2007~2018年中国陆地植被总初级生产力与日光诱导叶绿素荧光的时空格局及其气候调控

Spatiotemporal Patterns and Climate Regulation of Gross Primary Productivity and Sun-Induced Chlorophyll Fluorescence of Terrestrial Vegetation in China from 2007 to 2018

日光诱导叶绿素荧光(SIF)作为总初级生产力(GPP)的替代指标,在区域GPP估算上表现出巨大的潜力。植被SIF和GPP具有较好的线性关系,但是不同的气候条件对SIF-GPP关系的影响仍不清晰。利用2007~2018年MODIS GPP和GOME-2 SIF以及环境条件(温度、降水、辐射等)研究中国陆地植被GPP和SIF的时空格局以及环境因子的调控。结果发现中国陆地植被GPP和SIF时空格局是一致的,但是作为表征光能分配的新指标GPP/SIF在空间分布上存在显著的差异。此外,SIF产量(SIFYield)受到约束GPP的环境因子(最小温度、饱和水汽压差、土壤水分和APAR)的共同调控,间接证实了SIF和GPP紧密的联系。因此,由于在时间和空间上SIF与GPP的关系受到环境条件的调控,使用基于卫星的SIF准确估算区域GPP应该考虑环境因子的约束。

Sun-Induced chlorophyll Fluorescence(SIF),as a surrogate indicator of Gross Primary Productivity(GPP),shows great potential in regional GPP estimation. The SIF and GPP have a good linear relationship,but the influence of different climate conditions on the SIF-GPP relationship is still unclear. In this study,we used MODIS GPP and GOME-2 SIF and environmental conditions(temperature,precipitation,radiation,etc.)in China during 2007~2018 to study the temporal and spatial patterns of GPP and SIF of terrestrial vegetation and the constraint of environmental factors. The results found that the spatial and temporal patterns of GPP and SIF of terrestrial vegetation are similar,but there are significant differences in the spatial distribution of GPP/SIF that act as a new indicator of light energy distribution. In addition,the yield of SIF(SIFYield)is controlled by the environmental factors(minimum temperature,saturated vapor pressure difference,soil moisture,and APAR)that restrict GPP,which indirectly confirms the close connection between SIF and GPP. Therefore,since the relationship between SIF and GPP in time and space is regulated by environmental conditions,the use of satellite-based SIF to accurately estimate regional GPP should consider the constraints of environmental factors.