Atmospheric and Oceanic
Interactions
Air pressure
the force of air
on a surface
Did You Know?
 Air pressure is caused by
the weight of all the
molecules that make up
the air.
 - the combined force of air
on just 1 square foot of
surface, is about a
ton!
Did You Know?
a high pressure system usually brings cooler
temperatures and clear skies.
a low pressure system usually brings warmer
weather, storms and rain.
Coriolis Effect
the curving of
moving objects,
including wind,
from a straight path
due to Earth’s
rotation
Did You Know?
The Coriolis effect
causes wind and
ocean surface
currents to curve to
the right north of the
equator, and left
south of the equator.
Did You Know?
 There is an old urban myth that
the Coriolis effect causes water
going down drains or toilets to
turn different directions above
and below the equator?
 This myth is false! The Coriolis
effect doesn’t influence such
small bodies of water.
Air Mass
a large body of air that is similar in
temperature, humidity, and air
pressure throughout
Did You Know?
Air masses are
categorized by
temperature
and moisture.
Did You Know?
When two
different air
masses meet,
the boundary is
called a “front”
– there are 4
basic types.
Convection Current
the vertical
circular motion of
a fluid (such as
air) in which hot
material rises
while cold material
sinks
Did You Know?
Convection currents
can happen in any
material that flows,
liquid or gas –
 Earth’s mantle
 Atmosphere
 Oceans
 And lava lamps!!!
Did You Know?
 Convection currents
happen because heating
and cooling changes
density
 Heating decreases
density; less dense
material floats.
 Cooling increases
density; more dense
material sinks.
Land Breeze
a wind that blows from the land to
the sea at night
Did You Know?
 The air over the ocean stays
warm longer than the air
over the land, after the Sun
goes down?
 This causes convection
currents that create land
breezes blowing toward
the ocean at night.
Sea Breeze
a wind that
blows from the
sea to the land
during the day
Did You Know?
 On a hot, sunny day the
temperature of the sea
hardly changes but the
land heats up quickly.
 This causes the light
breezes to blow toward
land instead, making sea
breezes.
Psychrometer
instrument used
to measure the
humidity of air
Did You Know?
 Hotter air can hold
more water,
generally.
 Since your sweat can’t
evaporate to cool you
as quickly if humidity
is high, it feels even
HOTTER!
Did You Know?
 The most humid state
in the United States is
Washington.
 The most humid
regions of the world
are coastal areas near
the equator, like
Thailand and India.
Prevailing Winds
wind that blows
predominantly
from a single
direction
Did You Know?
 If it wasn’t for the
trade winds, America
might not exist!
 in the 18th century,
ships used them to
cross the Atlantic
Ocean.
Anemometer
instrument that
records wind
speed and
direction
Did You Know?
 The first anemometer was
invented in 1450 by an
Italian architect, Battista
Alberti.
 He was called the
“prophet” of the
Renaissance.
Deep Currents
 currents formed when
cold air temperatures
and high salinity (salt)
of surface currents
make water denser,
causing it to sink to
the bottom; thus
resulting in
movement
Did
You
Know?
 The ocean has three temperature
layers.
 1. The surface, temperatures vary 030 deg C.
 2. The thermocline, temperatures
decrease with depth.
 3. The deep layer is below 1000 m,
the temperature is near 0– 5 deg
C and there is no seasonal change.
Did You Know?
 Changes in deep currents can
slow the global currents enough
to cause “mini-ice ages”.
 1350-1850; scientists call it the
“Little Ice Age” and it affected
climate all over the world.
 Some scientists think it may be
happening, again.
Surface Currents
water movement
3-10 ft below the
surface nearshore
and 33 ft in deep
ocean areas
Did You Know?
 Surface and deep water
currents connect the
currents in all of Earth’s
oceans, in a giant “Global
Conveyor Belt”
 This means that what
happens in one ocean,
affects all of the world’s
oceans.
Gulf Stream
warm ocean
current flowing
Northeastwards
off the Atlantic
Coast of the U.S.
from the Gulf of
Mexico
Did You Know?
 The warm waters of the
Gulf Stream make it
possible for some areas of
Northern Europe have
milder climates than places
just as far north in Canada.
Hurricane
a large, rotating
tropical storm with
wind speeds of at
least 74 mph
Did You Know?
 Hurricanes lose
strength when they go
on land or into cold
waters, so they usually
form in oceans near the
equator.
 They need warm
waters to provide
energy for the storm.
Did You Know?
 Every second, a large
hurricane can release the
energy of 10 atomic bombs.