Environmental Engineering Reference
In-Depth Information
Residence ti
me
on ise
nt
ro
pic
s
urfaces
(da
ys)
0
200
400
600
800
1000
−
90
−
60
−
30
0
30
60
90
a
Latitude
Precipitation rate (mm/day)
90
0
−
90
180W
0
180E
Longtiude
b
1.0
2.
3.
4.
5.
6.
7.
8.
9.
10.
Fig. 2.4 Transport pathways of atmospheric constituents. Vertical distribution with latitude of the
residence time of aerosols along a neutrally buoyant layer (isentrope), considering only vertical
motion by heating in colors (a), with
black lines
marking surfaces of constant buoyancy
(isentropes). These results are based on the 75% heating rates (warming or cooling) of the six
hourly instantaneous results. Annually averaged precipitation rate (mm/day) in color, with annual
mean wind vectors for 850 hPa (just above the boundary layer) (b) (Figure from [
109
])
Inverse Modeling
Inverse modeling is the practice of using atmospheric concentrations to deduce the
sources and sinks of various important compounds [
119
]. Because many
biogeochemically relevant species have natural sources and sinks, they have
sources of uncertain magnitude. Inverse modeling has become quite common for
these constituents. The initial studies used simple models to best match available
data [
120
,
121
]. With time, studies focused on regional budgets but used higher
temporal and spatially resolved datasets and models to resolve regional and time-
varying sources as well as sophisticated statistical techniques [
122
-
124
]. These
studies (called top-down studies, because they use atmospheric concentrations to
constrain sources and sinks) provide important information about the sources and
can provide alternative views from upscaling flux measurements or inventories
