2003 Summary Review
summary review concentrates on 2003 activity but if you wish to access
more historical information please click on the appropriate heading:
The 2003 surveying season concluded in November. It was a very successful
season. All five
scheduled legs of Zone 2 acquisition (50-200m
contour area) have
been completed by the Marine Institute's new vessel, the Celtic Explorer,
in Donegal Bay. This represents more than 16,000 sq kms or 13.5% of
the Zone 2 area survey. Killybegs proved to be an ideal port base
for activities this year before she demobilised to Galway on 17 September.
2 data acquisition will continue through 2005. Above image represents
overall INSS coverage to November 2003.
The Explorer is equipped to gather sea floor information utilising
state-of-the-art hydrographic and geophysical equipment and is accurately
positioned using Fugro StarFix DGPS, which in addition to providing
decimetre-accurate positions, includes a sophisticated height correction;
permitting the injection of the tidal component into the acoustic
data sets. To accurately map the sea floor character and water depth,
the vessel is equipped with a Kongsberg Simrad EM1002 multibeam echo
sounder and a Kongsberg Simrad EA600 multi-frequency single beam echo
sounder. Simultaneous profiles of the shallow sub sea floor geology
are acquired using a pinger system. Whilst underway, continuous measurements
of the Earth's gravity field are recorded on a LaCoste & Romberg
SL Gravity meter, and a Geometrics G881 Magnetometer towfish is also
towed aft of the vessel.
processing and interpretation is carried out on board the vessel by
a team of experienced hydrographic surveyors, geophysicists, data
processors and CAD/GIS operators. At the end of each leg the shore
teams are presented with a series of completed charts, data tapes
and reports. Then the GSI in-house quality control mechanisms are
called upon and further processing commences together with the value-added
process. On right is a data example taken from the Explorer in August.
north of Donegal survey area is dotted with UKHO-reported wreck locations
and as many as 104 have so far been identified, including a few unidentified
ones as well. The images below are from earlier survey legs this year.
We are in discussions with the National Parks and Wildlife Service about
building a more comprehensive database of our findings, using their expertise.
3 - Groundtruthing Programme
the end of the fourth surveying season (2003) ten
vessels and one airplane had been involved in carrying out the National
Seabed Survey. 2003 saw the use of a further four vessels - the Celtic
Explorer, the Commissioners of Irish Lights vessel the Granuaile, the
British Antartic Survey's vessel the J. Clark Ross and the German research
vessel, the Polarstern. The Polarstern was used to further extend 2002's
highly successful ground-truthing programme and a profile of its cruise
can be found here.
or Groundtruthing is important because the various features being
imaged using the multibeam technique cannot be fully understood and
interpreted without groundtruth data. The Logachev was again used
this year for further work and has delivered excellent data from the
Porcupine at the edge of the continental margin.
Seperately, samples from four locations were recovered as part of
a taxonomic study of benthic species by the Martin Ryan Institute
in NUI Galway.
Image of Spider Crabs
© IFREMER 2003
ground truthing for seabed classification based on backscatter data
is the primary objective of the seabed sampling programme. Geochemical
and biological analysis of the samples was conducted last year and
this year's samples are currently being analysed. A presentation at
the 2003 Annual Seabed Seminar will outline the results from last
year's sampling programme. The
Logachev was again used this year. So too was the Polarstern and also
For a review of the GSI's Groundtruthing Programme please click here.
VICTOR ROV ©
in Zone 3 the British Antartic Survey's vessel the J. Clark Ross was used
to infill a triangular gap within the PAD deepwater area using their EM120
multibeam. The PAD - Petroleum Affairs Division - area was surveyed in
1996 to delineate the boundaries of Ireland's offshore area.
Following on from last year's
highly successful Lidar survey in Clew Bay in the Zone 1 area it was decided
to extend this survey further this year. So, an international tender process
was carried out that saw Tenix LADS again successful and they commenced
work Clew Bay, Newport Bay and Killala Bay
from last year's Survey which were initially
processed in Australia by the contractors, the Tenix
LADS Corporation and then QC-checked in GSI offices were found
to be excellent. A formal handover of the data to the Westport Harbour
Authority took place earlier this year and GSI has also given the
data to the British Hydrographic Office so that a more than 100 year
old navigation chart for the area can be updated.
The Granuaile became the tenth
vessel to join the National Seabed Survey fleet in October. She carried
out surveying in Zone 1 between Clogher Head and Drogheda. For a summary
of her cruise click here.