ENERGETICS%20

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ENERGETICS (pp. 59 63, Figures 4.2, 4.3, 4.4
in Knauss) Visible light energy, from the sun,
is absorbed by the earth system This occurs in
the 0.4 to 0.7 ?m wavelength range The earth
system looses energy by emitting infrared
radiation This occurs in the 1 to 50 µm
wavelength range Globally, there is a balance
between the radiative input and output Locally,
imbalances exist between solar input and longwave
output Local input/output imbalance imply
transport of heat poleward Both atmospheric and
oceanic flows carry heat poleward
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WATER from Lifes Matrix by Philip Ball Water
is exceptional in many ways agent of
geological, environmental and global change only
liquid in abundance on the planet All phase
transitions (ice-gtliquid-gtvapor) occur on
Earth Examples of water's exceptional
properties large specific heat capacity relative
to comparable materials large latent heat of
vaporization, melting and sublimation dissolves
both organic and inorganic materials dissolves
gases (e.g., carbon dioxide) the density of ice
is less than that of liquid water liquid water
exhibits density maximum at 4 oC
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From Lifes Matrix by Philip Ball Seawater
evaporates when the relative humidity of the
overlying atmosphere is less than 100. RHlt100
is common in the atmosphere Typically, the
energy required for evaporation comes,
indirectly, from the sun. If the solar energy
is not available, the liquid cools as it is
"forced" to evaporate by being in contact with
subsaturated air Evaporation increases the
salinity of sea water.
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THE HYDROLOGIC CYCLE from Lifes Matrix by
Philip Ball The water substance is cycled
through the atmosphere, the hydrosphere and the
cryosphere On land, precipitation is apportioned
into runoff and evaporation. Surprisingly,
evaporation typically dominates over runoff.
So roughly, precipitation evaporation 1
meter per year 1000 kg m-2 year -1
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Water is the solvent of marine
biogeochemistry 1) CO2 from the atmosphere
dissolves in seawater and is the carbon source
for photosynthesis 2) Plankton (producers) are
consumed by grazers, both die and settle 3)
Dead producers and grazers are consumed by
bacteria 4) Bacterial degredation produces
inorganic nutrients (mineralization) 5) Most
nutrients are soluble in sea water 6) Upwelling
returns the nutrients to the surface
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WATER MASSES Chapter 1 Knauss Wind driven
oceanic currents tend to be circular and thus
confine sea water into identifiable water
masses Also called gyres, these water-confining
oceanic circulations are maintained by
atmospheric motion Confinement is not perfect
but helps to delineate water masses
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Vertical motion (upwelling and downwelling) also
occurs At the scale of an ocean basin, sea water
moves vertically along constant water density
surfaces called isopycnals From measurements of
sea water properties at depth (i.e., pressure,
temperature and salinity), properties in the
water can be calculated and the source region can
be estimated Table A3.1 Assumptions 1)
no mixing during transit from source region 2)
no heating during transit from source region
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Polar
Equatorial
Polar
Note Sea water at 2000 db (2000 m depth) and
T0.109 C, has a temperature of 0.00 C if
brought the surface (this cooling results from
adiabatic expansion)
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Horizontal and vertical motion at the global
scale is manifested as a thermalhaline or
conveyer-belt circulation