International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 2
Number 3
September 2008
The Role of Operational Ocean Forecasting in
J. Graff
BMT, Teddington, England, UK
ABSTRACT: Advances in ocean modelling have led to improved performance for operational ocean
forecasting and the availability of continuously reliable forecast information for certain ocean regions of the
world. Although such forecasts are being increasingly adopted into a wide range of services across the
maritime industry they have not yet been considered as candidates to supplement or to substitute conventional
tide tables for navigation use. The issue is important in the context of climate change and the added
uncertainty now placed on the use of conventional tide table for navigation in complex coastal waters. In the
context of e-navigation it is timely to begin to explore the issue and examine how such forecasts might be
used and adopted. This requires closer connectivity between ocean forecasting and navigation communities
and the involvement of overarching organisations such as IMO and I GOOS. This paper raises the issue and
opens the debate.
Climate change driven by global temperature rise is
producing increasing variability of seasonal weather
and a marked increase in the frequency and severity
of storms. The consequential impact on the oceans is
significant, leading to global sea level rise, abnormal
coastal flooding and complex behaviour of tides and
currents in coastal waters. For navigation, especially
in coastal waters, weather forecasts are becoming
increasingly important and the need for a navigator
to estimate the deviation of true water levels and true
currents from those presented in official tide tables is
paramount. The accuracy of model generated ocean
forecasts has improved substantially over recent
years and operational services are becoming
increasingly available especially in context of
national flood tide warning, marine search and
rescue, port approaches and offshore operations.
Advances in satellite based internet broadband
directly enable web service delivery of data and
information which contributes to a new emerging
framework for e-navigation that offers possibility for
integrating operational ocean forecasts into onboard
ECDIS systems. This paper raises the concept of
adopting operational ocean forecasts as a formal
component of ECDIS and introduces some of the
main issues to be considered.
According to the forthcoming fourth IPCC report
(IPCC 2007 WG1 Release, 2007); “at continental,
regional and ocean basin scales, numerous long-term
changes in climate have been observed. These
include changes in arctic temperatures and ice,
widespread changes in precipitation amounts, ocean
salinity, wind patterns and aspects of extreme
weather including droughts, heavy precipitation, heat
waves and the intensity of tropical cyclones. Global
average sea level rose at an average rate of 1.8 [1.3
to 2.3] mm per year over 1961 to 2003. The rate was
faster over 1993 to 2003: about 3.1 [2.4 to 3.8] mm
per year. Whether the faster rate for 1993 to 2003
reflects decadal variability or an increase in the
longer-term trend is unclear. There is high
confidence that the rate of observed sea level rise
increased from the 19th to the 20th century. The
total 20th-century rise is estimated to be 0.17 [0.12
to 0.22] m.” The implication for the next century to
2100 suggests that tropical cyclone intensity and
extreme sea level frequency will increase and mean
sea level will rise 20 - 60 cm.
The SOLAS 1974 Convention governing Safety of
Life at Sea provides a comprehensive set of
regulations made up of XII chapters. Chapter V
Safety of Navigation; identifies certain navigation
safety services which should be provided by
Contracting Governments and sets forth provisions
of an operational nature applicable in general to all
ships on all voyages. This is in contrast to the
Convention as a whole, which only applies to certain
classes of ship engaged on international voyages.
Chapter V was updated in 2000 to take account of
new digital technologies and evolution of Electronic
Chart Data Information Systems ECDIS
SOLAS Ch V/1974 Regulation 20 pertaining to
Nautical Publications was revised and updated as
SOLAS Ch V/2000 Regulation 27: Nautical charts
and nautical publications, such as sailing directions,
lists of lights, notices to mariners, tide tables and all
other nautical publications necessary for the
intended voyage shall be adequate and up to date.
Regulation 27 is supplemented by an Annex 3:
Nautical Data and Publications which incorporates
Regulation that specifically lists Tide
Tables and Tidal Stream Atlases as publications
required onboard.
Whereas the SOLAS Convention and its
Regulations come under the auspices of the
International Maritime Organisation IMO, the
governance of navigation charts and tide tables
comes under the auspices of the International
Hydrographic Organisation IHO with important
scientific input addressing mean sea level and tidal
monitoring contributed under the auspices of the
International Oceanographic Commission IOC.
