Extreme value theory for precipitation: sensitivity analysis for climate change

Extreme value theory for the maximum of a time series of daily precipitatio n amount is described. A chain-dependent process is assumed as a stochastic model for daily precipitation, with the intensity distribution being the g amma. To examine how the effective return period for extreme high precipita tion amounts would change as the parameters of the chain-dependent process change (i.e., probability of a wet day, shape and scale parameters of the g amma distribution), a sensitivity analysis is performed. This sensitivity a nalysis is guided by some results from statistical downscaling that relate patterns in large-scale atmospheric circulation to local precipitation, pro viding a physically plausible range of changes in the parameters. For the p articular location considered in the example, the effective return period i s most sensitive to the scale parameter of the intensity distribution. (C) 1999 Elsevier Science Ltd. All rights reserved.