Tropical cyclone frequency inferred from intra-annual density fluctuations in longleaf pine

Authors: Tyler Mitchell*, UNC-Greensboro, Paul A. Knapp, UNC-Greensboro
Topics: Climatology and Meteorology, Field Methods
Keywords: climatology, paleoclimatology, dendrochronology
Session Type: Poster
Day: 4/5/2019
Start / End Time: 3:05 PM / 4:45 PM
Room: Lincoln 2, Marriott, Exhibition Level
Presentation File: No File Uploaded

Here 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 L+ IADFs in longleaf pine latewood 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 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.