75
cosmogenic nuclides
seabed while the core tube falls past the piston. Hence, friction in taking the
core is reduced. Giant piston corers may take cores of 20 m or more. The
hydraulic piston corer (HPC) is a type of piston corer which is lowered and
retrieved by the drill string hanging from a drill ship. Thus, by repetitive
operation in the same hole, cores are taken at about 4.5-m increments or
more through unlithified intervals. The rapid punch of the cores is activated by the buildup of hydraulic pressures in special chambers. Sequences of
200 m or more can be cored in this manner.
Coriolis force fictitious force, described by the French mathematician G.G.
Coriolis in 1835, that has to be introduced in the balance of forces when
motions are considered with respect to a rotating coordinate system. The
Coriolis force is introduced in the equations of motion if they refer to a
coordinate system that is fixed on the rotating earth. As follows from the
mathematical transformation from an absolute system to an earth-fixed system of coordinates, the Coriolis force has a horizontal component that is
maximal at the poles and zero at the equator, and a vertical component that
is maximal at the equator and zero at the poles. The latter can be neglected
in ocean dynamics, but in measuring the earth's gravity on a moving platform
like a ship one has to apply a correction because of this effect (Eiitviis correction). The horizontal component depends on the sine of the geographic latitude and acts in the northern hemisphere to the right of a moving mass element and in the southern hemisphere to the left. In ocean dynamics the horizontal component of the Coriolis force is expressed as the product of the
current velocity and the Coriolis parameter.
Coriolis parameter the parameter giving the effect of the Coriolis force on a current
on the rotating earth is indicated with f and is a sine function of the geographic latitude. In small-scale dynamics this parameter is often assumed to
be constant. This is called the (-plane approximation. The Coriolis parameter
in that case is treated as if the earth's surface were a conical surface, tangential to the globe at the latitude studied. For larger-scale studies this approximation is often replaced by a parameter that changes linearly with latitude,
with a proportionality factor ~. This is called the beta-plane approximation.
correlation a degree of relative correspondence between two sets of data. ~statistics and ~stratigraphic correlation.
cosmogenic nuclides due to cosmic radiation on atmospheric gases and stratospheric dust, a number of natural radionuc1ides are formed, with various
applications in ocean studies. Examples are (with their half-lifes in parentheses) 7Be (54 d), lOBe (2.7 106 y), l4C (5730 y), 26AI (7 105 y) and 32Si (170 y).
Each of them has an application in marine research, depending on its halflife and geochemical behavior.
cosmogenic nuclides
seabed while the core tube falls past the piston. Hence, friction in taking the
core is reduced. Giant piston corers may take cores of 20 m or more. The
hydraulic piston corer (HPC) is a type of piston corer which is lowered and
retrieved by the drill string hanging from a drill ship. Thus, by repetitive
operation in the same hole, cores are taken at about 4.5-m increments or
more through unlithified intervals. The rapid punch of the cores is activated by the buildup of hydraulic pressures in special chambers. Sequences of
200 m or more can be cored in this manner.
Coriolis force fictitious force, described by the French mathematician G.G.
Coriolis in 1835, that has to be introduced in the balance of forces when
motions are considered with respect to a rotating coordinate system. The
Coriolis force is introduced in the equations of motion if they refer to a
coordinate system that is fixed on the rotating earth. As follows from the
mathematical transformation from an absolute system to an earth-fixed system of coordinates, the Coriolis force has a horizontal component that is
maximal at the poles and zero at the equator, and a vertical component that
is maximal at the equator and zero at the poles. The latter can be neglected
in ocean dynamics, but in measuring the earth's gravity on a moving platform
like a ship one has to apply a correction because of this effect (Eiitviis correction). The horizontal component depends on the sine of the geographic latitude and acts in the northern hemisphere to the right of a moving mass element and in the southern hemisphere to the left. In ocean dynamics the horizontal component of the Coriolis force is expressed as the product of the
current velocity and the Coriolis parameter.
Coriolis parameter the parameter giving the effect of the Coriolis force on a current
on the rotating earth is indicated with f and is a sine function of the geographic latitude. In small-scale dynamics this parameter is often assumed to
be constant. This is called the (-plane approximation. The Coriolis parameter
in that case is treated as if the earth's surface were a conical surface, tangential to the globe at the latitude studied. For larger-scale studies this approximation is often replaced by a parameter that changes linearly with latitude,
with a proportionality factor ~. This is called the beta-plane approximation.
correlation a degree of relative correspondence between two sets of data. ~statistics and ~stratigraphic correlation.
cosmogenic nuclides due to cosmic radiation on atmospheric gases and stratospheric dust, a number of natural radionuc1ides are formed, with various
applications in ocean studies. Examples are (with their half-lifes in parentheses) 7Be (54 d), lOBe (2.7 106 y), l4C (5730 y), 26AI (7 105 y) and 32Si (170 y).
Each of them has an application in marine research, depending on its halflife and geochemical behavior.