Geophysical Research Letters Paper


A 2004 paper in Geophysical Research Letters examines observations of terrestrial precipitation from the latter half of the 20th century with precipitation simulated by the DOE-sponsored climate model, the Parallel Climate Model (PCM) with an aim to determine which external forcings of climate have had a detectable influence on precipitation. Consistent with a previous study using another model, it is found that the global mean response to all forcings combined, was significantly correlated with the observed precipitation. 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 (e.g., solar radiation) exert a larger influence on precipitation than longwave forcings (e.g., greenhouse agents). Mike Wehner of LBNL is one of the co-authors of the paper.


Gillett, P., A.J. Weaver, F.W. Zwiers, and M.F. Wehner. 2004. Geophys. Res. Lett. 31, L 12217, DOI:10.1029/20044GL020044(2004)