林火在空间上的波动性及其对全球变化的响应(Ⅰ)

研究表明,林火在时间方向具有一定的周期性,表现为一定频率的火周期。该文应用黑龙江省1980～1999年林火数据,分别计算出每年火灾发生的火点的质心经纬度坐标和火场面积质心的经纬度坐标,用波谱分析研究其质心随年份的波动现象。结果表明,1980-1999年的黑龙江省林火的火场质心分别是以东经126.97°,北纬49.63°为轴作东西、南北波动,波动具有明显的同期性,经度方向和纬度方向的周期均为3.3a,其东西南北波动的最大最小值分别为东经128.68°,北纬52.82°,东经123.08°,北纬46.86°。火点的质心分别以东经127.90°,北纬48.69°为轴作东西、南北方向的波动,波动不具有明显的周期性,其东西南北波动的最大最小值分别为东经129.22°,北纬50.37°,东经125.18°,北纬47.28°。

Spatial Fluctuation of Forest Fires and Their Response to Global Change

Forest fires have circles and frequency in time. This paper utilizes the historical forest fires data (1980-1999) in Heilongjiang province, and calculates the centroids of annual fire points and annual fire scars, the coordinates of centroids are denoted in geographic coordinates. We study the fluctuation of the centroids using spectrum analysis method. Results show: the centroids of forest fires scars fluctuate along the axis of East Longitude 126.97°and North Latitude 49.63°, and the fluctuation has clear circle. The circles along Longitude and latitude are both 3.3a. The extreme values in East, West, South and North are 128.68°E, 52.82°N, 123.08°E, 46.86°N respectively. The centroids of forest fires points fluctuate along the axis of East Longitude 127.90°and North Latitude 48.69°, and the fluctuation has no clear circle. The extreme values in East, West, South and North are 129.22°E,50.37°N,125.18°E,47.28°N respectively.