Extracting a Climate Signal from
169 Glacier Records (2005)
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Johannes Oerlemans: Professor of
Meteorology, Faculty of Physics and Astronomy,
Utrecht University (the Netherlands)
Research interests: glaciers, sea-level change,
palaeoclimatology, and dynamic meteorology
Science: 3 times
Nature: 8 times
Supplement to Oerlemans (2005)
Complexity in Natural
Landform Patterns (1999)
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Brad Werner, Professor of Geophysics, Scripps
Institution of Oceanography
All degrees from California Institute of
Technology
Focused on complex systems, self-organization,
and geophysical pattern formation
Several publications in both Science and Nature
on these topics
The Premise
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Landforms are simple in their form, occupying
only a small fraction of all possible forms
At the same time, landforms are complex due to
several interacting process components
Physical
 Chemical
 Biological
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Natural patterns are non-linear, dependent on an
infinite amount of dynamic variables
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A symptom of formation in an open system
How Do We Model Natural Patterns?
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A modeling approach must provide a way to
select the relevant internal dynamic variables
from an infinite array of those characterizing the
system
Must also account for changes in the
environment external to the system
Reductionism and Universality are the
existing modeling approaches
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Both inadequate for meeting the above requirements
Reductionism
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Contends the earth is too large and complex to
study as a whole
Focuses on the irreducible unit
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Micro spatial and temporal scales
Infers the behavior of a system through the sum
of its parts
Reductionism is inadequate due to its
inability to account for the external
environment
Universality
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Presents complex systems in their simplest form
Focuses on generalized principles
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Macro spatial and temporal scales
Universality is inadequate due to its
oversimplification of internal variables and
the external environment, making it difficult
to quantify and test models
Universality
Example: William Morris
Davis’ model of the
“Geographical Cycle” (1909)
http://www.staff.amu.edu.pl/~sgp/gw/wmd/wmdfig.html
Hierarchical Modeling
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Variables operate within a characteristic
temporal scale
Fast variables occur at a micro scale
 Slow variables occur at a macro scale
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Fast variables are constrained by slow variables
Slow variable behavior is generated by
interaction of fast variables
Internal dynamic variables within a system
correspond to external environmental variables
Hierarchical Modeling
Hierarchical Modeling
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Each hierarchical level is testable with respect to:
Dynamic relationship with faster variable (child)
 Dynamic relationship with slower variable (parent)
 Influence from external environment
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Change in the external environment may affect
dynamic relationships with faster and slower
variables
Questions
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Regarding Oerlemans article: Information is
presented in a very dense format. Was it clear to
you which results were most significant, and
what were they?
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Is there any one aspect of the way the article
was written or presented that hindered your
comprehension of the subject matter?
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The author states that a 25% increase in
precipitation is needed to compensate for mass
loss due to a 1 Kelvin warming. It has been
shown in other studies that global warming
causes increased precipitation. Is there an
equilibrium? Is there a point where the
dynamics will change once a threshold has been
reached?
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How do glacier studies help to reconstruct the
past?
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Can they provide information about
local/regional paleoenvironments? Or are
they global in scale?
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How does glacier data contribute to local
paleoecological/paleoclimatic
studies?
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Can modeling achieve an accurate picture of the
world? Is it designed to?
Do we expect to? Do we place too much or too
little stock in it?
When is it appropriate? When is it not
appropriate?
What are the ways that we can reduce/remove
bias from modeling?
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Where does Oerlemans’ recent work fit into the
classification of models that Werner describes?
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Do you think that Oerlemans’ model is just one
tier of Werner’s hierarchical model?
Using glacial characteristics as an example,
identify the internal dynamical variables
and corresponding external environmental
parameters.
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How do these studies fit into the sub-fields of
Resource Geography and GI Science?