DOI: 10.5061/dryad.fn2z34v57
title: An annually resolved 5700-years storm archive reveals drivers of Caribbean cyclone frequency

description: Predictions of tropical cyclone (TC) frequencies are hampered by
 insufficient knowledge of their natural variability in the past. A
 30-m-long sediment core from the Great Blue Hole, a marine sinkhole
 offshore Belize, provides the longest available, continuous and
 annually-resolved TC-frequency record. This record expands our
 understanding, derived from instrumental monitoring (73-years), historical
 documentations (173-years) and paleotempestological records (2000-years),
 to the past 5700 years. A total of 694 event-layers were identified. They
 display a distinct regional trend of increasing storminess in the
 south-western Caribbean, which follows an orbitally-driven shift in the
 Intertropical Convergence Zone. Superimposed short-term variations match
 Holocene climate intervals and originate from solar irradiance-controlled
 sea-surface temperature anomalies and climate phenomena modes. A 21st
 century extrapolation suggests an unprecedented increase in TC-frequency,
 attributable to the Industrial Era-warming.
description: # An annually resolved 5700-years storm archive reveals drivers of
 Caribbean cyclone frequency
 [https://doi.org/10.5061/dryad.fn2z34v57](https://doi.org/10.5061/dryad.fn2z34v57) ## Description of the data and file structure This supplementary dataset, integral to our research paper, contains all the raw data for understanding the key findings of our study. It includes: a historical record calibration (Table S1.), a stratigraphic and chronological correlation of event-layers in different Great Blue Hole cores (Table S2.), radiocarbon ages and **δ**13C values (Table S3.), quantitative textural analyses of 694 event-layer and 125 fair-weather samples (Table S4.), fine material analyses (Table S5.), correlation tests (Table S.6), XRF data (Table S7.), gray scale measurements (Table S9.) and event-layer counts in binned 50- and 100-years counting intervals (Table S9.). All the diffrent raw data promote transparency and allow varied data processing and re-analysis methods. ### Files and variables #### File: Table\_S1.xlsx **Description:** Table S1. (A) Historical record of tropical cyclones (TC) passing the Great Blue Hole within a 100-200 km radius, back to 1864 CE. TCs colored in red did not leave a visible event-layer in the sinkhole´s sediment succession. Measurements of event-layer thickness (cm), amount of coarse fraction &gt;63 μm (%) and mean grain size (μm) are, therefore, not applicable ("n/a") for these storms. No storm data (cells marked with "-") can be provided for three event-layers dated to the years 1913 CE, 1962 CE and 1965 CE, because the respective event-layer could not be attributed to a specific storm system of the historical record. (b) Site-specific sensitivity evaluation for a Holocene storm activity reconstruction. (c) (d) (e) Potential proxies for past storm intensity: correlation tests between textural data (event-layer thickness, amount of coarse fraction &gt;63 μm and mean grain size) and storm intensity parameters (wind speed, storm duration and distance). #### File: Table\_S2.xlsx **Description:** Table S2. Stratigraphic and chronological correlation of event-layers found in cores BH8 (this project) and BH6/7 (previous project) (*34*) using the open-source application Corelyzer v.2.2.1. The initial dating of event-layers (EL), found in core BH6/7, was age-corrected by correlating them to numbered Els, visible in core BH8. Event-layers that occur only in core BH6/7, but not in BH8, are marked as "n/a" (terminology of BH8 not applicable) in the column "BH8 (EL numbering)".  #### File: Table\_S3.xlsx **Description:** Table S3. Radiocarbon (14C) ages and δ13C values derived by Accelerator Mass Spectrometry (AMS) at Beta Analytic Inc., Miami, Florida, calibrated into calendar years before present (cal years BP) and compared to the varve ages of the dated sediments. #### File: Table\_S4.xlsx **Description:** Table S4.  Quantitative textural analysis (coarse fraction abundances &lt;63 μm and &gt;63 μm) of (A) 694 event-layer samples including their core depth (cm) and ages (CE/BCE and a BP). Please note that two event-layers (EL358 and EL397) cover a total of three additional table lines, as the corresponding tempestites extend through the core catchers (cc) of core segments number 9 and 10. (b) Similar quantitative textural analyses of 125 fair-weather samples. Red colored fair-weather samples in column "F" are disturbed or affected by erosion, while green colored samples are completely undisturbed or pristine. A determination of textural cut-offs (gf = coarse fraction; gs = grain size) for the undisturbed fair-weather samples (highlighted with the yellow colored cells) of units C, B and A, are included in columns "K/L" and "M/N" respectively. (c) Core depth (cm) and ages (a BP) of varved core sections, with an expected 5% error (*30*), and minimum and maximum ranges, were used to create Fig. 2. #### File: Table\_S5.xlsx **Description:** Table S5.  Fine material analyses were performed with a laser-optical particle analyzer (HORIBA Laser Particle Analyser-950). All visible event-layers (n = 32) from the historical record were analyzed and presented with absolute weights in grams (A) and relative abundances in percent (b). Fine materials of 32 additional samples (n = 28 fair-weather and n = 4 event-layers) were measured discretely across the core BH8 and presented with absolute weights in grams (c) and relative abundances in percent (d). #### File: Table\_S6.xlsx **Description:** Table S6.  Correlation tests between mean grain-size values, obtained from the 64 laser-optical particle analyzer measurements, and amounts of coarse fractions, received from the initial sieving tests (A-f). The mean grain-size values of all event-layers of core BH8 and discretely taken fair-weather samples (green coloration = undisturbed) were inferred by using the linear equation (y = 2.6664 x amount of coarse fraction %) from the calibration step (b), considering event-layer and fair-weather samples together. Data in bold are measured values (sieving test) and data in regular writings are calculated from the linear equation (g). #### File: Table\_S7.xlsx **Description:** Table S7.  (A) XRF raw data with focus on Strontium (Sr) and Calcium (Ca) contents (cps). The Sr/Ca ratio was calculated at 0.2 cm intervals for sediment core BH8. Subdivision into (b) event-layer (EL) and (c) annual-layers/fair-weather sediments (AL) with regard to a calculation of geochemical thresholds (highlighted with the yellow colored cells) for units C, B and A and all individual core segments. #### File: Table\_S8.xlsx **Description:** Table S8.  (A)Optical gray scale value raw data processed in a profile by using the open source image processing software ImageJ v.1.53t. Gray-scale values were automatically recorded at 0.20-0.40 mm intervals through the sediment core BH8. Subdivision into (b) event-layer (EL) and (c) annual-layers/fair-weather sediments (AL) with regard to a calculation of optical thresholds (highlighted with the yellow colored cells) for units C, B and A and all individual core segments. #### File: Table\_S9.xlsx **Description:** Table S9.  Raw data for the reconstruction of tropical cyclone (TC) frequency, separated in (A) 100-, and (b) 50-years counting windows. The first binned interval (22 BP) encompasses the period from 2022 CE (year of coring the sediment core BH8) to 2000 CE. The following intervals are consecutive 100- and 50-years observational windows considering varve ages before present, respectively. TC-frequency plots (bar charts) with site-specific thresholds (horizontal red line), standard deviations (horizontal dashed red lines) and LOWESS smoothed curves (blue line) are included. ## Code/software Microsoft Excel or a similar programme is required to open the provided raw data.