Transcript Denman-Opening_Talk

US GLOBEC Pan-Regional Synthesis:
An Outsider's View
Ken Denman
Canadian Centre for Climate Modelling and Analysis
Meteorological Service of Canada
University of Victoria
&
Institute of Ocean Sciences-DFO, Sidney, BC
Email: [email protected]
U. Victoria
US-GLOBEC Boulder Nov 06
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Outline of Talk
GLOBEC Motivation and Hypotheses
– what about the 'GLOB' part? long term and large scale
Where is US GLOBEC Today?
– mature regional studies and capabilities
Key Questions and Approaches
– 'local insights' versus 'universal truths'?
The State of Marine Ecosystem Modelling
– reuniting foodweb versus biogeochemical models
A Look into the Future
– climate change and other human impacts
– thinking beyond funding
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Motivation for GLOBEC
(Kawasaki et al.)
There exist hemispheric, multidecadal changes
BUT what is natural and what is caused by (over)fishing?
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A Closer Look
• Lack of synchronicity
in anchovy cycles
Plots like these for your
study regions would be
a highly desirable but
unattainable outcome of
the US GLOBEC program
• Negative correlation
with Benguela system
in S. Atlantic Ocean
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(S. Lluch-Cota, 2005)
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Working Hypothesis #1
We want to understand the systems we are studying
well enough to 'forecast' their future behavior
• Events such as the 'physteria hysteria' off the
Carolinas, or Hurricane Katrina, capture all the
news. Our society tends to react immediately
and intensely to these events. But how can we
respond (rather than react) as a scientific
community so as to help minimize the
likelihood/risk of occurrence and/or severity of
such events in the future?
• These 'crises' & our personal, institutional and
funding horizons lead us to focus on shorter
term, smaller scale, 'process-level' studies
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Working Hypothesis #2
When GLOBEC ends, it should be seen as having put
our Society in a better position to address issues
of Global Change
Definition:
Global change = Environmental change
resulting from human activities and from
climate change both natural and
anthropogenic.
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Yet Much Environmental Change of
Consequence Occurs on ENSO to Century
Timescales
• Statistical predictions will likely fail as the system
moves beyond the ensemble of realizations on which
the statistics were based.
• Forecasting these timescales results in the system
'losing its memory' of initial conditions
• We must assume future forcing conditions
• Parameters must be formulated to adapt as the ocean
environment changes
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Yet Much Environmental Change of
Consequence Occurs on ENSO to Century
Timescales
• Statistical predictions will likely fail as the system
moves beyond the ensemble of realizations on which
the statistics were based.
• Forecasting these timescales results in the system
'losing its memory' of initial conditions
• We must assume future forcing conditions
• Parameters must be formulated to adapt as the ocean
environment changes
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Where is US GLOBEC Today?
1. You have completed intensive field programs on
Georges Bank, in the Pacific Northwest/Alaska, &
in the Southern Ocean:
– they combine submesoscale projects with 'monitoring'
on seasonal to interannual scales
– you have developed advanced sampling technology &
detailed mechanistic spatially-resolved coupled
physical-biological models to capture and integrate
the understanding gained from the field programs.
2. You are about to enter into your 'Synthesis' phase
and need a set of criteria to focus calls for
proposals and eventually the reviewing of the
proposals.
3. You want to leave a LEGACY
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Key Questions and Approaches
1. Which scientific advances made by US GLOBEC have been
'local insights' and which ones are 'universal truths'?
Can we learn from studies 'Contrasting' the different
regions studied?
– physically-controlled vs top-down predator controlled?
– dominated by event-scale phenomena, versus seasonal
and longer scales?
– systems that 'erase the past' and reset each year (or
after each 'event', e.g. El Niño, 'regime shift', etc.),
versus those that integrate over multiple years and
have 'memory'?
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Key Questions and Approaches
2. How much of the detail built into
the regional models is 'Portable'?
Portability Index PI:
J ( AS )  J ( EP)
PI 
J ( AS // EP)  J ( EP // AS )
where J(Ri) is the cost function of fitting to region Ri
J(Rj // Ri) is the cost of fitting to Rj after optimizing on Ri
AS – Arabian Sea & EP – Equatorial Pacific
[Friedrichs, M. A. M, J. Dusenberry, L. Anderson, R. Armstrong, F. Chai, J. Christian, S.
Doney, J. Dunne, M. Fujii, R. Hood, D. McGillicuddy, K. Moore, M. Schartau, Y. Spitz,
and J. Wiggert, 2006. Assessment of skill and portability in regional marine
biogeochemical models: the role of multiple plankton groups. J. Geophys. Res.,
submitted July 2006]
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Model Intercomparisons and 'Portability'
• Models with multiple
Phytoplankton classes (rhs)
perform better than 1P
models when applied to
different regions (bottom
panels)
• Simple models perform
almost as well as complex
models in 'local
optimization' (panel b)
No Optimization
Simultaneous Optimization
Local Optimization
Cross-validation
[Friedrichs et al, submitted]
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Model Intercomparisons and 'Portability'
• EqPac:
No Optimization
Local Optimization
Chlorophyll constraint
accounts for largest cost
• Arabian Sea (not shown):
Productivity constraint
more important
• Complex Models
- different models with
Simultaneous Optimization
Cross-validation
similar cost may have
very different internal
flows
- need more observations
of 'internal' variables to
constrain flows
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Portability Index
Lower Cost  Higher Portability
OOPS!
