The Climatology of Land-Falling Tropical Cyclones in North Carolina

Abstract

This study documents the frequency variation of landfalling tropical cyclones (TCs) in North Carolina (NC) from 18871999. While there has been significant variability over the 113 year period, a visual inspection ofthe record suggests a strongly modulated pattern of activity with periods ranging from quiet to intense to somewhere in between. So, questions regarding multiple dominant frequencies in NC TC activity and whether or not the recent increase in the number of TCs affecting NC will continue into the next few decades are addressed in this study. Four principal modes and a residual are found in the NC landfalling TC time series. 1st mode has an inter-annual time scale of 2-7 years correlated with the Biennial Oscillation, the El NinolSouthern Oscillation (ENSO) phenomena and the inter-annual variability of precipitation in the African Western Sahel. 2nd mode has a time scale of 8-12 years correlated with the Atlantic sea surface temperature (SST) dipole pattern. 3rd mode has a time scale of 20-40 year correlated with the North Atlantic Oscillation (NAO). 4th mode has a time scale of 40-60 years positively correlated with the 40-60 year oscillation of both the tropical Pacific SST and the Western Sahel rainfall. The residual trend is bowed from ~0.9 events ~er year (ely) in the late 19 century to a low of -0.8 ely in the mid 20 century, rising slowly to about 1.0 ely presently. IAssociate Professor, Department of Marine, Earth and Atmospheric Sciences, Box 8208, North Carolina State University, Raleigh, NC 27695-8208 USA, JL;!~L.~j!-'.JL Il_<;S.l.!,.~_d\:! 2 Professor and Director External Affairs, College of Physical and Mathematical Sciences, Box 8201, North Carolina State University, Raleigh, NC 27695-8201 USA, .I~' 1.1. J~j ~'_U·~JJ~'~.(IJ_Ul_l;_0 !.!_,i:?_~l ~ 3 Assistant Professor, Ocean University, Qingdao, China