Weekly Science Reports

R/V Roger Revelle

14 March Chief Scientist's Report

This past week we finished southern end of the I6S line, stations 100-106. Ship and lowered adcp both showed a strong
(0.5 kt) SW flow along most of the southern end of the line, consistent with a Slope Current. Near 64 S the multi-beam
bathymetry showed a 300-400m deep canyon that might be the outer portion of the Ritcher Canyon. It was a very well-defined
canal-shaped seafloor feature that crossed and then paralleled our track. At the penultimate station we deviated east 4nm in
order to sample in the canyon but found nothing special apparent in the CTD or LADCP data at first look. Msg sent to N Ott
of AWI's Southern Ocean bathymetry project asking for further info. On 8 March we occupied our last station, #106. TM washed
their bottles, then at about 1100 we were underway until 1230 for the local noon optics cast. Watches maintained for underway
sampling.

On the way back there are two fronts we want to sample more intensively, the Polar Front (PF) and the Subtropical Front
(STF). They are part of a system of fronts from about 40-50 S in this sector that are difficult to distinguish along
one path. We can see the STF on satellite SST maps and it usually is a very strong narrow front, but we
also see that it is not a straight line but a convoluted stream. The PF is not clear on SST but does have a signal
on SSH. However, fronts often split, form eddies, or merge and their signals can be confused. Based on near-real-time
AMSRE-E SST and satellite altimetry SSH data the students made their best estimate of frontal locations and decided
upon a plan to sample this region with XBT drops. From these position estimates we slowed the ship to get better underway
doppler current data across the frontal region.

Once in the frontal region beginning near 51 S we went into an enhanced chemistry sampling schedule, taking
salt, nuts, O2, DIC, pH, Alk every hour instead of every 2 hr across the system. Slowing the ship with this pace automatically
got us higher resolution. By now, near latitude 39 S, we have finished all underway chemical sampling to pack and prepare
for arrival. Some slowing as time permits will take place on the remaining part of the transit to Cape Town, as we cross
the Agulhas Current system and enter the South Atlantic Ocean.

Kevin Speer

6 March Chief Scientist's Report

On 29 Feb the weather forecast was for a large storm, with 50 kts winds and 25ft seas, esp. south of 65 S.
Following some discussion this prediction led to a shifting of the plan to do the line into Gunnerus
Ridge and Bank first, and then attempt to finish the southern end of the 30 E line, rather than the reverse.

In any case, winds built to 50 kt, with at least one gust to 70 kts . Seas peaked at 40 ft. But at about 1400 hrs
a complete shift in winds and waves appeared with the winds dying down, and we put the CTD in the water.
Our by now very experienced winch operators played a major role keeping tension down running the winch.
CTD T failed on the way down, and the package was raised. We took advantage of this and the coming shallower
depths to remove the outer ring of bottles and proceed with 18, lowering the package area and helping to
prevent large wire tension swings. In this fashion we continued down the Gunnerus Ridge, an underwater
butte with a fairly flat top at about 1200m depth, decreasing mainly at the southern end near the ice edge.

Finally we met the sea-ice edge as depth reached 350m. After this cast we went back north to spend the
(short) night doing a yo-yo station to be able to estimate time variability in the stratification over a partial tidal
cycle. This will at the very least help us to produce better error estimates for our transport calculations. During
this period we did 17 yo-yo CTD casts during the night, over about 7 hour period, the last one collecting water.

On the 5 March we got a beautiful sunny day. Sunrise produced a green "flash" lasting a whole second, with all
on the bridge and the CTD watch on deck confirming the lasting color. As the sea-ice had cleared away (yes,
magically) during the night, we headed back south toward the Gunnerus Bump to look for shallower water.
Enjoyed the sights and were able to follow an open path in broken sea-ice, stopping for TM and CTD casts.
Station depth 300m.

Could see the Riiser-Larsen Peninsula in the distance to the SE like a giant white outcrop, moon-like and
creviced and fissured in the early morning light. Later it was less well defined in the hazier light of the day.
Very satisfying to see the continent, even a glacial part of it since I did not think we would ever be so lucky.
Some lucky souls on the day CTD watch saw penguins playing around the CTD as it was put in the water,
and were worried about hitting them as the CTD went in the water.

