Geoscience Reference
In-Depth Information
(a)
(b)
(c)
14
14
14
12
12
12
10
10
10
8
8
8
6
6
6
4
4
4
2
2
2
19.4
19.2
18.6
18.6
18.6
4
6
8
4
6
8
4
6
8
Radius (cm)
Radius (cm)
Radius (cm)
Figure 1.26.
Maps in the
(r
,
z)
plane of (a) the z
ona
l mean temperature field (in
◦
C) derived from the equilibrated simulation using
the 3D eddy-resolving numerical model (i.e.,
T
3
D
), (b) the corresponding 2D axisymmetric temperature field
T
2
D
, and ( c) the
equilibrated temperature field in a 2D axisymmetric model simulation using the THL97 eddy parameterization as obtained by
Pérez
[2006] for
T
=4Kand
=1.0rad/s(
= 0.599,
10
6
).
T
= 3.26
×
studies as rigorous means of testing theoretical hypothe-
ses and understanding of heat transfer in geophysical
problems.
A particular strength of the rotating annulus is its
ability to achieve some degree of dynamical similarity
with atmospheric and oceanic phenomena where back-
ground rotation is a dominating factor. In seeking to
generalize results from the laboratory to geophysical sys-
tems, however, it is just as important to take account of
the differences between experimental and natural systems
as their similarities. The difference in geometry between
cylindrical and spherical configurations is one obvious
factor that must be taken into account, especially with
regard to quantitative comparisons between experimental
and geophysical systems. In addition, unlike in a planetary
atmosphere or ocean, for example, diffusive boundary lay-
ers play major roles in the thermally driven annulus system
in maintaining the mean stratification and horizontal ther-
mal contrast in the quasi-geostrophic interior. This may
make it difficult to use results from laboratory circulation
systems to address mechanisms for setting the stratifica-
tion in an ocean or atmosphere, for example, unless the
experiment can be specifically reconfigured to reduce or
allow for the influence of boundary layers.
The work described in Section 1.4 provides a power-
ful example of how combining insights and results from
both real experiments and numerical model simulations
can help to unravel the quantitative effects of boundary
layer and quasi-geostrophic circulations within labora-
tory flows, thereby assisting in generalizing results from
the latter to other systems. This methodological approach
in intertwining laboratory measurements with numerical
simulation offers the prospect of greatly increasing the
scientific value of laboratory-based studies in the future
(a) by utilizing laboratory measurements to directly
validate and compare numerical modeling techniques
and to investigate e.g. convergence properties of model
simulations with increasing resolution,
(b) by enabling simulations to be run that can test
hypotheses under conditions (e.g., by artificially sup-
pressing key instabilities) that may be difficult to realize
directly in the laboratory, and
(c) ultimately to allow direct deterministic model
predictions from initial states obtained using statistical-
dynamical assimilation methods that combine model
simulations with laboratory measurements.
The latter directly emulates the operational practice
of numerical weather and climate prediction for Earth's
