earth science final - 20

atmosphere

layer of gases surrounding the planet and retained by its gravity

atmospheric composition

mixture of gases dominated by N2 O2 and Argon
lower=90 N and O2
toposphere=gases
gradually becomes thinner as it goes up then dissapears

ozone layer

layer in the strateosphere with a relatively high concentration of ozone molecules: blocks ultraviolet light

atmospheric/barmetric pressure

force per unit area exerted on any surface beneath or within it

air density

density of air varies depending on its temperature and moisture content. cool an dry air is denser than hot and moist air.

atmospheric convention

cool dry air moves downward and displaces moist warm are upward. vertical movement of air produces regions of low and high air pressure

global wind patterns

they result primarily from temperature dirven convection, moisture effects, coriolis effect, and seasonal shifts in solar heating.

the coriolis effect

results from earths rotation and deflects the air currents to the right of their initial path in the northern hemisphere and to the left in the southern hemisphere

water in the atmosphere

water vapor in the atmosphere is concentrated in the equatorial zone, with less in subtropic and very little in polar regions

seasonal variations

result from cariation in the amount of solar radiation reaching the ground. tilt of the earths axis as it rotates around the sun

mid latitude and polar regions

seasonal cycle marked primarily by changes in temperature

equatorial/subequatorial regions

little temperature difference, seasons defined primarily by precipitation

monsoon

a heavy rainy season that last for several months with lasting climatic effects

continents/oceans

water retains heat better than air, large bodies of water moderate temperature variation.

humid continental climate

continental interiors tend to be more humid and experience greater temperature cariation than coastal regions because of continental effects on wind

cloud formation

ornographic uplift: moist winds are forced upwards by land elevation, where they cool and precipitate on the windward side

earths oceans

interconnected salt water body that surrounds the continents and fills earths deepest depressions

earth currents

any more or less continuous directed movement of ocean water
forces: earths roatation, wind, temp, moon pull
influences: shape of ocean basin, depth contours, shoreline, wind direction

ocean zones

costal zone-area between low tide line and landward limit of highest storm waves
neritic zone-shallow water zone above continental shelf
oceanic zone-open water
mixed layer-surface zone of water warmed by sun
pycnocline-transition of abrupt vertical chang

salinity

concentration of dissolved salts in seawater, ocean water has an average sanity of 3.5

seawater salty?

sodium leached out of ocean floor when oceans first formed, chloride from outgassing of underwater volcanoes and hydrothermal vents
LESS: freshwater runoff, upwelling cold
MORE: warm confined circulation

ocean temperature

decreases with depth,
mixed layerL near surface water is warmed bu sin
thermocline: abrupt vertical temperature change
deep water: consistently cold

water density

mass of water per unit volume. saltwater is denser than freshwater, cold water is denser than warm water.

ocean stratification

water stratification occures when water of different densities form layers that act as barries to mixing

halocline

layer of abrupt vertical salinity change

density driven currents

deep ocean currents are driven by density and temperature gradients. denser water with salt sinks to the ocean bottom and forms dens bottom layer(downwelling)

bottom water circulation

dense bottom water spreads out and around most of ocean floor, mid ridges circulation and brings deep water back to surface (upwelling) at surface water moves towards poles to complete cycle

thermohaline circulation

deep ocean density driven ocean basin currents: flow under surface of ocean and are hidden from immediate detection

downwelling

downward movement of surface water generally caused by converging currents or by a water mass that becomes denser than the surrounding water

upwelling

upward movement of water rising from ocean depths to the surface replacing surface water that is driven away by winds
Marked by: cold temps, high productivity

salinity changes

ocean water salinity has changed significantly over the last 40 years, the tropical atlantic surface water become saltier while north atlantic becomes fresher

wind driven circulation

surface ocean currents are generally wind driven" typically develope a spiral roatation pattern because of imposed wind stress

ekman spiral effect

results in currents flowing at an angle to driving winds

gulf stream

powerful warm and swift wind driven ocean current the transports warm tropical water from the caribean sea and gulf of mexico

coriolis effect

deflection of currents by earths rotation clockwise in northern hemisphere and counter clockwise in southern

gyre

rotational circulation that forms in each ocean basin centered on the subtropical high pressure region acceleration causes sea level to fall along mainland coasts