Atmospheric Model Development
CMI is pursuing two
parallel strands in atmospheric model development.
- an Atmospheric Model of InterMediate complexity (AIM) which has simplified
physics and high computational efficiency. Coupled to an ocean
model AIM is being used extensively in CMI's
aquaplanet
research.
- a 'high-end' atmospheric model which utilizes complex
parameterizations of the land surface, boundary layers,
convection and radiation.
Both models use the hydrodynamical core of MITgcm.
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Time-mean, zonally averaged fields
from an aquaplanet simulation
Image
source - Marshall et al. 2007. |
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Hydrodynamical kernel based on MITgcm
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A snapshot of atmospheric
temperature (K) at 500 mb revealing th e
presence of synoptic systems (top). The
SST (oC) and ice distribution (bottom).
The underlying cubed sphere grid can be
seen - Image source - Marshall et al.
2007. |
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MITgcm simulates atmospheric dynamics by exploiting the
isomorphism between the equations governing a Boussinesq ocean in z-coordinates and the
compressible (hydrostatic) atmosphere in p-coordinates (see
Marshall et al, 2004). This novel approach brings a number of
advantages:
- all the software development (multi-processor, multi-threading, post
processing) is
available for deployment in the simulation of both fluids.
- algorithmic developments benefit both atmosphere and
ocean, e.g., the partial cell approach developed in
an oceanic context is reused in our atmospheric model in
the implementation of the Eta coordinate.
- advection schemes
suitable for highly non linear dynamics, that have been validated
in an atmospheric context, can readily be used for eddy-resolving
oceanic simulation.
The kernel is implemented on the cubed
sphere and employs an Eta vertical coordinate
with a non-linear lower
boundary condition. Read more about the dynamical
core... |
Click on an icon to read more about the
most recent of these developments here:
Publications:
2007
Marshall,
J., D. Ferreira, J-M Campin and D. Enderton (2007): Mean climate
and variability of the atmosphere and ocean on an aqua-planet:
J. Atmos. Sci:DOI: 10.1175/2007JAS2226.1
2004
Adcroft, A., J-M Campin, C. Hill and J. Marshall (2004)
Implementation of an atmosphere-ocean general circulation model
on the expanded spherical cube. Mon. Wea. Rev., 132 (12),
2845-2863
Marshall, J. A. Adcroft, J-M Campin and C. Hill (2004)
Atmosphere-ocean modeling exploiting fluid isomorphisms.
Mon. Wea. Rev., 132 (12), 2882-2894
Adcroft, A.,
Hill, C., Campin J-M, Marshall, J. and P. Heimbach, 2004:
Overview of the Formulation and Numerics of the MIT GCM.
Proceedings of the ECMWF seminar series on Numerical Methods,
Recent developments in numerical methods for atmosphere and
ocean modelling, 139-149.
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