Transcript Consistency between planetary heat balance and ocean

Consistency between planetary heat balance and ocean
heat storage
Clivar research focus team:
Karina von Schuckmann, Bernard Barnier, Carol Anne Clayson, Catia
Domingues, Sergey Gulev, Keith Haines, Simon Josey, Norman Loeb,
Pierre-Philippe Mathieu, Mathew Palmer, Anne-Marie Treguier, Kevin
Trenberth, Maria Valdivieso, Martin Visbeck, Martin Wild
Clivar RF: Consistency between planetary heat balance and ocean heat storage: General Context
 Climate is the result of energy transfer between
the different components of the Earth's system.
 Energy flows alter clouds, and weather and
internal climate modes can temporarily alter the
energy balance for periods of days to a several
decades.
 The only practical way to monitor climate change
at different time scales is to continually assess
the energy, mainly in the form of heat, in the
climate system.
Clivar RF: Consistency between planetary heat balance and ocean heat storage: General Context
Earth Energy Budget from 1970-2011
 Since the accelerated increased
concentration of greenhouse
gases from human activities,
energy is not balanced, leading
to an accumulation of heat in the
climate system
Climate feedback
(climate sensitivity)
Cummulative
energy flow into the
Earth system (ES)
IPCC, 2013
Balanced by
 warming of ES
 increase in
outgoing radiation
inferred from
changes global SST
Clivar RF: Consistency between planetary heat balance and ocean heat storage: General Context
Earth Energy Budget from 1970-2011
 Energy stored in the climate system:
~ 93% ocean
~ 4% melting ice (sea and land)
~ 3% warming of the atmosphere and land
Climate feedback
(climate sensitivity)
 The absolute measure of the Earth
Energy Imbalance and its changes over
time are vital pieces of information
related to climate change as this is the
single quantity defining the status of
global climate change and expectations
for continued global warming.
Energy accumulation
Cummulative
within the different
energy
flow into
components
of the
the
Earth
Earthsystem
climate(ES)
system
IPCC, 2013
Balanced by
 warming of ES
 increase in
outgoing radiation
inferred from
changes global SST
Clivar RF: Consistency between planetary heat balance and ocean heat storage: Challenge
Large uncertainties in our estimates challenge our ability to infer the
absolute measure of the Earth Energy Imbalance and its changes over time
 An ongoing accounting of where heat
goes and its manifestations is a great
need and has implications for
interpreting the recent past and
immediate future.
 Improved
knowledge
and
understanding of the climate system
will be translated into improved
climate assessments and more
reliable climate models, synthesizing
the
observations,
performing
attribution of what is happening and
why, and in making predictions and
projections on all space and time
scales.
Climate feedback
(climate sensitivity)
Energy accumulation
Cummulative
within the different
energy
flow into
components
of the
the
Earth
Earthsystem
climate(ES)
system
IPCC, 2013
Balanced by
 warming of ES
 increase in
outgoing radiation
inferred from
changes global SST
Clivar RF: Consistency between planetary heat balance and ocean heat storage: Motivation
Developing the knowledge, and observational capability, necessary to “track” the energy flows
through the climate system is critical to better understand the relationships between climate forcing,
response, variability and future changes.
Clivar RF: Consistency between planetary heat balance and ocean heat storage: GOAL
Ocean Heat Content
Radiation at TOA
Loeb et al., 2012
 Advancing our
knowledge through budget
constraints and assessment
studies
radiative
Air-Sea fluxes
Abraham et al., 2013
turbulent
Josey et al., 2014 (in prep.)
Clivar RF: Consistency between planetary heat balance and ocean heat storage: GOAL
An overaging goal is to bring together 4 climate research
communities all concerned with the energy flows in the Earth’s
System




atmospheric radiation
air-sea-flux
Ocean Heat Content
ocean reanalysis and climate models
to advance on the understanding of the uncertainties through
budget constraints.
This will increase our capabilities to answer pressing issues of
climate related research.
Clivar RF: Consistency between planetary heat balance and ocean heat storage: GOAL
The main objective of the activity is to analyze the consistency between
planetary heat balance and ocean heat storage estimates, data sets and
information products based on different parts of the global observing systems
(remote sensing (ESA/EO) and in situ) and ocean reanalysis under three tasks:
• Earth Observation Measurement Constraints on Ocean Heat
Budget (ESA EO)
• In situ observations of ocean heat content changes (GOOS and
CLIVAR/GSOP)

