地球系统模式中植被净初级生产力百年尺度时空变化及其与气候的关系

Spatial and Temporal Variations of Net Primary Productivity at Century Scale in Earth System Models and Its Relationship with Climate

利用6个地球系统模式模拟的植被净初级生产力(NPP)对1901~2005年NPP时空变化进行了研究,并结合气候因子分析了NPP的变化与气温和降水的关系。结果表明:(1)近百年来全球NPP呈现上升趋势,模式集合平均的趋势系数为0.88,通过了99.9%的信度检验;北半球的趋势比南半球明显。(3)近百年来800g(C)m^-2a^-1以上的NPP高值区主要分布在南美洲赤道地区、非洲赤道地区、中南半岛和印度尼西亚一带的热带雨林区;低值区主要分布在北半球高纬度地区、非洲北部地区、亚洲大陆干旱半干旱区以及青藏高原西北部地区。(3)全球NPP与气温百年演变在大部分地区主要为正相关关系,仅在赤道附近的南美洲、非洲以及印度地区为负相关关系,主要由于这些地区辐射是NPP的限制因子。全球NPP与降水的百年变化在大部分地区也主要是正相关关系,在非洲北部到西亚中亚的干旱半干旱地区为负相关关系。(4)6个地球系统模式在全球21个区域的大部分地区的NPP和气温降水的变化关系较为一致,西非地区不同模式变化不一致,NPP模拟的不确定性较大,其次是地中海地区。(5)东亚地区NPP与气候的百年演变同步并且相关性高,反映了强烈的植被大气相互作用过程。

The spatial and temporal changes in net primary productivity(NPP)during 1901-2005 were studied using six earth system models.The relationship between NPP changes and the climatic factors of air temperature and precipitation was analyzed.The results show that:(1)In the past 100 years,the global NPP has shown an upward trend.The trend coefficient of the ensemble model average is 0.88,which passes the 99.9%confidence test.The trend in the Northern Hemisphere is more pronounced than in the Southern Hemisphere.(2)In the past 100 years,high NPP values of 800 g(C)m^-2 a^-1 or higher are mainly distributed in tropical rainforest areas in the equatorial regions of South America,Equatorial Africa,the Indochina Peninsula,and Indonesia.Low NPP values are mainly distributed in the high latitudes of the Northern Hemisphere,Northern Africa,the arid and semi-arid regions of the Asian continent,and the northwestern Tibetan Plateau.(3)The global NPP had a positive correlation with temperature in most of the regions during this century period.This correlation only becomes negative for South America,Africa,and India near the equator,mainly because radiation in these areas is a limiting factor of NPP.The 100-year changes in the global NPP and precipitation are also primarily positively correlated in most regions,but are negatively correlated in the arid and semi-arid regions of Northern Africa and Western Asia.(4)The six earth system models yield relatively consistent NPP and temperature/precipitation changes in most of the 21 regions of the world.In West Africa,the pattern changes are inconsistent where the uncertainty of the NPP simulation is greater,followed by the Mediterranean region.(5)In particular,the evolution of the NPP in the East Asia region and climate is synchronized and highly correlated,which reflects the strong process of atmospheric interaction with vegetation.