Geography 3: Patterns in Physical Geography

By Paul Blankenship, NBCT December 2015

Introduction

• Geographers divide the physical environment into “spheres.”

• The non-living environment defines what is possible for life.

• The environment impacts humanity; humanity impacts the environment.

The Spheres

• The “spheres” of geography include the lithosphere, hydrosphere, atmosphere, and biosphere.

Lithosphere

• The lithosphere refers to the mineral world.

• “Lithos” is Greek for “stone.”

• The lithosphere includes mountains, soil, rocks, oil, natural gas, metals, and the molten core of the Earth.

Hydrosphere

• The hydrosphere refers to the waters of Earth.

• The hydrosphere includes the oceans, seas, rivers, lakes, streams, and all bodies of water.

Atmosphere

• The atmosphere is the gaseous part of the environment.

• The atmosphere is composed of many gases, such as nitrogen, oxygen, and water vapor.

Biosphere

• The biosphere is the living part of the environment.

• “Bios” is the Greek word for life.

• The biosphere includes plants, animals, fungi, bacteria, and other living things.

The Earth and Sun• “Heliophysics” is the science

of studying the Sun and its interaction with the Earth and the rest of the solar system.

• “Helios” is the Greek word for “sun.”

• The Sun provides the energy for life on Earth.

• Without the Sun everything on Earth would die.

Reasons for the Seasons

• Why does Earth experience seasons?

• The Earth is tilted on its axis relative to the Sun.

• The hemisphere tilted toward the Sun experiences summer. The other hemisphere is in winter at that time.

Earthquakes

• Earthquakes may affect the distribution of mass in the Earth.

• According to NASA’s Brian Dunbar a massive earthquake in Japan changed the length of Earth’s day, shortening it by 1.8 milliseconds.

Hurricanes• Hurricanes are caused by the

interaction of the Sun, oceans, and atmosphere.

• The Sun heats the waters in the tropics. The rising warm water vapor meets cool air and condenses into clouds and rain. High altitude winds interact with the rising water vapor in a positive feedback loop that results in increasing wind speed and a storm.

Monsoon• A monsoon is a seasonal weather

pattern.

• Winds blow one direction for part of the year, and then reverse.

• This results in a rainy season and a dry season.

• In the American southwest high pressure from the tropics forces warm, moist air into the Rocky Mountains where it meets cooler air, causing thunderstorms.

Monsoon• The Indian monsoon is

similar; warm water vapor from the Indian Ocean moves up on the Indian Subcontinent, meeting cooler air and bringing rain.

• The word “monsoon” technically refers to the change of winds, but is commonly used to refer to the resulting rain.

Tornadoes• Tornadoes begin to form before thunderstorms occur.

• A change in wind direction starts an invisible horizontal (sideways) shaft of air spinning in the lower atmosphere.

• Rising air in the thunderstorm pulls the shaft or air into a vertical (upright) position. The area of rotation is two to six miles wide.

• Tornadoes, hail, and powerful straight-line winds occur in and around this area of rotation.

Processes that Shape the Physical Environment

• Some physical processes shape the physical environment over the long term.

• These include extreme weather, plate tectonics, glaciers, circulation patterns in the atmosphere and hydrosphere, and the El Niño/La Niña patterns.

Long Range Effects of Extreme Weather

• Extreme weather, while dangerous in the short term, may also have long-range effects.

• For example, Hurricane Katrina not only caused death and destruction in 2005 but also damaged the barrier islands that protected the Gulf Coast from past hurricanes. Therefore, future hurricanes may prove even more devastating.

Plate Tectonics

• Plate tectonics, the motion of the plates that form the Earth’s crust over the molten interior, creates the lithosphere that people experience.

• Pressure between plates moving together creates earthquakes. Over millennia plate collisions form mountain ranges.

Glaciers• Glaciers are enormous rivers

of ice made from snow.

• Glaciers expand during ice ages, covering the polar region and extending over continents and oceans. They lock away water, resulting in lower sea levels.

• Glaciers retreat during periods of global warming. The retreat of glaciers forms lakes and erodes mountain ranges (interactive glacier map).

Ocean and Atmospheric Circulation

• Circulation in the air and water of the Earth changes the environment over the long term.

• The winds create the surface currents of the oceans.

• The release of heat stored in the ocean drives the winds.

• The movement of air and water cause erosion of soil and stone, gradually wearing down mountains and carving canyons.

El Niño-Southern Oscillation (ENSO)

• The El Niño-Southern Oscillation (ENSO) Cycle is the change in temperature in the eastern Pacific Ocean near the Equator.

El Niño-Southern Oscillation (ENSO)

• El Niño (Spanish for “the boy”) and La Niña (Spanish for “the girl”) are the warm and cold phases of the ENSO cycle.

El Niño-Southern Oscillation (ENSO)

• The ENSO Cycle occurs over two to seven years. El Niño events are more frequent than La Niña events. Each lasts nine to twelve months.

