Chin J Plant Ecol ›› 2008, Vol. 32 ›› Issue (4): 786-797.DOI: 10.3773/j.issn.1005-264x.2008.04.007

• Original article • Previous Articles     Next Articles

DYNAMICS SIMULATION OF NET PRIMARY PRODUCTIVITY BY A SATELLITE DATA-DRIVEN CASA MODEL IN INNER MONGOLIAN TYPICAL STEPPE, CHINA

ZHANG Feng, ZHOU Guang-Sheng(), WANG Yu-Hui   

  1. State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
  • Received:2007-09-03 Accepted:2008-02-18 Online:2008-09-03 Published:2008-07-30
  • Contact: ZHOU Guang-Sheng

Abstract:

Aims Vegetation net primary productivity (NPP) and its responses to global change have been focuses of global change research. Accurately estimating the spatial patterns and temporal dynamics of net primary productivity (NPP) of terrestrial ecosystems is of great interest to human society and is necessary for understanding the carbon cycle of the terrestrial biosphere. But only a few evidences in various biomes are available on the performance of global models of terrestrial net primary productivity (NPP) at ecosystem level.

Methods Vegetation net primary productivity (NPP) derived from a carbon model (Carnegie-Ames- Stanford Approach, CASA) and its inter-annual change at ecosystem level in Inner Mongolian typical steppe, China, are investigated in this study using 1982~2002 time series data sets of normalized difference vegetation index (NDVI) at 8 km spatial resolution and paired ground-based information on vegetation, climate, soil, and solar radiation, after CASA model is validated by the aboveground biomass of 13 years’ continuous observation.

Important Findings Results show that 21-year averaged annual NPP is 290.23 g C·m-2·a-1, ranging between 145.80 g C·m-2·a-1 and 502.84 g C·m-2·a-1. From 1982 to 2002, annual NPP shows a slightly increasing trend, while from 1982 to 1999 a significant increase (p<0.01) is observed, and the increasedNPP is mainly due to the increases of the amplitude of the NPP annual cycle. Annual precipitation significantly affects the variation of NPP, and there is no significant positive correlation between NPP and annual mean temperature.

Key words: CASA model, net primary productivity, Inner Mongolian typical steppe