Recommendations
Increase accessibility to numerical models by observationalists
In the past, modelers and observationalists have often worked in isolation. This sometimes results in
models that are not consistent with field measurements in either their formulation or their behavior.
Often sampling programs do not resolve the appropriate temporal and spatial scales or they focus on
specific processes that are either not parameterized in models or have only secondary or tertiary
importance. As observations become more sophisticated in terms of both the processes that can be
measured and the scales that can be resolved (both microscales and global scales), models have
assumed new importance as a framework within which data may be interpreted. Moreover, the
increasing focus on studies of coupled biological/physical processes and the need for scientific
research to focus on the prediction of ecosystem response to climate change has also elevated the role
of numerical modeling. Thus the complexity of both models and observations require a much closer
interaction between those who build and operate models and those who collect and analyze data.
Large-scale coupled biological/physical models are still in a state of infancy. It would be premature to
develop a single model of the Southern Ocean as it would not resolve critical physical and biological
processes. Rather, efforts should be focused on a variety of models that are limited either in the scales
or processes that are resolved. We expect that eventually researchers may wish to link some of these
models together; this will require that the underlying assumptions be clearly stated so that inherent
contradictions are avoided.
Specific Recommendations
- Encourage Southern Ocean JGOFS and GLOBEC activities that have both a modeling and a field
component
- Develop a variety of models focusing on specific processes or hypotheses but with clearly
defined interfaces and documented assumptions so that other researchers can understand and evaluate
the models
- Archive output of numerical models much as field and satellite observations are archived and
distributed
- Encourage the development of models that are structured as a set of testable hypotheses that
can be addressed by appropriately designed sampling strategies
Improve modeling capabilities in advance of Southern Ocean field studies for use in designing
sampling programs and analyzing data
Although present models are not capable for developing detailed sampling strategies, they can be used
to develop specific hypotheses for the field component of JGOFS and GLOBEC. Emerging research
areas, such as data assimilation and nested models, would benefit by expanded research in advance of
the JGOFS and GLOBEC field programs. Various diagnostic techniques, such as estimating
advective fluxes, could be used to design specific sampling strategies at the Southern Ocean station
sites.
Specific Recommendations
- Encourage modelers to work with researchers participating in Southern Ocean JGOFS and GLOBEC field studies
- Encourage development of data assimilation techniques for biogeochemical modeling
- Continue development of embedded or nested models which incorporate high resolution models within lower resolution models
- Use models to simulate advective fluxes around planned Southern Ocean stations and compare with observations as part of model diagnostics
Improve observing capabilities to take advantage of and test numerical models
Although many observationalists consider them primitive, present models can be used to guide field
programs in the types of observations that should be made to improve parameterizations and constrain
model behavior. For example, many of the core JGOFS measurements are standing stock
observations, yet most of the uncertainties in existing models concern rate parameters. There was a
strong consensus that data must be collected on size and functional classes of the ecosystem.
Although there is controversy regarding the level of detail that must be included in models, clearly
there are profound implications on carbon cycling as the structure of the ecosystem changes. As
assimilation techniques improve, it is essential that we develop a scientific basis for our estimates of
the error fields associated with the data being assimilated into the models. This may require tedious,
closely-spaced observations as these error fields may vary seasonally as well as regionally. Lastly, the
Southern Ocean will always be difficult to sample using conventional ship techniques. The JGOFS
and GLOBEC programs should draw upon developments in other programs to use low-cost or
expendable sensors to increase the scales that can be sampled.
Specific Recommendations
- Evaluate present JGOFS core observations in context of the needs of existing numerical models
- Develop models that resolve critical time and space scales as identified in field measurements
- Collect information on size and functional groups
- Quantify error covariances for data fields that are assimilated into models
- Continue to encourage the development of new automated and low-cost sensors to extend sampling coverage of the Southern Ocean
Establish a regular program to further the development of coupled physical/biogeochemical
models
Models of the Southern Ocean ecosystem must resolve complex physical dynamics as well as
complicated chemical and biological interactions. Because of the nature of the circulation in this vast
region of the ocean, these models must have high spatial resolution as well. However, our overall
goal should be the development of a closer alliance between models (which will always be gross
simplifications of reality) and observations (which will always provide a biased and undersampled
view of reality). We should continue activities that strengthen the links between these two
complementary ways of looking at a complex system.
Specific Recommendations
- Regularly assess the state of our knowledge and modeling capabilities
- Support annual workshops where models can be run and evaluated by both modelers and observationalists
