Acycle: Time-series analysis software for paleoclimate research and education

Abstract

Recognition and interpretation of paleoclimate signals in sedimentary proxy datasets are time consuming and subjective. Acycle is a comprehensive and easy-to-use software package for time series analysis in paleoclimate research and education. It is designed to speed paleoclimate time series analysis, especially cyclostratigraphy, and to provide objective methods for estimating astrochronology. Acycle provides for detrending with multiple options to track and remove secular trends. A selection of power spectral analysis methodologies is offered for the detection of periodic signals. Many of the functions are specific to cyclostratigraphy and astrochronology that are not found in standard statistical packages. A specialized function is provided to assess the astronomical (Milankovitch) forcing of paleoclimate series and search for the most likely sedimentation rate by evaluating the correlation coefficient between power spectra of an astronomical solution and sedimentary proxy data. Sedimentary noise modeling (for past sea-level changes) is also provided in Acycle. As an example, Acycle is applied to a sedimentary proxy series from the cyclostratigraphy of the Paleocene-Eocene thermal maximum (PETM) in Core BH9/05 from the Paleogene Central Basin, Svalbard. Acycle detects significant astronomical forcing in the proxy series and relatively stable sedimentation rates during and after the PETM. Acycle runs in the MATLAB environment or as stand-alone software on Windows and Macintosh OS X, and is open-source software.