Spatio-temporal variation in dry season determines the Amazonian fire calendar
Spatio-temporal variation in dry season determines the Amazonian fire calendar
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DOI：
10.1088/1748-9326/ac3aa3
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发表时间：
2021-11
影响因子：
6.7
通讯作者：
N. Carvalho;L. Anderson;C. A. Nunes;A. Pessôa;C. H. L. Silva Junior;J. D. Reis;Y. Shimabukuro;E. Berenguer;J. Barlow;L. Aragão
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作者：
N. Carvalho;L. Anderson;C. A. Nunes;A. Pessôa;C. H. L. Silva Junior;J. D. Reis;Y. Shimabukuro;E. Berenguer;J. Barlow;L. Aragão
火灾是威胁亚马逊的主要人为因素之一。尽管降雨和火灾之间有着明确的联系，但在亚马逊地区，人们对这些变量之间的时空关系仍然知之甚少。在这里，我们分层亚马逊流域根据旱季开始/结束，并调查其与火灾的时空变化的关系。我们使用了2003年至2019年活跃火灾的月度时间序列来描述全年的火灾动态，并确定火灾高峰月份。年平均活跃火灾中有50%以上（32246起）发生在高峰月份。在52%的细胞中，峰值发生在8月至9月之间，48%发生在8月至3月之间，表现出与旱季时空变化相关的明确的季节模式。火灾高峰发生在旱季的最后两个月，67%的细胞和20%的雨季的第一个月。旱季越短，活跃火灾的发生越集中在高峰月份，旱季在1至3个月之间的细胞中占70%以上。我们通过确定连续几个月集中了一年中至少80%的活跃火灾来定义关键火灾期。这一时期包括西北部1月至3月的两到三个月，在遥远的北方，它持续了七个月，在3月至4月结束。在南部，从8月开始，持续时间为2至3个月不等。在东北部，这是三到四个月，在八月到十二月之间。通过量化旱季在推动亚马逊流域火灾季节性方面的作用，我们提供了监测火灾动态的建议，这些建议可以支持决策者制定管理政策和措施，以避免对环境或社会有害的火灾。
Fire is one of the main anthropogenic drivers that threatens the Amazon. Despite the clear link between rainfall and fire, the spatial and temporal relationship between these variables is still poorly understood in the Amazon. Here, we stratified the Amazon basin according to the dry season onset/end and investigated its relationship with the spatio-temporal variation of fire. We used monthly time series of active fires from 2003 to 2019 to characterize the fire dynamics throughout the year and to identify the fire peak months. More than 50% (32 246) of the annual mean active fires occurred in the peak month. In 52% of the cells, the peaks occurred between August–September and in 48% between October–March, showing well-defined seasonal patterns related to spatio-temporal variation of the dry season. Fire peaks occurred in the last two months of the dry season in 67% of the cells and in 20% in the first month of the rainy season. The shorter the dry season, the more concentrated was the occurrence of active fires in the peak month, with a predominance above 70% in cells with a dry season between one and three months. We defined a Critical Fire Period by identifying the consecutive months that concentrated at least 80% of active fires in the year. This period included two to three months between January and March in the northwest, and in the far north it lasted up to seven months, ending in March–April. In the south, it varied between two and three months, starting in August. In the northeast, it was three to four months, between August and December. By quantifying the role of the dry season in driving fire seasonality across the Amazon basin, we provide recommendations to monitor fire dynamics that can support decision makers in management policies and measures to avoid environmentally or socially harmful fires.