<i>Couplerlib</i>: a metadata-driven library for the integration of multiple models of higher and lower trophic level marine systems with inexact functional group matching
End-to-end modelling is a rapidly developing strategy for modelling in marine systems science and management. However, problems remain in the area of data matching and sub-model compatibility. A mechanism and novel interfacing system (<i>Couplerlib</i>) is presented whereby a physical–bi...
Main Authors: | , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2016-03-01
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Series: | Geoscientific Model Development |
Online Access: | http://www.geosci-model-dev.net/9/947/2016/gmd-9-947-2016.pdf |
Summary: | End-to-end modelling is a rapidly developing strategy for modelling in marine
systems science and management. However, problems remain in the area of data
matching and sub-model compatibility. A mechanism and novel interfacing
system (<i>Couplerlib</i>) is presented whereby a physical–biogeochemical model
(General Ocean Turbulence Model–European Regional Seas Ecosystem Model, GOTM–ERSEM) that predicts dynamics of the lower trophic level (LTL)
organisms in marine ecosystems is coupled to a dynamic ecosystem model
(Ecosim), which predicts food-web interactions among higher trophic level (HTL)
organisms. Coupling is achieved by means of a bespoke interface, which handles
the system incompatibilities between the models and a more generic Couplerlib
library, which uses metadata descriptions in extensible mark-up language (XML)
to marshal data between groups, paying attention to functional group mappings
and compatibility of units between models. In addition, within Couplerlib,
models can be coupled across networks by means of socket mechanisms.<br><br>
As a demonstration of this approach, a food-web model (Ecopath with Ecosim, EwE) and a physical–biogeochemical model (GOTM–ERSEM) representing the North
Sea ecosystem were joined with Couplerlib. The output from GOTM–ERSEM varies
between years, depending on oceanographic and meteorological conditions.
Although inter-annual variability was clearly present, there was always the
tendency for an annual cycle consisting of a peak of diatoms in spring,
followed by (less nutritious) flagellates and dinoflagellates through the
summer, resulting in an early summer peak in the mesozooplankton biomass.
Pelagic productivity, predicted by the LTL model, was highly seasonal with
little winter food for the higher trophic levels. The Ecosim model was
originally based on the assumption of constant annual inputs of energy and,
consequently, when coupled, pelagic species suffered population losses over
the winter months. By contrast, benthic populations were more stable
(although the benthic linkage modelled was purely at the detritus level, so
this stability reflects the stability of the Ecosim model). The coupled
model was used to examine long-term effects of environmental change, and
showed the system to be nutrient limited and relatively unaffected by
forecast climate change, especially in the benthos. The stability of an
Ecosim formulation for large higher tropic level food webs is discussed and
it is concluded that this kind of coupled model formulation is better for
examining the effects of long-term environmental change than short-term
perturbations. |
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ISSN: | 1991-959X 1991-9603 |