Global water cycle ‘events’ and global mass redistribution at interannual to decadal time-scales

Global mean sea level (GMSL) exhibits an average secular increasing trend of 3.1 +/- 0.3 mm yr-1 over the last 30 years [NOAA, 2023]. However, more than 43% of the variability in the de-trended global satellite sea level record occurs on 2-3 year time scales in rapid global water cycle ‘events’, during which GMSL can rise or fall at more than twice the ambient secular rate, causing changes as large as 12 mm over a relatively short period. This means that rapid changes in the natural movement of water from the oceans to the land, which appear on the continents as strong mass-change hydrologic signals, can be of sufficient amplitude to offset (i.e. equal and opposite) the mass additions to the oceans from the ice sheets over 2-3 year periods, or to offset those contributions by as much as 50% over a decade. In this talk, we examine the long GRACE/GFO record of global mass budget closure to better characterize the history of these global water cycle events, describe their apparent nature, and quantify their future potential impact on apparent GMSL.