GEG 1301 Midterm

Physical Geography

- A method (spatial analysis)

- Holistic (encompasses the whole)

- Eclectic (integrate a wide range of subject matter from diverse fields)

Earth System Science

Interaction or links between a set of systems:

- Natural systems

- Geographic areas

- Society

- Cultural activities

- The interrelations (links) of all of these over space (global to microscopic)

5 Main Spheres

- Atmosphere

- Cryosphere

- Biosphere

- Lithosphere

- Hydrosphere

Atmosphere

Contains: CO2, Nitrogen, gasses, clouds (water vapor)

Characteristics of Systems

1. Open vs. closed systems

2. Amount of energy/matter exchange (system budget)

3. Systems' ability to change themselves (feedback)

All systems involve interactions, and most interactions take the form of exchange or cycles of energy and matter

Matter

Mass that assumes a physical shape and occupies space

Energy

Capacity to change the motion of, or to do some work, on matter

Open Systems

- Inputs/outputs of energy and/or matter

- E.g., forest; vegetation uses energy (sunlight) and matter (water, CO2) as input to the plant, and chemical energy (sugars and carbohydrates) and material (O2) is stored and released

- Earth is an open system in terms of energy: solar energy enters and goes back to space

Closed Systems

- Inputs/outputs of energy but no inputs/outputs of matter across the system boundaries (self-contained)

- E.g., global hydrological cycle; energy (heat) and matter (water) is exchanged, all matter is contained in the system - no loss or gain

- Earth is a closed system in terms of physical matter and resources such as air, water and material resources (recycling is thus crucial)

Cryosphere

Contains: cold regions (polar), ice, permafrost, sea ice

Biosphere

Contains: all living organisms, plants, animals, microbes

Lithosphere

Contains: rocks, bedrock, sedimentary, volcano

Hydrosphere

Contains: water (lakes, oceans), also solid and gaseous states

A System

- Set of variables and the relations (links) between them, are distinct from others outside the system

- May include a number of subsystems

- The spatial analysis (inter-relations) of all the physical elements and processes that make up the environment

- Allows us to explain what we're seeing

Subdivision

Rational ___ of a complex world

(Benefits of System Approach)

Between

Stresses relations ___ variables

(Benefits of System Approach)

Included

Increases likelihood that all relevant variables are ___

(Benefits of System Approach)

Quantification

Encourages ___ (modeling)

(Benefits of System Approach)

Prediction

Assists in ___ (theory making)

(Benefits of System Approach)

Decision-making

Assists in ___ for intervention

(Benefits of System Approach)

System Budget (Amount of Energy Exchanged)

- Addresses the relative quantities of inputs and outputs in a system

- If it gains energy/matter, it is positively balanced and the surplus goes into storage

- If it loses energy/matter, it is negatively balanced and the system experiences a decrease in storage

- If inputs/outputs balance, the system is in equilibrium

Positive Feedback Loop

- Enhances (magnifies) the original change

- Result increasingly differs from the starting state

- Tends to lead to instability/disruption in the system

- A direct relationship is positively (+) correlated

- Ex. the burning of gasses, deforestation, melting of icecaps

Negative Feedback Loop

- Damps down (diminishes) original change

- Tends to preserve/diminish the starting state

- Helps to stabilize and maintain the system

- An inverse relationship is negatively (-) correlated

- Ex. predator and prey relationship,

System Equilibrium

Most systems remain balanced over time as a result of negative feedbacks

Steady-state Equilibrium

- Values fluctuate around a steady average

- Ex. a river adjusts its erosive power as a result of changes in precipitation, but system remains in equilibrium

Dynamic Equilibrium

- Values of the average may themselves gradually change as a result of positive feedback

- Ex. climate change, average air temperature increasing

Metastable

- Results from an abrupt change from one state to another; a threshold is reached where it can n longer maintain equilibrium

- Ex. of a tipping point; coastal bluff collapse. System must adjust to new conditions

Morphological Approach

- Based on the physical properties of the environment (climate, exposure, slope angle, sediment type, etc.) and their relationships

- The relationships between these properties can be expressed by a web of correlations

