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Diagram of JKEO4, August 2009 - Octber 2010
The
JKEO4 mooring design is based on the m-TRITON mooring design modified for the
harsh conditions in the Kuroshio Extension region, and a little modified from
JKEO3. The
JKEO4 mooring is a slack mooring with scope 1.44 because of the severe
current regime. The upper portion of the mooring is kept fairly vertical (but
less so than taut-line moorings) by using a reverse catenary
design. Because the mooring line is larger than the ocean depth, the
subsurface pressure data should be used to remap the observations onto
nominal depths. With a watch circle radius of approximately 6 km, mariners
are asked to keep a safe distance from the mooring. The
surface buoy is a 1.9 m diameter polyurethane-coated polyethylene-foam
cylinder with 1.4 m height. It has a stainless pole with three plastic
cylindrical cases containing respectively the batteries, data logger, and
Argos data telemeter system, together with one plastic cylindrical case
containing pCO2 measurement system provided by Mutsu
Institute of Oceanography (MIO/JAMSTEC). When completely rigged, the system
has an air weight of approximately 1000 kg, a net buoyancy of nearly 3000 kg,
and an overall height of 5.5 m. The underwater container cases are
approximately 57 cm long and 22 cm diameter. The buoy can be seen on radar
from 4-8 miles depending on sea conditions. 10
mm diameter wire rope jacketed to 13 mm is used in the upper 700 meters to
guard against damage from fish bite. Fairings are attached at upper 300 m of
the wire rope. 8-strand 17 mm diameter nylon lines (500 m x 9 lines) are used
for the next 4500m of the mooring, shackle-connected to 2500 m of buoyant 19
mm diameter polypropylene mooring line (1000 m x 2 lines and one 500 m long
line). An acoustic transponder was added just above the glass spheres near
bottom for easy fixing of sinker position. The anchor was made from iron slab,
and weights 3800kg in air. All hardware is standard equipment as used in
other JAMSTEC moorings. Deployments follow the traditional anchor last
routine. As
with m-TRITON mooring systems, the subsurface sensors clamp onto the wire
rope strength member that serves as the inductive element. Addressable
modules on the cable allow the system to be expanded for new sensors by
adding the appropriate hardware and software interfaces. Flexibility in the
design also allows the interface of additional sensors including ocean
currents. Most measurements are made at a sample rate of 10 minute. These
high temporal resolution data are recorded internally and available after
mooring recovery. On
October 8, 2010, JKEO4 left the site and began drifting. The top buoy
including the logger system was recovered on October 12, 2010. The most of
subsurface sensors were recovered on February 22, 2011. Last updated on May 10, 2011 |
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Home/Overview
| Technical Info | Data
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Ocean-Atmosphere Interaction
Research Team, Ocean
Climate Change Research Program (OCCRP), Research Institute for Global
Change (RIGC), Japan Agency for Marine-Earth
Science and Technology (JAMSTEC) 2-15 Natsushima-cho
Yokosuka-city, Kanagawa, 237-0061, Japan |
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JKEO web master |