Assimilating zooplankton data 
Higher Cost & Lower Portability
WHY??
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3. Which functional representations in our models
are or can be formulated so that they vary with a
changing climate? (Do our approaches allow for
'emergent'? properties?)
Consider the Chlorophyll: Carbon ratio
 for example:
 our models are expressed in terms of C or N yet we estimate
phytoplankton biomass from Chlorophyll, and Chlorophyll captures
PAR, the light used in photosynthesis
 we obtain variable  based on the equation for 'balanced' Chl:C of
Geider et al. 1996, 1997, and
 observations/analyses from OSP during SUPER (Booth et al, 1993)
& our own during 1998-2000 (Peña & Varela, in prep.)  tedious
 our 'balanced'

is based on the previous 24h PAR (Jim Christian)
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C:Chl (= 1/ ) from OSP and Shelf Edge
First cruise?? 
- Winter: low, no gradient; Summer: 40 - 100
[Peña & Varela, submitted]
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C:Chl Ratio for Variable PAR at OSP
• Smooth black line
is
• smooth black line is
average daily PAR at OSP
• Red line is 'balanced' 1/
for PARt-1 averaged over
• mid-summer clear sky
PAR ~ 150+ W m-2
• Range ~ 25 – 120 gC/gChl
the upper 30 m
• BUT Chl changes little at OSP?
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Current State of Marine Ecosystem Modeling
Over the last decade, marine ecosystem model
development has diverged into several lines of
more or less independent activity. These
include:
1. upper food web models incorporating individualbased models (IBMs) and life history models of
herbivores and harvestable marine resources;
2. trophic models spanning many trophic levels but
focusing on harvestable marine resources;
3. biogeochemical models coupled to physical
climate models.
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End-to-End Ecosystem Modeling 'E2E'
International GLOBEC/ IMBER has organized an
End-to-End Ecosystem Task Team (e2e), whose
goal is:
• to guide the development of a full ecosystem
approach that links all components of the food
web with comprehensive climate models to explore
the impacts and feedbacks between global change
(in its broadest sense) and marine food webs.
(North American members: Dave Karl & Ken Denman).
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US GLOBEC Synthesis could have a goal to
develop an ecosystem model that would work
equally well (according to some 'cost function') in
all your regional study areas, embedded in the
same (ROMS?) circulation model.
• Need better metrics of uncertainty
• Need ensemble projections:
– give relative probability of different outcomes
– evaluate risk of the different outcomes
• Coupling the large scales to the small scales,
i.e. downscaling
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A Look into the Future
Global warming is here to stay
• Annual rates of emissions of CO2 are increasing,
and will continue to do so for the foreseeable
future (at least 30 years, due to coal generation
plants) [see next 2 slides]
• Polluting aerosols will be tackled and reduced due
their short atmospheric lifetimes and to the more
immediate threat to human health – which will lead
to an increase in the rate of warming (due to
current cooling effect of aerosols)
• All C4MIP coupled carbon-climate models show a
positive feedback to climate, i.e. coupled models
all sequester less CO2 to land and oceans than
uncoupled (Friedlingstein et al., 2006, J. Climate.)
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Stabilizing Concentrations Requires Large
Decrease in Emissions from Y 2000 Level
2 x CO2
Stabilizing Concentrations at 550 ppm requires
Decreasing CO2 Emissions by ~75% from present levels
IPCC TAR, 2001
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What Next? Rise in Coal-Fired Plants vs.
Carbon Capture and Storage Capability
IEA estimates they will release 140 GtC
cf. 165 GtCanthro. left in atmosphere in 1995
About 50% will remain in atmosphere (based on last 50 years)
i.e. equivalent to an increase in atmospheric CO2 of 33 ppm
Schiermeier, Q., News feature, Nature 442, 10 Aug. 2006.
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What Kind of Future?
• Stabilizing CO2 levels at 550 ppm by 2100 ('2 x
CO2') is probably not attainable through controlling
emissions.
• Stabilizing CO2 around 700-750 ppm is more likely
OR ? ?
• We need to consider mitigation measures,
e.g. proposal to inject sulphates into the
stratosphere, [Paul Crutzen, 2006, Climatic Change]
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The Ocean: Surface pH is Decreasing
How will that affect fisheries ecosystems?
?
[prepared by Arne Körtzinger (IFM,Kiel) for the IMBER Science Plan
on the basis of WOCE data: Schlitzer, 2000]
http://ioc.unesco.org/iocweb/co2panel/Publications.htm
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The Coastal Ocean: More Hypoxia Events?
Dead zone off Newport, Oregon 2002,04,06
[www.piscoweb.org
PISCO at OSU]
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Hypoxia Events: Are They Increasing?
What are the
causes?
• natural?
• climate change?
• other human
activities?
Can we predict
them?
[Grantham et al., 2004. Nature, 429, 749-753]
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Our Future?
 Our community doing 'basic' science will
be expected to spend more effort
addressing impacts (& risk analysis) +
adaptation + mitigation measures.
 That requires improved projections of
our future climate and ocean, and
inclusion of more 'impacts' directly into
our models
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