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SoMAS Ocean Glider Project Charles N. Flagg E-mail: Charles.Flagg@stonybrook.edu Maha AlNajjar E-mail: Maha.AlNajjar@stonybrook.edu Lucas Merlo E-mail: Lucas.Merlo@stonybrook.edu Jack McSweeney E-mail: Jack.Mcsweeney@stonybrook.edu |
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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. There were strong current
from the east so the cruise plan was shortened. These
conditions persisted through the cruise requiring
adjustments until the glider was retrieved off Manasquan
Inlet on May 19th with the help of TowBoatUS
The
summer DEC seasonal cruise using SBU01 started south of
Shinnecock on July 6th. Significant westward currents
as during the spring cruise necessitated a diversion toward
Atlantic City where the glider was retrieved with the help
of SeaTow Atlantic City.
On
August 3 the first of the NYSERDA launch using a Stony Brook
glider, SBU02, took place about 10 miles south of Fire
Island Inlet with the held of TowBoatUS Bayshore. This
cruise's primary purpose is to monitor marine mammal
presence in the vicinity of the planned offshore wind
farms. As a result, the cruise has a meandering path
to the southwest ending up off Little Egg Inlet/Atlantic
City where Rutgers' glider crew will retrieve it. The
glider was retrieved on August 24th.
Deployments
Useful Websites
MARACOOS
Ocean Map
This website shows a wide range of data
collected in the MAB as well as AVHRR satellite
surface temperatures
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
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
Islip
Airport Weather
Brookhaven
Airport Weather
OceanWeather.COM
Click on the Current
Marine Data and the corresponding area to
see wave height and wind data over the
oceans.