该文在利用朱文泉等(2007)构建的基于光能利用率的净初级生产力(NPP)遥感估算模型对内蒙古草原生态系统1982-2006年的NPP进行估算的基础上,选取包括降水量、温度、有效降水、有效温度和3种地表干湿度指数在内的气候指标,充分考虑地表覆盖状况和气候因子的时滞和累积效应,探讨了内蒙古草原生态系统NPP与气候因子之间的相互作用关系。结果表明,以年为时间单位,在年际水平上,温度相关的各指标与年NPP的关系并不明显,当年的气候条件对草原区植被的生长影响最大。以月为时间单位,年内月气温和降水是影响NPP的重要因素。且所有植被类型区在年内月际水平上气候各指标对NPP的影响时效最大为1个月,NPP和各气候参量的关系时效也为1个月;在年际水平上5-9月的NPP与降水、地表干湿度指数的互相关系数明显高于同温度各指标的互相关系数,表明降水是影响内蒙古草原NPP的主要气候因子,且降水的累积效应影响显著。不同植被类型区年际月NPP与降水指标之间的关系也各不相同。
Aims Net primary productivity (NPP) is a key parameter in vegetation growth and terrestrial ecosystem processes and plays an important role in carbon circulation.The relationship between NPP and climate is complicated and needed additional research.Our aim was to study this relationship in different time units and scales to uncover their interaction mechanism.Methods Based on remotely-sensed estimated NPP calculated by light use efficiency model,the relationship between NPP and climatic indices (including precipitation,temperature,and effective precipitation and temperature) and three land surface humidity indices during 1982-2006,are assumed in Inner Mongolia.We considered land cover condition and time lag and accumulation effect of climate factors,using time lag correlation analysis,to uncover the interaction between NPP and climate.Important findings Temperature related indices correlate poorly with annual NPP,and current year precipitation affects NPP the most.With month as the time unit,intra-annual monthly climatic factors are key factors influencing vegetation growth.In all vegetation types,intra-annual monthly climate indices could affect NPP in an effective time period of one month and so do NPP to climate.At the inter-annual level,monthly precipitation and humidity index affect NPP more than temperature related indices,which reveals that precipitation is the restricted climatic factor in this area with obvious accumulation effects.Areas with different vegetation types represent various relations between inter-annual monthly NPP and climatic indices.