El Niño-Southern Oscillation (ENSO)

• El Niño causes the U.S. Gulf Coast to experience wetter weather.

El Niño-Southern Oscillation (ENSO)

• La Niña causes the southern U.S. to have warmer winters.

Long-Range Effects of Erosion on Agriculture

• Farmers depend on top soil to grow crops. The nutrients needed by the crops are in the soil.

• Poor farming practices in the past caused soil erosion, leading to the Dust Bowl of the 1930s.

• Soil conservation is necessary to maintain the food supply of the world.

Long-Range Effects of Typhoons on Coastal Ecosystems

• Typhoons are hurricanes that happen in the western Pacific Ocean.

• Hurricanes and typhoons destroy coastal ecosystems through coastal erosion.

• Salt water from the ocean is swept into coastal wetlands, killing the vegetation holding the soil together with its roots.

• Aquatic species consumed by people as seafood may depend on habitats destroyed by coastal erosion.

Ecosystems and Biomes

• Ecosystems vary from place to place and over time.

• “Ecosystem” is defined as the organisms and their environment in a given area.

• “Biome” is defined as a type of ecosystem, such as rain forest, grassland, or tundra.

Soil• Soil changes in an ecosystem.

• Arable (farmable) soil is created as living things live and die on the land or rivers deposit soil rich in decomposing matter on the land through flooding or changing course.

• Early humans used fire to make land more fertile and to suppress undesirable plant growth.

• Failure to rotate crops or leave land fallow degrades the land and allows wind to carry away good top soil.

Climate• Climate changes over time.

• 716 million years ago the equator was covered in ice during a period known as “Snowball Earth.”

• During the Permian Period (299 to 251 million years ago) to the continents were together in a large mass called “Pangea.” The climate was extreme, ranging from freezing at night to over 100 degrees Fahrenheit during the day.

Climate• Climate changes over time.

• Humans survived the Ice Age of the Pleistocene Epoch and have endured climate change throughout the current Holocene Epoch.

• The Medieval Warm Period (9th to 13th centuries) saw higher temperatures improve crop yields in Europe.

Climate

• Climate changes over time.

• The Little Ice Age that followed motivated fur traders to explore North America.

• Today’s climate is the warmest in 1200 years. Carbon emissions by humans are commonly blamed for the current global warming.

Topography

• Elevation changes because of natural and human causes.

• Natural causes of elevation change include erosion, both gradual and sudden. Flooding may wash out gullies in a matter of hours.

• Strip mining removes the surface of the Earth to access minerals.

Floods

• Floods may quickly change the landscape.

• Flooding may destroy property, kill people and animals, and cause erosion.

• However, flooding near coastal wetlands brings needed fresh water and prevents coastal erosion by saving freshwater aquatic plants.

Forest Fires

• Fire is a natural part of many ecosystems.

• Forest fire prevention efforts, while well intended, may backfire if the buildup of fuel leads to more intense fires rather than more manageable fires. Controlled burning is used in some places to prevent the worst fires.

Reduction of Species Diversity Due to Loss of Natural Habitats

• Species specialize in living in certain environments.

• The sudden loss of these environments kills off species dependent on that environment.

• For example, the loss of Louisiana’s wetlands may result in the loss of some species that humans consume as seafood.

Reduction of Wetlands due to Replacement by Farms

• Some wetlands have been replaced by farms as farmers drain the swamps and convert them to fields.

• While this increases the amount of arable land it decreases the wetland environment available to some species.

Reduction of Forest and Farmland due to Replacement by Housing Developments

• Forests and farms are sometimes replaced by housing, commercial, and industrial development as people build new homes, businesses, and factories.

• The unplanned growth of cities is called “urban sprawl.”

Reduction of Previously Cleared Land due to Reforestation Efforts

• Some cleared land is being returned to forest.

• Land owners may plant fields in pine trees as long term investments.

• Environmentalist groups pay some landowners or purchase land to return to forest.

Geographic Issues Resulting from Human and Natural Processes

• Geographic issues result from human and natural processes such as increase or decrease in population, changes in tropical forests, and tsunamis.

Population Change• Population growth spurred by the availability of

antibiotics and a more reliable and plentiful food supply has vastly expanded the number of people in the world and therefore the demand for resources.

• However, the development of birth control and the movement from farm to city has caused population growth through birth to end in many developed nations. Populations leveled off.

Tropical Forests• The world depends on tropical forests, such as

the Amazon in Brazil, for part of the oxygen in the atmosphere.

• Many species depend on the tropical forests to survive. Some of these species may have medicinal properties or possess genetic traits that could be useful to scientists.

• Many acres of tropical forests are cleared every year to make way for human development.

Tsunamis• Tsunamis are massive waves; these are

sometimes called “tidal waves” but that is not the correct term.

• Tsunamis are triggered by underwater earthquakes.

