ABSTRACT: We present a new method for identifying historic tropical cyclone activity utilizing frequencies of intra-annual density fluctuations in longleaf pine in western Florida. In addition, in this work we provide information about the causal factors that determine the formation of intra-annual density fluctuations (IADFs) in longleaf pine latewood. Specifically, we test the viability of using late latewood (L+) IADFs in longleaf pine as a proxy for historic tropical cyclone frequency and precipitation for the period 1950-2017. The stabilized frequency of L+ IADF occurrence is significantly (p < 0.01) associated with the Palmer drought severity index (PDSI) for the months June through October, indicating that high amounts of late growing-season moisture promote the formation of IADFs in latewood. We find the strongest relationships between PDSI and IADF occurrence during September and October, indicating the influence of tropical cyclone (TC)-sourced precipitation on IADF formation. High IADF stabilized frequencies (i.e. >0.50) nearly always (88%) coincide with a TC tracking into the study area, and we find a significant (p < 0.01) relationship between TC-sourced precipitation and the stabilized frequency of L+ IADFs. Via this relationship, reconstruction of historic tropical cyclone frequency and precipitation is probable, which would allow for increased understanding of historic tropical cyclone activity prior to the historic climate record.

中文翻译：

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由美国佛罗里达长叶松的年内密度波动推断热带气旋频率

摘要：我们提出了一种利用佛罗里达州西部长叶松树年内密度波动频率确定历史热带气旋活动的新方法。此外，在这项工作中，我们提供了有关决定长叶松木晚年木材年密度波动（IADF）形成的因果信息。具体来说，我们测试了在长叶松树中使用晚木（L +）IADF作为1950-2017年期间历史性热带气旋频率和降水的代理的可行性。L + IADF发生的稳定频率与6月至10月的Palmer干旱严重程度指数（PDSI）显着相关（p <0.01），这表明大量的生长季后期水分促进了IADF在晚材中的形成。我们发现9月和10月PDSI与IADF发生之间最强的关系，表明热带气旋（TC）来源的降水对IADF形成的影响。高IADF稳定频率（即> 0.50）几乎总是与TC跟踪进入研究区域相一致（88％），并且我们发现TC降水与L + IADF稳定频率之间存在显着（p <0.01）关系。通过这种关系，有可能重建历史性热带气旋的频率和降水，这将有助于在历史气候记录之前对历史性热带气旋活动有更多的了解。50）几乎总是（88％）与TC跟踪进入研究区域一致，并且我们发现TC来源的降水与L + IADF的稳定频率之间存在显着（p <0.01）关系。通过这种关系，有可能重建历史性热带气旋的频率和降水，这将有助于在历史气候记录之前加深对历史性热带气旋活动的了解。50）几乎总是（88％）与TC跟踪进入研究区域一致，并且我们发现TC来源的降水与L + IADF的稳定频率之间存在显着（p <0.01）关系。通过这种关系，有可能重建历史性热带气旋的频率和降水，这将有助于在历史气候记录之前对历史性热带气旋活动有更多的了解。