SPATIO-TEMPORAL FEATURE OF ACTIVE FIRE OCCURRENCE ON THE LOESS PLATEAU FROM 2001 TO 2020 BASED ON MODIS
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.
万方数据
维普
