Climate Variability, Volcanic Forcing, and Last Millennium Hydroclimate Extremes
Overpeck, Jonathan T.
AffiliationUniv Arizona, Dept Geosci
MetadataShow full item record
PublisherAMER METEOROLOGICAL SOC
CitationStevenson, S., J.T. Overpeck, J. Fasullo, S. Coats, L. Parsons, B. Otto-Bliesner, T. Ault, G. Loope, and J. Cole, 2018: Climate Variability, Volcanic Forcing, and Last Millennium Hydroclimate Extremes. J. Climate, 31, 4309–4327, https://doi.org/10.1175/JCLI-D-17-0407.1
JournalJOURNAL OF CLIMATE
Rights© 2018 American Meteorological Society.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractMultidecadal hydroclimate variability has been expressed as "megadroughts" (dry periods more severe and prolonged than observed over the twentieth century) and corresponding "megapluvial" wet periods in many regions around the world. The risk of such events is strongly affected by modes of coupled atmosphere-ocean variability and by external impacts on climate. Accurately assessing the mechanisms for these interactions is difficult, since it requires large ensembles of millennial simulations as well as long proxy time series. Here, the Community Earth System Model (CESM) Last Millennium Ensemble is used to examine statistical associations among megaevents, coupled climate modes, and forcing from major volcanic eruptions. El Nino-Southern Oscillation (ENSO) strongly affects hydroclimate extremes: larger ENSO amplitude reduces megadrought risk and persistence in the southwestern United States, the Sahel, monsoon Asia, and Australia, with corresponding increases in Mexico and the Amazon. The Atlantic multidecadal oscillation (AMO) also alters megadrought risk, primarily in the Caribbean and the Amazon. Volcanic influences are felt primarily through enhancing AMO amplitude, as well as alterations in the structure of both ENSO and AMO teleconnections, which lead to differing manifestations of megadrought. These results indicate that characterizing hydroclimate variability requires an improved understanding of both volcanic climate impacts and variations in ENSO/AMO teleconnections.
Note6 month embargo; published online: 3 May 2018
VersionFinal published version
SponsorsNSF EaSM Grants [AGS-1243125, NCAR-1243107]; National Science Foundation; Office of Science (Biological and Environmental Research program) of the U.S. Department of Energy