Abstract:

This dataset consists of hydrographic and current velocity data collected at the Fisheries Oceanography in Coastal Alabama (FOCAL) Mooring from 2016-06-21 to 2016-08-19. This data was collected at the FOCAL mooring which is a small coastal ocean observing system 25 kilometers southwest of the mouth of Mobile Bay, Alabama (30.0902 N, 88.2116 W) operated by the Dauphin Island Sea Lab (DISL). Hydrographic data was obtained using a thermistor chain with five Sea-Bird Scientific SBE 56 temperature loggers at 6, 9, 11, 14, and 16 m from the surface and a near-surface (4.7m depth) CTD (Sea-Bird Scientific MicroCAT) sampling every 20 minutes. The current velocity data was collected using an RDI 600‐kHz which sampled every 20 minutes between 2 and 18 m from the surface. The ADCP also collected CTD data 0.5 m above the seafloor. 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. The overarching goal of the proposed research was to identify and determine the kinematic and dynamic transport processes that govern the distribution, dispersion, dilution, and fate of oil-derived substances in Alabama coastal waters. As such, the project examined the flow field characteristics on the Alabama shelf from both the Eulerian perspective. This dataset supports the publication: Coogan, J., Dzwonkowski, B., & Lehrter, J. (2019). Effects of Coastal Upwelling and Downwelling on Hydrographic Variability and Dissolved Oxygen in Mobile Bay. Journal of Geophysical Research: Oceans. doi:10.1029/2018jc014592

Suggested Citation:

Brian Dzwonkowski, Mimi Tzeng, and Grant Lockridge. 2019. Dataset for: Effects of Coastal Upwelling and Downwelling on Hydrographic Variability and Dissolved Oxygen in Mobile Bay. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-s40s-3785

Publications:

Coogan, J., Dzwonkowski, B., & Lehrter, J. (2019). Effects of Coastal Upwelling and Downwelling on Hydrographic Variability and Dissolved Oxygen in Mobile Bay. Journal of Geophysical Research: Oceans. doi:10.1029/2018jc014592

Purpose:

The objective of this ongoing research is to monitor the physical structure of the coastal ocean. The FOCAL mooring 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:

CTD data (20160621_20160819_SURF_13408_dv.dat and 20160621_20160819_BOT_3662_dv.dat; MicroCAT at a relative depth of 5m and ADCP CTD at 0.5 m from the bottom which is approximately 19m): n (count number), jday (Julian day beginning January 1, 2016, as day 0), T (temperature, degrees C), s (salinity, ppt), den (density, kg/m3), depth (m), month, day, hour, minute, seconds. Thermistors at relative depth of 9m (20160621_20160819_NT2_5153.dat, 11m (20160621_20160819_NT3_5182.dat), 14m (20160621_20160819_T4_1561.dat), and 16m (20160621_20160819_NT5_5126.dat): n (count number), jday (Julian day beginning January 1, 2016, as day 0), T (temperature, degrees C), month, day, hour, minute, seconds. Organized temperature files (20160621_20160819_alltemp.dat): n (count number), y (year, YYYY), m (month, MM), d (day, DD), hour (h, hh), mn (minute, mm), s (seconds, ss), jday (Julian day beginning January 1, 2016, as day 0), temperature (degrees C) for stations sur (surface, 5m), T01 (6m, thermistor not working), T02 (9m), T03 (11m), T04 (14m), 3ma (17m, thermistor not working), T05 (16m) and bot (bottom, 19m). Note there maybe be small-time drifter (~30-60min of the 2-month deployment) in one of the thermistors (file: 20160621_20160819_T4_1561.dat). Processed ADCP file (FOCAL_adcp_20160621_2016081, raw data in 21JUN000.000): n (sample number), bin, y (year, YYYY), m (month, MM), d(day, DD), h (hour, hh), min (minute, mm), t_day (Julien day, CDT), tdep (total depth, m), dep (bin depth), u (east/west horizontal velocity, cm/s), v (north/south horizontal velocity, cm/s), spd (speed, cm/s), dir (direction, degrees), ECMP (data flag), Interpolated (if interpolated). Note: NO compass correction has been made. Raw RDI ADCP files (21JUN000.000) Need 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. Sensor position on the FOCAL mooring line: CTD (13408) surface: 4.6 m, NT2(5153): 9.5m, NT3 (5182): 11.3 m, T4 (1561): 13.7 m, NT5 (5126): 15.5 m, CTD bottom (3662): 20.0 m. Water column depth: 20m. All data was collected at the DISL station (30°05.410'N, 88°12.694'W).

Methods:

The thermistors sample once per minute and are averaged every 20 minutes. The ADCP does a 5-minute burst sample (5-minute average) every 20 minutes. The CTD samples once per minute and are averaged every 20 minutes. General site details and sampling information can be found in Tzeng et al., (2016).

Instruments:

The instruments used are SBE 39 Thermister, SBE 37 CTD, and an RDI 600 kHz ADCP Workhorse Sentinel (upward looking on the bottom).

Error Analysis:

See Seabird Electronics technical reports.

Provenance and Historical References:

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 Other data supporting the associated publication (Coogan et al., 2019) are publicly available at NOAA's National Centers for Environmental Information (NCEI) under NCEI Accession numbers 0176497, 0188979, and 0190491 as mentioned below: Coogan, Jeffrey; Dzwonkowski, Brian (2018). Water temperature, salinity, and dissolved oxygen from CTD taken from small boat Pelagia in the Mobile Bay from 2016-07-14 to 2016-07-30 (NCEI Accession 0176497, https://accession.nodc.noaa.gov/0176497). Coogan, Jeffrey; Dzwonkowski, Brian (2019). Salinity, dissolved oxygen, water temperature, and pressure data collected from moored CTDs in Mobile Bay from 2016-07-12 to 2016-08-02 (NCEI Accession 0188979, https://accession.nodc.noaa.gov/0188979). Mortazavi, Behzad; Krause, Jeffrey (2019). Water quality data collected during 3 CTD surveys from a small boat in Mobile Bay from 2016-07-11 to 2016-07-19 (NCEI Accession 0190491, https://accession.nodc.noaa.gov/0190491).

Individual Files: