SCIENTIA GEOGRAPHICA SINICA ›› 2020, Vol. 40 ›› Issue (6): 1029-1038.doi: 10.13249/j.cnki.sgs.2020.06.019

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Response of Vegetation Change to Meteorological Drought in Northwest China from 2001 to 2018

Zhang Hua(), Xu Cungang, Wang Hao   

  1. College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, Gansu, China
  • Received:2019-07-01 Online:2020-06-01 Published:2020-12-07
  • Supported by:
    National Natural Science Foundation of China (41461011), Lanzhou Talent Innovation and Entrepreneurship Project (2019-RC-105).

Abstract:

Northwest China is one of the regions with severe drought in China. Based on the monthly MODIS NDVI data from 2001 to 2018, the normal difference vegetation index NDVI and the vegetation condition index VCI were used as indicators of vegetation growth status, combined with the SPEI values calculated from the monthly precipitation and monthly mean temperature data from 2001 to 2018. Using the univariate linear regression trend analysis method and Pearson correlation coefficient to analyze the variation trend and spatial distribution characteristics of vegetation condition and meteorological drought in Northwest China, as well as the response of vegetation to meteorological drought in multiple time scales. The results showed that the growth of vegetation in Northwest China showed a trend of improvement in the period from 2001 to 2018, but the spatial distribution was significantly different. The improvement of vegetation in the eastern region was higher than that in the central and western regions. The average SPEI of the five different time scales in Northwest China all showed an overall increase trend in the past 18 years, indicating that the degree of drought decreased. In space, the overall trend of aridification was higher in the central and western regions and lower in the east. The vegetation growth status was positively correlated with SPEI in most areas. The overall performance showed that the vegetation in the eastern part of the Northwest China had the highest response to meteorological drought, followed by the western part and the middle part. Among the different vegetation types, the sensitivity of grassland to SPEI-12 was the strongest, followed by arable land, while the response of forest land was slower; the response of each vegetation type to SPEI-3 and SPEI-12 was generally higher in most months of the growing season.

Key words: Northwest China, NDVI, meteorological drought, SPEI, response analysis

CLC Number: 

  • K903