- Ex. rainfall and potential runoff is dependent on... (grab image from slides)

Cascading Approach

- A series of subsystems connected together, such that the mass or energy output (i) from one subsystems becomes the input (A) for the adjacent subsystem

- Knowledge about flux of energy and/or matter through the environment

Process Response Approach

- Combination of cascading and morphologic

- The morphological from of a structure is related to the process that is energized by the cascade

- Chains of intersecting cascading and morphological components which mutually adjust themselves to changing input-output relationship

Control Approach

- Process- response modified by actions of humans; Human actions intervene to produce changes in the distribution of energy and matter

- Ecosystem can also be viewed as a form of control systems, where the process- response system is modified by physical, chemical and biological interactions

- Ex. Rideau lock system

Induction

- Gather data (e.g., location, dimensions movements) and look for patterns, trends and interconnections

- E.g.,

Deduction

- Start from known scientific principles to understand through reasoning

- E.g., All of our snowstorms come from the north because it's colder in the north.

The Solar System

- Milk way began to form 12 billion years ago

- Our Sun and the 8 planets appeared around 4.6 billion years ago

Speed of Light

300,000 kilometers per second

Perihelion

- Closest from the Sun (January 3rd)

- 147,255,000 km

Aphelion

- Farthest from the sun (July 3rd)

- 152,083,000 km

Rotation

- One day

- Counter-clockwise

Revolution

- One year

- Counter-clockwise

Plane of Ecliptic

Flat surface that intersects all points in Earth's orbit

⅓

About ___ of Earth's surface is habitable by humans

Continents

- 6: North/South America, Eurasia, Africa, Australia and Antarctica

- 29% of the world's landmass

Oceans

- 7: North/South Atlantic, Pacific, Indian, Southern, Artic and Mediterranean Sea

Continental Margins

- Component of Ocean Basin

- Extension of continents

- Continental shelf (broad platform)

- Continental slope (occurs at break in slope of shelf; convex slope)

- Continental rise (transition from slope to abyssal zone; concave slope)

Abyssal Zone

- Component of Ocean Basin

- Deepest Areas

- Abyssal plains

- Seamounts (volcanic mountains)

- Mid-oceanic ridges (volcanic mountain ranges)

North and South Hemisphere

Defined by the equator

East and West Hemisphere

Defined by the Greenwich Meridian

Eratosthenes

- Eratosthenes of Cyrene

- Greek mathematician

- The person to use the word "geography" and invented the field of geography as we know it

- Calculated the Earth's circumference without leaving Egypt, with remarkable accuracy (within 1.5% or 300 off)

Earth's Shape

- Shape described as an ellipsoid

- Contains many bulges and depressions

- Shape is therefore called a geoid

Parallels

- East-west lines defined by latitudes

- Never intersect

- Line connecting all points on the same latitudinal angle

- Name of the line (45th parallel)

Meridians

- North-south lines defined by longitudes

- Intersect only at the poles

- The line connecting all points of the same longitude

Latitude

- An angular distance measured in degrees north or south of the equator, which is 0º. Earth's poles are at 90º.

- These angles of latitude determine parallels along Earth's surface

- Name of the angle (45ºN)

Longitude

- Longitude is measured in degrees east or west of a 0º starting line, the prime meridian (Greenwich).

- Angles of longitude measured from the prime meridian determine other meridians. North America is west of Greenwich, UK; therefore, it is in the Western Hemisphere.

Geographic Zones

- Generalizations that characterize various regions by latitude.

- Think of these as transitional into one another over broad areas. Differences results from amount of solar energy that varies by latitude (and season)

Global Positioning System (GPS)

- A constellation of orbital satellites

- Provide location and time to a GPS receiver

- With Earth's rotation, a different number of satellites are "visible" at any given location

- Position is calculated from knowing distance (time differences) between receiver and at least 3 satellites

Global Time

- Today only 6 time zones cover the entire country

- Worldwide, there are a total of 24 time zones, each 15º (or 1 hour) wide.

