Study on Spatio-temporal Distribution and Heterogeneity of Climate Forces of Wildfires in Panxi Region

According to the data of wildfires and meteorological data in Panxi region from 2004 to 2020, this study firstly explored the spatial-temporal pattern of wildfires in Panxi region from temporal variation, spatial distribution, and distribution pattern of the main climate driving factors. Meanwhile, the spatial and temporal correlation between wildfires and meteorological factors in Panxi was studied by using ArcGIS grid method and bivariate spatial auto correlation analysis method. The result were as follow: From 2004 to 2020, the number of wildfires in Panxi region showed an increasing trend. From 2004 to 2014, the number of fires and the burned area fluctuated and increased. From 2015 to 2020, the number of fires decreased significantly, but the burned area showed an increasing trend. From the perspective of spatial distribution, the wildfire in the Panxi area mainly occurred in the valley basins and hilly areas, and are mostly concentrated on the edge of the hills. Panzhihua City was an area with frequent wildfires, followed by Liangshan Prefecture. From the perspective of time series correlation, there were differences in the responses of different levels of wildfires to meteorological factors in different periods. The highest temperature and precipitation in the fire danger period, relative humidity, and the number of consecutive days without precipitation were significantly correlated with the number of wildfires. The number of consecutive days without precipitation and average wind speed in the non-fire danger period were significantly correlated with the number of wildfires. There were also differences between meteorological elements and monthly lag of wildfires. Climate factors had a lag effect on the occurrence of wildfires in Panxi. Temperature and precipitation in early stage affected the occurrence of wildfires by affecting the ground fuel, and continuous drought was very likely to trigger fire. From the spatial correlation, the High−High value of wildfire frequency, air temperature, evaporation and continuous days without rain were mainly distributed in the valley basin and hilly region of Panxi region. The Low−Low value of precipitation, relative humidity and wildfire were distributed in the western Panxi, while the Low−High values were in the northern mountain plain region. The Low−High value of mean wind speed, scPDSI and wildfire were distributed in the western, while the Low−Low value were distributed in northeastern mountain plain. The high temperature and drought in valley basin and hilly area in Panxi region made wildfire showed aggregation effect. However, in the southern mountain area of Panxi region, due to the high altitude, there were few artificial activities and few fire sources. Although it was a high-temperature arid area, there was no wildfire aggregation effect.