Geoscience Reference
In-Depth Information
a
S
= 1.49. Of course, these estimates have a considerable spatial and temporal
scatter. In particular, using the data on the productivity of some oceans, we obtain
the values of the coef
cient a
ʦ
: the Atlantic Ocean
—
0.53; the Indian Ocean
—
0.25;
the Arctic Ocean
0.64.
Apart from photosynthesis, photolysis can be a source of oxygen in the atmo-
sphere, that is, the decomposition of water vapour under the in
—
11.1; the Paci
c Ocean
—
uence of UV
radiation in the upper layers of the atmosphere. However, the intensity of this
source in the present conditions is negligible. Nevertheless, denote this
fl
ux by
H
3
¼ a
H
W
A
, where W
A
is the water vapour content in the atmosphere, a
H
is the
empirical coef
fl
cient. If we assume that in the upper layers of the atmosphere a
constant share of W
A
can reside,
then at H
3
¼ 0
0039 t O
2
km
2
year
1
:
and
10
−
7
per year.
Vernadsky (1944) considered rocks metamorphism, basaltic volcanism, and
underground radioactive waters as possible sources of oxygen. However, there are
no suf
W
A
= 0.025 m, we have a
H
= 1.56
×
ciently reliable estimates of these
fl
fluxes and therefore it is impossible to
parameterize them.
The oxidation process both on land and in the water medium is the basic con-
sumer of oxygen on the Earth. The ability of oxygen to react with many elements of
the Earth crust forms the
fluxes of oxygen leaving the biospheric reservoirs. The
balance between the income-and-expenditure
fl
fl
fluxes of oxygen has been reached in
the course of the biospheric evolution.
Oxygen is spent on respiration of plants, animals, humans, and on the dead
organic matter decomposition both in the hydrosphere and on land. To parameterize
the income parts of the oxygen balance, linear models are used in MGBO unit.
Atmospheric ozone constitutes 0.64
10
−
6
of the atmospheric mass and belongs
to optically active gases. It absorbs UV solar radiation in the range 200
×
300 nm,
strongly affecting thereby the thermal regime of the stratosphere. Besides, ozone
has a number of vibration-rotation bands of absorption in the IR spectral region
(9.57
-
m).
The formation and destruction of ozone have been described in detail (Kondratyev
and Varotsos 2000).
Ozone forms in the upper stratosphere from molecular oxygen under the in
ʼ
m) and partially absorbs visible radiation in the Chappuis band (0.6
ʼ
u-
ence of UV solar radiation. In the lower stratosphere and troposphere, the source of
ozone is the decomposition of nitrogen dioxide under the in
fl
fl
uence of UV and
visible radiation. The formation of the vertical pro
le of the ozone concentration is
connected with its meridional and vertical transports. The general characteristic of
this pro
le is the total amount of ozone measured by the thickness of its layer in the
Dobson units (1DU = 0.001 cm).
Ozone was
first measured in the mid-19th century. At that time, a maximum of
ozone, for instance, over Europe and in the region of Great Lakes varied within
17
23 ppbv. At present, the ozone layer over western regions of North America in
April
-
5 ppbv. Due to a rapid economic
growth of many Asiatic regions followed by increased volumes of consumed fossil
fuels and respective increase of NO
x
and SO
2
emissions (5 % per year, on the
October is characterized by quantities 30
±
-
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