After noon we began the trek back starting with the 600m station on the slope, in cloudy skies and snowfall.
By nighttime we were along the track, watching several icebergs drift near the 800m station. These can have a
debris field around them of smaller bergs. Slow going in case of growlers (smaller bits of ice) in our path. Very
fine driving by the Mates and guidance from the Captain brought us onto station.

As of today 6 March we are on Station 100, at 3500m depth. Next stop the end of the 30 E line for the final
few stations before the long haul up to Cape Town.

Kevin Speer

> 28 Feb Chief Scientist's Report
>
> Near 64 S 30 E
>
> Past week ran fairly smoothly, and we gained some time lost in previous hard weather and seas,
> which had slowed operations. Just today, though, a series of hardware failures, beginning with
> the secondary temperature sensor, CTD pump, and rosette carousel kept us on station most
> of the day. A full-depth CTD cast and bottom water sample bottle was made before the carousel
> problem arose, but once onboard a new cable fixed that problem and a shorter, 1000m, water-sampling
> cast completed the station.
>
> Chemistry is caught up and beginning to be fed into the onboard data-base. This enables all of
> us to plot various quantities, check data, and start to interpret results. The CTD watch has been
> identifying fronts, calculating transport and mixed-layer heat and salt budgets.
>
> Everyone is enjoying the more peaceful weather south of 60 S, though winds are supposed to pick
> up soon. Air temperatures are now just below 0 C, and some ice has started building up on deck.
> Extra safety precautions are in place to remind people to be careful.
>
> Notable pools of fresher cooler surface water are present from time-to-time according to the
> underway system and the CTD. We heard from colleagues on the German ice-breaker Polar Stern
> who also reported some of the freshest surface water observed in 10 years. We are all wondering
> if global warming is at work or if the random low-frequency variability of weather causes such pools.
> The Polar Stern is at nearly the same latitude, but heading south along the Greenwich Meridian,
> then over to the German Antarctic Base. They found out where we are from meteorological
> charts received at sea that identify sources of data.
>
> Underway, to our left is the Cosmonaut Sea, to our right the Riiser-Larsen Sea. We will bear east off 30 E toward
> the Gunnerus Bank to finish the section, then head out along the Gunnerus Ridge. The point of doing
> this is to attempt to find the shallowest bathymetry outside the sea-ice edge and obtain observations
> as close as possible to the shelf, with luck within the Slope Current. Sea-ice images from National Ice Center and
> FSU have been helpful in preparing an approach plan. If time permits and ice conditions become
> prohibitive near 30 E we will occupy a section farther west.
>
> Kevin Speer

R/V Melville

R/V MELVILLE Science Report
15 October, 2007

This report covers the work done in the shipyard (Sasebo, Japan), the
sea trials and transit to Taiwan.

AMOS-
We experiences hardware failure with the computer running AMOS during
the transit. It appeared to be running OK during the yard period and up
until the time of failure. As far as I can tell, transfers with the
MarFac server are up to date. We're moving AMOS onto a spare computer in
the Lower Lab and plan to have it running again before the emd of the
port stop in Taiwan.

SUN Servers - running fine.

HiSeasNet - running as good as usual, has difficulty with tracking and
so takes considerable manual tuning to keep the system online

Meridian gyro - working well as long as GPS signal is coming in.

Seatex MRU5's - we reconfigured both to output EM3000 formatted data,
19200 baud rate. We had a problem with the RS232 splitter box operating
at this speed, but found another onboard that does the job.

Multibeam - The SeaBeam 2000 system was completely removed. Components
were loaded in a container, along with ship's spares, and are headed to
San Diego. Final disposition to be determined. A Kongsberg EM120 was
installed after considerable hull modification, including a streamlined
fairing for the receive array. The top-side electronics are taking up
space in the ship's Dry Stores. We need to think about creating more
storage space for the ship. New communication cables were installed by
STS from the Lower Lab to the EM120 electronics. Calibration (pitch,
roll and heading) was successfully performed during the transit. The
system has met specificiations and acceptance has been signed. However,
there are still a few outstanding issues.
a) The system was delivered with a controller running Windows. The
manufacturer states the software can run under linux, and we plan to do
so. However, we experienced several problems with the linux software and
are running the Windows computer.
b) The Operating Station (Windows computer) is in the Lower Lab. We need
to install a remote operating station in the Main Lab.
c) Calibration surveys are needed for the 2nd Seatex MRU5 (motion sensor).
d) The EM120 is not currently working with the CalComp plotter.

