基于GEE平台的钱江源国家公园森林火灾动态变化研究

Research on Dynamic Changes of Forest Fires in Qianjiangyuan National Parks Based from GEE Platform

  • 摘要: 以钱江源国家公园试点区及其周围10 km缓冲区为研究区域,基于GEE云平台、Landsat卫星影像以及卫星林火监测数据,结合目视解译与光谱指数法快速提取过火区域,并统计火灾发生时间、频率和过火面积的变化规律,使用景观指数描述过火区域的空间模式。结果表明:1999—2019年,研究区共发生19起森林火灾,其中春季和冬季森林火灾高发,分别占火灾总数的47.37%和42.11%;2013年平均单次森林火灾覆盖范围最广(83.54 hm2),2011年发生森林火灾次数最多(6次),过火区域的面积差异较大,而2014年和2019年仅各发生1次火灾;研究区过火区域面积共计约为766.55 hm2,在研究期间呈现先增加后减少的趋势。钱江源国家公园范围内过火面积仅为9.05 hm2(2011年和2014年分别为9.04 hm2和0.01 hm2)。本研究方法适用于借助免费历史Landsat数据快速获取30 m分辨率尺度的火灾信息,建立空间明确的灾情历史数据档案,及时、客观地评估国家公园灾害管理成效。

     

    Abstract: Taking the Qianjiangyuan National Park Pilot Area and the surrounding 10 km wide buffer zone as our research case, based on the Google Earth Engine(GEE) cloud platform, Landsat satellite imagery, and remote sensing based forest fire monitoring data, visual interpretation combined with spectral index method was implemented to extract the burned scars quickly. Then the extracted forest fires were statistically analyzed in terms of fire occurrence time, frequency, and burned area. In addition, several landscape indices were calculated to describe the spatial pattern of the burned scars. The results showed that during the period 1999 to 2019, 19 forest fires occurred in the study area, of which forest fires occurred in spring and winter seasons accounting for 47.37% and 42.11% of the fires, respectively. The biggest forest fire, with a size of 83.54 hm2, was observed in 2013, while the highest occurrence frequency of forest fires(6 times) was discovered in 2011, and their burned areas differed largely. In contrast, there was only one fire each in 2014 and 2019. The total burned area was approximately 766.55 hm2 during the study period, and there was a trend of increasing first and then decreasing in the study period. Besides, the burned area within Qianjiangyuan National Park was 9.05 hm2(9.04 hm2 and 0.01 hm2 in 2011 and 2014 respectively). The proposed method in the current work is suitable for quickly obtaining 30 m resolution scale post-fire information by means of free historical Landsat data, establishing a spatially explicit historical archive of disastrous events, and evaluating the effectiveness of disaster management for the national park timely and objectively.

     

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