title: Recent and future changes in extreme rainfall in the Catskills region of New York.
abstract: Recent flooding events in the Catskills such as Tropical Storm Irene have raised concerns regarding changes in the frequency of heavy rainfall. The extreme precipitation records of four long-term observing sites are analyzed based on two measures of heavy rainfall. The number of events that produce ≥50.8 mm of precipitation per year show little evidence of an increasing trend. Rather, the climatology of Catskills stations is marked by considerable year-to-year and decade-to-decade variability. Because of this variability, a different measure of extreme precipitation, the 100-year storm, attained its highest value in the early 1960s. This was an artifact of the reliance of the analysis procedure on a relatively short record that coincided with high precipitation. Current engineering design for infrastructure affected by extreme rainfall is based on this metric. After 1960, the 100-year storm declined, until rising again after 1990. This rise is consistent with a regional trend toward higher precipitation extremes. Climate-model projections show this trend continuing at a rate of 2-3% per decade through 2069. The serendipitously high 100-year-storm value computed in 1960 may provide some buffer to the expected effects of this change in extreme rainfall in the Catskills.
authors.affiliation: Northeast Regional Climate Center, Department of Earth and Atmospheric Science, Cornell University, Ithaca, New York.
authors.forename: Arthur T
authors.initials: AT
authors.lastname: DeGaetano
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Castellano
mesh_terms: D002980:Climate; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D005544:Forecasting; D005843:Geography; D008962:Models, Theoretical; D009518:New York; D011891:Rain
keywords: climate change; extreme value analysis; flooding; precipitation