Solar RadiationSolar Radiation

o 69% of incoming solar radiation is absorbed by atmosphere and earth

• Remainder is reflectedo Albedo

• The reflectance of solar energy off earth’s surface

• Dark colors = low albedo• forests, ocean, asphalt

• Light colors = high albedo• ice caps, desert sands,

clouds

o Sun provides energy for life, powers biogeochemical cycles, and determines climate

4 way 4 way Solar Radiation Solar Radiation makes makes life on earth possiblelife on earth possible

o warming the planet to a habitable tempo powers the biogeochemical cycleso allows producers to photosynthesize

and feed other living organismso stored in fuels – wood, oil, coal, nat’l

gas

Temperature Changes with LatitudeTemperature Changes with Latitude

o Solar energy does not hit earth uniformly• Due to earth’s spherical shape and tiltEquator (a)

High concentration Little Reflection High Temperature

Closer to Poles (c)

Low concentration

Higher Reflection Low

Temperature

From (a) to (c)

In diagram below

Temperature Changes with Temperature Changes with SeasonSeason

o Seasons caused by earth’s tilt (23.5°)

o Causes each hemisphere to tilt toward the sun for half the year

o Hem. Tilted toward sun receives more direct solar radiation & warmer temps.

o Northern Hemisphere tilts towards the sun from March 21- September 22 (warm season)

Temperature Changes with Temperature Changes with SeasonSeason

Seasons Seasons o Hem. tilted toward sun rec. more direct solar radiation

o Northern Hemisphere• Summer Solstice – Earth tilts toward sun

• First day of Summer• June 21 or 22

• Autumnal Equinox – Earth along side sun • First day of Fall• Sept 21 or 22

• Winter Solstice – Earth tilts away from sun • First day of Winter• Dec 21 or 22

• Vernal Equinox – Earth along side sun • First day of Spring• Mar 21 or 22

The AtmosphereThe Atmosphere

o Invisible layer of gases that envelopes earth

o Content• 21% Oxygen• 78% Nitrogen• 1% Argon, Carbon Dioxide,

Neon and Helium, …

o Density decreases with distance from earth

o Shields earth from high energy radiation

Atmospheric LayersAtmospheric Layerso Troposphere (0-10km)

• where we live• where weather occurs• temp decreases with altitude

o Stratosphere (10-45km)• temp increases with altitude• very stable• Ozone layer absorbs UV

o Mesosphere (45-80km)• temp decreases with altitude• down to -138oC, -216oF

Atmospheric LayersAtmospheric Layers

o Thermosphere (80-500km)• gases in thin air absorb x-rays

and short-wave UV radiation = very hot, 1000oC, 1832oF

• source of aurora

o Exosphere (500km and up)• outermost layer• no distinct boundary between

it and outer space• just continues to thin

Atmospheric CirculationAtmospheric Circulation

o Warm air rises, cools and splits to flow towards the poles

o ~30° N & S sinks back to surface

o air hits surface and splits to flow N & S

o air warms and rises again at ~60° N & S

o air sinks at poles

Moves heat from equator to the poles

Heat is transferred throughout Heat is transferred throughout atmosphere in 3 waysatmosphere in 3 ways

o Radiation• heat energy transferred in the form of rays or waves• land and water absorb heat

o Conduction• heat energy transferred through direct contact• air above land is in direct contact with land• *heat is always transferred from warmer to cooler

o Convection • heat energy transferred through the flow of a fluid

(liquid or gas)• warm air rises because less dense• cool air sinks because more dense

Surface WindsSurface Winds

o Large winds due in part to high and low pressures caused by global circulation of air

o Winds blow from high to low pressure

o Little wind at latitudes of 0, 30, 60 & 90 because air rising or sinking

LowLow

LowLow

LowLow

HighHigh

HighHigh

HighHigh

HighHigh

Prevailing WindsPrevailing WindsWinds are named for the direction FROM

WHICH they moveoPolar Easterlies

• blow from East to West• Between 90o and 60o N or S

oPrevailing Westerlies • blow from West to East • Between 30o and 60o N or S

oTrade Winds • blow from East to West• Between 0o and 30o N or S

Which of these are “our“ winds?Prevailing Westerlies

Global Ocean CirculationGlobal Ocean Circulation

o Prevailing winds produce ocean currents and generate gyres

o Example: the North Atlantic Ocean• Trade winds blow west• Westerlies blow east (these are our winds)• Creates a clockwise gyre in the North

