|
TI: |
Title
Electromagnetic fields generated by a three
dimensional global ocean circulation |
|
AU: |
Author
Tyler, RH; Mysak, LA; Oberhuber, JM |
|
AF: |
Author Affiliation
Applied Phys. Lab., Univ. Washington, Seattle, WA,
USA |
|
SO: |
Source
J. GEOPHYS. RES. (C OCEANS), vol. 102, no. 3, pp.
5531-5551, 1997 |
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IS: |
ISSN
0148-0227 |
|
AB: |
Abstract
A simplified form of the motional induction
equation is used to calculate the dominant
three-dimensional (3-D) electromagnetic (EM)
fields generated by a specified steady 3-D global
ocean circulation. The EM calculations require, at
most, vertical integrations and do not require
running a global 3-D model. Two cases for ocean
bottom conductivity are considered: an
electrically insulating ocean bottom and a
high-conductance sediment layer. The
approximations are discussed, and the solutions
are plotted for various depth levels. Many aspects
of the dominant ocean-generated EM fields
(particularly the electric currents near the sea
surface and the magnetic fields) are shown to be
insensitive to ocean bottom conductivity. Other
aspects (particularly the horizontal electric
field in shallow water) are very sensitive. We
perform a global integration to estimate the role
of the "nonlocal" electric currents. We find that
the importance in including these nonlocal
currents when making EM field estimates is the
same or less than that for including a model for
the bottom conductance. Hence the simple EM
estimates from one- dimensional integrations are
not improved in globally integrated models until
these models include a realistic model for bottom
conductivity. |
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LA: |
Language
English |
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SL: |
Summary Language
English |
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PY: |
Publication Year
1997 |
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PT: |
Publication Type
Journal Article |
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DE: |
Descriptors
electromagnetism; ocean circulation; World Ocean;
models |
|
ER: |
Environmental Regime
Marine |
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TR: |
ASFA Input Center
Number
CS9714161 |
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CL: |
Classification
Q2 02164 Ocean circulation and currents; O 2090
Instruments/Methods |
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EM: |
Entry Month
9707 |
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SF: |
Subfile
ASFA 2: Ocean Technology Policy & Non-Living
Resources; Oceanic Abstracts |
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AN: |
Accession Number
4071454 |
