摘要
近年来随着全球气候变化,活跃火发生频次显著增加,在不同地区开展活跃火发生机制的研究对于理解活跃火演变规律至关重要。本研究基于黄土高原2001~2020年Modis火点数据和土地覆盖数据,利用ArcGIS、ENVI等软件绘制研究区火点分布图并进行趋势分析,评估研究区的活跃火时空分布与土地覆盖类型之间的关系,探讨了黄土高原活跃火的时空规律,得到以下主要结论:1)黄土高原活跃火发生频次和强度空间分布格局相似,主要集中在黄河沿线以农田为主的东部平原,且强度较高,中西部活跃火分布相对较少,强度相对较低;2)黄土高原活跃火集中发生在春夏季,呈三峰分布,分别在春季3~4月、夏季6月和秋季10月达到峰值,其中3~4月草原火和森林火的贡献较大,而6月及10月农田火贡献最大;3)按土地覆盖类型进行分析,城市火和农田火是黄土高原地区活跃火发生的主要类型,占比可达总活跃火数量的69%,其次是草原火和森林火,说明黄土高原活跃火受人为因素影响较大;4)野火(包括草原火、森林火、灌木火和裸地火)主要集中在冬春季发生,城市火和农田火主要集中在夏秋季发生。近20年,由于研究区秸秆禁烧政策和城市的防火措施的实施,城市火和农田火呈减少趋势,冬春季的增温导致研究区野火呈增多趋势。
In recent years,with global climate change,the frequency of fire has increased significantly,conducting research on the mechanisms of fire occurrence in different regions is crucial for understanding fire evolution patterns.The Chinese Loess Plateau(33°41′~41°16′N,100°52′~114°33′E)is located in the East Asian monsoon zone,and is characterized by a fragile and sensitive ecological environment,which is a vital region for climate and ecological study;at the same time,the region has long-term human activities,providing an ideal place for us to study the relationship between fire,climate environment,and human activities.Currently,remote sensing is the main way to obtain the spatial and temporal information of active fires.And Modis(Moderate-resolution Imaging Spectroradiometer)is one of the standard active fire data products.In this paper,the spatiotemporal distribution features of the active fire frequency and intensity in the Loess Plateau from 2001 to 2020 were investigated based on MODIS fire data;the distribution pattern and long-term trend of active fire were quantitatively examined with ArcGIS and ENVI;and the relationship between the spatiotemporal distribution of active fire and land cover types in the study area was analyzed.The following conclusions were obtained:(1)Due to the dense population in the eastern part of the study area,especially along the Yellow River,farmland fires and urban fires are frequent,resulting in a high frequency of active fires;and the distribution of forest vegetation in this area is relatively denser,resulting in a higher intensity of active fire.While,the less population and forest in the central and western parts of the Loess Plateau resulting in a lower frequency and intensity of active fire.(2)The frequency of active fires on the Loess Plateau averaged 223 per year,and the average annual intensity varied from 36.38 MW to 81.99 MW,with an overall fluctuating and increasing trend over the last 20 years.Active fires occur mainly in spring and summer,with a three-peak distribution of fire events,peaking in March-April,June and October.Monthly average active fire intensity peaks in April(81.06 MW),with the lowest value in August.Average active fire intensity is stronger in winter and spring than in summer and autumn.Among them,forest and grassland fires make a contribution during March-April;while June and October coincide with the crop harvests,leading to the frequent occurrence of active fires due to the burning of straw and agricultural residues.(3)According to the analysis of land cover types,urban fires(40%)and farmland fires(29%)are the main types of active fires in the Loess Plateau,accounting for 69%of the total number of active fires,followed by grassland fires(16%)and forest fires(12%),with barren fires(2%)and shrub fires(1%)together accounting for about 3%,which indicates that active fires in the Loess Plateau are greatly influenced by human.(4)Wildfires(including grassland fires,forest fires,shrub fires,and barren fires)mainly occur in winter and spring,while urban fires and farmland fires mainly occur in summer and autumn.In the last 20 years,urban and farmland fires have shown a decreasing trend due to the implementation of the straw-burning ban policy and urban fire prevention measures,while the warming in winter and spring has led to an increasing trend of wildfires in the study area.
作者
郑昕馨
孙楠
罗凡
ZHENG Xinxin;SUN Nan;LUO Fan(School of Earth Science and Resources,Chang'an University,Xi'an 710054,Shaanxi;Shaanxi Provincial Key Laboratory of Early Life and Environment,Northwest University,Xi'an 710069,Shaanxi)
出处
《第四纪研究》
CAS
CSCD
北大核心
2024年第1期191-200,共10页
Quaternary Sciences
基金
国家自然科学基金项目(批准号:42372215)
陕西省自然科学基金面上项目(批准号:2022JM-170)
长安大学中央高校基本科研业务费专项项目(批准号:300102271402)共同资助。
关键词
MODIS
黄土高原
气候变化
活跃火
时空特征
Modis
the Loess Plateau
climate change
active fire
spatial-temporal feature
