- 行业: Earth science
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The UK charity dedicated to the protection of the marine environment and its wildlife.
All of the northward-moving water from the Straits of Florida to a point off Cape Hatteras where the current ceases to follow the continental slope. It is one of the swiftest of ocean currents (flowing at a rate of 2 to 5 knots). The Florida current can be traced directly back to the Yucatan Channel because the water flowing through the channel continues on the shortest route to the Straits of Florida and only a small amount sweeps into the Gulf of Mexico, later to join the Florida current. After passing the Straits of Florida the current is reinforced by the Antilles current , but the name Florida Current is retained as far as Cape Hatteras. The Florida current is part of the Gulf Stream system .
Industry:Earth science
An instability of an unbounded parallel shear flow to the growth and nonlinear development of waves with phase speed in the along flow direction approximately equal to the speed of the inflection point of the shear. This is also referred to as shear instability and is a specific example of barotropic instability. The instability, whether in homogeneous or stratified fluid, occurs due to a resonant coupling between wave-like disturbances on either flank of the shear flow where the gradient of the shear is non-zero. Increasing stratification acts to inhibit the growth of the instability.
Industry:Earth science
A generally southwestward-flowing ocean current of the Indian Ocean; one of the swiftest of ocean currents. Throughout the year, part of the south equatorial current turns south along the east coast of Africa and feeds the strong Agulhas current. To the south of latitude 30=AE$=AFS, the Agulhas current is a well-defined and narrow current that extends less than 100 km from the coast. To the south of South Africa the greatest volume of its waters bends sharply to the south and then toward the east, thus returning to the Indian Ocean by joining the flow from South Africa toward Australia across the southern part of that ocean. = However, a small portion of the Agulhas current water appears to round the Cape of Good Hope from the Indian Ocean and continue into the Atlantic Ocean.
Industry:Earth science
An approximation to the internal gravity wave spectrum (for waves with large horizontal extent compared with the vertical extent) which is observed to have the same structure throughout the deep ocean. The energy density spectrum is proportional to Ef/omega (omega^2-f^2)^(-1/2) ~= Ef/omega^2 (for omega>>f) for waves of frequency omega in which f is the Coriolis parameter and E is a nondimensional parameter empirically determined to be E ~= 6*10^(-5). For a wide range observations E has been found to vary by no more than a factor 2.
Industry:Earth science
An eastward flowing current of the South Atlantic Ocean that is continuous with the northern edge of the Antarctic circumpolar current .
Industry:Earth science
An eastward flowing current of the South Pacific Ocean that is continuous with the northern edge of the antarctic circumpolar current .
Industry:Earth science
An equatorial wave whose dispersion relation is asymptotic to that for equatorial Kelvin waves for large positive (eastward) zonal wavenumbers and asymptotic to equatorial Rossby waves for large negative (westward) zonal wavenumbers. Rossby-gravity waves are also called Yanai waves and ``mixed'' Rossby-gravity waves. In the shallow water approximation, the dispersion relationship is given by frequency omega= k c (1-(1+4�eta/(k^2 c))^(1/2))/2, in which k is the zonal wavenumber, �eta is the meridional gradient of the Coriolis parameter at the equator, and c=(gH)^(1/2) for which g is the acceleration of gravity and H is the mean fluid depth.
Industry:Earth science
An idealized vortex in unbounded fluid with uniform vorticity inside an elliptical patch and zero vorticity outside. For an ellipse with semi-axes a and b and vorticity omega in its interior, it rotates steadily with angular velocity omega ab/(a+b)^2.
Industry:Earth science
An instability of an unbounded stratified parallel shear flow to the development of cusp-like waves that propagate with phase speed in the along flow direction significantly different from the speed of the inflection point of the shear. The propagating phase speed of Holmboe instability distinguishes it from Kelvin-Helmholtz instability. The instability occurs only in stratified fluid due to a resonant coupling between an internal gravity wave and a wave-like disturbance where the background shear varies vertically.
Industry:Earth science
