基于波谱-Granger因果检验的稻田甲烷排放通量昼夜变化成因分析  

Causes of diurnal variation of methane flux in paddy fields based on spectral Granger causality analysis

作　　者：戴声佩 居为民[3] 赵志忠[1] DAI Shengpei;JU Weimin;ZHAO Zhizhong(College of Geography and Environmental Science,Hainan Normal University/Key Laboratory of Tropical Island Land Surface Processes and Environmental Changes of Hainan Province,Haikou 571158,China;Institute of Scientific and Technical Information,Chinese Academy of Tropical Agricultural Sciences/Key Laboratory of Applied Research on Tropical Crop Information Technology of Hainan Province,Haikou 571101,China;International Institute for Earth System Sciences,Nanjing University,Nanjing 210023,China)

机构地区：[1]海南师范大学地理与环境科学学院/海南省热带海岛地表过程与环境变化重点实验室,海口571158 [2]中国热带农业科学院科技信息研究所/海南省热带作物信息技术应用研究重点实验室,海口571101 [3]南京大学国际地球系统科学研究所,南京210023

出　　处：《生态学报》2025年第4期1925-1937,共13页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(42107487)。

摘　　要：稻田甲烷(CH_(4))排放通量的研究是当前陆地生态系统碳循环研究的重要组成部分和热点问题之一。利用2016年江苏句容生态实验站稻麦轮作农田生态系统涡度相关原位观测数据,分析了稻田CH_(4)排放通量昼夜变化特征及其主要影响因子(总初级生产力GPP,gross primary productivity、潜热通量LE,latent heat flux、空气温度TA,air temperature、土壤温度TS,soil temperature),并采用波谱-Granger因果分析方法,从因果分析角度重点探讨了稻麦轮作农田生态系统中水稻生长季的稻田CH_(4)排放通量昼夜变化原因,结果表明:在稻麦轮作农田生态系统中小麦生长季的农田CH_(4)排放通量较低,昼夜变化特征不明显;水稻生长季的稻田CH_(4)排放通量呈现明显单峰值昼夜变化特征,峰值出现在13:00—16:00之间。在小时尺度上,GPP和LE昼夜变化的峰值出现的时间(11:30和14:00)早于稻田CH_(4)通量(14:30),而温度(TA、TS)峰值(15:30和16:30)滞后于稻田CH_(4)通量和GPP、LE。在频率域上GPP、LE、TA、TS与稻田CH_(4)通量在1d和12h周期上存在较强的共振关系;GPP、LE与稻田CH_(4)通量之间存在明显的因果关系,而TA、TS与稻田CH_(4)通量之间在长时间尺度上的因果关系更加明显。在日内时间尺度,相对于气温和土壤温度,与光合和蒸散相关的GPP、LE是更重要的稻田CH_(4)通量昼夜变化的影响因子。本研究可为构建稻田CH_(4)排放模型提供因果机理性解释。The study of CH_(4) emission flux in rice fields is an important part and one of the hot issues in the current carbon cycle research of terrestrial ecosystems.This paper was devoted to identifying diurnal change patterns of CH_(4) emission fluxes by using eddy covariance(EC)measurement,and to analyzing the linkages of CH_(4) fluxes with different biophysical factors on a diurnal timescale based on the spectral Granger causality analysis method in Jurong Ecological Experimental Station(JREES)in 2016.The results show that:the CH_(4) fluxes showed distinguishable diurnal variations with single peaks during 13:00—16:00 h local time.In the non-rice growing season,the CH_(4) fluxes were very low,and the diurnal variation characteristics were not obvious.At the diurnal timescale,CH_(4) fluxes reached daily maximums at 14:30 h,later than gross primary productivity(GPP)(11:30 h)and latent heat flux(LE)(14:00 h),and earlier than air temperature(TA)(15:30 h)and soil temperature(TS)(16:30 h).Wavelet coherence has high periodic coherence at the 24 h and 12 h timescales and lower periodic coherence at the weekly timescales between TA,TS,and CH_(4) fluxes throughout the rice-growing season.GPP regulates CH_(4) fluxes after accounting for the effects of LE,TA,and TS on CH_(4) fluxes.LE mirrored the diurnal pattern of CH_(4) fluxes when the effects of TA and TS on CH_(4) fluxes were considered.Therefore,GPP and LE related to photosynthesis and evapotranspiration are more important factors affecting the diurnal variation of CH_(4) fluxes in rice fields than air temperature and soil temperature.This study can provide a causal mechanism explanation for constructing a CH_(4) emission model from rice fields.

关 键 词：波谱-Granger因果检验 稻田生态系统 甲烷通量 昼夜变化 因果分析 

分 类 号：S181[农业科学—农业基础科学]