Place: 4274 Chamberlin Hall (Refreshments will be served)
Speaker: Steve Vavrus, UW Department of Atmospheric and Oceanic Sciences
Abstract: Anecdotal evidence suggests an increasing occurrence of extreme weather in recent years, but a major impediment to identifying and quantifying trends is the absence of a common measuring stick. Many definitions of extreme weather exist, but they are often haphazard and not comparable to one other for quantifying the aggregate behavior of extremes. To help remedy this problem, I created a simple, non-parametric index of extreme weather based on the combined percentile rankings of temperature and precipitation (at monthly or longer timescales). This integrated index reveals that extreme weather has indeed been unusually pronounced in recent years in Madison and across Wisconsin. However, the reasons for the high index values vary considerably by location. The temporal and spatial variations of extreme weather in Wisconsin and elsewhere are probably a combination of chaotic weather processes and emerging anthropogenic climate change.