Speaker: Toby Ault from Cornell University
Title: “A robust null hypothesis for the potential causes of mega drought in western North America.”
Abstract: Multidecadal megadroughts in western North America are periods of aridity as severe as the worst droughts of the 20th century, but much longer lasting. Here the statistics of these events are evaluated against the null hypothesis that they occur as a result of stochastic forcing with stationary noise statistics over a sufficiently long time period. A linear inverse model is used to generate the null distribution of this hypothesis based on late 20th century global sea surface temperature variability and western US hydroclimate. The null hypothesis cannot be rejected for any reconstructed value of widespread western US drought, meaning that megadroughts do not require exotic climate patterns or external forcings to occur.