OVERSEAS VISIT REPORT
AGU/ASLO Ocean Sciences Meeting - San Diego
- 9 - 13 February 1998
George Cresswell
INTRODUCTION
Sexual attraction is generally not something that one has to give any consideration to at conferences on physical oceanography or remote sensing. However, when one attends the large, multi-disciplinary and very vibrant Ocean Sciences meeting with roughly 1000 papers and 700 posters it becomes a possibility:
Copepods are tiny crustacea that form a large part of the biomass of the oceans. They are heavily predated upon and so they have to be very productive. How do the males and females find each other? For me one of the most exciting sessions at the meeting addressed this problem.
It transpires that in the darkness of the ocean the females are able to let the males know where they are. Copepods leave a vortex tube-like wake that persists for at least 45 seconds. The females add pheromones to this as they swoop about (presumably eating or just cruising).
The males meanwhile follow an isotropic 3-D zigzag pattern with long sweeps. As soon as one encounters a wake its swimming pattern changes dramatically and it moves in a small angle zigzag within the wake. If it finds that it is going down instead of up the wake, then it throws in a U-turn. As a male becomes confident that he is closing in then he accelerates until the final contact.
Some of the photographs taken with the lasers and mirrors apparatus suggest that perhaps the copepods even put wavy signals on their wakes with their secondary antennas ("Bill? This is Mary. Why don't you drop by?").
Isn't it great? I told a bureaucrat friend of mine in Canberra about it. He wanted to know why research money was being spent on useless things.
But, anyway let's take a wider view of the meeting:
THE MEETING
The papers were presented in as many as 10 parallel sessions. The work was exciting and of a high calibre. I was impressed with the clever techniques used to milk information from, for example, current meter records at the mouth of the Red Sea to the Indian Ocean. This was in the middle of a war zone, which the oceanographer said made the mooring recoveries more interesting than most.
The results from modelling of various parts of the world's oceans gave results that appeared tantalisingly realistic.
A session on ocean layers that are a metre or so thick generated considerable interest. In these layers density changes rapidly and so there is greatest resistance to distortion. They have biological importance so, for example, one layer may contain predominantly diatoms while another, some metres below, may contain only dinoflagellates. The traditional biologist with a net of course catches both, possibly leading to an incorrect assumption that the organisms have some interdependence.
Remote sensing of course plays a pivotal role in many fields of ocean science and it featured quite strongly in many sessions, and here are some examples:
Code 11E - Remote Sensing Posters;
12B - Remote Sensing, Bio-optics, Phytoplankton Fluorescence Posters;
12D - General Optics II Posters;
31A - Recent advances in instrumentation;
31D - New tools and their applications to fisheries Posters;
32C - Climate variability, etc Georges Bank Posters;
32F - Polar regions oceanography Posters;
41D - Boundary Current Posters;
42L - Bio-optical measurements, Spectra, and Modelling.
In addition to the above, I have been through the abstracts to locate most of the papers/posters that included remote sensing work. Here I list their codes and indicate the satellites, techniques, or noteworthy points:
11B-10 Ocean internal waves - space shuttle photography
11E-7 GOES cloud detection algorithm for SST
11E-8 Global and regional SST trends
11M-11 Airborne lidar and video of surface waves
12B-11 2 m resolution satellite imagery from the previous Soviet Union
12M-7 Ocean research in the service of education - introducing satellite oceanography
12N-3 AVHRR detection of fronts on the shelf and slope Hatteras to Nova Scotia
21B-10 Aerosols detected with CZCS
21B-11 An update on SST from AVHRR
21C-1 Suspended sediment in a bay in Alaska using AVHRR channels
21F-5 Coastally trapped Kelvin waves detected with TOPEX/Poseidon
21F-7 TOPEX
21O-11 Time and space patterns in CZCS imagery of US shelf and slope waters
22C-12 Primary production, Arabian Sea, PAR, CZCS, SST, aerosols
22F-7 Altimeters Geosat, Topex/P, ERS - transport calculations
22F-8,9 TOPEX, eddies in the Gulf of Alaska
22N-10 Remote sensing reflectance for scattering and absorption coefficients for coastal and riverine waters
31D-8 Model for the behaviour of tuna at fronts - satellite oceanography
31K-3 RADARSAT and ERS SAR imagery of ocean surface with passing hurricane
32A-1 Lidar for fish detection and water properties
32A-2 SeaWIFS
32A-5 SeaWIFS Gulf of Mexico
32A-6 Landsat - coral reefs
32B-10 SeaWIFS and chlorophyll off Cape Hatteras
32C-1 AVHRR SST Georges Bank
32F-1 Sea ice age, thickness and deformation from RADARSAT ScanSAR
32F-7 AVHRR mapping of the Antarctic Front
32G-4 TOPEX mapping of baroclinic Rossby waves
32L-8 Bering Sea, eddies, variability - airborne SeaWIFS simulator
32L-9 Upwelling - OCTS, AVHRR
32L-10 Phytoplankton - CZCS
41A-1 to 9 Satellite SST and colour for the Bering Sea coccolithophorid bloom
41B-3 Rio de la Plata - AVHRR - upwelling
41B-11 Landsat TM removal of background noise
41B-12 Chilean inland sea - CZCS
41D-3,4 Benguela current rings - TOPEX
41D-7 Florida Strait - 3 years of AVHRR
41J-3 Internal solitons - SAR
41J-6 Real time forecasting for the shelf break - AVHRR and sea instruments
42A-6,7 Santa Barbara channel - blooms - AVHRR, SeaWIFS
42J-7 Chesapeake outflow using airborne real-aperture radar
42L ALL THESE PAPERS SEEM RELEVANT FOR SATELLITE OCEAN COLOUR AND PHYTOPLANKTON
52D-8 SAR (RADARSAT) observations of deep ocean convection
52F-9 Californian coastal eddies - SAR (analysed 110 ERS SAR images for 1992-95), AVHRR, SeaWIFS - eddies had diameters 1-30 km.
Further details of the meeting are available on the web:
http://www.agu.org/meetings.waisos98.html#instr
Put in a keyword for a list of paper titles and then select for each abstract.