Chinese Geographical Science ›› 2021, Vol. 31 ›› Issue (4): 684-695.doi: 10.1007/s11769-021-1217-5

• Articles • Previous Articles    

Vegetation Index Reconstruction and Linkage with Drought for the Source Region of the Yangtze River Based on Tree-ring Data

LI Jinjian1, WANG Shu1,2, QIN Ningsheng2, LIU Xisheng3, JIN Liya1   

  1. 1. School of Atmospheric Sciences, Plateau Atmosphere and Environment Key Laboratory of Sichuan Province, Chengdu University of Information Technology, Chengdu 610225, China;
    2. Institute of Plateau Meteorology, China Meteorological Administration, Chengdu/Heavy Rain and Drought-Flood Disasters in Plateau and Basin, Key Laboratory of Sichuan Province, Chengdu 610072, China;
    3. Hydrology and Water Resources Bureau of Qinghai Province, Xining 810000, China
  • Received:2020-12-04 Published:2021-06-28
  • Contact: LI Jinjian
  • Supported by:
    Under the auspices of the Second Tibetan Plateau Scientific Expedition and Research (STEP) Program (No. 2019QZKK0103), National Natural Science Foundation of China (No. 41772173, 41405077), the Thousand Talents Program for High-end Innovation of Qinghai Province, the Applied Basic Research Project of Qinghai Province (No. 2019-zj-7045)

Abstract: Variations in vegetation are closely related to climate change, but understanding of their characteristics and causes remains limited. As a typical semi-humid and semi-arid cold plateau region, it is important to understand the knowledge of long term Normalized Difference Vegetation Index (NDVI) variations and find the potential causes in the source region of the Yangtze River. Based on four tree-ring width chronologies, the regional mean NDVI for July and August spanning the period 1665–2013 was reconstructed using a regression model, and it explained 43.9% of the total variance during the period 1981–2013. In decadal, the reconstructed NDVI showed eight growth stages (17541764, 17661783, 1794–1811, 1828–1838, 1843–1855, 1862–1873, 1897–1909, and 1932–1945) and four degradation stages (16791698, 17261753, 1910–1923, and 1988–2000). And based on wavelet analysis, significant cycles of 2–3 yr and 3–8 yr were identified. In additional, there was a significant positive correlation between the NDVI and the Palmer Drought Severity Index (PDSI) during the past 349 yr, and they were mainly in phase. However, according to the results of correlation analysis between different grades of drought/wet and NDVI, there was significant asymmetry in extreme drought years and extreme wet years. In extreme drought years, NDVI was positively correlated with PDSI, and in extreme wet years they were negatively correlated.

Key words: Normalized Difference Vegetation Index (NDVI), reconstruction, dendrochronology, tree ring, Source Region of the Yangtze River