Observation of atmospheric and climate dynamics from a high resolution ice core record of a passive tracer over the last glaciation

Abstract

Here we present a temporal analysis of diluted calcium from the Greenland Ice Core Project Summit ice core over a length corresponding to the duration of the last glacial period (92–8 ka). Our analysis suggests that this signal can be split into two distinct temporal components whose dynamics are characterized by respective timescale regimes. Timescales longer than approximately 200 years show a strong negative correlation with the temperature proxy δ18O signal. This we interpret as a result of the temperature dependence of processes governing source area efficiency. At faster timescales, ≤200 years, correlation with the temperature proxy is significantly weakened, while its variability or mean absolute deviation is negatively correlated with the δ18O; this we believe is a sign of the turbulent nature or “storminess” of the atmosphere during the glacial climate. Furthermore, this component of the signal displays intermittency and multifractality supporting our interpretation of an observation of atmospheric dynamics. This then provides a signal of atmospheric and climate dynamics back to 92 ka.