Why is one area of the earth’s land surface a desert, another a grassland, and another a forest?

Climate- long term weather patterns

Weather- momentary conditions of the atmosphere; created by the unequal heating & cooling of the earth’s surface.

I. Climate

Temperature & Precipitation- major factors that determine an areas climate.

Humidity- the amount of water vapor air holds, which is dependent upon temperature.

Winter solsticeDec. 22Sun vertical at 23.5oS

Winter solsticeDec. 22Sun vertical at 23.5oS

Autumnal equinoxSep. 23Sun vertical at equator

Summer solsticeJune 21Sun vertical at 23.5oN

Vernal equinoxMarch 21Sun vertical at equator

Northern Hemisphere Names

Earth further from sun

Earth closer to sun

Solar irradiance-

What are some factors that effect exposure to irradiance?

The radiant energy emitted by the sun.

It is highest at the equator and lowest at the poles.

We are interested in conditions near the Earth’s surface

Convection cell model

Non-rotating Earth

Add rotation and add landmasses unequal heating and cooling of the Earth

Physical properties of the atmosphere: Density

• Warm, low density air rises

• Cool, high density air sinks

• Creates circular- moving loop of air (convection cell)

Physical properties of the atmosphere: Water vapor

• Cool air cannot hold much water vapor, so is typically dry

• Warm air can hold more water vapor, so is typically moist

• Water vapor decreases the density of air

Physical properties of the atmosphere: Pressure

• A column of cool, dense air causes high pressure at the surface, which will lead to sinking air

• A column of warm, less dense air causes low pressure at the surface, which will lead to rising air

ITCZ intertropical convergence zone= doldrumsLow pressure, wet climate

High pressure, dry climate

Low pressure, wet climate

30o

30o

60o

60o

90o

90o

0o

High pressure, dry climate

A) Idealized winds generated by pressure gradient and Coriolis Force. B) Actual wind patterns owing to land mass distribution..

Seasonal changes in the position of the ITCZ

January

Winter monsoon-Dry

Summer monsoon-Wet

BiomeA major type of ecological community, determined largely by climate.

Forest

Tundra

Grassland

Desert

Tundra Chaparral

Tropical rainforest

Temperate Evergreen Forest

Temperate Deciduous Forest

Polar Ice

Grassland Taiga Desert Mountain Zones

Marine Biome

• Consists of oceans, coral reefs, and estuaries• The ocean is the largest of all ecosystems.• The ocean contains a diverse array of plants and

animals at various depth zones.• Coral reefs consist mainly of coral.• Estuaries are areas where fresh and salt water

environments converge. Mangroves, oysters, crabs and marsh grasses are examples of species in this environment.

Marine Biome

Hydrologic Cycle

Water Cycle in Hawaii

Rain shadow effect

The Coriolis effect• The Coriolis effect

– Is a result of Earth’s rotation– Causes moving objects to follow

curved paths:• In Northern Hemisphere, curvature

is to right• In Southern Hemisphere, curvature

is to left

– Changes with latitude:• No Coriolis effect at Equator• Maximum Coriolis effect at poles

The Coriolis effect on Earth

• As Earth rotates, different latitudes travel at different speeds

• The change in speed with latitude causes the Coriolis effect

equator

Quito

Buffalo

79oW

North Pole

South Pole

N

Quito

Buffalo

equa

tor

Buffalo moves 783 mphQuito moves 1036 mph

15o

• Gyres are large circular-moving loops of water• subtropical gyres

• Five main gyres (one in each ocean basin):• North Pacific• South Pacific• North Atlantic• South Atlantic• Indian

• Generally 4 currents in each gyre• Centered about 30o north or south

latitude

Current GyresCurrent Gyres

Geostrophic flow and western intensification

• Geostrophic flow causes a hill to form in subtropical gyres

• The center of the gyre is shifted to the west because of Earth’s rotation

• Western boundary currents are intensified

Figure 7-7

Western intensification of subtropical gyres

• The western boundary currents of all subtropical gyres are:– Fast– Narrow– Deep

• Western boundary currents are also warm• Eastern boundary currents of subtropical gyres

have opposite characteristics

Boundary Currents in the Northern Hemisphere

Type of Current General Features Speed Special Features

Western boundary Currents warm swift sharp boundary Gulf Stream, Kuroshio narrow w/coastal circulation,

deep little coastal upwelling

Eastern Boundary Currents cold slow diffuse boundariesCalifornia, Canary broad separating from coastal

shallow currents, coastal upwelling common

Wind-driven surface currents

Pacific Ocean surface currents

What do Nike, rubber What do Nike, rubber ducks, and hockey ducks, and hockey gloves have to do with gloves have to do with oceanography?oceanography?

