Velocity and Transport Characteristics of the Louisiana-Texas Coastal Current
Abstract
The Louisiana-Texas Coastal Current (LTCC) is a major dynamic feature responsible for the distribution of fresh water, sediment and nutrients on the northwestern shelf of the Gulf of Mexico. Earlier studies have indicated that this current exhibits a distinct although asymmetric annual cycle during which it flows downcoast, i.e., westward along the Louisiana coast and then southward along the Texas coast in fall, winter, and spring; however, in summer, the flow reverses and moves upcoast. This annual cycle of the LTCC is clearly observed with measurements from a cross-shore current meter mooring array located south of Cameron, LA in 1996 and 1997. Analyses of these data show that the currents are indeed downcoast between September 1996 and January 1997 with modest mean velocities up to 6 cm/s. During the expected upcoast regime of June-August 1996, our data show mean eastward speeds of 2-6cm/s. Cross-shelf spatial correlation length scales of the currents are well in excess of 60km during the downcoast regime but they are distinctly smaller (30-5O km) during the upcoast regime. Coherence analysis and predictions from a wind-driven model indicate that the downcoast currents and volume transport associated with them are highly coherent with alongshore wind stress. This wind stress also controls fluctuations of the upcoast currents and transport; however, it is not a dominant forcing. The data indicate that during the analyzed summer season, the alongshore sea-surface slope was also an important driving force of the LTCC.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2005
- Accession Number
- ADA448949
Entities
People
- Ewa Jarosz
- Stephen P. Murray
Organizations
- United States Naval Research Laboratory