| Analysis on the changing trend of vegetation cover rate and its driving factors in middle reaches of Heihe River |
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| DOI：10.7606/j.issn.1000-7601.2018.03.37 |
| Key Words: vegetation cover rate groundwater table water consumption precipitation oasis region desert area |
| Author Name | Affiliation | | ZHANG Gengxi | College of Water Resources and Architectural Engineering, Northwest A & F University, Yangling, Shaanxi 712100, China | | SU Xiaoling | College of Water Resources and Architectural Engineering, Northwest A & F University, Yangling, Shaanxi 712100, China | | MA Xinyi | College of Water Resources and Architectural Engineering, Northwest A & F University, Yangling, Shaanxi 712100, China |
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| Abstract: |
| The changing trend of vegetation cover rate has been obtained by using the NDVI data during 2002 to 2011 in middle reaches of Heihe River. The whole region can be divided into oasis region and desert area by selected suitable NDVI threshold value. The influences of ground water table, water consumption in middle reaches and cumulative precipitation to the areas of two regions and the change of vegetation cover rate were discussed respectively. The results showed that:As a whole the vegetation cover rate in middle reaches of Heihe River was assumedan in creasing trend,from 32% in 2002 had increased to 36% in 2011. The expansion of oasis area was the largest contribution factor for increasing vegetation cover rate. During 10 years, the oasis areas has increased 10%. The main factors to influence the expansion of oasis area were the ground water table and water consumption in middle reaches. But the change of the vegetation cover ratein oasis was rather small,so its influence can be ignored.The change of vegetation cover ratein desert region was major influenced by the cumulative precipitation.So it is feasible by using ground water table, water consumption in middle reaches and cumulative precipitation to forecast changing trend of regional vegetation cover rate and distinguishing the impacts between human activities and climate change on regional vegetation cover rate. |
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