• Tsunamis are powerful, destructive forces. In addition to the immediate damage, they cause coastal erosion that makes affected areas even more vulnerable in the future.

Conclusion

• Geographic patterns in the environment that result from processes within the atmosphere, biosphere, lithosphere, and hydrosphere of Earth's physical systems affect the world.

Alabama Geography Standard 3

• 3. Compare geographic patterns in the environment that result from processes within the atmosphere, biosphere, lithosphere, and hydrosphere of Earth's physical systems.

• Comparing Earth-Sun relationships regarding seasons, fall hurricanes, monsoon rainfalls, and tornadoes

• Explaining processes that shape the physical environment, including long-range effects of extreme weather phenomena

• Examples:  processes-plate tectonics, glaciers, ocean and atmospheric circulation, El Niño, long-range effects-erosion on agriculture, typhoons on coastal ecosystems

Alabama Geography Standard 3

• Describing characteristics and physical processes that influence the spatial distribution of ecosystems and biomes on Earth's surface

Alabama Geography Standard 3

• Comparing how ecosystems vary from place to place and over time

• Examples: 

• place to place

• differences in soil, climate, and topography over time-alteration or destruction of natural habitats due to effects of floods and forest fires, reduction of species diversity due to loss of natural habitats, reduction of wetlands due to replacement by farms, reduction of forest and farmland due to replacement by housing developments, reduction of previously cleared land due to reforestation efforts

• Comparing geographic issues in different regions that result from human and natural processes

Alabama Geography Standard 3

• Examples: 

• human

• increase or decrease in population, land-use change in tropical forests

• natural

• hurricanes, tsunamis, tornadoes, floods

Sources• Dell'Amore, National Geographic News PUBLISHED

Fri Mar 05 21:06:00 EST 2010, Christine. ""Snowball Earth" Confirmed: Ice Covered Equator." National Geographic. March 5, 2010. Accessed December 29, 2015. http://news.nationalgeographic.com/news/2010/03/100304-snowball-earth-ice-global-warming/.

• Dunbar, Brian. "Japan Quake May Have Shortened Earth Days, Moved Axis." NASA. March 14, 2011. Accessed December 29, 2015. http://www.nasa.gov/topics/earth/features/japanquake/earth20110314.html.

Sources• "Hurricane vs Typhoon." Diffen - Difference and

Comparison. Accessed December 29, 2015. http://www.diffen.com/difference/Hurricane_vs_Typhoon.

• "The ‘Medieval Warm Period.’” NOAA Paleoclimatology Global Warming. August 20, 2008. Accessed December 29, 2015. http://www.ncdc.noaa.gov/paleo/globalwarming/medieval.html.

• National Ocean Service. "What Are El Niño and La Niña?" What Are El Niño and La Niña? June 11, 2015. Accessed December 29, 2015. http://oceanservice.noaa.gov/facts/ninonina.html.

Sources

• NOAA. "The Monsoon." NOAA NWS Western Region Geo RSS News Headline. Accessed December 29, 2015. http://www.wrh.noaa.gov/fgz/science/monsoon.php?wfo=fgz.

• NWS. "Tornadoes..." NWS Publications: Tornadoes. June 28, 2010. Accessed December 29, 2015. http://www.nws.noaa.gov/om/brochures/tornado.shtml.

Sources• Parikh, S. J., and B. R. James. "Soil: The Foundation of

Agriculture." Nature.com. 2012. Accessed December 29, 2015. http://www.nature.com/scitable/knowledge/library/soil-the-foundation-of-agriculture-84224268.

• Perlman, Howard. "Glaciers and Icecaps: Storehouses of Freshwater.” The USGS Water Science School. June 28, 2010. Accessed December 29, 2015. http://water.usgs.gov/edu/earthglacier.html.

• "PFEL-Atmosphere-Ocean Climate Interactions 1." PFEL-Atmosphere-Ocean Climate Interactions 1. Accessed December 29, 2015. http://www.pfeg.noaa.gov/research/climatemarine/cmfoceanatm/cmfoceanatm.html.

Sources• St. Petersburg Coastal and Marine Science Center.

"Coastal Change Hazards: Hurricanes and Extreme Storms." Storm-Induced Coastal Change. June 8, 2015. Accessed December 29, 2015. http://coastal.er.usgs.gov/hurricanes/coastal-change/index.php.

• Varani, Annette. "Hurricane Field Studies: Feature Articles." Hurricane Field Studies: Feature Articles. October 23, 2001. Accessed December 29, 2015. http://earthobservatory.nasa.gov/Features/HurricaneFieldStudy/.

Sources

• "The World's Lungs." The Economist. September 25, 2010. Accessed December 29, 2015. http://www.economist.com/node/17093495.

• Zell, Holly. "The Sun-Earth Connection." NASA. October 29, 2015. Accessed December 29, 2015. http://www.nasa.gov/mission_pages/sunearth/index.html.