Ecoinformatics Problems of Global Climate Change - New Ecoinformatics Tools in Environmental Science: Applications and Decision-making - page 472

5.9.3 Types of Aerosol Models

Models of the atmospheric pollution dynamics are divided into Gaussian, Eulerian,
and Lagrangian methods of parameterization which describe processes of pollutant
scattering. Within each type there are statistical, box, correlative, and determinate
sub-models. The most important division of the models space is the division by the

methods applied, since in this case the models are strictly divided by their infor-
mation bases.
The Gauss-type models need information about the height of the source of
pollutants and dispersion characteristics inside the pollutants

'

cloud. Different
approximations of the Gauss jet in the vicinity of a point source depend on
parameters of atmospheric surface layer stability. The model

'

guration is
affected by the geophysical characteristics. With the source present in the zone of
transition from water surface to land, clusters can be selected with stable and
unstable behavior of the pollutants jet. With respect to the horizontal coordinate
x on land, with wind direction along this coordinate, three zones can be selected
with characteristic features: the zone of undisturbed dispersion, the zone of depo-
sition; and the zone of delay. Detailed description of the related models is given in
Eqs. ( 1.2 )

' s con

fields of pollutant over territories
on scales up to 100 km. For large territories, other types of models are used.
The information base of the Euler- and Lagrange-type models is formed
according to the Cauchy problem for Eq. ( 1.5 ). Depending on a variety of real
situations the data base composition ensuring a realization of the model of the
pollutants transport becomes hierarchical. This hierarchy determines a relationship
between spatial and temporal scales, it determines an accuracy of the model and its
other characteristics. Numerous global data bases consist, as a rule, of information
levels with an object orientation.
Knowledge of the wind

( 1.5 ). These models describe well the

-

field components is necessary for modeling the pro-
cesses of atmospheric pollutants propagation over the territory of the region inde-
pendent of a spatial scale. In the presence of many sources of atmospheric pollution
in the region, information is needed about the 3-D wind field, and this is only

possible with combined measurements and modeling. Usually, for large regions or
in studies of conditions of pollutants propagation at the land-water boundary, the
grid Euler-type model is used:

@ u =@ x þ @ v =@ y þ @ w =@ z ¼ 0 ð 5 : 6 Þ

u @

þ @

@

t þ u

@

x þ v

@

y þ w

@

z ¼ fv v g

ð

K M @

=@ Þ=@ ; ð 5 :

7 Þ

u =@ u =@ u =@ u z z

@ v @ t þ u @ v @ x þ v @ v @ y þ w @ v =@ z ¼ fu g u

þ @ K M @ v =@ z

ð Þ=@ z ; ð 5 : 8 Þ

@ T =@ t þ u @ T =@ x þ v @ T =@ y þ w @ u =@ z ¼ @ ð K H C þ @ ð T =@ z Þ Þ=@ z ; ð 5 : 9 Þ