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A 2200-Year Storm History from North Carolina's Barrier Islands
Mallinson, D.J., Smith, C.W., Mahan, S., Culver, S.J. and McDowell, K. 2011. Barrier island response to late Holocene climate events, North Carolina, USA. Quaternary Research 76: 46-57.

The authors write that "the Outer Banks barrier islands of North Carolina, USA, contain a geologic record of inlet activity that extends from ca. 2200 cal yr BP to the present," which they say "can be used as a proxy for storm activity."

What was done
Working with 27 vibracores obtained between 2004 and 2006 on Hatteras and Ocracoke islands at selected sites to target specific ground penetrating radar reflections and facies defined in Mallinson et al. (2010), as well as several additional vibracores on the Hatteras Flats during 2008 to target seismic facies, Mallinson et al. employed optically stimulated luminescence (OSL) dating of inlet-fill and flood tide delta deposits, recognized in cores and geophysical data, to provide a "basis for understanding the chronology of storm impacts and comparison to other paleoclimate proxy data."

What was learned
The five U.S. researchers say their comparisons suggest that "the Medieval Warm Period (MWP) and Little Ice Age (LIA) were both characterized by elevated storm conditions as indicated by much greater inlet activity relative to today," and they say that "given present understanding of atmospheric circulation patterns and sea-surface temperatures during the MWP and LIA, we suggest that increased inlet activity during the MWP responded to intensified hurricane impacts, while elevated inlet activity during the LIA was in response to increased nor'easter activity."

What it means
Mallinson et al. conclude that their data indicate that relative to climatic conditions of both the Medieval Warm Period and Little Ice Age, there has more recently been "a general decrease in storminess at mid-latitudes in the North Atlantic," reflecting "more stable climate conditions, fewer storm impacts (both hurricane and nor'easter), and a decrease in the average wind intensity and wave energy field in the mid-latitudes of the North Atlantic," which further suggests that the mean temperature of the past century or more has likely been neither as cold nor as warm as it was during comparable periods of the LIA and MWP, respectively.

Mallinson, D.J., Smith, C.W., Culver, S.J., Riggs, S.R. and Ames, D. 2010. Geological characteristics and spatial distribution of paleo-inlet channels beneath the Outer Banks barrier islands, North Carolina, USA. Estuarine, Coastal and Shelf Science 88: 175-189.

Reviewed 24 August 2011