A 1/16° eddying simulation of the global NEMO sea-ice–ocean system
Analysis of a global eddy-resolving simulation using the NEMO general circulation model is presented. The model has 1/16° horizontal spacing at the Equator, employs two displaced poles in the Northern Hemisphere, and uses 98 vertical levels. The simulation was spun up from rest and integrated for 11...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-08-01
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| Series: | Geoscientific Model Development |
| Online Access: | http://www.geosci-model-dev.net/9/2665/2016/gmd-9-2665-2016.pdf |
| Summary: | Analysis of a global eddy-resolving simulation using the NEMO
general circulation model is presented. The model has 1/16°
horizontal spacing at the Equator, employs two displaced poles in the
Northern Hemisphere, and uses 98 vertical levels. The simulation was spun up
from rest and integrated for 11 model years, using ERA-Interim reanalysis as
surface forcing. Primary intent of this hindcast is to test how the model
represents upper ocean characteristics and sea ice properties.
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Analysis of the zonal averaged temperature and salinity, and the mixed layer
depth indicate that the model average state is in good agreement with
observed fields and that the model successfully represents the variability
in the upper ocean and at intermediate depths. Comparisons against
observational estimates of mass transports through key straits indicate that
most aspects of the model circulation are realistic. As expected, the
simulation exhibits turbulent behaviour and the spatial distribution of the
sea surface height (SSH) variability from the model is close to the observed
pattern. The distribution and volume of the sea ice are, to a large extent,
comparable to observed values.
<br><br>
Compared with a corresponding eddy-permitting configuration, the performance
of the model is significantly improved: reduced temperature and salinity
biases, in particular at intermediate depths, improved mass and heat
transports, better representation of fluxes through narrow and shallow
straits, and increased global-mean eddy kinetic energy (by ∼ 40 %).
However, relatively minor weaknesses still exist such as a lower than observed magnitude of the SSH variability. We conclude
that the model output is suitable for broader analysis to better understand
upper ocean dynamics and ocean variability at global scales. This simulation
represents a major step forward in the global ocean modelling at the
Euro-Mediterranean Centre on Climate Change and constitutes the groundwork
for future applications to short-range ocean forecasting. |
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| ISSN: | 1991-959X 1991-9603 |