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BRUCE HACKETT ET AL.
are transported from place to place and how they are altered along the
way. The transport of objects and substances by currents is commonly
referred to as drift, and is the subject of this paper.
There are a number of drifting objects and substances in the ocean
that are of concern or interest to us, most important of which are the
nutrients and phytoplankton that form the basis for life in the ocean.
However, in this work we will focus on a special class of drifting things:
those that derive from human activities and have potentially serious
consequences for human activities and the marine ecosystem. Specifically, we will look at (large) floating objects and oil spills. These are
quite different things, but in the present context of ocean forecasting,
they share a dependence on knowledge of the physical conditions in the
ocean, chiefly currents. Furthermore, they share a potential for negative
impact sufficient to warrant the development of services, including the
prediction of their drift and fate, to mitigate those impacts.
In the case of drifting objects, we are concerned with objects of great
value in themselves, such as a human body, and those that (also) pose a
threat to maritime safety, such as a floating container. The task at hand
is either to find and recover a lost object (search-and-rescue, or SAR)
or to track a known object until remedial action can be taken. Many
countries have established national SAR services for handling emergency
situations, and some also run trajectory models to aid in the search. The
objects that are of interest in this type of service range from smaller than
a human (debris from a wreck) to large ships, although the scope and
administrative organization of the services vary from country to country.
In this work, we will focus on examples for SAR and ship drift.
Oil spills are quite different inasmuch as the object is a fluid that
spreads and can change properties quite dramatically once it is spilled
into the ocean. The source of the oil may be on the surface (a ship)
or subsurface (an offshore wellhead blowout). Also, oil on the surface
can be mixed down into the water column by wave action and be transported by subsurface currents. Oil spills fall generally into two classes:
small spills from ships, typically from illicit flushing of ballast tanks, and
large catastrophic spills, either from tanker accidents or from offshore
large accidents that are responsible for the most dramatic damage to the
environment. In most countries, detection and combatment of oil spill
incidents is a national service that includes a drift forecast component.
In the following, we will look at current practises in forecasting the
drift of floating objects and oil spill fate, using examples from operational
services in Norway. Two aspects of these services will be addressed: the
installations. Small spills from shipping are so numerous that they
account for the bulk of the worldwide input of oil to the sea, but it is the
BRUCE HACKETT ET AL.
are transported from place to place and how they are altered along the
way. The transport of objects and substances by currents is commonly
referred to as drift, and is the subject of this paper.
There are a number of drifting objects and substances in the ocean
that are of concern or interest to us, most important of which are the
nutrients and phytoplankton that form the basis for life in the ocean.
However, in this work we will focus on a special class of drifting things:
those that derive from human activities and have potentially serious
consequences for human activities and the marine ecosystem. Specifically, we will look at (large) floating objects and oil spills. These are
quite different things, but in the present context of ocean forecasting,
they share a dependence on knowledge of the physical conditions in the
ocean, chiefly currents. Furthermore, they share a potential for negative
impact sufficient to warrant the development of services, including the
prediction of their drift and fate, to mitigate those impacts.
In the case of drifting objects, we are concerned with objects of great
value in themselves, such as a human body, and those that (also) pose a
threat to maritime safety, such as a floating container. The task at hand
is either to find and recover a lost object (search-and-rescue, or SAR)
or to track a known object until remedial action can be taken. Many
countries have established national SAR services for handling emergency
situations, and some also run trajectory models to aid in the search. The
objects that are of interest in this type of service range from smaller than
a human (debris from a wreck) to large ships, although the scope and
administrative organization of the services vary from country to country.
In this work, we will focus on examples for SAR and ship drift.
Oil spills are quite different inasmuch as the object is a fluid that
spreads and can change properties quite dramatically once it is spilled
into the ocean. The source of the oil may be on the surface (a ship)
or subsurface (an offshore wellhead blowout). Also, oil on the surface
can be mixed down into the water column by wave action and be transported by subsurface currents. Oil spills fall generally into two classes:
small spills from ships, typically from illicit flushing of ballast tanks, and
large catastrophic spills, either from tanker accidents or from offshore
large accidents that are responsible for the most dramatic damage to the
environment. In most countries, detection and combatment of oil spill
incidents is a national service that includes a drift forecast component.
In the following, we will look at current practises in forecasting the
drift of floating objects and oil spill fate, using examples from operational
services in Norway. Two aspects of these services will be addressed: the
installations. Small spills from shipping are so numerous that they
account for the bulk of the worldwide input of oil to the sea, but it is the