DRI Update: 26 October 1999

The last DRI Update was on Oct. 12, and since then we have all been quite busy out here, and in particular I have been too busy to put together an update on events until now.

In general, the experimental work in SAX99 is going exceptionally well. The experiment layout presented at the June workshop has come to reality in every respect. We now have a total of 20 cables coming to the Seward Johnson from permanent structures on the bottom, and the ARL ROV is typically deployed three times per day off the fantail.

Deployment of the APL penetration equipment proceeded as planned. Eighteen hydrophones were deployed in the sediment in three vertical arrays, with horizontal insertion via a cofferdam. Data sets for penetration and backscatter are being obtained as the transmitting tower is moved by divers 5 to 10 times a day. Data quality is excellent. Separate attenuation measurements were made yesterday with a diver deployed hydrophone array.

ARL penetration data are being obtained via transmissions from the ARL ROV to a buried array inserted via waterjet. Typically about three ROV deployments are made each day. Both backscatter and penetration data have been recorded. Scattering from fish is a source of interference that can be avoided. Night ROV ops used laser striping to highlight bottom roughness.

The SIO (Jaffe/Moore) laser line scanner is in operation to examine temporal change of bottom roughness. Operation continues daily, and temporal changes are being observed in high-precision single line scans. It turns out that fish like to concentrate within the scanner framework, raising interesting questions about the perturbing effects of the measuring apparatus, not just in this case, but also for other SAX99 measurements that attempt to measure fine-scale sediment structure.

Data from the Tracor tower and three TAPS units continue to flow once a minute from each sensor by cable to an instrumented van on the Seward Johnson bow and from there by radio to the Tracor base at the Sandman Motel, now being manned by Van Holliday. These data have revealed easily detected daily zooplankton and nekton migration effects, but Van believes the current full moon is suppressing much of the migration. Van will be relieved by McGehee and Greenlaw during the ASA meeting next week, and will return after the meeting. As diver time permits, several additional biomanipulations are planned for the TAPS-8 scanning system located on the Tracor tower. These will be supported by the Jumars team.

Last weekend the tower for Joe Lopes and his group from CSS was deployed and five cables were brought on board the Seward Johnson. In addition, most of the target field was deployed Sunday, and the remaining part will be deployed on Tuesday. Joe's group has now checked out their systems and things are progressing well. They are preparing for the bistatic SAS measurements and are collecting backscatter data.

Soon after the Seward Johnson first arrived at the experimental site (Oct. 14), Mike Richardson (with Sean Griffin and John Bradley) successfully deployed ISSAMS at five sites (low frequency site, Lopes site, E of BAMS/XBAMS area, ARL penetration site, APL penetration site) to measure sediment physical and geoacoustic properties at each site. Additional ISSAMS measurements were made from the "normal" Seward Johnson position to pursue research issues. The ISSAMS measurements were made from Oct. 14-18.

In addition, Peter Dahl's (APL) wave buoy was deployed on Oct. 14th from the Seward Johnson and has been gathering wave data continuously since then. Peter's student, Brian Strully, was on hand for the deployment and to check out the data quality.

I will not be able to do justice to all the work that has been done so far from the Pelican without taking more time to get input, since I have been on the Seward Johnson since Oct. 13, but I will at least mention the main efforts.

DJ Tang has deployed his conductivity probe system (IMP) five times from the Pelican. Successful data sets were obtained on three of those deployments, including a deployment yesterday, going down before 10:00 with recovery at 20:30 to hopefully observe effects of faunal emergence from the sediment at sunset (but the nearly full moon and clear skies will likely reduce such effects). Preliminary processing indicates that, in addition to 3D volume inhomogeneities, IMP provides direct 2D measurements of topography. We decided not to attempt the transfer of IMP from the Pelican to the Seward Johnson; it was unloaded from the Pelican at CSS on Oct. 25, and its work in SAX99 is now completed.

The NRL group has been doing a large variety of environmental measurements: cores for sound speeds and other later analysis, permeability measurements (Dawn Lavoie and Allan Reed), stereophotography for roughness (Kevin Briggs) to mention just three areas. Dale Bibee carried out airgun measurements for low frequency studies. Some delays were experienced when those measurements were being done, in part because the Pelican had difficulty holding a sufficiently tight position. So, while airgun results were obtained, other aspects of Dale's work did not get completed (e.g, hammer plate, gas content), and he will return in early November to do further work. The NRL group has also been heavily involved in sediment manipulation measurements (roughness and discrete) in the region of BAMS (joint work with APL).

Rob Wheatcroft and his group have completed a series of sediment X-radiography measurements as well as high resolution sediment porosity measurements using a diver deployed conductivity probe, and just disembarked at CSS on Oct. 25th. In addition, Rob's tripod has gathered data on sediment roughness change throughout SAX99 and continues to do so at this time. Rob also has two other study areas off the SE and SW moorings, and will return near the end of SAX99 to recover the tripod and make further measurements.

Pete Jumars and Liko Self on the Pelican and Jill Schmidt on the Seward Johnson have worked together to study the effects of defaunations in selected study areas and to examine the contributions of sand dollars to acoustic backscatter . (Recently the contributions of starfish have also been examined.) This work involves diving from small boats, and on recent typical days the small boat activity (including work by NRL and Wheatcroft' s group) has been extensive. Jill has also been pursuing her studies of microbial abundance and spatial distribution relative to sand grain contacts.

The weather and wave conditions have been excellent most of the time. We have usually had NW, N, or NE winds, so that even though wind speeds have occasionally exceeded 20 knots, the short fetch has meant that the waves have been modest with no swell. Thus, working conditions have been nearly perfect. We had a few anxious moments as Hurricane Irene developed and moved toward Florida. However, Irene's track took it across southern Florida into the Atlantic, and we only experienced a short period of southeast swell associated with the hurricane, with no significant impact on our work.

The missile test at nearby Eglin AFB mentioned in earlier updates took place on Oct. 19. Fortunately, our ships did not have to move, and we observed two missile firings from the Seward Johnson on that day.

At the time of the last update the four Seward Johnson moorings had been deployed, with clump weights in place, but with questions on whether the anchors were properly set. This turned out to require some extra attention with several dives needed to examine the anchor sets. The pesky anchor in the NE mooring was hand dug in to improve the set, but later northerly winds pulled it out again. In the end, we borrowed another anchor from the Seward Johnson and added it to the NE mooring.

The idea of maintaining the rooms at a nearby shore site (the Sandman Motel) has proved to be very useful for people as they come and go. Kate Bader from APL has been our person at the Sandman. She spends her time picking up people and dropping them off at airports and doing a 1001 errands for everyone involved in SAX99 as well as for both ships. She has been an incredible asset; just ask anyone who has been here.

I also want to mention the efforts of Le Olson from APL. He has managed the technical aspects of the deployments. Our work is progressing smoothly mostly because he made it happen. The remaining ship schedules for SAX99 are included below. The ship activity for the period Oct. 17-25 is also included to show recent activity.

Pelican Leg 6, Oct. 17-22:


NRL: Dawn Lavoie, Allan Reed
APL: DJ Tang, Mike Welch, Skip Kolve, John Elliott
UM: Pete Jumars
UW: Liko Self
OSU: Rob Wheatcroft, Maziet Cheseby, Cara Fritz (total 11)

Oct. 17:

Load Tang (APL) equipment (IMP), Lavoie/Reed (NRL) equipment.
Transit to FWB.

Oct. 17-21: IMP deployments

Lavoie, Reed: permeability measurements.
Continue Jumars/Schmidt/Self and NRL/APL/BAMS manipulations.
Continue NRL coring.
Continue Wheatcroft/Cheseby/Fritz IRP and coring ops.

Oct. 19:

1300: Shuttle Kolve to shore.
1700: Shuttle Thistle, Suderman to shore.

Oct. 21: (AM) Shuttle Lavoie to shore.

Oct. 22:

(AM) Shuttle Reed to shore.
1330: Shuttle Elliot to shore.
1400: Deploy IMP.
1600-2200: Transit to CSS.

Pelican Leg 7, Oct. 22-25:

UM: Jumars
UW: Self
OSU: Wheatcroft, Cheseby, Fritz
CSS: Joe Lopes, Ed Kloess, Iris Paustian, John Stroud
APL: Tang, Welch
(total 11)

Oct. 22:

2200-2300: Load Lopes (CSS) tower. Transit to FWB.

Oct. 23:

AM: Shuttle Tim Orsi (PSI), Dick Bennett (Seaprobe), Jana Avant, Maritza Abril to Pelican.
Deploy Lopes tower.
Recover IMP.
Reload film on Wheatcroft tripod.
(PM): Tang, Welch , Paustian, Stroud to Seward Johnson (total 11)

Oct. 24:

(PM) Shuttle Orsi to shore.
Lopes, Kloess, from Pelican to Seward Johnson.
Tang, Welch from Seward Johnson to Pelican (total 10)
1900: Begin transit to CSS.

Oct. 25:

0700-0900: Off load NRL equipment and rad van (level on dock).


Personnel on Oct. 17:

APL: Eric Thorsos, Kevin Williams, Darrell Jackson, Le Olson, Eric Boget, Russ Light, Vern Miller, Mike Kenney, Paul Aguilar, Brian Strully, Tom Lehman, Mike Ohmart

ARL: Nick Chotiros, James Piper, David Gage, Bret McCurley

NRL: Mike Richardson, Kevin Briggs, Ricky Ray, Dan Lott, Sean Griffin, John Bradley

TRACOR: Van Holliday, Charles Greenlaw UW: Jill Schmidt

SIO: Fernando Simonet (total 26)

Oct. 17:

Complete TRACOR lines to SJ bow; continue TRACOR and ARL tests.
Deploy APL frame, cofferdam, cofferdam insertion into sediment.
PM: Shuttle Holliday, Greenlaw, Simonet to shore (total 23).

Oct. 18: Continue ARL deployment and tests. Continue APL deployment.

Oct. 18 (PM): Shuttle Jules Jaffe (SIO), Karl Moore (SIO), Simonet to Seward Johnson Shuttle McCurley to shore (total 25).

Oct. 18 (evening) : Begin laser line scanner assembly (Jaffe/Moore/Simonet).

Oct. 19: APL buried array insertion. Complete laser line scanner assembly.

Oct. 19:

1300: Shuttle Kenney, Griffin to shore.
1500: Shuttle Bradley, Strully to shore ( total 21).

Oct. 20:

(AM):Shuttle Jim Phalin (USN), Al Furet (USN) to Seward Johnson.
1300: Shuttle Holliday and Greenlaw to Seward Johnson.
1700: Shuttle Simonet to shore. Shuttle Kate Bader to Seward Johnson (total 25).
1900-2100: Pelican researchers to Seward Johnson for dessert and "show & tell".

Oct. 21

(AM): Shuttle Bader to shore. Shuttle Rob McDowell (NRL) to Seward Johnson.
1300: Shuttle Holliday, Greenlaw, Jaffe to shore (total 22).

Oct. 23:

(PM): Shuttle Richardson, Briggs, Ray, Lott, McDowell, Phalin, Furet, Ohmart to shore. Tang, Welch, Paustian, Stroud from Pelican to Seward Johnson (total 18).

Oct. 23-24: Lopes tower deployment: bring lines on board; deploy acoustic targets.

Oct. 24: Lopes, Kloess to Seward Johnson from Pelican. Tang, Welch to Pelican from Seward Johnson (total 18).

Oct. 25 (PM): Shuttle Ben Ochoa (SIO), Eric Smith (ARL), Tang to Seward Johnson (total 21).

Schedule of Remaining Activity

Pelican Leg 8, Oct. 25-29


UM: Pete Jumars
NRL: Mike Richardson, Kevin Briggs, Ricky Ray, Dan Lott
UW: Liko Self, Paul Johnson, Mike Hutnak Seaprobe: Dick Bennett
(total 9)

Oct. 25

0900-1100: Load Johnson equipment, Lyons stereocamera.
1100: Depart CSS.
1200-1500: Stereophotos and cores at PCB.
1500-2000: Transit to FWB.

Oct. 26 (AM): Richardson, Briggs, Ray, Lott to Seward Johnson.

Oct. 26-28: Johnson tripod deployments. Continue Jumars/Self/Schmidt manipulations and studies.

Oct. 26 (PM): Shuttle Jehrome Stockstill (Seaprobe) to Pelican.

Oct. 27 (AM): Shuttle Bennett to shore.

Oct. 28 (PM): Shuttle Stockstill to shore.

Oct. 28: 1900: Begin transit to CSS.

Oct. 29:

0700: Unload Johnson equipment. Reload rad van.
1200: Begin transit to Cocodrie.


Oct. 26:

(AM): Shuttle Gage, Piper, Moore to shore Richardson, Briggs, Ray, Lott to Seward Johnson from Pelican.
(PM): Shuttle David Smith (ARL) to Seward Johnson (total 23).

Oct. 27 (AM): Shuttle Chotiros to shore (total 22).

Oct. 27-29: CSS SAS measurements from CSS ship (Mr. Offshore).

Oct. 29 (late AM): Shuttle Piper to Seward Johnson (total 23).

Oct. 30:

(AM): Shuttle Jumars, Self to Seward Johnson (total 25). Recover laser line scanner.

Oct. 31:

(AM): Shuttle Ochoa to shore. Shuttle Peter Jackson, David Gunn to Seward Johnson (total 26).

Nov. 1:

(AM): Shuttle Dale Bibee, Allan Reed to Seward Johnson.
(PM): Shuttle Reed to shore (total 27).

Nov. 2 (PM): Shuttle Thistle and Suderman to Seward Johnson (total 29).

Nov. 4 (PM): Shuttle David Smith to shore (total 28).

Nov. 5:

(AM): Shuttle Roger Banks to Seward Johnson.
(PM) Shuttle Lopes, Kloess, Paustian, Stroud to shore (total 25).

Nov. 9:

(AM): Shuttle Chotiros to Seward Johnson. Shuttle Eric Smith, Bibee, Richardson, Briggs, Ray, Lott, Peter Jackson, Gunn to shore (total 18).

Nov. 10 (PM): Shuttle Jaffe to Seward Johnson (total 19).

Nov. 11 (PM): Shuttle Thistle and Suderman to shore. Shuttle Gage to Seward Johnson (total 18).

Nov. 12 (AM): Shuttle Wheatcroft, Cheseby to Seward Johnson (total 20).

Nov. 12-14: Recover equipment.

Personnel at beginning of equipment recovery: Thorsos, Williams, Jackson, Tang, Olson, Boget, Light, Miller, Aguilar, Lehman, Chotiros, Piper, Gage, Banks, Jumars, Self, Schmidt, Wheatcroft, Cheseby, Jaffe

Nov. 13 (AM): Shuttle Holliday, Greenlaw, McGehee to Seward Johnson (total 22).

Nov. 14: Transit to CSS.

Nov. 15: Off load at CSS, begin transit to Harbor Branch.