Abstract:
The 2015 Karenia brevis bloom was compared to the 2007 Florida Panhandle Karenia brevis bloom, which showed a westward advection pattern, but did not intensify along the Mississippi coast. Two different regional applications of NCOM-Navy Coastal Ocean Model (1-km resolution NCOM-GoM/Gulf of Mexico and 6-km resolution NCOM-IASNFS/Intra Americas Sea Nowcast Forecast System) were used to understand the circulation and transport pathways. A built-in particle trace function in IDL™ (Interactive Data Language) was used to track the passive movement of particles released inside the delineation of the first satellite bloom observation of each year (17 September 2007, 23 September 2015). Particles were allowed to move until the last satellite observation of the bloom (17 November 2007, 19 December 2015). A second set of particles was released when the bloom was near Alabama (6 October 2007, 12 November 2015). All particles were released at 2-m depth to avoid instability in surface current vectors. The particles were tracked in two-dimensions without vertical advection or diffusion. This dataset is in support of the publication: Soto, I. M., Cambazoglu, M. K., Boyette, A. D., Broussard, K., Sheehan, D., Howden, S. D., Shiller, A. M., Dzwonkowski, B., Hode, L., Fitzpatrick, P. J., Arnone, R. A., Mickle, P. F., & Cressman, K. (2018). Advection of Karenia brevis blooms from the Florida Panhandle towards Mississippi coastal waters. Harmful Algae, 72, 46–64. doi:10.1016/j.hal.2017.12.008
Suggested Citation:
Soto Ramos, Inia. 2018. Lagrangian particles used to model Karenia brevis blooms in the northern Gulf of Mexico during fall 2007 and 2015. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7TQ603Q
Data Parameters and Units:
This dataset contains 4 Lagrangian particle simulation (4 folders) with 8-11 particles each. The track for each particle was saved in a *.dat file with Longitude (decimal degrees) and Latitude (decimal degrees). The filename includes the start and end time of the particle simulation, the particle number (PN) and the depth it was released (Particle_MMDDYYYYTHH_to_ MMDDYYYYTHH_PN_2m.dat).
Methods:
Ocean current components (u, v) from a regional application of the Navy Coastal Ocean Model (NCOM) for the GoM at 1-km resolution and from the Intra-Americas Sea Nowcast Forecast System (IASNFS) at 6-km resolution were used to understand circulation and transport pathways during the blooms of 2015 and 2007, respectively. Both model domains covered the entire GoM, with IASNFS additionally covering the Florida Straits, the Caribbean Sea, and parts of the Western North Atlantic Ocean . A higher temporal and spatial model resolution for 2007 is not available for the study region. Regardless of the lower resolution of the NCOM-IASNFS, this is still a reliable source to approximate the major circulation patterns in the GoM during this time frame. Model predictions were 24-h moving averaged to eliminate the tidal signal and these daily averages were used for the analysis. The NCOM model data for Fall 2015 is in dataset R4.x260.000:0064. The IASNFS data can be found in https://www.northerngulfinstitute.org/edac/oceanNomads/IASNFS.php. A built-in particle trace function in IDL™ (Interactive Data Language) was used to track the passive movement of particles released inside the delineation of the first satellite bloom observation of each year (17 September 2007, 23 September 2015). Particles were allowed to move until the last satellite observation of the bloom (17 November 2007, 19 December 2015). A second set of particles was released when the bloom was near Alabama (6 October 2007, 12 November 2015). All particles were released at 2-m depth to avoid instability in surface current vectors. The particles were tracked in two-dimensions without vertical advection or diffusion. The IDL particle trace function delineated the path of massless particles through a vector field at given locations (seed points). The integration parameter in IDL was set to a 4th order Runge-Kutta scheme, and the step size was three hours for NCOM-GoM and six hours for NCOM-IASNFS.
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