Atlantic

o Circular pattern influenced by coriolis effect

Coriolis EffectCoriolis Effect

o Earth’s rotation influences direction of wind• Earth rotates from East to West• Deflects wind from straight-line path

o Coriolis Effect• Influence of the earth’s rotation on movement

of air and fluids• Turns them Right in the Northern Hemisphere• Turns them Left in the Southern Hemisphere

o chalk board globe

Coriolis EffectCoriolis Effect

o Visualize it as a Merry-Go-Round (see Visualize it as a Merry-Go-Round (see below)below)

Global Ocean CirculationGlobal Ocean Circulation

Trade windsTrade winds

WesterliesWesterlies

Position of LandmassesPosition of Landmasses

Very little land in the Southern Hemisphere

Large landmasses in the Northern Hemisphere dictate ocean currents and flow

Vertical Mixing of OceanVertical Mixing of Ocean

Ocean Interaction with Atmosphere- Ocean Interaction with Atmosphere- ENSOENSO

o El Niño-Southern Oscillation (ENSO)• Def: periodic large scale warming of surface waters of

tropical eastern Pacific Ocean

o Alters ocean and atmospheric circulation patterns

o Normal conditions- westward blowing tradewinds keep warmest water in western Pacific

o ENSO conditions- trade winds weaken and warm water expands eastward to South America

• Big effect on fishing industry off South America

ENSO Climate PatternsENSO Climate Patterns

Weather and ClimateWeather and Climate

o Weather• conditions in the atmosphere at a given

place and time• temperature, precipitation, cloudiness, etc.

o Climate• average weather conditions that occur in a

place over a period of years• 2 most important factors: temperature and

precipitation• Earth as many climates

Rain ShadowsRain Shadowso Mountains force humid air to riseo Air cools with altitude, clouds form and

precipitation occurs (windward side)o Dry air mass moves down opposite

leeward side of mountain

TornadoesTornadoes

o Powerful funnel of air associated with a severe thunderstorm

o Formation• Mass of cool dry air collides with warm humid

air• Produces a strong updraft of spinning air

under a cloud• Spinning funnel becomes tornado when it

descends from cloud

o Wind velocity= up to 300mpho Width ranges from 1m to 3.2km

Hurricanes / Tropical CycloneHurricanes / Tropical Cyclone

o Giant rotating tropical stormso Wind >119km per houro Formation

• Strong winds pick up moisture over warm surface waters

• Starts to spin due to Earth’s rotation• Spin causes upward spiral of clouds

o Damage on land• High winds• Storm surges

Internal Planetary ProcessesInternal Planetary Processeso Layers of the earth

• Crust (oceanic & continental), mantle, core• Lithosphere – crust + upper mantle

• rigid rock layer • tectonic plates

• Asthenosphere – lower mantle• molten

o Plate Tectonics - study of the processes by which the lithospheric plates move over the asthenosphere

Plate Boundary- where 2 plates meeto 3 types

• convergent – plates moving toward each other• volcanoes & EQ

• divergent - plates moving away from each other

• mid-ocean ridges, volcanic activity• transform – plates sliding/grinding past each

• earthquakes

Mantle Convection• Causes plate movement• Convection currents in asthenosphere move

beneath lithosphere and drag plates along

Plates and Plate BoundariesPlates and Plate Boundaries

Types of Plate BoundariesTypes of Plate Boundaries

• oceanic-continental crust = subduction of oceanic plate (as shown) • Examples:• Andes Mountains• Cascade Range in

Oregon and Washington state – Mt. Saint Helen’s

• continental-continental = no subduction; HUGE mountain ranges

• Examples: • Himalayas, Apalachian

Mountains

Convergent Plate Boundary: plates move toward each other

Types of Plate BoundariesTypes of Plate Boundaries

Divergent Plate Boundary: plates move away from one anotherExamples: Mid-Atlantic Ridge

Types of Plate BoundariesTypes of Plate Boundaries

o Transform Plate Boundary: plates move horizontally in opposite, parallel directions

o Examples: • San Andres Fault,

CA

EarthquakesEarthquakes

o Caused by the release of accumulated energy as rocks in the lithosphere suddenly shift or break• Occur along faults• Energy released as seismic wave

o Focus- where earthquake originates below the surface

o Epicenter- located on the earth’s surface, directly above the focus

o Richter scale and the moment magnitude scales are used to measure the magnitude

TsunamiTsunami

o Giant undersea wave caused by an earthquake, volcanic eruption or landslide• Travel > 450mph

o Tsunami wave may be 1m deep in ocean• Becomes 30.5m high on shore

o Magnitude 9.3 earthquake in Indian Ocean• Triggered tsunami that killed over 230,000

people in South Asia and Africa