Geoscience Reference
In-Depth Information
Consequently, the purpose of this study is to improve the ADAM model
by improving dust emission conditions and the surface vegetation distribu-
tion in the source region with the monitored meteorological data at Duolun
in Inner Mongolia. The improved ADAM model (ADAM2) was employed
to simulate the Hwangsa event that was observed in Korea from 10 to
12 March 2004.
2. Model Description
2.1.
The meteorological model
The meteorological model used in this study is the nonhydrostatic version
of the fifth-generation mesoscale model (MM5) developed at the Pennsylva-
nia State University/National Center for Atmospheric Research employing
the
x
,
y
and terrain following
σ
-coordinatesystemasinRef.3.Thedomain
of the model is shown in Fig. 1. The domain includes major source regions
of Asian dust: the Sand, Gobi, Loess, and Mixed soil areas.
1
The model has
150
120 grid points with a horizontal resolution of 30 km and 25 vertical
layers. The simulation covers the period from 8 to 15 March 2004, for which
the evolutionary feature of each dust storm is fully resolved in the model
domain.
×
2.2.
The Asian dust aerosol model
The ADAM model is an Eulerian dust-transport model that includes the
specification of the dust source regions delineated by the statistical analysis
of the dust data reported according to WMO specifications. So statistical
analyses of dust emission conditions were derived for the four regions of
Sand, Gobi, Loess, and mixed soil surface, with the dust emission flux being
proportional to the fourth power of the friction velocity with modification
of the land use types in each source-grid region. The suspended particle-
size distribution was parametrized using the log-normal distributions of soil
particle-size distribution bins in the source regions based on the concept of
the minimally and fully dispersed particle-size distribution. The detailed
description of the ADAM model is given in Park and In
1
and Park and
Lee.
2
The ADAM model uses 11 size bins with the same logarithm intervals
for particles of 0.1-37
µ
minradius.
The estimation of dust emission amounts ranging from 0.1 to 37
µ
min
radius used in the ADAM model is given as
F
a
=
1
f
i
R
i
u
∗
−
×
α
×
if
u
∗
≥
u
∗
t
,
(1)
i
