四川农业大学学报

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基于CASA模型的四川植被净初级生产力及其时空格局分析

  

  1. 1. 成都理工大学地球科学学院,成都 610059; 2. 中国科学院成都生物研究所,成都 610041
  • 收稿日期:2013-05-02 出版日期:2013-09-27 发布日期:2013-09-27

Spatial-temporal Variations of Net Primary Productivity of Sichuan Vegetation Based on CASA Model

  • Received:2013-05-02 Online:2013-09-27 Published:2013-09-27

摘要:

【目的】估算四川植被的净初级生产力并分析其时空格局及影响因素,为深入认识该区域的植被生产力状况提供数据支持。【方法】在原CASA模型基础上,以MODIS卫星数据为依托,对光合有效辐射值提取、最佳区域气温反演、水分胁迫系数演算这3种方法进行了改进,进而估算了四川地区2000-2011年期间的植被净初级生产力(NPP)。【结果】1)四川植被NPP的多年平均值为303.27gC/m2•a,变化范围在285-340 gC/m2•a之间。2)四川植被NPP的季节变化明显,其中夏季是NPP主要积累期;同时由于区域气候变暖导致的物候期延长,秋季NPP的累积量呈逐年上升趋势。3)四川植被NPP空间分异明显,总体表现出由东南向西北逐渐减少的趋势,且呈垂直地带性特征明显。 4)降雨量是驱动NPP的主要因子;温度及光合有效辐射也对NPP影响显著(P<0.001)。【结论】近10年来四川植被NPP变化主要由生长旺季本身变化所致;其时空分布格局总体表现出随温度、水分、光合有效辐射以及海拔增加而增大的趋势;改进后的CASA模型可以有效地模拟四川植被NPP的时空格局特征。

关键词: CASA模型;植被NPP;MODIS数据;时空格局

Abstract:

【Objective】The aim of this study was to estimate the net primary producvity (NPP) and spatial-temporal variations of Sichuan vegetations and to provide data support for better understuding of vegetation productiviry of this region. 【Method】The data of MODIS was used to modify the three methods of photosynthetically active radiation (PAR) extraction, regional temperature inversion and water stress coefficient calculation based on CASA model and the results were applied to estimate seasonal dynamics and spatial variations of NPP of Sichuan vegetation from 2000 to 2011.【Results】(1) The total NPP of Sichuan vegetations varied from 285 to 340 gC/m2•a, averaging about 303.27 gC/m2•a. (2) There was clear seasonal changes in NPP of Sichuan and summer was main accumulation stage for NPP. Autumn NPP were increased year by year due to warming-extended phenology (3) The spatial distribution of NPP in Sichuan showed a rising tendency from northwest to southeast and elevational differenced in NPP was pronounced. (4) NPP in the study was mainly driven by precipitation. In addition, average temperature and PAR had significant effects (P<0.001). 【Conclusion】Changes in NPP of Sichuan vegetation were caused mainly by growing season in resent 10 years. The spatial-temporal variations of NPP generally increased with increasing temperature, moisture, PAR, and elevation. It was relatively reliable to use the modified CASA model to estimate vegetation NPP.

Key words: CASA model; vegetation NPP; MODIS data; spatial-temporal variation