Chapter 7: Global Climate & Biomes

Variations in climate determine the dominant plant growth forms of terrestrial biomes

Objective(s): SWBAT explain the forces that drive

global circulation patterns and how those patterns determine weather & climate.

SWBAT describe the unequal heating of the Earth.

SWBAT diagram the atmospheric circulation of the Earth.

SWBAT describe the coriolis effect.

Variations in climate determine the dominant plant growth forms of terrestrial biomes

Objective(s): SWBAT describe gyres & upwelling. SWBAT summarize El Nino oscillation. SWBAT summarize the major terrestrial biomes.

SWBAT analyze climate diagrams.

Variations in climate determine the dominant plant growth forms of terrestrial biomes

C7: Global Climate

Layers of the Atmosphere

Thermosphere: largest span of altitude; blocks harmful X-ray and UV radiation.

Mesosphere: Middle layer. Stratosphere: Ozone layer

absorbs most of the UV-B radiation

Troposphere: layer closest to the Earth. Densest layer of the atmosphere containing most of the nitrogen, oxygen and water vapor. Almost all weather occurs here.

C7: Global Climate

Weather - the short term conditions of the atmosphere in a local area. These include temperature, humidity, clouds, precipitation, wind speed and atmospheric pressure.

Climate - The average weather that occurs in a given region over a long period- typically several decades to thousands of years

Chapter 7: Global Climate

C7: Global Climate

Climate varies in different parts of the Earth due to: Patterns of global air circulation Ocean currents This distributes heat and precipitation

unevenly

C7: Global Climates

3 Major Factors affect air circulation in the lower atmosphere: Variation in angle at which the Sun’s rays

strike the Earth (unequal heating of earth’s surface)

Chapter 7: Global Climates

3 Major Factors affect air circulation in the lower atmosphere: Rotation of the Earth on its axis.

Chapter 7: Global Climates

Earth’s Rotation on its axis

As Earth rotates, its surface moves much faster at the equator than in the mid-latitude regions and polar regions due to the variation in the circumference of the Earth’s surface.

Coriolis effect: the deflection of an object's path due to Earth's rotation.

Earth’s Rotation & Coriolis effect

3 Major Factors affect air circulation in the lower atmosphere: Some areas of the Earth reflect more solar

energy than others. (properties of air, water and land) Albedo: The percentage of incoming light that is reflected from

the surface. The higher the albedo of a surface, the more solar energy is reflected and the less that is absorbed.

Chapter 7: Global Climates

Albedo Averages

Albedo

Properties of air that influence its movement: Density: Less dense air rises. Warm air has

a lower density than cold air, so warm air rises.

Water Vapor Capacity: Warmer air has a higher capacity for water vapor than cold air. Saturation Point: The maximum amount of

water vapor that air will retain at a given temperature

C7: Global Climates

Atmospheric Global Circulation

Polar Cell: convection currents formed by air that rises at 60° N & S and sinks at the poles.Mid-Latitude Cell (ferrel cell): convection currents between 30° & 60°Hadley Cells: convection currents between the equator and 30° N & S **Regions at30° N & S are typically, hot, dry deserts

The prevailing winds systems of the world are produced by: Atmospheric convection currents Coriolis Effect

http://video.pbs.org/video/2365036901/ https://www.youtube.com/watch?v=Pb69HENUZs8 https://www.youtube.com/watch?v=dt_XJp77-mk https://www.youtube.com/watch?v=i2mec3vgeaI

C7: Global Climates

Earth’s axis of rotation is tilted at 23.5˚, therefore Earth’s orbit around the sun causes most regions of the world to experience seasonal changes in temperature and precipitation. (causes seasons)

Earth’s Tilt and the Seasons

Ocean currents are driven by a combination of temperature, gravity, prevailing winds, the Coriolis effect, and the locations of continents.

Warm water, like warm air, expands and rises. Gyres- the large-scale patterns of water

circulation. The ocean surface currents rotate in a clockwise direction in the Northern Hemisphere and a counterclockwise direction in the Southern Hemisphere.

Ocean currents can affect the temperature of nearby land masses.

Ocean Currents

5 Major Gyres Worldwide

SUBTROPICAL GYRES, Form at Center of Subtropical High PressureDiagram reinforces how Coriolis Effect Causes Cold Water Upwelling as well

Fish Ingestion of Plastichttp://vimeo.com/8306883Planet 100https://www.youtube.com/watch?v=xc6LvdsyJ4UCharles Moorehttps://www.youtube.com/watch?v=en4XzfR0FE8Ocean Pollution Awarenesshttps://www.youtube.com/watch?v=1qT-rOXB6NI5 Gyres Research Team5 Gyres Team Website: http://5gyres.org/

As more plastic trash flows from……our watersheds to the sea, scientists are finding that plastic debris is accumulating in the each of the 5 oceanic gyres. Research conducted by the Algalita Marine Research Foundation highlighted the “Pacific Garbage Patch”, – an area of plastic accumulation in the North Pacific between California and Hawaii. Studies by the Sea Education Association, (SEA), in the Atlantic have documented plastic pollution in the North Atlantic Gyre.

