Elements of Sea Level in a Changing Climate. Stephen Griffies, NOAA
In this talk, we survey the physics of global and regional sea level, with a focus on how sea level has changed in the past century and may change in the future. We start by exploring global mean sea level changes arising from ocean heating (thermosteric sea level rise) and from changes to the ocean mass. Regional sea level variations can be large relative to the global mean, meaning they are a primary concern for sea level impacts. Examples of such regional variations include fluctuations due to natural modes of climate variability (e.g., Pacific Decadal Variability, North Atlantic Oscillation, Atlantic Meridional Overturning Circulation), and from mass redistributions that alter the earth’s gravity field. Scenarios for future global mean sea level changes typically include an upward trend due to ocean warming. Less certain is our ability to project changes involving ice sheets. We conclude the talk by describing a mechanism for potentially large ice sheet melt arising from projected changes in Southern Ocean winds and the associated shallowing of relatively warm coastal currents circling Antarctica.
Stephen Griffies is a senior research scientist at NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL) in Princeton, NJ. His education includes a PhD in physics, masters in applied math, and bachelors in chemical engineering. After a three-year post-doc at Princeton University’s Geosciences Program, he joined the GFDL staff in 1996. His research centers on aspects of the ocean’s role in the global climate system, both from a fundamental process perspective and large-scale climate perspective. A recent focus of his work involves the study of global and regional sea level fluctuations/trends, which forms the topic of his talk.