Acta Geographica Sinica ›› 2021, Vol. 76 ›› Issue (5): 1231-1244.doi: 10.11821/dlxb202105014

• Climate Change and Land Surface Processes • Previous Articles     Next Articles

Spatial and temporal variations of frozen ground and its vegetation response in the eastern segment of China-Mongolia-Russia economic corridor from 2000 to 2015

LIU Zhenhai1(), WANG Shaoqiang1,2,3, CHEN Bin2()   

  1. 1. School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China
    2. Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
    3. College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2020-08-09 Revised:2021-04-18 Online:2021-05-25 Published:2021-07-25
  • Contact: CHEN Bin E-mail:lzhzlw@cug.edu.cn;chenbin@igsnrr.ac.cn
  • Supported by:
    The Science and Technology Strategic Pilot of the Chinese Academy of Sciences(XDA20030203);Scientific Research Foundation of China University of Geosciences(162301192642)

Abstract:

The eastern segment of the China-Mongolia-Russia economic corridor is situated in the overlap region of the southeast margin of Eurasia permafrost region and the southern border of the tree line, where fragile frozen ground and ecosystems have been maintained. In this study, we analyzed the spatiotemporal distribution and annual change of frozen ground, leaf area index (LAI), and the vegetation green-up data in the eastern China-Mongolia-Russia economic corridor from 2000 to 2015 based on the MERRA-Land data product, GLOBMAP LAI, and MODIS EVI dataset. The main controlling environmental factors of the green-up date and the status of vegetation growth in the different periods over a year were calculated by grey correlation analysis, and then the response of vegetation growth in typical areas to the freezing-thawing changes of the frozen ground was analyzed. Some conclusions can be drawn as follows. (1) In the past 16 years, permafrost and seasonal frost in the eastern China-Mongolia-Russia economic corridor was persistently and significantly degraded, which was mainly reflected by the early thawing and delayed freezing of the frozen ground in time, and manifested as the disappearance of permafrost and the uplift of the lower limit of seasonal frost in the southern isolated permafrost, and the thickening of the active layer in the southern continuous permafrost in space. (2) In about 48% of forest areas, the onset day of frozen ground melting is the main factor affecting the start of vegetation greening season. The growth situation of vegetation in forest areas is altered by the soil water from thawing frozen ground and the hydrothermal mechanisms of peatland. (3) With the transition from forest and peatland to meadow or farmland, the frozen ground degrades and in turn further facilitates the fade of peatland. Exploring the synergetic relationship between the degradation of frozen ground and the ecological environment is helpful to identify the vulnerable regions of degrading frozen ground and the sensitive regions of the ecological environment under the influence of climate warming and human activities.

Key words: eastern China-Mongolia-Russia economic corridor, ground freeze-thawing process, vegetation growth, gray correlation analysis