¥Time series of annual counts or exceedences
–E.g., number of exceedence above 90th percentile
¥Some studies use thresholds as high as 99.7th percentile
¥Coupled with simple trend analysis techniques or
standard detection and attribution methods
–Detected anthropogenic influence in observed
surface temperature indices
–Perfect and imperfect model studies of
potential to detect anthropogenic influence in temperature and
precipitation extremes
¥Statistical issues include
–̉resolutionÓ of observational data
–adaptation of threshold to base period
–use of simple analysis techniques that
implicitly assume data are Gaussian