Cartography

Science and art of map making that combines geography, engineering, computer science and art

Map

A generalized view of an area, as seen from above and reduced in size

Scale

- Relates map units to ground units (real world)

- Small-scale maps Illustrate a large territory General representation of phenomena

- Large-scale maps Illustrate a small territory Detailed representation of phenomena

- The greater the denominator, the smaller is the scale of the map

Projection

- Process of transforming the spherical planet (3D) to a flat map (2D)

- A projection is a systematic representation of part or all of the Earth onto a flat surface

- Distortion is inevitable

1. Parallels are parallel to each other, evenly spaced and always decrease in length towards the pole

2. Meridians converge at both poles, are always evenly spaced along any individual parallel, distance between meridian always decrease toward the poles

3. Parallels and meridians always intersect each other at right angles.

Conical Projection

- Construction of conical projections with one (tangent) or two (secant) standard parallels.

- Least distortion occurs where the globe touches the standard parallel(s).

- Longitude appears as straight lines.

- Latitudes appear as arcs.

- Best use: mid-latitudes

- Advantage: shortest distance between two points are projected as straight lines

Cylindrical Projection

- Construction of cylindrical projections with one (tangent) or two (secant) standard parallels.

- Least distortion occurs where the globe touches the tangent line.

- Latitudes and longitudes appear as straight lines and intersect each other at 90 degree angle

- Best use: equatorial regions.

- Advantage: a straight line preserves angles and can be used for navigation

Mercader Projection

- A type of cylindrical projection

- Best used for navigation; preserves right angles

- Preserves shapes, but heavily distorts the area of mid and high latitudes

- UTM (Universal Transverse Mercator) coordinate system divides the Earth into 60 zones, each of is 6º of longitude in width centered over a meridian.

- Zones are numbered 1 through 60.

Symbols in Mapping

- Point represent locations

- Lines represent linear objects or linkages: roads, isolines and contouring

- Polygons represent area of objects or quantitative/qualitative ranges

Geographic Information System (GIS)

- Is capable of storing, manipulating, analyzing and quantifying patterns and relations within a single dataset; or between datasets.

- Combines spatial (where it is) and attribute (what it is) data

- Any data source which can be referenced spatially can be used; includes remote sensing data

Remote Sensing

Is the science (and to some extent, art) of acquiring information about the Earth's surface without actually being in contact with it. This is done by sensing and recording reflected or emitted energy and processing, analyzing, and applying that information

Principles of Remote Sensing

- Source of energy or illumination

- Interaction with the atmosphere

- Interaction with the target

- Recording of energy by the sensor

- Transmission, reception and processing of the energy

- Interpretation and analysis of processed image

- Application

Passive Remote Sensing

- The instrument receives reflected solar energy or radiated energy from the surface

- Most common: visible light, near and middle infrared energy, thermal energy

- Humans do it continuously with our eyes

- Cameras/sensors capture the wavelength for which it is designed for

Active Remote Sensing

- The instrument sends out its own energy, which is reflected back to it

- Most common: Radar, Lidar

Air Photographs

- 50-60% overlap between images along same flight line

- Multiple flight lines are flown with 20-30% overlap

Exogenic Energy

- >99.9%

- E.g., erosion

Endogenic Energy

- (

Heat Energy

- Radiation (energy that travels through space): Ex. Reheating a cold cup of coffee in a microwave oven.

- Conduction (transfer of energy through matter): Ex. Heat transfers into your hands as you hold a hot cup of coffee

- Convection (transfer of energy through fluids or gasses): Ex. Heat transfers as the barista "steams" cold milk to make hot cocoa

- Sensible Heat (measure of kinetic energy, can be measured with a thermometer): Ex. heating tarmac

- Latent Heat (heat stored in matter and exchanged during phase change)

Solar Activity

- The sun shines from the energy it releases

- Fusion of H atoms create He

- Mass of He is much lower than H, so mass difference is converted into energy (E = mc*2)

- This radiant energy causes the Sun to generate heat and light

Sunspots

- Are surface disturbances caused by magnetic storms on the Sun; appears as dark areas

