Title:Closing the global mean sea level rise budget

Time: 14:00-15:00, May 21st, 2013 (Tuesday)

Location: Big conf.room, 3rd floor

Speaker: Jianli Chen

Center for Space Research, University of Texas at Austin

Abstract:

Changes in global mean sea level reflect mainly the sum of three contributions: water mass changes in the ocean basins, steric (ocean density) changes, and variable ocean basin volumes due to post-glacial rebound and other influences. Closing the global sea level budget implies reconciling these various observations and estimates, and has been a challenging topic. Here we show that the closure of sea level rise budget can be achieved by reducing leakage into the oceans of terrestrial signals in GRACE data. The study covers the period 2005-2011 when Argo float coverage is reasonably global. Argo data indicate a steric sea level rise of 0.60 ± 0.27 mm/yr in this period. A new mass estimate from GRACE is 1.80 ± 0.47 mm/yr, with the majority (1.73 ± 0.28 mm/yr) from polar ice sheets and mountain glaciers melting. The sum of steric and mass effects in this period is 2.40 ± 0.54 mm/yr, which agrees very well with satellite altimeter rate of 2.39 ± 0.48 mm/yr. The significantly larger influence of melting ice sheets and mountain glaciers on observed sea level rise (~75%) is contrary to previous IPCC assessments, but consistent with widely reported accelerated ice meltings in recent years.