2004-2007 Barber’s Point

Japan Tsunami 2011Prediction of Marine Debris Drifting Trajectories

Hawaii

http://www.hawaii247.com/2011/04/07/tsunami-2011-japan-debris-likely-to-hit-hawaii-twice/

http://www.hawaii247.com/wp-content/uploads/2011/04/JapanTsunamiDebrisFlow.jpg

Sea Surface Temperature

Origin and paths of tropical cyclones

• Tropical cyclones are intense low pressure storms created by:

– Warm water

– Moist air

– Coriolis effect

Hurricanes produce storm surge

• Storm surge:– Is a rise in sea level

created by hurricane coming ashore

– Can be up to 12 meters (40 feet) high

– Causes most destruction and fatalities associated with hurricanes

Dynamics of a Tropical Cyclone

Counter current circulation in Northern Hemisphere

L

Air moves toward zone of low pressure and veers off course to right

Hurricanes in Hawaii

Hurricane season- June 1 to November 30

Hurricanes approach from both east and south

Hawaii rarely gets hit

Hawaii is subtropical

Hurricane Path in Hawaii

Hurricane Iniki 1992

Hurricane Daniel Aug 2000

Just missed us.

Hurricane Andrew

Eddy

Warm core ring1. Rotates clockwise2. Found on the landward side of the current

Cold core ring (cyclonic eddy)1. Rotates counterclockwise2. Forms on the ocean side of the current

A circular movement of water formed along the edge of a permanent current

In an average year, 10-15 rings are formed

150-300 km in diameter

Speed 1 m/sec

Sargasso Sea

Ekman spiral

• Ekman spiral describes the speed and direction of flow of surface waters at various depths

• Factors:– Wind– Coriolis effect

Ekman transport• Ekman transport is

the overall water movement due to Ekman spiral

• Ideal transport is 90º from the wind

• Transport direction depends on the hemisphere

Ekman Transport

Water flow in the Northern hemisphere- 90o to the right of the wind directionDepth is important

Upwelling and downwelling• Vertical movement of water ()

– Upwelling = movement of deep water to surface• Hoists cold, nutrient-rich water to surface• Produces high productivities and abundant marine life

– Downwelling = movement of surface water down• Moves warm, nutrient-depleted surface water down• Not associated with high productivities or abundant

marine life

upwelling

downwelling

Langmuir Circulation

Global Warming

The E-M Spectrum

Fate of Solar Radiation Fate of Solar Radiation Reaching the EarthReaching the Earth

reflectionreflectioncloudsclouds

snow and icesnow and ice

the earth’s surfacethe earth’s surface

atmospheric dustatmospheric dust

reflectionreflectioncloudsclouds

snow and icesnow and ice

the earth’s surfacethe earth’s surface

atmospheric dustatmospheric dust


absorptionabsorptionatmosphereatmosphere

oceansoceans

landland

plant photosynthesisplant photosynthesis

absorptionabsorptionatmosphereatmosphere

oceansoceans

landland

plant photosynthesisplant photosynthesis


radiationradiationradiationradiation

The Greenhouse Effect

Greenhouse GasesGreenhouse Gases

Carbon DioxideMethane

Nitrous OxideWater Vapor

Ozone

Thousands of Years Before Present

Tem

per

atu

re C

han

ge

(oF

)

Atm

osp

her

ic C

O2

(pp

m)

Year

Temperature

Carbon Dioxide

Tem

per

atu

re C

han

ge

(oF

)

Atm

osp

her

ic C

O2

(pp

m)

