Detection of volcanic influence on global precipitation

Observations of terrestrial precipitation from the latter half of the 20th century are compared with precipitation simulated by the Parallel Climate Model to determine which external forcings have had a detectable influence on precipitation. Consistent with a previous study using another model, we found that the global mean response to all forcings combined was significantly correlated with that observed. A detection and attribution analysis applied to the simulated and observed precipitation indicated that the volcanic signal is detectable both on its own and in a multiple regression with other forcings. These results are consistent with the hypothesis that shortwave forcings exert a larger influence on precipitation than longwave forcings.