Evaluating the impacts of climate change on rainfall extremes for Hawaii and coastal Alaska

This paper will specifically address the calculation of trends in, and climate change impacts on, extreme rainfall events and their return periods using daily and monthly station data from across Hawaii and for coastal areas of Alaska. Rainfall return periods were determined using Generalized Extreme Value (GEV) analysis, which relies on annual maximum series of rainfall observations. Early results suggest that the frequency of heavy rain events is increasing across the Hawaiian Islands and coastal Alaska. If current climate change scenarios are taken into account, as we will demonstrate through the application of different climate change indices – the so-called “Frich” indices (Frich et al. 2002), preliminary results indicate that extreme rainfall episodes are likely to increase. We will present these results and discuss climate change related trends in rainfall extremes using the daily and monthly rainfall indices. In addition, we will offer examples of “event anatomies” pertaining to extreme rainfall events in Hawaii, to demonstrate the application of this research for use by emergency managers, coastal managers, and the public.

Reference:

Frich, P., L.V. Alexander, P. Della-Marta, B. Gleason, M. Haylock, A.M.G. Kleintank and T. Peterson, 2002: Observed coherent changes in climatic extremes during the 2nd half of the 20th century. Climate Research, 19, 193-212.