Atmospheric CO2 & Surface Temperature TrendsAtmospheric CO2 & Surface Temperature Trends

Sea level rise

Increased plant primary productivity

Shifts in the distribution of plants and animals

Water contamination and outbreaks of water-borne diseases

Increased storm severity

Potential melting or enlargement of polar ice caps

Changes to patterns of rainfall

More severe droughts or increased precipitation

changes to ocean circulation patterns

Predicted changes with increased greenhouse warming

Ice Age 18,000 years ago

Sea Level Changes due to Ice Ages and Ice Cap Melting

Year

Ch

ang

es in

Mea

n S

ea L

evel

Mean Sea Level RiseMean Sea Level Rise

Summer Arctic Sea Ice Decline Comparison between 1979 & 2005Summer Arctic Sea Ice Decline Comparison between 1979 & 2005

Year

Late Summer Arctic Sea Ice ExtentLate Summer Arctic Sea Ice Extent

Sea

Ice

Ext

ent

(mill

ion

km

2 )

Permafrost melting

Permafrost melting

Drunken forest

Year

North Atlantic Tropical Storms10-year running averageNorth Atlantic Tropical Storms10-year running average

Nam

ed T

rop

ical

Sto

rms

1 Meter Sea Level Rise Waikiki1 Meter Sea Level Rise Waikiki

http://www.soest.hawaii.edu/HMRG/FloodingOahu/index.phphttp://www.soest.hawaii.edu/coasts/sealevel/waikiki.html

Sea Level Rise

• Destroys coastal habitat (e.g. salt marshes, mangroves)

• Destroys human property• Increases pollution• Decreases freshwater supply

Effect on Marine Life• Phytoplankton bloom due to light and

temperature cues• Changes will impact food web• Hypoxia may result

Effect on Fisheries

• Migrations are in response to temperature• May impact fisheries

Effect on Corals• Coral bleaching • Leads to loss of habitat and food for reef-

dependent species

CurrentsOceanic conveyor belt may change ocean currents • Currents carry plankton• Bring food and oxygen• Distribute eggs and larvae• Remove wastes and pollutants

Salinity• Animals have a narrow range of tolerance• Glacial melting inputs lots of freshwater

Acidity• CO2 makes water acidic• Corals and other calcium carbonate species

can’t make skeleton• Impact on plankton development impacts food

web

Temperature• Higher temperature results in less O2

- Results in hypoxia• Ice melting leaves no resting/hunting areas for

polar bears• Antarctic Krill impacts food web

Invasive Species• Algae smothers coral• Invasive species out-compete natives

Weather Events

More severe weather patterns• El Niño• Hurricanes • Mudslides• Forest Fires• Drought

El Niño-Southern Oscillation (ENSO)

• El Niño = warm surface current in equatorial eastern Pacific that occurs periodically around Christmastime

• Southern Oscillation = change in atmospheric pressure over Pacific Ocean accompanying El Niño

• ENSO describes a combined oceanic-atmospheric disturbance

El Niño

• Oceanic and atmospheric phenomenon in the Pacific Ocean

• Occurs during December• 2 to 7 year cycle

Sea Surface Temperature

Atmospheric Winds

Upwelling

Normal conditions in the Pacific Ocean

El Niño conditions (ENSO warm phase)

La Niña conditions (ENSO cool phase; opposite of El

Niño)

El NiñoNon El Niño

1997

Non El Niño

El Niño

thermocline

upwelling

El Niño events over the last 55 years

El Niño warmings (red) and La Niña coolings (blue) since 1950. Source: NOAA Climate Diagnostics Center

http://www.cdc.noaa.gov/ENSO/enso.mei_index.html

http://www.cdc.noaa.gov/ENSO/enso.mei_index.html

Effects of severe El Niños

1. What is a convection cell?2. What are current atmospheric CO2

levels?3. Why don’t we see many hurricanes in

Hawaii?4. What is the fate of the majority of solar

radiation that strikes the Earth?5. What is a drunken forest?6. Describe the rain shadow effect.7. How are biomes defined?

Inquiry

Why is one area of the earth’s land surface a desert, another a grassland, and another a forest?

Documents

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