Re-analysis of Tropical Storm and Hurricane Probabilities of Occurrence for Coastal Areas of the United States, Canada, and Bermuda for 1851 to 2017

Authors: Richard C Daniels*, Washington State Department of Transportation
Topics: Coastal and Marine, Climatology and Meteorology, Global Change
Keywords: Hurricane, Tropical Cyclone, Coastal, Hazards
Session Type: Guided Poster
Day: 4/6/2019
Start / End Time: 9:55 AM / 11:35 AM
Room: Roosevelt 3.5, Marriott, Exhibition Level
Presentation File: Download


In 1990-1997 the U.S. Global Change Research Program sponsored the creation of several data sets to document past and current climate conditions; among these was an analysis of “Storm Occurrences and other Climate Phenomena Affecting Coastal Zones” (1991). The “Storm Occurrences” dataset included a tropical cyclone probability of occurrence analysis for 1 by 1 degree latitude, longitude cells for the Atlantic Hurricane Basin based on data from 1899 to 1989 for the United States, Canada, and Bermuda. In this study, tropical cyclone probabilities of occurrence for the Gulf of Mexico and Atlantic seaboard were recalculated using the National Hurricane Center's (NHC's) North Atlantic hurricane database, version 2. I compared the new data with the old to determine if there was a statistically significant change in the probabilities of tropical cyclones. Hurricane probabilities were calculated for three 55 year periods (1851-1906, 1907-1962, 1963-2017) and the original reference period. Tropical/subtropical storm probabilities were recalculated for 1899-1989 as well. For the reference period a R2 of 0.76 (mean difference +1.4%) for hurricanes and a R2 of 0.71 (+2.24%) for tropical storms/subtropical storms was found. The populations for these two data sets were NOT significantly different at the 99% confidence interval. Any visible variation in frequencies between the two data sets was attributable to modifications in the source data. For the three 55-year hurricane periods a weak correlation was found (<0.44). On the Gulf and East coast hurricane activity increased by 0.8% from the 1851-1906 to 1907-1962 and by 0.9% from 1907-1962 to 1963-2017.

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