 associated with human activities, and
receives close to 100% of fresh water lost from land ice.
• Measurements of ocean climate variables are needed to test and improve
climate models
• Observations of climate
variables must be
sustained over long time
scales
• Concerns regarding
sustained funding for
long-term observing
NOAA
Statement of Task Maintaining long-term, continuous, ocean-data records for understanding, monitoring changes in, and
modeling climate changes are essential, yet, challenging. An ad hoc committee will consider processes for
identifying and characterizing the most critical, long-term ocean observations and identify
limitations of the current approaches.
When considering the various processes for selecting and characterizing high-priority, long-term ocean
observations, the committee will discuss potential factors such as:
• Accuracy, precision, frequency, and spatial resolution of observations;
• Duration of observations (e.g., what criteria would be used to determine when observations should be
sustained at high priority, are no longer needed for a given parameter or when an observation would be
superseded by a different type of observation, for example through a new/different technology);
• Inherent value and/or tradeoffs of increasing multidisciplinary observations across a limited number of
networks/platforms vs initiating additional observing systems;
• Complementarity of an observation to another set of observations (or network); and,
• Current or near-future technology that could be used to develop a more cost-effective observational
system.
The committee's report will identify challenges to maintaining long-term observations and suggest
avenues for potential improvement. During the study, the committee will convene a workshop to gather
expert opinions on the process for prioritizing long-term, ocean climate observations and discuss international
approaches to selecting and sustaining ocean observations, as well as other topics that are important for the
design of sustainable, long-term ocean observing systems.
Study Activities
• An information gathering workshop held in Washington, DC
with members of the U.S. and international ocean observing
community.
• Discussions with representatives from foundations and the
private sector to explore their contribution and potential for
further involvement in ocean observing.
Three Global Budgets
• The committee focused on three global budgets: heat, carbon, and
fresh water. – Sea level rise is described as a reflection of the heat and fresh water
budgets
• Sufficient understanding of climate requires the ability to reconcile the
inputs to, exchanges among, and storage of climate elements within the
ocean, land, and atmosphere.
• Observations allow for accurate characterization of the key processes used
to close the budget within a model, critical to projecting future changes.
Heat Budget
Budget closure requires observations of:
• ocean heat content
• air-sea heat exchange
• heat transport by ocean currents
• mixing
In situ heat content estimates. Johnson et al.
2016. Bull. Amer. Meteor. Soc. 97(8)
Central to understanding the
delayed warming of the
Earth’s surface temperature
Carbon Budget
Budget closure requires
observations of:
• either surface water partial
pressure of CO2 (pCO2) or pH,
• total dissolved CO2
• alkalinity
In situ carbon estimates. Doney et al. 2009. Annual
Review of Marine Science 1, with data from Bates et al.
2014. Oceanography 27(1)
Helps predict future
atmospheric CO2
concentrations and
informs the rate at which
ocean acidification
increases.
Fresh Water budget
Budget closure requires observations of:
• salinity
• temperature
• sea ice
• velocity and mixing
• fluxes of freshwater into and out of
the ocean--precipitation, continental
and ice sheet runoff, and evaporation
Trends in surface salinity associated with
precipitation and evaporation. Rhein et al. 2013.
IPCC AR5
Changes in salinity reflect
changes in the global hydrologic
cycle. Salinity and temperature
determine seawater density, which
sets the vertical stratification of
the ocean.
Sea-Level Change
• Heat content provides estimates of
rates of thermosteric sea-level rise
• Fresh water input from land ice
contributes to sea-level rise
• Ocean current observations are
required to evaluate the transport of
heat and salt, and for their
contributions to regional sea-level
change.
Trends in global sea level measured by satellite
(black, blue) and Argo floats (red). Leuliette and
Nerem. 2016. Oceanography 29(4)
Reflects the heat and
fresh water budgets
Atlantic Meridional Overturning
Circulation
Overturning circulation pathways are a critical property of the climate system--redistributing and storing heat and carbon absorbed from the atmosphere.
Historic observations have been limited, leading to misunderstanding of the natural variability and complex processes.
Regular observations began in 2004,challenging notions of a simplified conveyor belt and also showed that natural variability occurred on shorter timescales.
Further observations will be needed to contribute to the mechanistic understanding of the MOC.
Benefits beyond Climate
• An ocean climate observing system also benefits many
areas of science, commerce, and safety
– Weather forecasting including hurricane and El Niño forecasting
– Marine resource management including fisheries productivity and
ocean acidification
– Data products for safe and optimal shipping and fishing
NOAA NASA B.S. Halpern / Wikimedia Commons
Improving ocean observations
• Closing the budgets will be aided by expansion of observations into
poorly sampled regions, by the development of methods to quantify
as yet unmeasured processes, and by the deployment of new sensors
to sample biogeochemical properties and aid investigation of the
carbon budget.
NOAA
NASA
NOAA SOCCOM/Climate Central
International Coordination
Distribution of deployed in situ platforms from Sep 2017. JCOMMOPS
• Global Climate Observing
System (GCOS) coordinates in
situ and remote systems to
meet requirements for climate
observations.
