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