Survey data for coastal current in northern Gulf of Mexico, Mar. 2021
Document Type
Data Set
Publication Date
8-2022
Abstract
ADCP data in netCDF format were obtained on R/V Pelican along a 30-km transect in coastal Louisiana. The ensemble average intervals were 2-min. The survey was done March 3-5, 2021.
DOI
10.31390/oceanography_coastal_wavcis.04
Recommended Citation
Li, C. (2022). Survey data for coastal current in northern Gulf of Mexico, Mar. 2021. https://doi.org/10.31390/oceanography_coastal_wavcis.04
wh1200.nc (2015 kB)
COinS
Comments
This specific dataset was published in:
Li, C., A. Sheremet, W. Huang, P. Dash, A. Katkar, M. N. Allahdadi, N. Chaichitehrani, C. M. Bachmann, V. H. Rivera-Monroy, "Dynamic impact of transiting weather systems on coastal currents in the northern Gulf of Mexico", Deep Sea Research Part II: Topical Studies in Oceanography, Volume 216, 2024, 105395, DOI: https://doi.org/10.1016/j.dsr2.2024.105395.
Abstract:
Moving weather systems determine the history of wind variations with patterns as the systems transit through the ocean. These weather systems are integrated entities that can provide a system level perspective. A vessel-based survey repeatedly occupying a 30-km transect 12 times in 36 h provided non-aliased measurements of velocity field that showed how the along-shelf transport varied by more than three-fold in response to a transiting high-pressure weather system following an atmospheric cold front. To further illustrate the impact of different weather systems, we analyzed time series data from moored ADCPs, which showed influence on the velocity field from infrequent summertime cold fronts and remote hurricanes moving through the region, one on the west and the other on the east of the study site. Rotary spectrum analysis showed that the flow field rotated mostly clockwise with a smaller but non-negligible counterclockwise component, consistent with near inertial oscillations mixed with weak tidal currents. A theoretical model is presented by a Laplace transform and a general relationship between the velocity field and forcing functions is obtained, which shows that the contributions to the rotary velocity field from various forcing functions are through mathematical convolutions between the forcing functions and the complex frictional-rotary inertial function (CFRIF). These convolutions include an integrated effect of history of the forcing. CFRIF is effectively a frictional rotary filter that favors inertial oscillations. The wind-stress induced velocity field over a few days is computed and it shows significant variations after the passage of a cold front, with a magnitude consistent with observations. The wind-stress induced velocity is a few times greater than the density driven flow during the ship-based observations. The weather systems passing through the region can impact coastal currents causing a great variability over short time scales.
Keywords: Coastal current; Weather systems; Gulf of Mexico; Vessel-based measurements; Laplace transform; Rotary filter