1
Here θ
slope
is the slope of the trend line that is ILCT,
i
corresponds to 5 periods and can be set from 1 to 5,
S
i
is the lakes
’ area in period i. The total tendency reflects the change trend in 5 periods from 1976 to 2009. The trend line of each
lake’s area is the simulation change trend of the lake area from 1976 to 2009. Here the trend line is not a simple connection
between last year and the first year, in which θ
slope
0 shows the expanding trend, otherwise declining trend.
4.2.1 The change of typical lakes
Table 5 is a typical lake area list in SRTR from 1976 to 2009. It can be found from table 5 that the typical lakes’ area in SRTR
experiences a process decreased first and then increased. And in 2000 for the sector, the total area reduced from1976 to 2000,
and enlarged after 2000. But the amplitude is small, 80.90km
2
in 2009 more than that in 1976. There are 7 lakes increased area l: Eling lake, Wulanwula lake, Chibuzhangcuo lake,
Lexiewudan lake, Cuorendejia lake, Quemocuo lake, Yinma lake,
and the total expand area is 143.77km
2
, about 7.26 more than 1976. The other 9 lakes reduced area: Zhaling lake,
Jinxiwulan lake, Kekexili lake, Kusai lake, Zhuonai lake, Donggeicuona lake, Taiyang lake, Cuodarima lake, Mingjing
lake, and the total atrophy area is 62.87km
2
. Here 11 of the 16 typical lakes increased during 2000 to 2004, 9 during 2004 to
2009, 4 during 1976 to 1995, 5 during 1995 to 2000. Tab.4 the Typical Lakes
’ Area in SRTR from 1976 to 2009 unit: km
2
Name 1976
1995 2000
2004 2009
Rate of Total
Change Trend
Index
Eling lake 618.00
614.12 620.64
609.59 623.47
5.47 0.641
Wulanwula lake 540.59
535.77 532.06
558.30 569.62
29.03 8.059
Zhaling lake 530.71
523.95 520.68
516.43 530.12
-0.60 -0.87
Jinxiwulan lake 317.08
292.53 287.79
309.07 306.24
-10.85 -0.514
Kekexili lake 312.97
306.30 304.92
314.34 312.86
-0.12 0.782
Chibuzhangcuo lake
282.78 288.93
292.57 282.31
293.42 10.64
1.466
Kusai lake 271.45
261.82 258.01
264.54 264.58
-6.87 -1.102
Zhuonai lake 259.52
258.78 256.93
259.95 257.76
-1.76 -0.235
Donggeicuona lake
248.87 237.35
228.15 231.70
228.97 -19.90
-4.545
Lexiewudan lake
238.67 221.61
225.15 237.39
242.43 3.76
2.33
Cuorendejia lake
137.31 201.68
207.63 199.40
200.84 63.53
12.478
Taiyang lake 101.91
103.69 101.41
101.91 101.30
-0.61 -0.3
Cuodarima 92.36
80.86 76.23
83.98 74.35
-18.01 -3.29
Mingjing lake 92.30
78.32 77.45
87.98 88.15
-4.15 0.136
Quemocuo 84.24
83.53 83.22
83.01 88.26
4.02 0.752
Yinma lake 78.59
100.99 108.27
108.62 105.91
27.32 6.227
Total
4207.3 7
4190.2 2
4181.0 7
4248.5 2
4288.2 7
80.90 22.01
The change of lake area not only is reflected by expansion and contraction of the shore line, but also performed by the
connection with and partition from the around small lakes. As shown in figure 4, the map of lakes changed most obviously
within the 16 typical lakes shows there are around small lakes merged with or isolated from the main lakes which lead to
lake’s area vary obviously. But the changing of the shore line is not the main reason for the lakes around small lakes. For the
change of Lake area lake like Cuorendejia,Cuodarima,Yinmahu, is most typical.
Fig. 4 the Typical Lakes Area Change from 1976 to 2009
4.2.2 The change trend of the typical lakes
