摘要
北方农牧交错区地处半湿润/半干旱生态脆弱过渡带,干旱是影响该区植被生产力的关键因素之一。探究干旱对植被总初级生产力的影响,对深刻理解气候变化下生态系统生产力变化响应特征及优化区域碳水循环具有重要意义。为了更好地了解水分限制区不同干旱特征对GPP影响,本研究以北方农牧交错区为例,基于长时间序列的标准化降水蒸散发指数(SPEI3,1900—2020年)和植被总初级生产力(GPP,1982—2018年)等数据,首先采用小波分析明确SPEI3与GPP强相关周期,在此基础上利用游程理论识别干旱特征,进而分析了北方农牧交错区干旱特征与GPP的变化趋势,最后厘定了不同干旱特征对GPP的影响。结果表明:(1)1982—2018年北方农牧交错区SPEI3与GPP在半年周期和年周期存在显著相关关系,滞后效应随时间变化而变化;年际分析能够减弱滞后效应对SPEI3与GPP相关性的影响;(2)1900—2020年北方农牧交错区干旱历时、干旱烈度和烈度峰值均呈现显著增加趋势,干旱烈度随着干旱历时和烈度峰值的增加而加剧,干旱特征高值区往往具有更强的增加趋势;(3)1982—2018年北方农牧交错区GPP总体呈现增加趋势,GPP高值区表现出更强的增加趋势;(4)不同干旱特征对GPP变化的影响不同,贡献率绝对值表现为干旱烈度>干旱历时>烈度峰值;整体来看,干旱特征共同解释了GPP变化面积的18.1%,干旱历时和干旱烈度显著抑制GPP增加;(5)不同的土地利用上植被GPP变化对干旱特征响应不同,乔木和灌木GPP下降主要来自干旱历时的负贡献,草地和耕地GPP下降则由干旱烈度的负贡献主导。
Climate change has been projected to increase the drought duration and intensity in the future,with greater impact on the Gross Primary Production(GPP)in areas.However,despite our increasing understanding of the drought impacts on GPP in recent decades,there is still little understanding of how different drought features(i.e.,duration,intensity,peak)GPP.A better understanding of the impact of different drought features on GPP under climate change can help optimize the regional carbon water cycle.In this study,we took the Farming-Pastoral Ecotone of Northern(FPEN)in China as an example and used long-term time series Standardized Precipitation Evapotranspiration Index(SPEI3)during 1900—2020 and GPP during 1982—2018.Firstly,the cross wavelet transform and wavelet coherence analysis was employed to reveal the correlation relationship between SPEI3 and GPP at different temporal scales.Then,the drought features were identified by runs theory,and the trend of drought features and GPP were analyzed using the Theil-Sen Median trend analysis with the Mann-Kandall test in FPEN.Finally,the effects and relative contributions of different drought features on GPP were determined by partial correlation analysis and multiple linear regression analysis.The results show that:(1)There was a strong correlation between SPEI3 and GPP at the scales of half year(6±1 month)and 1 year(12±2 month)in FPEN during 1982—2018,and the 1-year scale had a stronger relationship.Meanwhile the lag effect of SPEI3 and GPP changed with time.Therefore,we clarified that the interannual analysis was able to reduce the effect of lag effect on the correlation between SPEI3 and GPP;(2)The drought duration,intensity,and peak all showed a significantly increasing trend in FPEN during 1900—2020.Drought intensity increased with increasing drought duration and peak.The drought features with higher values often had a stronger increasing trend;(3)GPP showed a trend of“increase-decrease-increase”,with a significant increasing trend during 1982—2018,and the high values of GPP showed a stronger increasing trend;(4)Different drought features have different effects on GPP changes.The absolute contribution rate of drought features was in the order of intensity>duration>peak.Overall,drought features together explained 18.1%of the GPP change.Drought duration and intensity significantly inhibited GPP growth,with the relative contribution rate of-0.05 and-0.35,respectively;(5)GPP of different land covers responded differently to drought features.The drought duration and intensity has negative contribution to the GPP changes in forests/shrubs and grasslands/croplands,respectively.
作者
周温存
刘正佳
王坤
邹时林
钟会民
陈芳鑫
ZHOU Wencun;LIU Zhengjia;WANG Kun;ZOU Shilin;ZHONG Huimin;CHEN Fangxin(School of Surveying and Mapping Engineering,East China University of Technology,Nanchang 330013,China;Key Laboratory of Regional Sustainable Development Analysis and Simulation,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China;College of Resources and Environment,University of Chinese Academy of Sciences,Beijing 100049,China;Technology Policy Studies,Bureau of Development and Planning,Chinese AcademyofSciences,Beijing 100864,China)
出处
《地球信息科学学报》
CSCD
北大核心
2023年第2期421-437,共17页
Journal of Geo-information Science
基金
国家自然科学基金项目(41971218)
中国科学院A类战略性先导科技专项(XDA23070302)。
关键词
植被总初级生产力
小波分析
干旱特征
游程理论
趋势分析
偏相关分析
相对贡献率
gross primary production
wavelet analysis
drought features
runs theory
trend analysis
partial correlation analysis
relative contribution rate
作者简介
周温存(1997—),女,江西九江人,硕士生,研究方向为遥感与地理信息系统应用。E-mail:2020110334@ecut.edu.cn;通讯作者:刘正佳(1986-),男,山东青州人,博士,副研究员,硕士生导师,主要从事农业地理方面的研究工作。E-mail:liuzj@igsnrr.ac.cn。
