Mapping of a Mid-depth Salinity Maximum Intrusion south of New England in June 2021

This dataset contains data from a process-oriented research cruise aboard the R/V Neil Armstrong from June 18th to July 2nd. The goal of this cruise was to map the three-dimensional structure of a mid-depth salinity maximum intrusion of warm salinity slope water extending onto the continental shelf south of New England. This was done through the use of Autonomous Underwater Vehicles (two REMUS 100 vehicles and one Tethys class AUV (Long Range AUV or LRAUV)), a towed Rockland Scientific Vertical Microstructure Profiler (VMP 250), and ship-board CTD and ADCP measurements. More details about the processing, data coverage, and usage can be found in the accompanying manuscript. This cruise took place on the shelf waters south of Cape Cod, MA, extending to the shelf break, with all of the data collected between 40°N to 41°N and 71.5°W to 70°W. Attached is a data map showing the location of all data included within this dataset.  

File Descriptions: 

Datamap.jpg 

A map of the locations of all data included within this dataset. 

CTD_summer2021.mat  

This file contains profiles from the ship-board CTD (SeaBird 911+). Raw data was processed and gridded into 1 decibar bins using standard procedures in  Seasave V 7.26.7.121 (Look at cnv file header for details about processing). This file is organized as a structure, with each variable in the data being a different field called by dot notation and each row with the structure being a different CTD profile. Biooptical variables are not quality-controlled.  

• CTD.time: the time of each profile in the MATLAB datetime format (from the processed SeaBird header file) in GMT 

• CTD.lon: degrees longitude of the profile (from the processed SeaBird header file) 

• CTD.lat: degrees latitude of the profile (from the processed SeaBird header file) 

• CTD.pres: the pressure in decibar at each location of the profile  

• CTD.sal: the seawater practical salinity in psu  

• CTD.temp: the seawater in-situ temperature in °C  

• CTD.flor: seawater fluorescence in mg/ m3 

• CTD.depth: depth at each location within the profile in meters 

• CTD.density: sigmatheta (the potential seawater density with respect to a reference pressure of 0 db) in kg.m3 minus 1,000kg/m3 

CTD_Darter_MMMdd.mat and CTD_Edgar_MMMdd.mat 

These files contain the data from the REMUS 100 missions, with Darter and Edgar being the two different REMUS 100 vehicles.  

• Conductivity: conductivity in mS/cm  

• Depth: depth in meters 

• Latitude: degrees latitude  

• Longitude: degrees longitude 

• Mission_number: the number of the REMUS mission 

• Mission_time: time during the mission in seconds since midnight in GMT  

• Salinity: the seawater practical salinity in psu  

• Sound_speed: the sound speed in m/s  

• Temperature: the seawater temperature in °C 

LRAUV_20210623T194917.mat and LRAUV_20210624T145829.mat 

These files contain data from the Tethys Class LRAUV (Long Range AUV) missions. Each file contains 10 structure variables.  

• CTD_Seabird: structure containing the bin median temperature in °C and salinity in PSU.  

• depth: the depth at each data point in meters.   

• fix_residual_percent_distance_traveled: underwater dead-reckoned navigation error (based on GPS fix when on surface) as a percentage of distance traveled 

• latitude: Latitude at each data point (not corrected for vehicle drift in underwater current)  

• latitude_fix: latitude of GPS fix (vehicle surfaced) 

• longitude: Longitude at each data point (not corrected for vehicle drift in underwater current) 

• longitude_fix: longitude of GPS fix (vehicle surfaced) 

• platform_battery_charge: The battery charge in ampere-hour  

• time_fix: time in seconds since January 1, 1970 (epoch time) 

VMPtransact_YYYYMMdd.mat

Vertical Microstructure Profiler (Rockland Scientific VMP 250) 

These files contain the processed data for each Vertical Microstructure Profiler (Rockland Scientific VMP 250) transect, consisting of multiple profiles. Data has been gridded on a 1 decibar equidistant grid using standard procedures in Rockland Scientific’s processing software. Note: Bio-optical variables and dissipation rates have not been quality-controlled.  

• Time: Time in MATLAB datenum format (days since 0000-00-00 00:00:00) in GMT 

• z: Pressure in decibar 

• T: in-situ temperature in degC 

• cnd: conductivity in mS/cm  

• Chl: Chlorophyll from fluorescence in mg/ m3 

• turb: Turbidity in NTU 

• eps: dissipation rate inferred from microstructure shear in m^2/s^3. (Note: Dissipation estimates come from standard fitting of microstructure data within a 1 decibar bin to a turbulence spectrum within Rockland Scientific’s standard processing. The dissipation data in the provided files has not been quality-controlled. 

 VMP-data was georeferenced by comparing the time stamps of VMP and processed ADCP files.  

ADCP_ar50_wh300.mat 

This file contains the data from the shipboard ADCP (Teledyne WH300 kHz). ADCP data was processed aboard using standard procedures in UHDAS/CODAS (University of Hawaii Technical Services Program, servicing UNOLS vessels (https://currents.soest.hawaii.edu/docs/adcp_doc/index.html). Vertical bin size is 2 m. u: zonal (positive towards east) velocity component in m/s 

• v: meridional (positive towards north) component in m/s   

• txy: time, longitude, and latitude of the velocity profiles. Time is in decimal days, with noon of Jan 1 being 0.5 decimal days and noon of January 20th being 19.5 decimal days of the reference year. For another example, 6am on June 18, 2021, is decimal day 168.25. All times are in GMT.    

• refyear: The reference year from which the decimal days are calculated. 

• depth: vertical coordinate of the velocity bin center     

• pgood: percent good, a quality parameter showing the fraction of good pings within an ensemble average. 

• spd_u: zonal ship speed in m/s 

• spd_v: meridional ship speed in m/s 

• tr_temp: ADCP transducer temperature in deg C 

• amp: backscatter amplitude in relative units