Figure 3. Sandy Desertification Map of Qinghai lake Area in 1973
Classes
■ Other
■ Water
Light
■ Low-grade
Middle
■ High-grade
■ Strong
Figure 4. Sandy Desertification Map of Qinghai lake Area in 2003
3.2 Spatial change of Land Sandy Desertification in
Qinghai Lake Area
According to the classification data distilled from the RS image
in Qinghai Lake Area, this paper get the statistics of the
classification data of Land Sandy Desertification in 1973 and
2003 in Qinghai Lake Area. Table 2 is the statistics.
Table 2 Classification of Sandy Desertification in Qinghai Lake
Area (Unit: hm 2 )
1973
2003
Classification
Ratio(%)
Classification
Ratio(%)
Light
38.9
light
3.8
Low-grade
29.4
Low-grade
20.3
Middle
10.9
Middle
20.6
High-grade
10.5
High-grade
21.6
Strong and
intensive
0
Strong and
intensive
23.1
Water
9.6
Water
6.4
Other
0.8
other
4.3
4 DISCUSSION
NDVI vs Land Sandy Desertification: Figure 5 is the NDVI
map retrieved from ASTER. From the map, we can indicate
that the vegetation cover is low in this area for the number is
generally low. Also we can see that the NDVI has strong rela
tionship with Sandy Desertification, so NDVI can be served as
an index for estimating Sandy Desertification in the next re
search.
Figure 5. NDVI from ASTER of Qinghai lake Area in 2003
RS vs Land Sandy Desertification: With the help of climate
data, social and economic data, Remotely Sensed data can do
much work on Sandy Desertification. ASTER has a higher
resolution in VNIR and some bands in SWIR and TIR, which
can have much help in classification.
Water vs Land Sandy Desertification: From figure 3 and 4,
we can see that water have strong relationship with land sandy
desertification, with the water decreasing, high-grade has
doubled and strong and intensive has changed from 0 to 23.1%.
Time Change vs Land Sandy Desertification: In the 20
years from 1973 to 2003, the Land Sandy Desertification in
qinghai lake area is serious, this can be seen from table 2.
From figure 6, we can see artificial factors become the main
factor of the Land Sandy Desertification.
With the RS images, the authors have evaluated the Land
Sandy Desertification in Qinhai Lake area. With the Economic
development and population increase, artificial factors become
the main factor of the Land Sandy Desertification. So reducing
the artificial factor is the optimal way to prevent and cure the
Land Sandy Desertification such as controlling population
increasing, change the uncultured product fashion.
In the following works, we will collect the impaction of vege
tation distribution, soil type and other factors on land sany
desertatification.
REFERENCES:
Cha Yong, et al,1997, Application Of Remote Sensing
Technology On Desertification Dynamics: A Case Study In
Yulin City, Shaanxi Province[J], Journal of Desert Research,
17(3):286~290.(In Chinese)
Dong Yuxiang, 1995, Study on the Degree Judgment and
Regionalization of Sandy Desertification in China[J], Journal
of Desert Research, 15(2):170~174.(In Chinese)
Hu Peng,et al,2002, GIS Principle, Wuhan: Wuhan University
Press.(In Chinese)