INTRO TO MARINE SCIENCE - Chapter 6 Reading Notes

The Atmosphere and the Oceans

Solar Constant

2 cal/cm²/min

• Approached only at latitudes between 23 ½ degrees N and 23 ½ degrees S because only between those latitudes does sunlight strike earth at a right angle

The solar radiation per unit of surface area __________ with increasing latitude in each hemisphere, because the greater the latitude, the longer the distance through the atmosphere the sun’s rays must travel.

decreases

Heat Budget

to maintain a constant average temperature, earth and its atmosphere must reradiate as much heat back to space as they receive from the sun

On average, more heat is gained than lose at _______________.

equatorial latitudes 

On average, more heat is lost than gained at _______________.

higher latitudes

Ice Flow

a floating chunk of ice that is less than 10 km in its greater dimension

Fast Ice

sea ice that is anchored to a landmass or shallow parts of the continental shelf

Drift Ice

sea ice that floats freely

Pack Ice

continuous, or near continuous sea ice

Icebergs

massive and irregular in shape, float with about 12% of their mass above the sea surface; formed by glaciers

Troposphere

the lowest layer of the atmosphere

• Temperature decreases with altitude

• Heat and water move between earth’s surface and the atmosphere, causing the motions that produce the winds, the weather, the ocean’s waves and ocean surface currents

Stratosphere

above the troposphere

• Temperature increases with increasing altitude

Ozone

highly reactive form of oxygen, occurs principally in the stratosphere

• Absorbs ultraviolet radiation from sunlight – therefore raising temperature of the stratosphere

• By absorbing UV rays, the ozone lowers incidence of UV light at earth’s surface, protecting living organisms from harmful high-intensity UV rays

Mesosphere

above the stratosphere

•  Little absorption of solar radiation – temperature decreases with height

Thermosphere

above mesopshere

% of Nitrogen in atmosphere

78

% of oxygen in atmosphere

21

% of argon in atmosphere

1

What 3 variables is the density of air controlled by?

1. temperature

2. the amount of water vapor in the air

3. latitude

Dobson unit

most common unit for measuring ozone concentration – 1 unit is the number of molecules that would be required to create a layer of pure ozone 0.01 mm thick at a temp of 0 degrees C and a pressure of one atmosphere

What is the average amount of ozone in atmosphere is roughly _____ Dobson units

300

• height of 2 pennies stacked together

Atmospheric Pressure

the force with which a column of overlying air presses on an area of earth’s surface

Low pressure zone

where the density of air is less than average, and atmospheric pressure is below average

High pressure zone

regions of air density greater than average

In the Northern Hemisphere surface winds blow from _____________, and upper winds blow from south to north

north to south

• called north winds

In the southern hemisphere surface winds blow from ___________ and upper winds blow from north to south

south to north 

• called south winds

What are winds named for?

the direction from which they flow

Coriolis effect

the deflection of moving air relative to earth’s surface

Air is deflected to the _____ in the northern hemisphere

right

Air is deflected to the _____ in the southern hemisphere

left

Trade winds

between 0 degrees and 30 degrees N and S, the surface winds are deflected relative to earth, blowing from the north and east in the northern

Westerlies

between 30- and 60-degrees N, the deflected surface flow produces winds that blow from the south and west, while between 30 and 60 degrees S, they blow from north and west

Polar easterlies

between 60 degrees N and the north pole, the winds blow from the south and east, while between 60 degrees south and the south pole they blow from the south and east

Doldrums

the area of rising air at the equator

Horse Latitudes

the high pressure areas at 30 degrees N and S

Intertropical Convergence Zone (ITCZ)

the formal name for the zone of low pressure and rising air near the equator