Upwelling - as the surface currents separate from one another, deeper waters rise and replace the water that has moved away.

This upward movement of water brings nutrients from the ocean bottom that supports the large populations of producers, which in turn support large populations of fish.

Upwelling

Thermohaline circulation- oceanic circulation that drives the mixing of surface water and deep water.

Crucial for moving heat and nutrients around the globe and can take hundreds of years to complete.

Thermohaline Circulation

1. Warm water flows from the Gulf of Mexico to the North Atlantic, where some of it freezes and evaporates.

2. The remaining saltier, denser water sinks to the ocean bottom.

3. The cold water current travels along the ocean floor, connecting the world’s ocean.

4. The cold, deep water eventually rises to the surface in the North Pacific and circulates back to the North Atlantic

Thermohaline Circulation

Thermohaline Circulation

(ENSO): Every 3 to 7 years, the interaction of the Earth's atmosphere and ocean cause surface currents in the tropical Pacific Ocean to reverse direction.

Trade winds near South America weaken.

This allows warm equatorial water from the western Pacific to move eastward toward the west coast of South America.

Movement of warm water & air toward South America suppresses upwelling off the coast of Peru and decreases productivity there, reducing fish populations near the coast.

These periodic changes in wind and ocean currents are collectively called the EL Nino-Southern Oscillation, or ENSO.

El Nino Southern Oscillation (ENSO)

Impact of ENSO globally: Cooler and wetter conditions in the SE

USA Unusually dry weather in South Africa

and SE Asia

EL Nino Southern Oscillation (ENSO)

Global Circulation Patterns during El Nino

When air moving inland from the ocean containing a large amount of water vapor meets the windward side of a mountain range , it rises and begins to experience cooling.

Because water vapor condenses as air cools, clouds form and precipitation falls.

The presence of the mountain range causes large amounts of precipitation to fall on its windward side.

Cold, dry air then travels to the other side of the mountain range (the leeward side), descends and warms, releasing little moisture resulting in semiarid or arid conditions

Rain Shadows

Rain Shadows

Climate affects the distribution of species around the globe.

Organisms possess distinct growth forms due to adaptations to local temperature and precipitation patterns.

Biomes- The presence of similar plant growth forms in areas possessing similar temperature and precipitation patterns.

Variations in climate determine the dominant plant growth forms of terrestrial biomes

Biome Locations

Biomes: Arctic Tundra (Cold Grasslands)

Temperatures Range by Season (-34º C - 12ºC)Rainfall (15 – 25 cm/yr) Specific Abiotic Factors: Soggy Summers, permafrost; cold & dark much of yearPlants: Treeless, Short grasses & shrubsAnimals: Caribou, polar bears, wolves, birds, insects, salmon, trout

Cold, treeless biome with low-growing vegetation. In winter, the soil is completely frozen.

The tundra's growing season is very short, usually only about 3 months during summer.

The underlying subsoil, known as permafrost is an impermeable, permanently frozen layer that prevents water from draining and roots from penetrating.

Biomes: Arctic Tundra (Cold Grasslands)

Biomes: Boreal Forest (Evergreen Coniferous Forest)

Cool Temperatures (-54º C - 21ºC)Rainfall (30 – 84 cm/yr)Specific Abiotic Factors: Summers are short & moist, winters are long, cold & dryPlants: Spruce & Fir trees, Deciduous trees Animals: moose, beavers, deer, mountain lions, birds, & wolverines

Forests made up primarily of coniferous (cone-bearing) evergreen trees that can tolerate cold winters and short growing seasons.

Boreal forests are found between about 50˚ and 60˚ N in Europe, Russia and North America.

This subarctic biome has a very cold climate, and plant growth is more constrained by temperature than precipitation.

The soil is nutrient-poor due to slow decomposition.

Biomes: Boreal Forest(Evergreen Coniferous Forest)

Temperate Rainforests

Our Local Temperate Rainforest

Moderate temperatures and high precipitation typify the temperate rainforest.

The temperate rainforest is a coast biome and can be found along the west coast of North America from northern California to Alaska, in southern Chile, on the west coast of New Zealand, and on the island of Tasmania.

The ocean currents help moderate temperature fluctuations and provide a source of water vapor.

This biome has a nearly 12-month growing season where winters are rainy and summers are foggy.

The mild temperatures and high precipitation supports the growth of very large trees.

