Introduction

The glider project at Stony Brook University grew out of the New York Department of Conservation's need to understand and monitor the New York Bight and its long-term health and productivity.  As a result, the School of Marine and Atmospheric Sciences at Stony Brook University developed a ten year program to measure the hydrography, chemistry and fishery biomass from seasonal cruises on the RV Seawolf and ~30 day ocean glider cruises covering the New York Bight area.  Subsequently, a collaborative program between Rutgers, Stony Brook and the University of Maine was proposed to NOAA to use the gliders that were being deployed in the Middle Atlantic Shelf and the Gulf of Maine to monitor ocean acidification in the area.  The ocean acidification monitoring makes use of a new pH sensor developed by Sea Bird Electronics, in collaboration with Grace Saba's group at Rutgers, that can be mounted on the gliders.  This new sensor has been added to the Stony Brook glider with its first cruise starting February, 2021.

The SoMAS ocean glider operation is intended to provide long term and seasonal data of the basic physical conditions in the New York Bight as part of the New York DEC's ocean monitoring effort.  The glider, SBU01, is a Webb Research Slocum G3 shallow water unit, maximum depth is 350m, equipped with the standard suite of sensors measuring temperature, conductivity, pressure, dissolved oxygen, chlorophyll fluorescence and turbidity.  The intent is to deploy the glider seasonally from south of Long Island on a cruise that includes a series of transects out to the edge of the continental shelf ending up off Sandy Hook or Little Egg Inlet, New Jersey for retrieval.  The glider propels itself through a series of dives and climbs making about 20 km per day, slower in shallow water, faster in deep water with fewer dive/climb iterations.  With the rechargeable batteries in the glider, cruise duration in MAB waters is about 32 days and ~600 km.  So far, there have been six cruises in the MAB, shown below, adding more than 13,000 vertical profiles of T, S, O2, Fl and Turbidity to the database.  In January the SeaBird CTD/pH sensor was added to the glider to provide seasonal and spatial distributions of pH to assist in monitoring the impact of CO2 absorption in the ocean.

Piloting of the glider is accomplished through a two-way Iridium satellite connection initiated by the glider when it surfaces at approximately three hour intervals.  Using Webb Research supplied software, the Slocum Fleet Mission Control or SFMC, heavily decimated realtime data are sent ashore and mission modifications can be sent to the glider.  The near realtime data that have been uploaded from the glider are currently being minimally processed by Rutgers' glider group into netcdf files for each surfacing and uploaded onto NOAA's ERDDAP server accessible via https://marine.rutgers.edu/cool/data/gliders/deployments.  

Post cruise, the complete set of glider data are offloaded from the glider's memory cards and processed using a set of routines based upon those developed by John Kerfoot (Rutgers), Robert Todd (WHOI) and Ruth Curry (BIOS).  That processing system calibrates the data, does a QA/QC check on the validity of the results and stores the data in a large Matlab file.  The Matlab files are accessible through the project server.  Work is underway to convert the Matlab files to the a netcdf file format so that they can be uploaded onto NOAA's ERDDAP server.  The glider data is so voluminous that using the ERDDAP server is the only practical way of making the data available to potential users.  The conversion of our Matlab based data sets to the netcdf-based ERDDAP data sets is under way and almost complete as of June 2022.

June, 2022, Glad to report that SBU01 has finally returned from a long sojourn at Webb for calibration and checkup.  Next deployment is scheduled for mid_July.

Weather and a faulty start delayed the 7th deployment, SBU01-07,  to August 5th.  After 29.8 days and ~600km, 540km along track, the glider was retrieved off Manasquan, NJ by TowBoatUS at 0730 EDT on September 5th.  Aside from the usual sensors, CTD, pH, O2, chlorophyll and transmission, a small Vemco fish-chip receiver was mounted on top of the glider.  Battery power was an issue on this deployment and changes in sampling and surfacing were made in an effort to conserve power. 

On October 11 at 1935 GMT the glider was sent off forth on cruise SBU01-08.  Sensors included the CTD with pH, Ecopuck, DO and a small Vemco fish chip receiver mounted on top.  Here is a picture of glider ready for is first test dive.  This deployment did not end quite as expected and turned into a bit of a saga.  As the plots for SBU01-08 below show, the cruise seemed to end half-way through out at the edge of the shelf.  On October 29th we lost contact with the glider.  The sometimes happens if the glider gets swamped by a big wave but it usually calls back.  Didn't this time.  In fact we did not hear from it for days and were about to write it off.  Then on November 5th, a week after we'd lost contact, it called home ~160km southwest of where it was when last heard from.  Great excitement!  The glider then proceeded north at ~7kts.  That's not usual so clearly on a boat.  We then tracked the unit back ashore, across Delaware, into Maryland and to the backyard of Tom (Butch) Wright.  Butch and a friend were fishing over one of the canyons at the edge of the the shelf in his boat, Off Site, when they heard a thump and looked over the side and there was the glider.  The best guess is that the glider was caught in some fishing gear and it was that that got snagged on the boat's propeller.  The glider was fine.  At least no propeller marks.  One question was, why did Butch bring the glider aboard?  There is a sticker on the glider that gives the SBU contact information and also says to retrieve the glider after a certain date which is updated for each deployment.  So, thinking that this deployment should end by mid-November but thinking October, the retrieve date was written as "Oct 15".  Turns out to have been a good error because the next port of call for the glider was going to be Ireland.  So hurrah for Butch!  The glider is back at SoMAS and undergoing a "post mortem".  The next deployment is scheduled for February.

The new G3s glider arrived in late January equipped with a CTD/pH unit, a chlorophyll/turbidity sensor, a dissolved sensor and the DMON2 passive acoustic sensor to listen for whales of various kinds.  A portion of output from the DMON2 is telemetered ashore along with the other decimated sensor data.  The DMON2's internal computer makes preliminary identifications of whale calls which are then sent ashore to be assessed by Mark Baumgartner's group at WHOI.  Positive ID's of whales then are broadcast to a user group that includes the shipping industry in an effort to minimize ship strikes.

The new G3s, designated as SBU02, was deployed for the winter DEC seasonal cruise on February 22, 2023 south of Shinnecock as before.  The new glider behaved well sending data ashore.  However, currents in the MAB at this time were unusually high averaging as much as a knot to the west and southwest.  Given the glider's speed through the water of about 0.3 m/s the glider had a difficult time completing the first leg of the cruise out to the edge of the shelf.  As a result it became clear that we were not going to be able to complete the cruise track as planned and in fact were not going to able to make it as far north as the usual pickup point off Manaquan Inlet.  So the glider was diverted to an area off Atlantic City and the glider was recovered on March 18th with the help of the SeaTow group out of Atlantic City.

SBU02 was launched on April 20th south of Shinnecock for the spring DEC seasonal cruise.  The glider struggled to reach the first waypoint due to strong current from the east so the cruise plan was shortened.  The plan was shortened again on May 7th and the glider is currently heading west before turning northwest toward the recovery point.

Deployments

Useful Websites

Deployed Gliders

MARACOOS Ocean Map
    This website shows a wide range of data collected in the MAB as well as AVHRR satellite surface temperatures

ERDDAP Glider Data Portal

AIS
    This website shows the current location of all the vessels in the region and is used in piloting to minimize possible collisions with the glider

DOSITS on Passive Acoustics

Robots for Whales

NDBO Buoy 44025
    Shows data from a 3-meter discus buoy South of Long Island.
NDBO Buoy 44066
    Shows data from a 3-meter discus by Hudson Canyon