m. This is between the visible and microwave
regions of the spectrum. It is further divided into the
near (0.75 to 1.5 m), intermediate (1.5 to 20 m),
and far (20 to 1000 m) ranges. Most of the energy emitted
by the Earth and its atmosphere is at infrared wavelengths, and it
is generated almost entirely by large-scale intramolecular
processes. The tri-atomic gases such as water vapor, CO2,
and ozone absorb infrared radiation and play important roles
in the propagation of infrared radiation in the atmosphere.
The most up-to-date scenario for these interbasin circulation processes starts with 14 Sv of upper and intermediate level water being converted to NADW in the North Atlantic and flowing southward across the equator to join the ACC. This loss from the Atlantic is compensated by 10 Sv of upper level entering via the Drake Passage and 4 Sv entering from the Indonesian Throughflow through the Australasian Mediterranean and around Africa. The Indian Ocean receives 24 Sv of lower level cold water from the ACC, returning 14 Sv as cold water and transforming 10 Sv to upper level water. This latter 10 Sv flows south of Australia, across the South Pacific, and through the Drake Passage into the Benguela Current regime. This joins the afore mentioned Indonesian Throughflow, crosses the equator, and flow with the Gulf Stream into the North Atlantic to replace the lost NADW. The Pacific takes 20 Sv of cold water from the ACC and returns it as less cold water, with about half of it traversing the North Pacific.
This is a simplified two-layer version of a more complicated four-layer circulation scheme developed by Schmitz (1995) which includes intermediate and upper layer compensations flows as well as abyssal and deep interbasin thermohaline circulation layers. The greatest uncertainties remain in the Indian and Pacific Oceans, especially with the flows associated with vertical exchange, which in itself is perhaps the least well established feature of ocean circulation.
is defined by
where I is the radiance, 
the
zenith angle,
and 
the infinitesimal solid angle.
The rate at which radiation is incident upon a unit area.
The isopycnal method was originally applied such that all
densities were calculated relative to the ocean surface, i.e. as
either sigma-t or
sigma- . This was later
modified when it was found that, due to the nonlinearity of the
equation of state for seawater, maximum values could exist well
above the ocean bottom - ostensibly signifying a hydrostatic
instability. The problem was rectified by the use of
potential densities calculated relative to different pressures
as was required by the situation, i.e. sigma-1 for densities
relative to 1000 decibars (db),
sigma-2 for 2000 db, etc., a procedure that is still followed
today.