Temperate Rainforests

Biomes: Temperate Seasonal (deciduous) Forest

Temperatures Range by Season (Winter: -30º C - 25ºC/Summer: )Moderate Rainfall (75 – 150 cm/yr) {most during spring}Specific Abiotic Factors: Well defined seasons; Summers are hot, winters are coldPlants: Oak, Beech and Maple Trees (drop leaves in fall)Animals: squirrels, rabbits, skunks, deer, birds, deer, foxes, black bears, raccoons

Receive over 1 m (39 inches) of precipitation annually.

Found in the eastern United States, Japan, China, Europe, Chile and eastern Australia.

Dominated by broadleaf deciduous trees such as beech, male, oak and hickory.

Warmer summer temperatures favor decomposition so soils generally contain more nutrients than those of boreal forests.

Temperate Seasonal Forest

Found on the coast of southern California, southern Australia, southern Africa and in the area surrounding the Mediterranean Sea.

Hot, dry summers and mild, rainy winters are characteristic of this biome.

There is a 12-month growing season, but plant growth is constrained by low precipitin in summer and by relatively low temperatures in winter.

Wildfires are common and plants of this biome are well adapted to both fire and drought.

Temperate Shrubland/Chaparral

Temperate Shrubland/Chaparral

Temperatures Range by Season (10º C - 40ºC)Rainfall (38 – 100 cm/yr){mostly in winter} Specific Abiotic Factors: Summers are very dry and hot, winters are cool and wetPlants: Oaks (deciduous and evergreen)Animals: foxes, jackrabbits, birds, bobcats, lizards, snakes

Biomes: Temperate Grassland

Temperatures Range by Season (-40º C - 38ºC)Moderate Rainfall (50 – 89 cm/yr) Specific Abiotic Factors: Summers are hot, winters are coldPlants: Grasses and herbsAnimals: gazelles, bison, deer, mice, coyotes,Foxes, wolves, birds, snakes, grasshoppers, spiders

This biome has the lowest average annual precipitation of any temperate biome. (25cm - 90 cm)

These are found in the Great Plains of North America, in South America, and in central Asia and eastern Europe.

Cold, harsh winters and hot, dry, summers characterize this biome.

Plant growth is constrained by both insufficient precipitation in summer and cold temperatures in winter.

Plants include grasses and non woody flowering plants that are well adapted to wildfires and frequent grazing by animals

Temperate Grassland

Biomes: Tropical Rain Forest

Warm Temperatures (24º C - 26ºC)Abundant Rainfall (200 – 1000 cm/yr)Specific Abiotic Factors: humid all year, hot & wetPlants: Broadleaved Evergreens, Bamboo, Sugar CaneAnimals: Elephants, Sloths, Elephants, Cobras

In the tropics, average annual temperatures exceed 20˚C.

This biome is located approximately 20˚ N and S of the equator.

They are found in Central and South America, Africa, Southeast Asia, and northeastern Australia.

Precipitation occurs frequently and this biome is warm and wet with little temperature variation.

Tropical rain forests have more biodiversity per hectare than any other terrestrial biome and contain up to two-thirds of Earth's terrestrial species.

Tropical Rain Forest

Biomes: Tropical Seasonal Forest (Savanna)

Warm Temperatures (20º C - 30ºC)Moderate Rainfall (50 – 130 cm/yr) {mostly during the rainy season}Specific Abiotic Factors: Summers are hot & rainy, winters are cool & dryPlants: Grasses, scattered treesAnimals: Lions, hyenas, elephants, cheetahs, zebras, birds, insects

Warm temperatures and distinct wet and dry seasons characterize this biome.

Tropical seasonal forests are common in much of Central America, on the Atlantic coast of South America, in southern Asia, in northwestern Australia, and in sub-Saharan Africa.

Soil in this biome is fairly fertile and can be farmed due to high decomposition rates, but the low amount of precipitation constrains plants from using the soil nutrients that are released.

Grasses and scattered deciduous trees are common.

Tropical Seasonal Forest (Savanna)

Biomes: Subtropical Desert

Range in Temperature: {High: 20º C - 49ºC Low: -18º C – (-10ºC )}

Low Rainfall (2 – 26 cm/yr)Specific Abiotic Factors: varying temps, low rainfallPlants: Cacti, Joshua Trees, SucculentsAnimals: Lizards, Bobcats, birds, tortoises, snakes, antelope, desert toads, rats, ground squirrels

This biome is found at 30˚ N and S with hot temperatures and extremely dry conditions.

The Mojave Desert in the southwestern United States, the Sahara in Africa, the Arabian Desert of the Middle East and the Great Victoria Desert of Australia are all subtropical deserts.

Cacti, euphorbs and succulent plants are well adapted to this biome.

Subtropical Desert