A single-column ocean biogeochemistry model (GOTM–TOPAZ) version 1.0
<p>Recently, Earth system models (ESMs) have begun to consider the marine ecosystem to reduce errors in climate simulations. However, many models are unable to fully represent the ocean-biology-induced climate feedback, which is due in part to significant bias in the simulated biogeochemical p...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-02-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://www.geosci-model-dev.net/12/699/2019/gmd-12-699-2019.pdf |
| Summary: | <p>Recently, Earth system models (ESMs) have begun to
consider the marine ecosystem to reduce errors in climate simulations.
However, many models are unable to fully represent the ocean-biology-induced
climate feedback, which is due in part to significant bias in the simulated
biogeochemical properties. Therefore, we developed the Generic Ocean
Turbulence Model–Tracers of Phytoplankton with Allometric Zooplankton
(GOTM–TOPAZ), a single-column ocean biogeochemistry model that can be used
to improve ocean biogeochemical processes in ESMs. This model was developed
by combining GOTM, a single-column model that can simulate the physical
environment of the ocean, and TOPAZ, a biogeochemical module. Here, the
original form of TOPAZ has been modified and modularized to allow easy
coupling with other physical ocean models. To demonstrate interactions
between ocean physics and biogeochemical processes, the model was designed
to allow ocean temperature to change due to absorption of visible light by
chlorophyll in phytoplankton. We also added a module to reproduce upwelling
and the air–sea gas transfer process for oxygen and carbon dioxide,
which are of particular importance for marine ecosystems. The simulated
variables (e.g., chlorophyll, oxygen, nitrogen, phosphorus, silicon) of
GOTM–TOPAZ were evaluated by comparison against observations. The temporal
variability in the observed upper-ocean (0–20 m) chlorophyll is well
captured by the GOTM–TOPAZ with a correlation coefficient of 0.53 at point 107 in the Sea of Japan. The
surface correlation coefficients among GOTM–TOPAZ oxygen, nitrogen,
phosphorus, and silicon are 0.47, 0.31, 0.16, and 0.19, respectively. We
compared the GOTM–TOPAZ simulations with those from MOM–TOPAZ and found that
GOTM–TOPAZ showed relatively lower correlations, which is most likely due to
the limitations of the single-column model.
Results also indicate that source–sink terms may contribute to the biases in
the surface layer (<span class="inline-formula"><60</span> m), while initial values are important for
realistic simulations in the deep sea (<span class="inline-formula">>250</span> m). Despite this
limitation, we argue that our GOTM–TOPAZ model is a good starting point for
further investigation of key biogeochemical processes and is also useful to
couple complex biogeochemical processes with various oceanic global
circulation models.</p> |
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| ISSN: | 1991-959X 1991-9603 |