Adapting to life: ocean biogeochemical modelling and adaptive remeshing
An outstanding problem in biogeochemical modelling of the ocean is that many of the key processes occur intermittently at small scales, such as the sub-mesoscale, that are not well represented in global ocean models. This is partly due to their failure to resolve sub-mesoscale phenomena, which play...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-05-01
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| Series: | Ocean Science |
| Online Access: | http://www.ocean-sci.net/10/323/2014/os-10-323-2014.pdf |
| Summary: | An outstanding problem in biogeochemical modelling of the ocean is that many
of the key processes occur intermittently at small scales, such as the
sub-mesoscale, that are not well represented in global ocean models. This is
partly due to their failure to resolve sub-mesoscale phenomena, which play a
significant role in vertical nutrient supply. Simply increasing the
resolution of the models may be an inefficient computational solution to this
problem. An approach based on recent advances in adaptive mesh computational
techniques may offer an alternative. Here the first steps in such an approach
are described, using the example of a simple vertical column (quasi-1-D)
ocean biogeochemical model.
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We present a novel method of simulating ocean biogeochemical behaviour on a
vertically adaptive computational mesh, where the mesh changes in response to
the biogeochemical and physical state of the system throughout the
simulation. We show that the model reproduces the general physical and
biological behaviour at three ocean stations (India, Papa and Bermuda) as
compared to a high-resolution fixed mesh simulation and to observations. The
use of an adaptive mesh does not increase the computational error, but
reduces the number of mesh elements by a factor of 2–3. Unlike previous work
the adaptivity metric used is flexible and we show that capturing the
physical behaviour of the model is paramount to achieving a reasonable
solution. Adding biological quantities to the adaptivity metric further
refines the solution. We then show the potential of this method in two case
studies where we change the adaptivity metric used to determine the varying
mesh sizes in order to capture the dynamics of chlorophyll at Bermuda and
sinking detritus at Papa. We therefore demonstrate that adaptive meshes may
provide a suitable numerical technique for simulating seasonal or transient
biogeochemical behaviour at high vertical resolution whilst minimising the
number of elements in the mesh. More work is required to move this to
fully 3-D simulations. |
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| ISSN: | 1812-0784 1812-0792 |