PROGRESS IN GEOGRAPHY ›› 2004, Vol. 23 ›› Issue (3): 91-99.doi: 10.11820/dlkxjz.2004.03.012

• Original Articles • Previous Articles     Next Articles

SVI and VCI Based on NDVI Time-Series Dataset Used to Monitor Vegetation Growth Status and Its Response to Climate Variables

QI Shuhua1,2, WANG Changyao1, NIU Zheng1, LIU Zhengjun1   

  1. 1. The State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing Applications, CAS, Beijing 100101, China;
    2. School of Geography and Environment, Jiangxi Normal University, Nanchang 333000
  • Received:2003-06-01 Revised:2004-02-01 Online:2004-05-25 Published:2004-05-25

Abstract:

In this paper, the 20-year NDVI time-series dataset composed every ten days was used to induce SVI (Standard Vegetation Index) and VCI (Vegetation Condition Index). The vegetation growth status spatial pattern for China, at the first ten days of March and May in 2000 , was studied with SVI. Results showed that the winter maize was eugonic in March, but in May winter maize was not in good status; and the area where vegetation was not in good status compared with the past years was enlarged from March to May. Considering the validity of VCI in monitoring vegetation growth status has been approved by some studies and the maganificent correlation between SVI and VCI, we reached the conclusion safely that SVI is valid in monitoring vegetation growth condition. A 20-year rain and average air temperature dataset collected at 10 meterological stations located at differrent vegetation cover type was used to study the VCI and SVI’s response sensitivity to climate variables. Results showed that: (1) The dominant factor on vegetation growth is spatio-temporal and land cover type specified; (2) For forestory cover type, SVI and VCI exhibit some relation with the total precipitation before due time at the first ten days of March, while in May irrelevance between SVI or VCI and climate variables was found that can be explained by NDVI saturation phenomena always happening on forest cover area; (3) For meadow/grassland and shrub, air temperature exhibits a little more remarkable relativity than precipitation especially for VCI; (4) For crop area, according VCI, vegetation growth status has more remarkable relativity with air temperature in March, while precipitation has become the preponderant factor on growth status at May especially for winter wheat area; (5) The drought indice based on time-domain spectral vegetation index were not always valid because their response to precipitation was spatialy and temporaly specified; (6) VCI is more excellent at indicating climatic changes.

Key words: global change, NDVI, SVI, VCI, vegetation