内蒙古温带草原NPP时空变化特征分析

Temporal and Spatial Pattern of Temperate Steppe NPP in Inner Mongolia

温带草原植被净初级生产力(net primary productivity,NPP)及其对气候变化的响应研究是全球变化的核心内容之一。利用MODIS遥感数据驱动的LUE模型模拟内蒙古温带草原NPP,分析其对气候因子变化的响应关系。结果表明,1)温带草原2001-2014年多年平均NPP值为235.65gC·m^(-2)·a^(-1),呈东北向西南递减的趋势。草甸草原NPP值最大(358.97gC·m^(-2)·a^(-1)),典型草原次之(237.17gC·m^(-2)·a^(-1)),而荒漠草原值最小(127.77gC·m^(-2)·a^(-1));2)温带草原NPP总体上呈上升趋势,集中在锡林郭勒东部和呼伦贝尔的草甸草原和内蒙西部地区的荒漠草原,而典型草原则有下降的趋势,集中在阴山和锡林郭勒中部地区;3)温带草原NPP总体上对降水的敏感性强于对温度的敏感性。草甸草原NPP同时受降水和温度影响,其中温度更为重要,典型草原和荒漠草原NPP主要受降水的影响。

Temperate steppe net primary production （NPP） and its response to climate factors is one of the key issues in global change research. In this study, the temporal and spatial pattern of temperate steppe NPP were estimated by using a light use efficiency （LUE） model driven by MODIS atmosphere and land parameters in the Inner Mongolia Autonomous Region （IMAR） from 9,001 to 2014. The results indicated that 1） spatial distribution of annual temperate steppe NPP showed a gradual decrease from the northeast to the southwest in IMAR. Mean annual NPP values for temperate steppe, meadow steppe, typical steppe and desert steppe biomes were 235.65,358.97,237.17 gC. m-2 . a-1 and 127.77 gC. m-2 a-1,respec- tively. 2） There was a rising trend in temperate steppe NPP during 2001 to 2014. Meadow steppe （in east Xilingol and H ulunbuir） and desert steppe （in west IMAR） exhibited obvious increasing trend,while typi- cal steppe in Yin mountainous region and the center of Xilingol showed a decrease trend. 3） Precipitation was the dominant driving force of temperate steppe NPP in IMAR. Meadow steppe NPP was correlated to both precipitation and temperature, but with more dependence on temperature, while precipitation influ- enced typical steppe and desert steppe NPP more seriously.