[1]YAN Junjie,CHEN Chen,ZHAO Yang,et al.Dynamics of Grassland Coverage in Ili River Valley Based on TINDVI[J].Research of Soil and Water Conservation,2021,28(03):331-339.
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Research of Soil and Water Conservation[ISSN 1005-3409/CN 61-1272/P] Volume:
28
Number of periods:
2021 03
Page number:
331-339
Column:
Public date:
2021-04-20
- Title:
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Dynamics of Grassland Coverage in Ili River Valley Based on TINDVI
- Author(s):
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YAN Junjie, CHEN Chen, ZHAO Yang, SHAMULI·Davutibai, LIU Haijun
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(Institute of Resources and Ecology, Yili Normal University, Yining 835000, China)
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- Keywords:
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changes of grassland coverage; TINDVI; MODIS data; Ili River Valley
- CLC:
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Q948.1
- DOI:
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- Abstract:
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Dynamics of grassland vegetation is one of the important contents of global change research. Ili River Valley, which is rich in grassland types, was selected as the research area. On the basis of MODIS NDVI, the time integrated normalized difference vegetation index(TINDVI)was calculated. Taking TINDVI as the indicator of grassland coverage, we used the spatial analysis of GIS and method of Mann-kendall nonparametric test to analyze the dynamics of grassland coverage in Ili River valley from 2000 to 2018, and discussed the comparative advantage between TINDVI and NDVImax(NDVImax represents the best growing status of vegetation in a growing season). The results showed that:(1)the annual-averaged range of TINDVI, calculated by NDVI accumulation in a growing season, of the grassland in Ili River Valley was 0~11; spatially, the difference of TINDVI along the elevation was obvious, and the proportion of grassland with TINDVI>4.0 reached up to 75.69% in the whole area;(2)in the period 2000—2018, the grassland TINDVI in Ili River Valley showed a non-significant increasing trend, compared with a non-significant decreasing trend of NDVImax; the annual changing rate was 0.015 and -0.000 1 for TINDVI and NDVImax, respectively; spatially, 73.95% of the grassland TINDVI increased, and 57.28% of the NDVImax decreased; the proportion of grassland showing opposite changing trends in TINDVI and NDVImax reached up to 42.58%, and the interannual changes in the growth process of the grassland vegetaion was the reason for the opposite changing trends;(3)the changes of the correlation between grassland coverage and precipitation and temperature along the elevation in the Yili River Valley was obvious; compared with NDVImax, TINDVI was more sensitive to changes in precipitation and temperature, and the correlation between grassland coverage and precipitation was higher than that of temperature;(4)the interannual change of the growing process is also an important aspect of grassland change, and the TINDVI accumulated from NDVI in the growing season has certain application value in quantifying grassland coverage change.