Speaker: Dr. Ichiro Fukumori, California Institute of Technology/Jet Propulsion Laboratory 

Title: "Deducing Causal Mechanisms of Sea Level Change in the Beaufort Sea"

Abstract: Over the last two decades, sea level across the arctic’s Beaufort Sea has been rising an order of magnitude faster than its global mean. This rapid regional sea level rise is mainly a halosteric change, reflecting an increase in freshwater content comparable to the Great Salinity Anomaly. Here we provide a new perspective of these variations using a global data-constrained ocean and sea ice model of the Estimating the Circulation and Climate of the Ocean (ECCO) consortium. Causal relationships are quantified using the model’s adjoint and controlling processes are identified analyzing property budgets.

The study reveals wind stress and sea ice melt jointly driving the multi-decadal variation. Strengthening anticyclonic winds surrounding the Beaufort Sea intensify lateral Ekman convergence of relatively fresh near-surface water. The strengthening winds also enhance convergence of sea ice and ocean heat that increase the region’s sea ice melt. A growing disparity between where sea ice forms and where it melts results in this rare example of melting floating ice causing large-scale sea level rise.

ECCO is implementing a novel “point-and-click” interface for analyzing its model, including its adjoint such as conducted here. We encourage and invite exploration of these tools which will be demoed.