Variability and predictability of sea-level extremes in the Hawaiian and U.S.-Trust Islands-a knowledge base for coastal hazards management

摘要

The objective of this study is to provide an improved climatology of sea level extremes on seasonal and long-term time scales for Hawaii and the U.S-Trust islands.Observations revealed that the Hawaiian and U.S.-Trust islands,by and large,display a strong annual cycle.For estimating the statistics of return period,the three-parameter generalized extreme value(GEV)distribution is fitted using the method of L-moments.In the context of extremes(20-to 100-year return periods),the deviations in most of the Hawaiian Islands(except at Nawiliwili and Hilo)displayed a moderate sea-level rise(i.e.,close to 200 mm),but the deviations in the U.S.-Trust islands displayed a considerably higher rise(i.e.,more than 300 mm)in some seasons due to typhoon-related storm surges.This rise may cause damage to roads,harbors,and unstable sandy beaches.Correlations between the El Nino-Southern Oscillation(ENSO)climate cycle and the variability of seasonal sea level have been investigated.Results show that correlation for the station located west of the International Date Line(DL)is strong,but it is moderate or even weaker for stations east of the DL.The skill of SST-based Canonical Correlation Analyses(CCA)forecasts was found to be weak to moderate(0.4-0.6 for Honolulu,Kahului,Hilo,and Wake,and 0.3 or below for Kahului,Mokuoloe,and Johnston).Finally,these findings are synthesized for evaluating the potential implications of sea level variability in these islands.