Why the sea is boiling hot: global warming and sea level rise
James Carton(1) and Semyon Grodsky(1)
University of Maryland,
Computer and Space Sciences Bldg,
College Park 20742,
In the first part of this study we use a global data assimilation reanalysis (SODA 1.4) to examine the relative contributions of steric and eustatic components of sea level rise. The work is motivated by recent altimeter observations indicating an increase in the rate of sea level rise during the past decade to 3.2mm/yr, well above the centennial estimate of 1.5-2mm/yr. Dynamic height calculated relative to 1000m from the SODA1.4 reanalysis, used as a proxy for the steric component of sea level, is compared with satellite-derived sea level for the years 1993-2004. The similarity of the rate of increase in the thermosteric contribution to sea level rise to the altimeter sea level record, as well as the similarity of its spatial structure suggests that the recent acceleration in sea level rise is explainable to within the error estimates by fluctuations in warming and thermal expansion of the oceans. Experiments with the data assimilation analysis explore these error bounds.
In the second part of this study we compare the rate of heating required to explain the trend in steric sea level with estimates of global heating as indicated by satellite radiances in order to investigate the sources of the implied thermal imbalance.