Noble gas evidence of a millennial-scale deep North Pacific palaeo-barometric anomaly

Precise measurements of dissolved noble gases along the GP15 GEOTRACES Pacific Meridional Transect reveal the oldest northern bottom waters equilibrated with the atmosphere at a higher barometric pressure than more recent waters. Here, using a radiocarbon-calibrated multi-tracer-based diagnostic model, we reconstruct the magnitude and timing of this palaeo-barometric pressure anomaly. We hypothesize this multi-millennial trend in sea-level pressure results from local and regional processes extant in Antarctic Bottom Water formation regions. Noble gas concentrations in the deep North Pacific indicate that sea-level pressure in Antarctic Bottom Water formation regions has changed over the past 2,000 years.