In:
Geoscientific Model Development, Copernicus GmbH, Vol. 12, No. 12 ( 2019-12-03), p. 4999-5028
Abstract:
Abstract. The Coupled Model
Intercomparison Project phase 6 (CMIP6) HighResMIP is a new experimental design for global
climate model simulations that aims to assess the impact of model horizontal
resolution on climate simulation fidelity. We describe a hierarchy of global
coupled model resolutions based on the Hadley Centre Global Environment Model 3 – Global Coupled vn 3.1 (HadGEM3-GC3.1) model that ranges from
an atmosphere–ocean resolution of 130 km–1∘ to 25 km–1∕12∘, all using the same forcings and initial conditions. In
order to make such high-resolution simulations possible, the experiments
have a short 30-year spinup, followed by at least century-long simulations
with constant forcing to assess drift. We assess the change in model biases as a function of both atmosphere and
ocean resolution, together with the effectiveness and robustness of this new
experimental design. We find reductions in the biases in top-of-atmosphere
radiation components and cloud forcing. There are significant reductions in
some common surface climate model biases as resolution is increased,
particularly in the Atlantic for sea surface temperature and precipitation,
primarily driven by increased ocean resolution. There is also a reduction in
drift from the initial conditions both at the surface and in the deeper
ocean at higher resolution. Using an eddy-present and eddy-rich ocean
resolution enhances the strength of the North Atlantic ocean circulation
(boundary currents, overturning circulation and heat transport), while an
eddy-present ocean resolution has a considerably reduced Antarctic
Circumpolar Current strength. All models have a reasonable representation of El Niño–Southern Oscillation. In general, the biases present after 30 years of simulations do not change character markedly over longer timescales,
justifying the experimental design.
Type of Medium:
Online Resource
ISSN:
1991-9603
DOI:
10.5194/gmd-12-4999-2019
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2019
detail.hit.zdb_id:
2456725-5
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