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Fair weather and storm sand transport on the Long Island, New York, inner shelf
Author(s) -
LAVELLE J. W.,
SWIFT D. J. P.,
GADD P. E.,
STUBBLEFIELD W. L.,
CASE F. N.,
BRASHEAR H. R.,
HAFF K. W.
Publication year - 1978
Publication title -
sedimentology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.494
H-Index - 108
eISSN - 1365-3091
pISSN - 0037-0746
DOI - 10.1111/j.1365-3091.1978.tb00331.x
Subject(s) - geology , storm , plume , advection , oceanography , tracer , current (fluid) , winter storm , flux (metallurgy) , sediment transport , current meter , sediment , hydrology (agriculture) , atmospheric sciences , geomorphology , meteorology , physics , materials science , geotechnical engineering , nuclear physics , metallurgy , thermodynamics
Both spring‐summer and fall‐winter sand transport have been observed on the Long Island, New York, inner shelf at water depths of 20‐22 m using a radio‐isotope sand tracer system. The extent of dispersal of the tagged, fine sand was measured at 3 week intervals in two 70 day experiments. In the late spring and early summer, movement was primarily diffusive in nature, extending 100 m around the line of tracer injection, while late fall‐winter patterns had strong advective features, including an ellipsoidal outline extending approximately 1500 m westward of the injection points after the passage of several storms with strong northeasterly winds. Near‐bottom current observations made with Savonius rotor sensors identify the event responsible for the bulk of the transport over the 135 day observation period as a storm flow of 2 days duration. Tracer and current observations together suggest that westward winter storm flow along the Long Island shelf is the major mechanism of sand transport at these depths on a yearly time scale. A least‐squares fit of several of the observed winter patterns with a plume model yields average sediment mass flux lower bounds of 3.2 × 10 −3 gm/cm/sec and 1.7 × 10 −1 gm/cm/sec for ‘typical’ and extreme winter storm activity.