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Acta Prataculturae Sinica ›› 2012, Vol. 21 ›› Issue (1): 239-247.

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Modelling light use efficiency of alpine meadows on the Northern Tibetan Plateau based on the MODIS algorithm

WU Jian-shuang1,2, ZHOU Yu-ting1,2   

  1. 1.Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China;
    2.Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Online:2012-02-20 Published:2012-02-20

Abstract: Light use efficiency (LUE) is defined as the ratio of primary production to absorbed photosynthetically active radiation (APAR) by a vegetation canopy and it reflects the capability of using luminous energy. Quantitative analysis of the temporal and spatial variations of primary production is based on the quantitative analysis LUE and is an important component of quantitative analysis of the global carbon cycle. Therefore, quantitative analysis of the global vegetation LUE is an important component of quantitative analysis of the global carbon cycle. The LUE of alpine meadows on the Northern Tibetan Plateau were modeled based on the MODIS LUE algorithm in 2004-2005. Daily minimum air temperature (Tamin) and vapor pressure deficit (VPD) were used to calculate the temperature attenuation scalar (Tscalar) and water attenuation scalar (Wscalar), respectively. Based on correlation analysis and multiple stepwise linear regression analysis, the Tscalar might explain more seasonal variations of LUE than the Wscalar. Modeled LUE values were about 14.97% and 16.57% larger than observed LUE values in 2004 and 2005, respectively. However, there was no significant difference between modeled LUE and observed LUE. This means that the LUE model based on the MODIS algorithm had high accuracy to model LUE of alpine meadows on the Northern Tibetan Plateau. Correlation analysis showed that the correlation coefficient between observed LUE and Tamin was larger than that between observed LUE and mean air temperature. This indicated that Tamin was better than mean air temperature in quantitative analysis of the LUE seasonal change. The LUE model based on the MODIS algorithm accurately quantified the LUE of alpine meadows on the Northern Tibetan Plateau.

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