Ocean (or coupled) reanalysis for atmosphere-ocean heat exchange, consistency
of regional heat budgets and ocean heat content estimate (CLIVAR/GSOP,
SeaFlux)
Clivar RF: Consistency between planetary heat balance and ocean heat storage
FOCUS
What is the magnitude of Earth's energy imbalance (EEI) and how does it vary over time?
Issues/Gaps:
1. We need to identify what is required to further reduce the uncertainties aiming to provide an agreed upon range
for EEI (beyond just 0.5-1.0 W/m2). Best estimate from Argo OHC, but time series are short. OHC estimates show
inconsistencies, in particular for the historical record TOA measurements have large unknown biases (order 6 W
m-2) and uncertainty of the individual surface energy balance components are more than an order of magnitude
larger than the absolute amount of the Earth imbalance.
2. We need to evaluate consistencies between in-situ and reanalyses OHC and satellite observing systems (an
inventory of changes in heat that matches top-of-atmosphere (TOA) imbalance continually over time), and the
different products itself, e.g. during the Argo era based on consistent and coordinated effort to intercompare the
various methods (assessment and model constrains and reanalysis ensemble studies, IQuOD initiative). Still
inconsistencies due to quality assurance, mapping, climatology and instrument calibration.
Clivar RF: Consistency between planetary heat balance and ocean heat storage
FOCUS
How are TOA net radiation and ocean heating rate distributed regionally and vertically (OHC)?
Issues/Gaps:
1. We need to evaluate the relative importance of the ice-covered ocean, marginal seas and deep ocean (>
2000m) of ocean heat content change and to understand how heat is transferred vertically and use Reanalyses to
dynamically gap fill OHC estimates in space and time.
2. How do regional patterns change in time and can regional OHC tendency patterns, along with other patterns
eg. sea level, be used to test/falsify Climate model variability hypotheses?
Deep ocean observing system still in its initial phase. Individual Ocean Reanalyses unable to provide error
estimates and most ocean reanalyses have still low resolution (1 degree).
Clivar RF: Consistency between planetary heat balance and ocean heat storage
FOCUS
How can we better constrain the surface energy fluxes and their spatio-temporal variations?
Issues/Gaps
1. We need to have a better quantitative knowledge of the energy fluxes at the Earth’s surface by improving the
consistency amongst the different satellite-derived surface flux products by developing evaluation metrics to
allow routine determination of the accuracy of different flux products: use of in situ surface radiation networks
and ocean heat content constrains (Argo, reanalyses: ESA funding). They cannot be directly measured from
satellites and are afflicted with large uncertainties and the level of agreement between different surface flux
datasets is poor. Ocean Reanalysis transports of Heat not yet proven reliable and both mean and transient
variability of transports should both be evaluated.
2. The role of air-sea fluxes in the interplay between the ocean and the atmosphere at different time scales
(driving/controlling mechanisms for air-sea exchanges) and associated problems for linking heat content
change with surface flux change. Long (multidecadal) homogeneous time series of surface fluxes, at least on
basin scales do not exist or highly uncertain from observations and are also very uncertain in multidacadal
reanalyses.
Clivar RF: Consistency between planetary heat balance and ocean heat storage: DIscussion
“What are the expected outcome and who will use the info?”
Outcome
 refinement of the global climate research community
 Enhancement on uncertainty evaluation and assessment of the different components of the climate
budgets by assessing already applied methods, developing new methods and inter-comparison
initiatives (link to ongoing initiatives, and development of new priorities and initiate their realization)
 Insight into climate research topics, and link to socioeconomic impacts
Use:
 climate research community
 global observing system programs, institutions, initiatives and operational centers (using
recommendations and perspectives for climate research applications
 internationally organized scientific initiatives and programs
Clivar RF: Consistency between planetary heat balance and ocean heat storage: DIscussion
“How can the science issues be best addressed in the context of internationally coordinated
science?”
“How can Clivar help to mobilize the needed resources and how can Clivar best support the
initiative?”
“Where are the opportunities and challenges during the implementation?”
“How can Clivar panels support the activity?”
“Which other, e.g. Global Environnement Change (GEC) projects are involved in the
activity?”
What are the most appropriate governance and management structures?
=> Strong link with GEWEX: moving to a joint activity?