Abstract:

This dataset contains CTD data collected from the R/V Point Sur during September 2016 GoMix I cruise (PS17_06, cruise DOI https://doi.org/10.7284/909424). The experimental site is on the continental slope of the northern Gulf of Mexico, next to the Deepwater Horizon Spill site. During the cruise, there were 3 meridional and 18 zonal sections of CTD tow-yo's. For each tow-yo, 8 to 46 vertical profiles were collected depending on the time length of the tow-yo. The rest were CTD stations. The CTD used was a SEA-BIRD 911plus/917plus double sensor. The high-resolution data are available both in ASCII format and Matlab format. 1-m bin averaged files are created separately to generate the bin-averaged profiles and saved as Matlab files.

Suggested Citation:

Kurt Polzin, Zhankun Wang, Steve DiMarco. 2020. Oceanographic profiles from CTD casts and tow-yos collected from the R/V Point Sur during GoMix I cruise (PS17_06) in the northern Gulf of Mexico from 2016-09-19 to 2016-09-27. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-zkef-0305

Purpose:

Data was collected in support of studies of GoMix project with the goal of understanding the mechanisms, spatial inhomogeneity and temporal intermittency of boundary mixing along the Northern Deepwater Gulf.

Data Parameters and Units:

GoMix1_CTD_1m_bin_mat files: latitude, longitude, temperature [Celcius], temperature2 [Celsius], salinity [], salinity2 [], pressure [dBar], beam attenuation [m^-1], CDOM [mg m^-3], dissolved oxygen [umol l^-1], dissolved oxygen2 [umol l^-1], chlorophyll fluorescence [mg m^-3], sigmat [kg m^-3], sigmat2 [kg m^-3], altimeter [m], descent rate [m], absolute salinity [g kg^-1], absolute salinity2 [g kg^-1], depth_bins [m], qc_mask [], qc2_mask []. GoMix1_CTD_high_resolution_mat files: time elapsed [sec], latitude, longitude, pressure [dBar], depth [m], temperature [Celsius], temperature2 [Celsius], conductivity[uS cm^-1], conductivity2[uS cm^-1], salinity [], salinity2 [], dissolved oxygen [umol l^-1], dissolved oxygen2 [umol l^-1], chlorophyll fluorescence [mg m^-3], CDOM [mg m^-3], beam attenuation [m^-1], absolute salinity [g kg^-1], absolute salinity2 [g kg^-1], sigmat [kg m^-3], sigmat2 [kg m^-3], altimeter [m], potential temperature [Celsius], potential temperature2 [Celsius], descent rate [m]. GoMix1_CTD_raw_cnv files: time elapsed [sec], latitude, longitude, altimeter [m], beam attenuation [m^-1], beam transmission [%], conductivity [uS cm^-1], conductivity2 [uS cm^-1], CDOM [mg m^-3], chlorophyll_a [mg m^-3], nitrogen saturation [ml l^-1], dissolved oxygen [umol l^-1], dissolved oxygen2 [umol l^-1], pressure [dBar], temperature [Celsius], temperature2 [Celsius], salinity [], salinity2 [], sigmat [kg m^-3], sigmat2 [kg m^-3], depth [m], descent rate [m], geopotential anomaly [J kg^-1], potential temperature [Celsius], potential temperature2 [Celsius], absolute salinity[g kg^-1], absolute salinity2 [g kg^-1], density [kg m^-3], density2 [kg m^-3], flag[].

Methods:

Data from the CTD were acquired at 24 Hz. The CTD data were acquired by an SBE Model 11 plus CTD Deck Unit, providing demodulated data to a computer in the engineering room running SeaBird software. After the cruise, the raw CTD data were run through the SeaBird data conversion software (SeaBird, Version 7.25.0.151). Data Conversion performs the first step in data processing, converting the raw CTD and auxiliary sensor data (typically frequencies and voltages) to engineering units. Data Conversion uses the instrument configuration file, which defines sensors, sensor channels, and calibration coefficients, to convert raw data to engineering units. The conductivity was advanced approximately 0.073 seconds relative to pressure for CTD alignment. No low pass filter was applied to the data to reserve the high-resolution signals. The practical salinity was calculated using DERIVE sal.cfg and the absolute salinity, density and potential temperature were calculated using DERIVE EOS80.

Instruments:

SEA-BIRD 911plus CTD, SEA-BIRD 917plus CTD.

Individual Files: