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Calendar Monday, April 2 GEOSCIENCES MARINE CHEMISTRY & GEOCHEMISTRY SEMINAR - George Luther, University of Delaware, will present a title to be announced in 4500 Hubbs Hall at 4 p.m. (Julia Bowles, jbowles@ucsd.edu) Wednesday, April 4 GEOSCIENCES MARINE CHEMISTRY & GEOCHEMISTRY SEMINAR - (Note special day) Wally Broecker, Lamont-Doherty, will present a title to be announced in 4500 Hubbs Hall at 4 p.m. (Julia Bowles, jbowles@ucsd.edu) Thursday, April 5 COMPAS RECRUITMENT CANDIDATE - Kraig Winters, University of Washington, Applied Physics Laboratory, will present "A Lab/Numerical Study of the Transient Development of Wind-Driven Coastal Upwelling" in 101 Nierenberg Hall, 9:30 - 11:00 a.m. (Detlef Stammer, x23376) CAL SPACE SEMINAR - Seminars have been changed from Wednesdays to Thursdays.
The start time is still 12 noon in the same location -- Jacobs School
of Engineering (EBU1) room 4307. Today, John Garvey, Garvey Spacecraft
Corporation, will present "Low-Cost Launch Vehicle Development in the
Academic Environment." AOS SEMINAR - Genevieve Lada will present "A Model of Gas Transfer via Bubbles in the Surf Zone" in 330 NTV at 4 p.m. (Amber Rieder, amber@mpl.ucsd.edu) THE ROBERT D. TSCHIRGI MEMORIAL FREE PUBLIC LECTURE - Christian de Duve, Nobel Laureate for Medicine, Christian de Duve Institute of Cellular Pathology, Brussels, Belgium, will present "Reflections on the Origin and Evolution of Life" at Mandeville Center Auditorium on Muir campus at 4 p.m.; reception at 5:15 p.m. Directions & Parking at UCSD: Follow "DE DUVE LECTURE" directional signs from La Jolla Village Drive (west); right on Gilman Drive; right on Osler Lane; right into Lot 604; see attedant for free parking permit. Shuttles to and from Lot 604 and the Mandeville Auditorium are available. First shuttle leaves Lot 604 at 3 p.m.; last shuttle leaves at 7 p.m. For information, contact NSCORT/Exobiology Central Office at (858) 534-1891. Friday, April 6 RON MCCONNAUGHEY'S RETIREMENT PARTY - Party on the Pier for our bud Ron! 4 p.m. BE THERE! (Jill Ives, x43948) Notices PERSPECTIVES IN OCEAN SCIENCE - A new program that you should all be aware of (and excited about!) will be launched on April 11. The Birch Aquarium will host a monthly lecture series called "Perspectives on Ocean Science." The purpose of this lecture series is to provide public outreach and to communicate SIO science to the general public. Presentations will take place in the Aquarium Galleria on the second Wednesday of each month. Coffee, juice, and bagels will be served at 7:30 a.m. and the presentation will begin at 8 a.m. All SOS donor-level members and other selected guests will be invited at no charge. However, SOS members and all nonmembers will be charged $8/person. Students and faculty free. All inquiries/reservation requests should be directed to x47336. UCSD-TV will tape all presentations and each will be available for viewing on the aquarium Website. GRAHAM UPDATE - The checks keep coming in! WOW! Thanks! Charles is doing a little better. Not much change. If you wish to donate vacation hours to him via the Catastrophic Leave Program, contact Sharon Williams, shwilliams@ucsd.edu. Please make out your check to Mrs. Lori Graham and send them to me at Mail Code 0210. You all are just toooooo much! (Jill Ives, x43948) Ship News Cruise Report by the Scientific Party of SEAWEED-03-RR R/V Roger Revelle, Feb 25 - March 25, 2001 - R/V Roger Revelle completed a month long series of sea floor mapping surveys around the Big Island of Hawaii on behalf of the US Naval Oceanographic Office (NAVO). Support from the ship's force was excellent particularly since this was the first full scale mapping effort conducted by this ship with her new Kongsberg-Simrad Inc (KSI) EM120 multibeam sonar system installed in January, 2001. The EM120 is a 12 kHz swath bathymetry sonar capable of measuring depths across multiple athwartships angular sectors that are steered at transmit time to compensate for the ship's pitch and yaw motion, yielding up to 191 soundings per pings in the achievable total athwartships angular sector. After verification of the sonar's calibration, three seafloor patches were mapped for a total area of 188,657 km2. The first patch is centered at 22o-45'N/153o-30'W and covers about 27,235 km2 of abyssal hills trending 340 deg, with 3 small seamounts appearing at the western end of the area. The second patch is centered at 20o-40'N/152o-0'W and covers about 64,270 km2 of mostly north trending abyssal hills that are bent and displaced west by the Molakai Fracture Zone in the northern 1/3 of the survey area. The third patch lies south and southwest of the Big Island of Hawaii and covers about 97,153 km2 of mostly flat seafloor dotted with many small volcanos and a dozen large seamounts, at least three of which are not reported on the most recent navigation charts. A large linear depression, roughly 400 m deep and trending 311 deg, runs across the survey area south of the Big Island. Most of the surveys were in 4500-5500 m of water depth, and the sonar maintained an average swath width of 130 deg (~4.3 times the water depth). This corresponds roughly to a 50% improvement in coverage and data density over what was achievable with the SeaBeam 2112 multibeam sonar that was delivered with the ship in 1996. In similar survey conditions, the SeaBeam 2112 rarely maintained a swath width of 110 deg (~2.9 times the water depth) and its soundings were at fixed 1 deg increments athwartships. The quality of the bathymetry data recorded with the EM120 was generally very good with few artifacts, except for a wobble at the edges of the swaths attributed to lack of accuracy in sensing the roll motion. Although the magnitude of this wobble is only about 20-30 m in 5000 m of water depth, its periodicity makes it stands out in an otherwise clean swath. To help resolve this issue, a new motion sensor will be tested during the ship's transit from Hilo, HI, to San Diego, CA, at the end of April 2001. Seatex will loan us one of its Seapath 2000 sensor that has a higher accuracy rating than either its MRU5 or the TSS DMS05 sensors presently installed aboard R/V Revelle. Overall data quality improved as the science party became more familiar with this new sonar system and as the weather improved. During 2.5 weeks, survey work proceeded in sea state 5 with wind and seas mostly out of the east, causing severe loss of data to bubble sweepdown on eastbound tracks of the E-W survey pattern originally requested by NAVO. After completing the second patch, the survey pattern was reoriented N-S to avoid heading into the seas, and data quality remained good on all tracks. Significant time was spent during the survey juggling with various data formats to try and produce bathymetry maps. KSI's Neptune processing software package was used for first order data verification and presentations, and to export xyz files that could be processed through the Generic Mapping Toolkit (GMT). Exporting the raw EM120 format into either MBSystems or NAVO's gsf_geoswath and Area Based Editor was only partially viable because neither package seems to have a full description of the EM120 format and numerous reading errors plagued the data conversions. Reconciliation of these software packages with the EM120 format is a high priority task. We were unable to use KSI's sidescan mosaicing software (Poseidon) or Roxar's C-Floor terrain modeling software because of license incompatibilities that must be resolved in the near future. Results obtained at the end of this cruise have shown that, over exactly the same seafloor area at 20o 15'.25N/158o 30'W in 4440 m of water depth, the new EM120 sonar achieves 85% wider swath coverage with higher sounding density than the SeaBeam 2112 it has replaced (140 deg angular sector with 191 beams for EM120 vs. 112 deg angular sector with 113 beams for SB2112). Once fine tuned, this sonar system will be a formidable mapping tool for the UNOLS community.
R/V ROGER REVELLE
R/V MELVILLE
R/V NEW HORIZON
R/V ROBERT GORDON SPROUL
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