Abstract:

The oceanographic community routinely collects time-series data of hydrographic properties and water current velocity of the marine environment. Such data are essential for establishing baseline characteristics of marine and estuarine ecosystems. This data from small coastal ocean observing system 25 kilometers southwest of the mouth of Mobile Bay, Alabama, that the Dauphin Island Sea Lab (DISL) has been operating. The overarching goal of the research is to identify and determine the kinematic and dynamic transport processes that govern the distribution, dispersion, dilution, and fate of oil-derived substances in Alabama's coastal waters. As such, the project examined the flow field characteristics on the Alabama shelf from the Eulerian perspective. The data were collected between 2011-01-27 and 2011-05-18. During that period, the instruments were deployed on 2011-01-27, replaced on 2011-04-13, and replaced again on 2011-05-18. The instrument data (five thermistors, two moored CTDs, and a YSI) have also been combined in a summary file. Also included are velocity data from an upward-looking and oxygen and salinity measurements from the YSI. The DISL mooring is located at 30° 05.410'N, 88° 12.694'W, in 20 m of water.

Suggested Citation:

Brian Dzwonkowski, Kyeong Park, and Mimi Tzeng. 2016. Fisheries Oceanography in Coastal Alabama (FOCAL) Mooring data, January, April, and May 2011. Distributed by: Gulf of Mexico Research Initiative Information and Data Cooperative (GRIIDC), Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N77S7KTZ

Publications:

Dzwonkowski, B., Park, K., & Collini, R. (2015). The coupled estuarine-shelf response of a river-dominated system during the transition from low to high discharge. Journal of Geophysical Research: Oceans, 120(9), 6145–6163. doi:10.1002/2015jc010714

Tzeng, M. W., Dzwonkowski, B., & Park, K. (2016). Data processing for a small-scale long-term coastal ocean observing system near Mobile Bay, Alabama. Earth and Space Science, 3(12), 510–522. doi:10.1002/2016ea000188

Purpose:

The objective of this ongoing research is to monitor the physical structure of the coastal ocean. This data is a subset of the regularly maintained FOCAL mooring. The site is the longest running time series of water column data in the Mississippi Bight and is an important asset for assessing long-term changes in the physical state of the region. Hydrographic and current velocity data from this site have been used in multiple physical and interdisciplinary studies of circulation, hydrography, and the biophysical interactions associated with the inner shelf of the Northern Gulf of Mexico.

Data Parameters and Units:

The CTD files contain: temperature, ITS-90 [deg C]; conductivity [S/m]; pressure [db]; salinity, PSS-78 [PSU]; sound velocity, Chen-Millero [m/s]; time [Julian days]; and flag [0]. NOTE: There is no data from the 15.2 mab (meters above bottom) CTD from first deployment period. Each YSI file includes: sample number; time [Julian day]; temperature [deg C]; salinity [ppt]; density [kg/m^3]; depth [m]; O2 [mg/l]; O2 saturation [%]; year [2011]; month [MM]; day [DD]; hour [HH]; and minute [MM.MM]. NOTE: DENSITY output is off by +1000 units. For example, "2026" should be "1026". Each thermistor file includes: temperature [degrees C]; date [DD mon YYYY], and time [HH:MM:SS]. Organized temperature files (20110413_20110518_alltemp.dat and 20110127_20110414_alltemp.dat) contain: n [sample number], year [y], month [m], day [d], hour [h], minute [min], second [s], Julian day [jday], surface CTD [temperature, deg C], T01 [temperature, deg C], T02 [temperature, deg C], T03 [temperature, deg C]), T04 [temperature, deg C], 3 mab YSI [temperature, deg C], T05 [temperature, deg C], and bottom CTD [temperature, deg C]. The ADCP files contain: n [sample number] , bin, y [year], m [month], d [day], h [hour], min [minute], t_day [Julian day], tdep [total dep, m], dep [bin depth, m], u [cm/s], v [cm/s], spd [speed, cm/s], dir [direction, degrees], ECMP [data flag, "...."], and Interpolated [interpolation flag, "...." no]. The raw RDI ADCP files, JAN11000.000 and APR11000.000, require RDI software to convert to human readable files. WinADCP (Teledyne, 2015) can export data from the raw file (*.000) directly to a MATLAB file without requiring additional reformatting steps.

Methods:

The thermistors sample once per minute. The ADCP does a 5-minute burst sample (5 minute average) every 20 minutes. The CTD samples once per minute. The YSI samples once every 20 minutes..

Instruments:

The instruments used are SBE39 thermistor, SBE37 CTD, YSI 6600, and an RDI 600 kHz ADCP Workhorse Sentinel (upward looking on the bottom).

Individual Files: