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Please join us as we welcome Dr. Sarah Purkey from the Lamont-Doherty Earth Observatory of Columbia University for her seminar titled "Regional and global rates of ocean mass addition between 1996-2006 from a full-depth sea level rise budget".  Refreshments will be served.

Abstract

Over the past three decades the deep ocean has warmed and freshened, possibly linked to a slowdown in the bottom limb of the Meridional Overturning Circulation.  These deep steric changes are an important contributor to current sea level rise (SLR) rates but are often either ignored or left as an error in most SLR budgets.  Here, I present a full-depth SLR budget using full-depth in-situ ocean data and satellite altimetry centered between 1996 and 2006.  The SLR rates for this period are compared to regional and global trends in ocean mass addition estimated directly using data from the Gravity Recovery and Climate Experiment (GRACE) from 2003–2013.  Despite the different time periods and spatial coverage reflected in the two independent methods, both capture the same large scale mass addition trend patterns and suggest a global mean trend of ocean mass of 1.5 (±0.4) mm yr-1.  Further analysis with the residual method shows the error introduced into the mass budget if the deep steric contributions below 700, 1000, 2000, 3000, and 4000 m are neglected are 65%, 38%, 13%, 8% and 4% respectively.  These findings reinforce that the deep ocean can not be ignored in regional and global SLR budgets.