F77 & THUMMS (backup email) - software is on board to upgrade this
system, but STS has not had the time to do so.

Gravimeter - the system was giving Data Not Valid errors during the port
stop and sea trials. Power cycling seems to be cleared the error
condition, but the system is being closely watched.

SeaSpy magnetometers - The SeaSpy magnetometer system was tested during
the transit and found to be in working condition. The system was
deployed in gradiometer mode on several occasions. Both 100m
interconnecting cables were used at different times. The winch is in
good operating condition. Operations were changed to use the SeaLink
software on a Knudsen PC to control and configure the magnetometers, and
new software was developed to log the magnetometer data on the SUN server.

PC's - several Windows workstations are down following the yard period.
STS is attending to these as time permits.

Sub-bottom Profiler - The Knudsen deck units were examined and brought
to prime condition. The software on the computers was upgraded. Both 12
kHz transducers are working well. The 3.5 kHz transducer array had to be
removed and reinstalled to accommodate the EM120 multibeam. The system
is pinging, but no useful data is being acquired. This should be given
high priority to bring back online.

ADCP - a new 150 kHz RDI Ocean Surveyor and 300 kHz RDI Mariner were
delivered to the shipyard the day before R/V MELVILLE was scheduled to
leave dry dock. The existing 150 kHz Narrowband transducer was removed
immediately. Although we were told the 150 kHz Ocean Surveyor would bolt
in its place, we discovered otherwise. There was not time to fabricate
mounting hardware, so the 150 kHz Narrowband was reinstalled. Plans are
being made to install the Ocean Surveyor at the earliest opportunity.
The Mariner will be used on the pipe string in the port instrument well.
An adapter is being designed and fabricated for this. The 75 kHz Ocean
Surveyor and 150 kHz Narrowband were tested and found operational during
the transit.

CTD - a Seabird CTD was assembled and a test cast to 200 m performed
during the transit. The system is ready for use on the upcoming cruise leg.

XBT - New software was developed to provide sound speed profiles to the
EM120. The system is working well.

CCTV - new cameras and tilt/pan motors were installed above the bridge,
port and starboard. These are working well, except are prone to
vibration when underway at full speed. Additional support is needed.

Dynamic Positioning - STS installed cables to provide signals from the
Meridian gyrocompass and Seatex MRU5 motion sensor to the new Kongsberg
Dynamic Positioning system.

Underway Data System - Meteorological and sea surface measurements were
taken during the transit. The uncontaminated seawater pump and all
sensors are in working condition. New routines were added to provide sea
surface sound speed data to the Kongsberg EM120.

Winch monitoring system - A new system to monitor winch operation was
installed. STS needs to investigate and plan for computer logging and
display of winch speed, payout and tension, as was done with the
previous system.

R/V New Horizon

1.    161900Z April 2007
2.    Position: Lat: 33-48.0N, Long: 121-02.2W
3.    Course: 115 T
4.    Speed:  4.3 knots
5.    Distance: 104.0 nm
6.    Steam Time:     24 hrs  00 min
7.    Station Time:     00 hrs  00 min
8.    Fuel: 1200
9.    Sky: cloudy
10.    Wind: 330 @ 16 kts
11.    Sea: moderate
12.    Swell: 310 @ 10-14 ft
13.    Barometer: 1019.0
14.    Temperature: Air: 16.0  Sea: 12.8
15.    Equipment Status: Normal
16.    Comment: Underway on Murphy cruise. Returning to San Diego due to rough weather. ETA Tuesday 
morning, April 17, 2007.

Master, R/V New Horizon

R/V Robert G. Sproul

No information is available at this time.