Depth-dependent temperature change contributions to global mean thermosteric sea level rise from 1960 to 2010

Abstract

The dependency of global mean thermosteric sea level changes to temperature at different depths down to 700m is investigated from 1960 to 2010 using two separate gridded temperature datasets, and compared with reconstructed estimates of sea level change. The rates of thermosteric sea level changes are closely correlated with those of reconstructed sea level changes with correlation coefficients larger than 0.8, but the former has smaller amplitudes than the latter, indicating contributions to total sea level change from processes other than upper ocean temperature changes examined here. Most of the net thermosteric sea level rise (~92%) can be attributed to temperature changes of the upper ocean (0–300m), but an intriguing temporal lag is found between thermal anomalies of the upper (0–300m) and lower (300–700m) layers in the historical temperature datasets, suggestive of a time-lag associated with heat penetrating from the surface into deeper layers of the ocean. Results of global mean thermosteric sea level estimates from the two different temperature datasets are found to be consistent with each other in time and in depth.