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

WATER – from Life’s Matrix by Philip Ball

Water is exceptional in many ways: agent of geological, environmental and global changeonly liquid in abundance on the planetAll phase transitions (ice->liquid->vapor) occur on Earth

Examples of water's exceptional propertieslarge specific heat capacity relative to comparable materialslarge latent heat of vaporization, melting and sublimationdissolves both organic and inorganic materialsdissolves gases (e.g., carbon dioxide)the density of ice is less than that of liquid waterliquid water exhibits density maximum at 4 oC

From Life’s Matrix by Philip Ball

Seawater evaporates when the relative humidity of the overlying atmosphere is less than 100%. RH<100% 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.

THE HYDROLOGIC CYCLE – from Life’s 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

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

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

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 region2) no heating during transit from source region

Polar Equatorial Polar

Note: Sea water at 2000 db (~2000 m depth) and T=0.109 C, has a temperature of ~0.00 C if brought the surface (this cooling results from adiabatic expansion)

Horizontal and vertical motion at the global scale is manifested as a thermalhaline or conveyer-belt circulation