We can see from 
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© concentration 
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| 6:00 Q 
OUDS IN THE 
> given by Aria 
age files of the 
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his case, the dust 
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pread dust cloud 
nt the Asian dust 
f we would look 
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f 3D dust clouds 
tCDF (Network 
fficult to process 
cessing software. 
ith the MeRAF 
  
format to those with VRML file format (.wrl) is also provided 
in the Aria regional package. We used the file transform 
software to output dust cloud files with the extension wrl. 
After that, they were read into the CG software, 3dsMAX, and 
were transformed to the dae format that is associated with 
COLLADA. It is possible to display the 3D dust cloud with the 
dae file format in the Google Earth, but as shown in Fig.3, the 
dust cloud is not successfully placed along the curvature of the 
Earth because it is represented in the xyz orthogonal coordinate 
system. We will need another method to represent 3D dust 
clouds on the global scale in the Google Earth. 
    
Fig.3 Asian dust cloud with dae format represented in the 
Google Earth 
32 A method for Displaying 3D Dust Clouds in the Google 
Earth 
The Google Earth provides the capability to easily display the 
image over the existing terrain. We use the image overlay 
functionality provided in the Google Earth to display dust 
clouds 3-dimensionally. To do that, we need to slice the 3D dust 
cloud thin. We first read the 3D dust cloud with the wrl file 
format in the 3dsMAX and divide the 3D cloud distributed at 
the altitude of about 6300m into 10 layers, each of which is the 
same thickness. This was done by the boolean operation 
between the 3D cloud and the box of a rectangular 
parallelepiped with the thickness of 630m. We made the 
rendering of the extracted layer of the 3D cloud and saved it as 
the png image. The image of a layer made by such operations is 
shown in Fig 4. 
  
  
Fig4 The image of the sliced one layer (High concentration 
areas in a layer are shown by the thick color. ) 
3.3 Animation of 3D Dust Clouds 
We use 120 files output in every an hour by the long-range 
transport simulation from 00:00 on March 19 to 23:00 on 
March 23, 2010 to make an animation of 3D Asian dust clouds 
in the Google Earth. As described in the section 3.2, we need to 
generate many images for displaying even one dust cloud 3- 
dimensionally. Therefore, a software system for describing the 
KML (Keyhole Markup Language) script for the animation of 
3D dust clouds was produced by using the VBScript. This 
software system consists of two components. One component 
produces the KML script file for the image overlay used in 
representing a 3D dust cloud, and the other produces the KML 
script for the animation of 3D dust clouds. In the KML script 
for the animation, the start time and end time, the name of KML 
file for the image overlay in each of 3D dust clouds are 
described. The name of KML file for the image overlay is 
referred in the <NetworkLink> tag. If the start time, the number 
of 3D dust clouds for the animation, the number of slicing a 3D 
dust cloud and the number of images inserted between layers 
are input in this software system, the KML script file and the 
image folder in which images for the animation are saved are 
generated automatically. In this case, the end time for the 
animation is computed from the number of 3D dust clouds for 
the animation because we have files output in every an hour 
from the long-range transport simulation. We can animate 3D 
Asian dust clouds over East Asia in the Google Earth by this 
KML file. Figs.5 and 6 show images of Asian dust clouds at 
00:00 on March 20, 2010 and at 8:00 on March 20, 2010, 
respectively. Figs.7 and 8 show Asian dust clouds in case that 
we looked at Asian dust clouds transversely. Fig.9 shows Asian 
dust cloud covering the sky in the case that we are in the dust 
cloud. In Figs.5 to 8, the concentration of dust cloud is higher 
than 0.1mg/m3. As seen from Figs.7 and 8, 3D Asian dust 
clouds generated by the method described above are represented 
as smooth 3D cloud objects. The animation of 3D dust clouds 
generated for dust events observed in Japan on April 1, 2007 
was also carried out. As a result, it was shown that it is possible 
to make the 3D representation of Asian dust clouds in the 
Google Earth as if we would look at the dust cloud covering the 
sky from the ground surface. 
4. CONCLUSIONS 
We estimated the released region and mass flux of Asian dust in 
cases of “Kosa” phenomena observed in Japan on April 1, 2007 
and March 21, 2010 to carry out the long-range transport 
simulation of Asian dust. from March 19 to 23, 2010. In order 
to evaluate results of the transport simulation of Asian dust 
clouds, the concentration of Asian dust clouds was compared 
with that of SPM measured at various places in Japan. As a 
result, it was found that the long-range transport simulation of 
Asian dust clouds provided good results. 
A new method for displaying the 3D concentration distribution 
of Asian dust clouds in the Google Earth was proposed. We 
divided the 3D dust cloud distributed at the altitude of about 
6300m into 10 layers, each of which is the same thickness. Each 
layer was transformed to the image by using the Max script 
given in the 3dsMAX software. After that, we used the image 
overlay functionality provided in the Google Earth to display 
Asian dust clouds 3-dimensionally. The animation of 3D Asian 
dust clouds in the Google Earth was made, by using the 
software system we produced for describing the KML script for 
the animation of 3D dust clouds. As a result, it was found that 
3D Asian dust clouds generated by the method described in this 
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