- Sunspots have activity cycle of 11 years

- Most common feature on the active sun

Flares

- Sudden release of energy created when sunspots transform rapidly into more stable configurations

- Strongly influence the behavior of solar wind

Solar Wind

- Clouds of highly charged particles (mostly protons and electrons) that is discharged from the Sun's outer atmosphere

- These charged particles first interact with Earth's magnetic field and are deflected towards Earth's poles

Aurora Borealis/Australis

- Dynamic patterns of brilliant lights in high-latitude regions

- Produced by interactions of solar winds (electrically - charged particles) and magnetosphere

- Colors depend on which atoms is struck in the upper atmosphere (Nitrogen, Oxygen) and altitude of the collision

- Purple/blue - N ~ 95km

- Green - O ~ 240km

Sun: Core

Where thermonuclear reactions occur

Sun: Radiation Zone

The layer that lies just outside the core, to which radiant energy is transferred from the core in the form of photons

Sun: Convection Zone

Energy continues to move through, transfer of heat through liquid or gas

Sun: Photosphere

White visible light is emitted, where sunlight comes from

Sunspots

Darker and cooler areas

Sun: Chromosphere

Thin layer of the sun where temperatures rise tremendously, emits a reddish light

Sun: Prominence

Large structures made of tangled magnetic field lines, suspended above earth's surface

Solar Flares

An intense burst of radiation coming from the release of magnetic energy associated with sunspots

Radiant Energy

Energy from the Sun that travels in the form of waves

Wavelength

- Type of electromagnetic radiation

- Distance between 2 crests

Frequency

- Type of electromagnetic radiation

- # of waves passing a fixed point in 1 second

Radiation Balance

- Determined by different principles (physical laws):

- How much energy is emitted from a body: Stefan-Boltzmann Law

- The characteristics of the energy emitted ( max wavelength): Wien's Displacement Law

- Reduction in intensity of the energy with distance: Inverse Square Law

- Solar constant

Inverse Square Law

- Earth is 150 x 10*6 km away from the Sun

- Earth only receives ~ 0.5 x 10*9 of the Sun's energy output (half of one-billionth)

- Intensity reduces according to the square of the distance from the energy source (Inverse square law)

- Intensity = 1 / distance*2

Solar Constant

- Earth's distance from the Sun results in the interception of a small fraction of the Sun's total energy output

- Half of 1 billionth of Sun's total energy

- The average amount of radiation received at the top of the atmosphere (thermopause; ~ 480 km above the Earth surface) = 1367 W/m*2

Effect of Earth's Curved Surface

1. Presents a continuously varying angle to the incoming parallel rays of insolation

2. Differences in angle results in uneven distribution of insolation and heating

3. Reduces the intensity at higher latitudes

4. Distance traveled through the atmosphere is greater (subject to more scattering and reflection)

Effect of Earth's Tilt

1. Insolation is perpendicular to the surface only at lower latitudes (between 23.5ºN and 23.5ºS) - known as the subsolar point

2. Latitude of subsolar point changes throughout the year

- It is above the equator twice a year (equinoxes)

- It is above the Tropic of Cancer(June 20-21) and Tropic of Capricorn (December 21-22) once a year

Uneven Distribution of Insolation

- Earth's tilt causes imbalance in the intensity of solar radiation received; tropics receive more concentrated insolation (energy per unit area)

- Annually, the tropics receive 2.5 times the amount received at the poles

- Earth's revolution causes seasonal variations in amount of insolation received

- Earth's rotation causes daily variations in amount of insolation received

Insolation Variation

- Combines solar insolation and duration of daily sunlight

- Isolines represent daily mean insolation in Wm*2

Heliocentrism

A cosmological model in which the Sun is assumed to lie at or near a central point (e.g., of the solar system or of the universe) while the Earth and other bodies revolve around it

Earth Energy System

Heating and cooling system for buildings or structures that use a fluid to exchange heat with the ground or water

Earth's Three Heat Reservoirs

Volcanoes/fumaroles (holes in the earth where volcanic gases are released), hot springs and geysers

Greenhouse Effect

The process through which heat is trapped near Earth's surface by substances known as 'greenhouse gases.'