PROGRESS IN GEOGRAPHY ›› 2010, Vol. 29 ›› Issue (4): 507-512.doi: 10.11820/dlkxjz.2010.04.018

• Original Articles • Previous Articles    

Seasonal Time Lag Response of NDVI to Temperature and Precipitation Change and Its Spatial Characteristics in Tibetan Plateau

DING Mingjun1,2, ZHANG Yili1, LIU Linshan1, WANG Zhaofeng1, YANG Xuchao1   

  1. 1. Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101,China;
    2. School of Geography and Environment, Jiangxi Normal University, Nanchang 330022, China
  • Received:2009-08-01 Revised:2010-01-01 Online:2010-04-24 Published:2010-04-24

Abstract:

Today, human activities become more and more intense. How to minimize human disturbance is very important in the study of the relationship between vegetation and climate. The Tibetan Plateau, as one of the few extensive regions escaped from human disturbance, provides an ideal site for studies on the response of natural vegetation cover to water/thermal conditions. Based on the trend surface of TN (short for time series of ten-day NDVI), TP (short for time series of ten-day rainfall) and TT (short for time series of ten-day temperature) , which all are multi-year means, ARCGIS9.2 software and lag cross-correlation method are used to analyze the temporal and spatial characteristics of the relationships between water/thermal climate elements and vegetation cover. The main results are as follows: (1) Except high-cold desert vegetation and forest vegetation, the TN has very good correlation with TT and TP on the Tibetan Plateau, especially in the areas with a vegetation cover of moderate density, such as meadow and grassland. (2) NDVI has a hysteresis effect towards temperature and precipitation and in the northern part (Qaidam Basin and the north of Kunlun Mountains) and southern part of the Tibetan Plateau, the vegetation responds to the water/thermal changes slowly, but in the middle and east parts of the Tibetan Plateau, the vegetation responds to the water/thermal changes quickly; (3) Different vegetation types respond to water/thermal condition differently. The descending order of the responding degree for each vegetation type is: alpine cold meadow, alpine cold grassland, alpine cold brush, periglacial cushion vegetation, desert, and forest.

Key words: correlation, hysteresis effect, NDVI, Tibetan Plateau, water/thermal conditions