Geoscience Reference
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global mean SAT. For instance, the causes of climate cooling in the late 19th
—
early 20th century have not been explained. Of course, the model considered cannot
simulate changes of regional climate. The role of North-Atlantic oscillations in
climate formation has not been revealed. On the whole, the fact that possibilities of
approximate energy-balance models do not exceed the limits of substantiation of
rather conditional scenarios of climate but cannot describe the dynamics of the real
climate system raises no doubts. This conclusion refers also to results obtained with
much more complicated global interactive climate models (Liao et al. 2011).
On the whole, global climate models (GCMs) are comprised of fundamental
concepts (laws) and parameterisations of physical, biological, and chemical com-
ponents of the climate system. These concepts and parameterisations are expressed
as mathematical equations, averaged over time and grid volumes. The equations
describe the evolution of many variables (e.g. temperature, wind speed, humidity
and pressure) and together de
ne the state of the atmosphere. These equations are
then converted to a programming language, de
ning among other things their
possible interacting with other formulations, so that
they can be solved on a
computer and integrated forward in discrete time steps.
A very simple model of the radiative equilibrium of the Earth is:
ð
1
aÞ
S
p
r
2
rp
r
2
e
T
4
¼ 4
ð
5
:
1
Þ
where the left hand side represents the incoming energy from the Sun and the right
hand side represents the outgoing energy from the Earth, calculated from the
Stefan
Boltzmann law assuming a constant radiative temperature; T is global mean
temperature that is to be found; S (
-
1,367 W m
−
2
) is the solar constant
≈
—
the
incoming solar radiationper unit area;
ʱ
(
≈
0.3) is the Earth
'
is average albedo;
10
6
m) is Earth
10
−
8
JK
−
4
m
−
2
s
−
1
) is the Stefan-
r (
≈
6.371
×
'
s radius;
˃
(
≈
5.67
×
Boltzmann constant;
∈
(
≈
0.612) is the effective emissivity of earth.
r
2
can be factored out, giving the temperature
The constant
π
p
1
a
T ¼
ð
Þ
S
=
eðÞ
4
5
:
2
Þ
lat.) cannot
reliably simulate (and, moreover, forecast) climate changes on regional scales,
Mearns et al. (1999) showed that to resolve such problems, two approaches can be
used:
(1) statistical (with regard to observational data) scaling (reducing to a higher
spatial resolution) of the numerical modeling results obtained with the help of
low-resolution models;
(2) expanding such models by including the
Noting that climate models with a low spatial resolution (
*
3
°
-
6
°
“
nested
”
regional models with a
higher resolution.
In this connection, Mearns et al. (1999) undertook a comparison of scenarios of
anthropogenic climate change (with a doubled CO
2
concentration) calculated with
the use of the NCAR
“
nested
”
model RegCM2 and semi-empirical method of
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