Tide tables themselves are a responsibility of
individual countries that are required to ensure
adequate provision of information to ensure safety of
navigation in their national waters. The UK
Hydrograghic Office has traditionally provided a
global coverage of tide table data in addition to that
for UK waters only. Nowadays, most countries with
extensive coastlines have the capacity to produce
their own national tide tables with UK and USA
providing greater global coverage. However,
whereas tables providing tidal height predictions are
easily produced, increasingly accurate and readily
available, the same is not true for tidal stream atlases
which are still based on rudimentary tidal chart data
and increasingly outdated content of the important
Pilot publications.
Currently, the carriage and usage of tide table and
tidal stream atlas data by vessels for navigation
seems to be very varied with no overall governance
pertaining to use of best available data or guidance
as to its interpretation. National hydrographic
authorities such as USA, UK, Australia and New
Zealand are increasingly making their national tide
table predictions available freely over the internet
and other internet sites such as using XTide software
can now be found offering tide table predictions on
demand for almost any global locations. However, a
quick look at freely available predictions for the
same port from three different sources show
differences that suggests a need to address the
question of compatibility and compliance. In
congested coastal regions and major port approaches
pilotage is already being facilitated by access to real-
time readout from regional tide gauges or current
meters. In operational engineering environments
sensitive to sea state such as offshore construction or
large structure tow-out, the provision of numerical
model based sea level and current forecasts,
allowing for non-tidal effects, is already an
established requirement.
The increasing access to a widening range of tidal
predictions that may be used for navigation is a
situation that has to be recognised as a potential
problem and one that has to be addressed.
Advances in ocean modelling have led to radically
improved performance for operational ocean
forecasting and the availability of continuously
reliable forecast information of sea levels and
currents for certain ocean regions of the globe. In
Europe which is well served by its national
forecasting agencies work is advanced in moving
towards a unified approach for providing operational
ocean forecast coverage for regional European Seas
and Atlantic waters. Similar capacity exists amongst
national forecasting agencies in other parts of the
globe such as USA, China, Japan and Australia.
Although such ocean forecast data are being
increasingly adopted by industry to meet marine
operation needs ranging from search and rescue to
ship routing and tow-out they have not yet been
considered as candidates to supplement or to
substitute conventional tide tables for navigation.
Part of the reason may be to do with the complex
make-up and uncertain positioning of GOOS the
Global Ocean Observing System, which is a
permanent global system for observations, modelling
and analysis of marine and ocean variables to
support operational ocean services worldwide.
Connectivity between GOOS and IMO/IHO is
clearly lacking.
The intergovernmental IOC-WMO-UNEP
Committee for GOOS (I-GOOS) was initially
established by the IOC Executive Council at its
twenty-fifth Session (Paris, March 1992) as the IOC
Committee for GOOS (resolution EC-XXV.3), to,
inter alia, replace the Committee on Ocean
Processes and Climate. WMO and UNEP agreed to
co-sponsor the Committee in 1993.
GOOS is not an entity but is a platform for:
International cooperation for sustained
observations of the oceans
Generation of oceanographic products and
Interaction between research, operational, and
user communities
GOOS is implemented by:
Member states via their government agencies,
navies and oceanographic research institutions
working together in a wide range of thematic panels
and regional alliances.
The complex structure of GOOS is illustrated in
Figure 1 below.
Fig. 1. Structure of GOOS from
The GOOS Project Office is the organizational
and coordination hub of GOOS. The office is hosted
within the IOC/UNESCO headquarters in Paris,
France and is funded by UNESCO/IOC, USA, UK,
The nature of GOOS implementation mechanism,
as highlighted above in italics, together with the dual
domain services vision responsibility, for coastal and
open oceans, as indicated in Figure 1, creates a
highly confusing picture with regard to figuring out -
how the national ocean forecast service providers
(mainly the Meteorological Offices) should be
connected with the IMO SOLAS navigation
requirements? In other words how to create a
suitable IMO-I GOOS-IHO partnership that will help
to realise modern tidal navigation needs?
