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decomposition is described by the linear function C 3 =
ʼ 1 (pH)
· SO4L · T L , where
cient depending on soil acidity, day 1 K 1 ; T L is the soil
ʼ 1 is the proportion coef
temperature,
K. The initial value of SO4L is estimated proceeding from the humus
supply considering that the content of sulfur in humus is prescribed by the
parameter a g , %. According to the available observations of the input of H 2 S into
the atmosphere from the ocean, the
°
ux H 4 varies widely from low values to high
values at the transition from the stagnant waters to zones of upwellings. The
fl
ux H 4
is assumed to be the function of the ratio of the rates of H 2 S oxidation in the photic
layer to the rate of the vertical uplifting of water. Therefore to describe the H 4 fl
fl
ux,
use the parameter t H2SU , which re
ects the life-time of H 2 S in the water medium:
H 4 =H 2 SU/t H2SU . Determine the value of t H2SU as a function of the rate of the
vertical advection v z and concentration of oxygen O 2 in the upper layer Z H2S thick:
t H2SU = H2SOU
fl
ʸ 2 are
determined empirically, the value of O 2 is either calculated by the oxygen unit of
the global model or prescribed from the global database.
The reaction of oxidation of H 2 StoSO 2 in the atmosphere, on land, and over the
water surface is characterized by a rapid process of the reaction of hydrogen sulphide
with atomic and molecular oxygen. At the same time, the reaction of H 2 S with O 3 in
the gas phase is slow. It is impossible to describe within the global model the
diversity of the situations appearing here, however, an inclusion of the
·
v z (
ʸ 2 +O 2 )/[O 2 (
ʸ 1 + v z )], where the constants
ʸ 1 and
uxes H 2 and
C 4 into the unit of sulfur enabled one to take into account the correlation between the
cycles of sulfur and oxygen. These
fl
fluxes are parameterized with the use of the
indicator t H2SA of the life-time of H 2 S in the atmosphere: C 4 = AH 2 SL/t H2SA ,
H 2 = AH 2 SO/t H2SA . The mechanism to remove SO 2 from the atmosphere is described
by the
fl
uxes H 7 , H 8 , H 27 , C 7 , C 8 , and C 9 . Schematically this mechanism consists of a
set of interconnected reactions of SO 2 with atomic oxygen under the in
fl
uence of
various catalysts. A study of the succession of reaction enables one to estimate the
life-time of SO 2 for oxidation over land it SO2L and water surface it SO2A1 . This makes it
possible to assume the following parameterizations of the
fl
fl
uxes H 8 and C 9 :
H 8 = ASO 2 O/t SO2A1 , C 9 = ASO 2 L/t SO2L .
Sulfur dioxide is assimilated from the atmosphere by rocks, vegetation, and
other Earth
is covers. Over the water surface this assimilation is connected with the
intensity of turbulent gas
'
fl
fluxes and surface roughness. We describe a dry depo-
sition of SO 2 over
the vegetation by the model C 7 = q 2 RX, where q 2 ¼
q 0 2 ASO 2 L
r tl is the atmospheric resistance to the SO 2 transport over the
vegetation of the l type, day m 1 ; r s is the surface resistance of the s type to the SO 2
transport, day m 1 ; RX is the produce of vegetation of the X type, mg m 2 day 1
(calculated by the biogeocenotic unit of the global model); q
=
ð
r tl þ r s
Þ;
2 is the proportion
coef
cient. The parameters r tl and r s are functions of the types of the soil-vegetation
formations and estimated, respectively, at 0.05 and 4.5 for the forests, 0.9 and 3 for
grass cover, 0.5 and 2 for bushes, 0.8 and 1 for bare soils, 1.9 and 0 for water
surfaces, 2 and 10 for snow cover.
The process of washing-out of SO 2 from the atmosphere with changing phase to
H 2 SO 4 and a subsequent neutralization on the surface of the l type is described by
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