CoAuthors

R. S. Nerem (CU Boulder, United States)

The altimeter record has revealed with unprecedented accuracy the character of sea level rise over the past 30 years, including its regional structures and temporal variability. Like all satellite records however, its brevity makes it susceptible to transient effects, particularly at its endpoints. One major such event is the June 1991 eruption of Mt Pinatubo, which occurred just prior to the launch of TOPEX/Poseidon in Aug 1992 and had a significant impact on flows of energy and moisture through the climate system.

Here, using two ensembles produced with the Community Earth System Model (CESM), the effects of the eruption on both global and regional sea level rise are documented. It is found that while the eruption initially suppressed sea level, mainly through its cooling of the oceans, it led to a more rapid rate of rise over the subsequent decade as the ocean, atmosphere, and land recovered from the eruption's effects. The global-scale responses of the eruption are well captured by both CESM ensembles and quantifed, allowing for their removal from the altimetry record in order to isolate anthropogenic effects. In addition, a regional response pattern in sea level is simulated by both CESM ensembles. Significantly greater model dependence is identified for the pattern of response however and while some features are common to both, other features are model dependent. The net effect of the eruption on regional sea level trends and implications for interpreting the observed trend map are identified and discussed.