Alexander J. Wright

Sea-level variability in the northwest Atlantic during the past 1500 years: A delayed response to solar forcing?

[1] Numerical experiments with a coupled oceanatmosphere model (ECBilt) have shown that centennial variations in sea level (SL) in the northwest Atlantic may be associated with deep-ocean salinity anomalies generated by solar-forced variations in the North Atlantic overturning circulation. Here we compare simulated SL curves for the Gulf Stream region with reconstructed, late-Holocene SL records from Connecticut (USA). Simulated SL variations lag the solar forcing record by ca. 120 year. This lag is found to be robust over a small number of different experiments. The reconstructed SL curves visually match the solar forcing optimally when lagging it by ca. 125 yr. A quantitative test shows that the correlation is significant, while this result is not sensitive to dating uncertainties. The temporal response pattern of the simulated SL curves compares reasonably well with the reconstructions. INDEX TERMS: 4556 Oceanography: Physical: Sea level variations; 1650 Global Change: Solar variability; 4255 Oceanography: General: Numerical modeling; 4267 Oceanography: General: Paleoceanography; 3030 Marine Geology and Geophysics: Micropaleontology. Citation: van de Plassche, O., G. van der Schrier, S. L. Weber, W. R. Gehrels, and A. J. Wright, Sea-level variability in the northwest Atlantic during the past 1500 years: A delayed response to solar forcing?, Geophys. Res. Lett., 30(18), 1921, doi:10.1029/ 2003GL017558, 2003.

ON THE EROSIVE TRAIL OF A 14TH AND 15TH CENTURY HURRICANE IN CONNECTICUT (USA) SALT MARSHES

This paper examines if an erosive hiatus found in the peat stratigraphy and marsh-accumulation record from northwest Hammock River Marsh (HRM), Connecticut (CT) can be attributed to a 14th or a 15th century hurricane, each documented by a radiocarbon-dated overwash fan in Succotash Marsh (SM) (Rhode Island) about 90 km to the east. Given that (i) the best estimate age range for the 15th century overwash deposit in SM (1400-1440 cal AD, 2 sigma ) overlaps entirely with that for first plant growth after erosion at HRM (1390-1450 cal AD, 2 sigma ), while the best estimate age range for the 14th century overwash deposit (1290-1410 cal AD, 2 sigma ) overlaps just 10 yr, and (ii) interpretation of the available stratigraphic and sedimentary evidence from HRM suggests that a high-energy event offers the simplest explanation for the observed marsh erosion, we conclude that a plausible link exists between the 15th century hurricane and the marsh erosion in HRM. The best estimate age range for the 14th century hurricane appears to overlap for 91% with the age range for the first plant growth (1290-1400 cal AD, 2 sigma ) following marsh erosion in East River Marsh (CT), located about 12 km west of HRM. These results imply that erosive boundaries in salt-marsh peat deposits have potential as markers of past hurricane activity.