The IMO Maritime Safety Committee (MSC) at its
81st session in May 2006 decided to initiate a high
priority item on "Development of an e-navigation
strategy", with a target completion date of 2008. The
aim is to develop a strategic vision for e-navigation,
to integrate existing and new navigational tools, in
particular electronic tools, in an all-embracing
system that will contribute to enhanced navigational
safety while simultaneously reducing the burden on
the navigator. E-navigation would thus incorporate
new technologies in a structured way and ensure that
their use is compliant with the various navigational
communication technologies and services, such as
ECDIS, that are already available, providing an
overarching, accurate, secure and cost-effective
system with the potential to provide global coverage
for all ships.
E-navigation compliments the emergence of the
term Marine Electronic Highway MEH (Sekimizu et
al 2001, Gillespie 2005) and the initiation in 2006 of
a key MEH pilot demonstration project in the Straits
of Malacca and Singapore. The four-year regional
demonstration project aims to link shore-based marine
information and communication infrastructure with
the corresponding navigational and communication
facilities aboard transiting ships, while being also
capable of incorporating marine environmental
management systems. IMO state that “The overall
system - would also include positioning systems,
real-time navigational information like tidal and
current data, as well as providing meteorological and
oceanographic information …”
Development of an e-navigation strategy by IMO
is currently under active discussion with responses
now in place for reporting back to the IMO NAV53
meeting in July 2007. As of 20
April 2007 there are
: Ocean Observing
Panel for Climate
Technical Commission for
Oceanography and Marine
66 response documents posted on the IHO web site,
one of which; the IALA Definition and Vision for
E-Navigation, posted 29
March 2007 (IALA 2007)
presents a descriptive model for e-navigation that
clearly highlights inclusion of oceanographic predic-
tions as input for creating operational navigation
information in an e-navigation context. Key applica-
tions identified by IALA are route planning, under
keel clearance, berthing and SAR response. Bearing
in mind the important role played by IALA the
International Association of Marine Aids to
Navigation and Lighthouse Authorities in driving the
adoption of key technology applications such as
VTS Vessel Traffic Systems and AIS Automatic
Identification of Ships, its contribution highlighting
oceanographic predictions, ie., operational oceano-
graphy, should be treated with great seriousness and
should be considered as the opening to develop
inclusiveness of the GOOS community into the
e-navigation framework. It is noticeable that amongst
the 66 contributing responses on e-navigation posted
on the IHO web site that reflect world-wide
participation, I could not identify any representatives
of the GOOS community.
The maritime community is currently in the process
of establishing a strategy for adoption of e-navigation
as an enabling framework for integration of new
forms of technology and information to aid and
enhance safety of navigation world-wide. A key
component for safe navigation is the use of best
available tide and current predictions. In the context
of climate change and its impact on the seas it is
necessary to consider how operational ocean forecasts
might supplement or replace onboard tidal publica-
tions. The global ocean modelling and forecasting
community GOOS is advancing and improving
capacity to provide operational forecasts. Currently
the GOOS community and the maritime navigation
community are not closely connected; it is timely
that closer connectivity should be encouraged. The
following three recommendations are proposed.
1 In view of the increasing availability of tidal
predictions over the internet it seems necessary to
develop guidelines governing use of these data for
2 Consideration should be given to the use of
operational ocean forecasts for navigation and a
strategy should be developed for their adoption
and use.
3 Formal cooperation between the maritime
navigation community represented by IMO, IHO
and IALA and the operational ocean forecasting
community represented by I GOOS should be
established as a matter of priority.
Gillespie, R. 2005. Global Marine Electronic Highway:
proposed vision and architecture. Canadian GeoProject
Centre, 2005.
IALA 2007. The IALA Definition and Vision for E-Navigation.
e-NAV2-output 11, March 2007.
IPCC 2007. Contribution of Working Group I to the Fourth
Assessment Report of the Intergovernmental Panel on
Climate Change. Summary for Policymakers. April 2007.
Sekimizu, K., Sainlos, JC. & PAW, JN. 2001. The Marine
Electronic Highway in the Straits of Malacca and Singapore
An innovative project for the management of highly
congested and confined waters. IMO, July 2001.
SOLAS 2004. SOLAS (2001 and 2002 AMENDMENTS)
IMO, London, ISBN 92-801-4183-X, 2004.