• Global Ocean Observing System
(GOOS) was developed to meet
research and operational
requirements for sustained
ocean observations for
climate, as well as ocean
health and real-time services
Framework for Ocean Observing
• The committee found the Framework and the associated procedures for establishing
the Essential Ocean Variables (EOVs) are constructive for defining ongoing
requirements (precision, frequency, spatial resolution) for sustained ocean
observations and provide a solid foundation for selecting and prioritizing ocean
variables for sustained observing.
• The Framework is an ongoing process that allows for new priorities as societal and
scientific priorities change and capabilities matures.
Essential Ocean Variables
for Climate
Specification documents describe the observing platforms and sampling
requirements, dependent on the phenomena being captured, for each EOV.
Physical Variables:
• Sea state
• Ocean surface stress
• Sea ice
• Sea surface height
• Sea surface temperature
Biogeochemical Variable:
• Inorganic carbon
• Surface currents
• Subsurface currents
• Sea surface salinity
• Subsurface salinity
• Ocean surface heat flux
Readiness
level:
CONCEPT
PILOT
MATURE
International Coordination
Conclusion: The Global Ocean
Observing System organization
has effectively engaged countries
and built capacity for ocean
climate observing. A challenge
remains in obtaining global access
to national Exclusive Economic
Zones for drifting platforms
which could be addressed by
NORLC. French R/V Pourquoi Pas. Argo Program
Ocean Observing in the U.S.
• Federal activities: – Investments from individual agencies: NOAA, NSF, NASA, ONR
– The National Ocean Partnership Act (1996) established
• the National Ocean Partnership Program (NOPP),
• the National Ocean Research Leadership Council (NORLC; under the National
Ocean Policy, the NOC assumed the responsibilities of the NORLC),
• and the Ocean Research Advisory Panel (ORAP).
IOOS Organization. Interagency Ocean Observing Committee
— The Integrated Coastal and
Ocean Observing System
(ICOOS) Act (2009)
established
• the Interagency Ocean
Observations Committee
(IOOC) and the
• U.S. Integrated Ocean
Observing System (IOOS).
Need for Long-term Planning
Conclusion:
• A decadal plan for the U.S. ocean observing system would be the most
effective approach for ensuring critical ocean information is available to
understand future climate.
• Consistent with the Framework for Ocean Observing.
• Elements of a decadal plan include: identification of requirements,
assessment of the adequacy of the current system, components to be
deployed over the ten-year period, potential for technological
advancements, and an estimate of resources necessary to implement the
plan.
• NORLC could be responsible for its periodic assessment and update possibly
utilizing the IOOC and the ORAP.
Ocean Observing Workforce
Conclusion: Direct scientific involvement in sustained observing
programs, from design to implementation to analysis, synthesis, and
publication, ensures that the ocean observing system will be robust in
terms of data quality, incorporation of new methods and technologies,
and scientific analyses. Thus intergenerational succession of scientists
is critical for sustaining the observations on climate timescales. The
OCP could focus on improving career incentives for the scientific
workforce as a priority.
Building BGC Argo
floats at University of
Washington. SOCCOM
Project
Observation Technology
• The ocean is a complex environment, both technologically and logistically.
Conclusion: Declining investments
have slowed the development of new
technology, which is proven to expand
the capability, the efficiency, and
therefore the capacity of the
observing system. Philanthropic
efforts have in part filled this gap and
the OCP could encourage more support
there.
Seaglider. NOAA
Research Fleet
Conclusion: While new technology holds promise for access to the ocean, a
capable fleet of research vessels, including those with global reach, is essential
to sustaining the U.S. contribution to ocean observing.
• A fleet of global and ocean class ships is necessary for making direct
observations and for deploying and maintaining observing platforms.
NOAA Ship Ronald H. Brown. NOAA
Diverse Actors
• The committee found the scientific, technical, and engineering staff at
academic and government oceanographic institutions to be essential for
developing technology, operating observing platforms, and utilizing data.
• Philanthropies are a potential partner for supporting ocean observing as many
have made substantial investments in areas such as marine technology, ocean
research, education and outreach, conservation, and exploration and
discovery, though to date have not usually invested in long-term projects.
• Given that ocean observations for climate provide a wide range of benefits to
the agricultural, shipping, fishing, insurance, and energy-supply industries,
efforts can be made to draw support for ocean observing from the
commercial sector.
Need for Partnerships
• Conclusion: An Ocean-Climate Partnership (OCP) organization
would be an effective mechanism to increase engagement and
coordination of the ocean observation science community with
non-profits, philanthropic organizations, academia, U.S. federal
agencies, and the commercial sector. Through their shared
interests in the observational data and associated products, the
OCP members could work together toward the goal of sustaining
the ocean climate observing system.
Potential New Models of Support
• Ocean climate data is needed to inform national security, economic, and
societal decisions on climate change and other ocean-related issues and,
given the inter-governmental negotiations required for participating in a
global system, responsibility for supporting the ocean observing system falls
predominantly on the federal government in the United States.
• Opportunities exist to expand partnerships and coordination with the private
and nonprofit sector.
For additional information:
Emily Twigg, [email protected]
Report available at: https://www.nap.edu
Sponsored by the Arthur L. Day
Fund of the National Academies
and the National Oceanic and
Atmospheric Administration