2051 Geography Dr. Richard Kesel Introduction What is geography: earth/ describe Approaches o A. systematic o B. regional o C. man-environment Region arbitrary, homogeneous character
The Earth Shape: oblate spheroid o diameter 7927 miles o 27 miles shorter through poles o 72% water 1. N. Hemisphere land 2. S. Hemisphere water o depths Crust 2.7 density than water Maps and Grid Systems Problem: two dimensional surface Map Properties o A. direction/ azimuth o B. distance o C. area/ relative to each other o D. shape Area and shape cannot be shown accurately on the same map Types of Projections Planar/plane Conic Cylindrical Math/others Scale Verbal o One inch= one mile Graphic o 0_____1______2_____3______ Fractional
o 1/62,500; 1/63,360 o Small scale vs. large scale o 1/250,000(verbally- one inch = 4 miles) Metes-Bound Survey Grid System Latitude- imaginary line running between East and West, measures and angular distance North to South; 0-90 degrees Longitude- imaginary line running North to South, measures angular disk; East to West; 0-180 degrees Contour Lines 1. Line on map that connects points of equal elevation 2. Contour interval 3. Interpolate 4. Bench marks (BM) highest this point would go is 49 ft
Slope 1. Shape 2. Ingredient a. Ratio b. Percent c. Degrees Bearings Azimuth Azimuth East: 90 Azimuth South: 180 Azimuth West: 270
Compass points to magnetic north Baton Rouge Time: BR 1 PM Monday What time is it in NY? 2 PM Monday What time is it in LA? 11 AM Monday BR 11:30 PM Sunday What time is it in NY? 12:20 AM Monday What time is it in LA? 9:30 PM Sunday What Causes Seasons? Rotation on Earth's axis Revolution around the sun
Tilt of Earth on axis Parallelism of axis Earth's axis is always facing the same direction at a 23.5 degree tilt Surface water Overflow, runoff (unconfined) o Rainfall reason for surface runoffs o infiltration Gullies, rills Channels, rivers Overland flow Rainfall intensity, duration infiltration 1. Grain-size Grain-size= sand; largest is gravel at 2.0 mm 2. Porosity- bunch of holes in it with a bunch of air space 3. Permeability- water can flow through it (sponge) 4. Other Slope Vegetation- the more vegetation it holds the water back Terms Porosity Permeability Aquifer doesn't transmit water; high permeability Field capacity Wilting point Field Capacity saturated soil; water that remains (does not drain away after 24 hours) Wilting Point point below which plants can no longer vacuum moisture from the soil Porosity= Vv/V Degree of Saturation= Vw/ Vv Water Content= Ww/Ws Steeper the slope- more run-off Influent vs. Efficient
Discharge= Q= (A x V) cfs (cubic feet per second) - velocity is most rapid in the middle of the channel v v v v v v v v v 1 2 3 4 5 Q1= A (w x d) x v total= Q= 1 + 2 + 3 + 4 + 5 + 6 Highest mischarge in Mississippi River happens in the month of April Hydrograph
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Geo/ Morphology Subject can vary in scale, time, spatial context Few laws mostly concepts 1. Uniformitarianism- present is the key to the past 2. Limitations- change in intensity and process Concepts- continued Systems o A. closed o B. open Equilibrium Threshold Steady state Energy input Matter input Open System
Energy output Matter output
Pleistocene Age (2.5 m.y.) and influence Most of Earth's topography no older than Pleistocene. The geologic and climate changes of the Pleistocene were critical in shaping most landscapes Realm of Geomorphology A. Endogenic Processes B. Exogenic processes (originate outside the Earth) C. Rock type (as stage for action) Endogenic 1. Earth movements: folding, daulting 2. Volcanic eruptions: basalt 3. Magma: molten deep in crust Exogenic 1. Weathering: rock break down 2. Erosion: pick up (wind, water, ice) 3. Transport 4. Deposition: wind, water, ice Scales influencial system the smaller scales change most 3 types of rocks 1. Igneous rocks 2. Sedimentary Rocks 3. Metamorphic Rocks (its appearance and texture change completely) These rocks work in cycles Solar Energy Extrusive Igneous Rocks Sediment
Intrusive Igneous Rocks
Sedimentary Rocks
Heat Absolute base level= sea level How it can change 1. Tectonic- uplifts (subside), regional thing 2. Eustatic- sea levels change worldwide due to change in ocean volume; result of the coming and going of glaciers 3. Isostatic- regional effect "Ring of fire"- ring of volcanoes and earthquakes around the Pacific Ocean Eustatic glaciers oceans Rivers and Atmospheres Weathering Physical disintegration Chemical decomposition Physical Weathering Need bare rock (exposed) Heating and Cooling- extreme temperature changes o Diurnal changes (changes from day to night) o Thermal expansion coefficients The more space the better Freezing and throwing o Need poles, cracks, or joints o Number of freeze thaw cycles (diurnal vs. annual) Salts Vegetation Exfoliation
Chemical Weathering Need water Change of substance Goes very deep below the surface Intensity increases with temperature Intensity and rate decrease with depth Produces a regolith o Regolith weathered material above the bedrock o Van't Hoff's law rate of chemical reaction doubles for every ten degree centigrade rise in temperature Notes from book
Earth systems science our emerging view of the Earth as a complete entity, an interesting set of physical, chemical, and biological systems Geography science that studies the relationships among natural systems, geographic areas, society, cultural activities, and the interdependence of all of these over space Spatial nature and character of physical space, its measurement, and the distribution of things within it Five spatial themes: 1. Location 2. Region 3. Human- Earth relationships 4. Movement 5. Place Spatial Analysis geography synthesizes (brings together) topics from many fields, integrating info to form a whole earth concept - process is central to geographic analyses Physical Geography spatial analyses of all the physical elements and processes that make up the environment: energy, air, water, etc System Analyses Analytical tool System any ordered, interrelated set of things and their attributes, linked by flows of energy and matter - matter= mass that assumes a physical shape and occupies space - energy = a capacity to change the motion of, or to work on matter Open system Inputs of energy and matter flow into the system and outputs of energy and matter flow from the system - Earth is an open system in terms of energy, because solar energy enters freely and heat energy leaves, going back into space (equilibrium, threshold, steady state) Closed system a system that is shut off from the surrounding environment so that it is selfcontained - Earth is a closed system in terms of physical matter and air resources Feedback loops as a system operates, it generates outputs that influence that system in its own operations. These inputs function as "information" that is returned to various points in the system via pathways; feedback information can guide and sometimes control further system operations Ex] Photosynthesis: any increase or decrease in the daylight (sunlight availability), carbon dioxide, or water produces feedback that causes specific responses in the plant Negative feedback if feedback information discourages response in the system ex] bad reviews affecting ticket sails Positive feedback if feedback information encourages increased response in the system Steady- state condition energy and material system that remains balanced over time, conditions are constant or recur Steady-state Equilibrium rates of inputs and outputs in a system are equal and the amounts of energy and matter in storage within the system is constant (fluctuate around an average) Dynamic Equilibrium changing trend over time; increasing or decreasing system operations may occur gradual
Threshold tipping where point; it can no longer maintain its character, so it lurches to a new operational level - Metastable Condition Models simplified, idealized representation of part of the real world The simplicity makes a system easier to understand Adjusting the variables in a model produces differing conditions and allows predictions of possible system operations Earth four spheres: Abiotic non-living systems Biotic living systems Abiotic spheres atmosphere, hydrosphere, lithosphere Biotic sphere biosphere Atmosphere thin, gaseous veil surrounding Earth, held to the planet by the force of gravity Hydrosphere Earth's water in the atmosphere, on the surface, and in the crust near the surface Water exists in all three states: liquid, solid (frozen), and gaseous Cyrosphere: ice sheets, ice caps, fields, glaciers, ice shelves, sea ice, and subsurface ground ice Lithosphere Earth's crust and a portion of the upper mantle directly below the crust Biosphere intricate, interconnected web that links all organisms with their physical environment Evolves, reorganizes itself, faces extinctions, manages to flouirish Geodesy the science that determines Earth's shape and size by surface and mathematical calculations Geoid meaning that the shape of Earth is earth shaped - "geoidal epoch" Latitude angular distance north or south of the equator, measured from the center of the Earth - on a map lines go east and west Parallel a line connecting all points along the same latitudinal angle Longitude angular distance east or west of a point on Earth's surface measured from the center of the Earth - on a map lines go north and south Meridian a line connecting all points along the same longitude - Prime Meridian a meridian designated at 0 degrees (Greenwich Prime Meridian) Great Circle is any circle of Earth's circumference whose center coincides with the center of Earth - only parallel is a great circle equatorial parallel A plane intersecting the globe along a great circle divides the globe into two equal halves and passes through the center Small Circle these circles have centers that don't coincide with Earth's center A plane that intersects the globe into unequal sections- this plane doesn't pass through the center of the globe
Greenwich Mean Time (GMT) consistent universal time was established International Date line 180 degree meridian; marks the place where each day officially begins Coordinated Universal Time time signal system replaced GMT universal time in 1972 and became the legal reference for official time in all countries Daylight saving time the idea to extend daylight for early evening activities; proposed by Benjamin Franklin; not adapted until ww1 then again in ww2 Map a generalized view of an area, usually some portion of Earth's surface, as seen from above and greatly reduced in size Cartography the part of geography that involved map making Scale ratio of the image on the map to the real world Representative fraction is expressed with either a colon or a slash, as in 1:125,000 or 1/250,000 - any unit is applicable as long as it is applied to both sides of the fraction Graphic scale a bar graph with units to allow measurement of distances on the map Map projection reduction of a spherical Earth to a flat surface a) Direction b) Distance c) Area (can show climates) d) Shape (can be used for navigational purposes) e) Proximity - Equal area and true shape cannot be shown accurately on the same map
Mercator Projection true shape projection, with meridians appearing as equally spaced straight lines and parallels that are spaced closer together near equators; cylindrical projection Subsolar point only point receiving insolation perpendicular to the surface - differences in the angle of solar rays at each latitude result in an uneven distribution of insolation and hearing - all other places beside the subsolar point receive insolation at an angle less than 90 degrees and experience more diffuse energy (higher latitudes)
Seasonality refers to both the seasonal variation of the sun's position above the horizon and changing day lengths during the year Altitude angle between the horizon and the sun Declination the latitude of the subsolar point Day length duration of exposure to insulation - the equator always receives equal hours of day and night Reasons for seasons: seasons result from variation in the sun's altitude above the horizon, the sun's declination, and the day length during the year
This is created by several factors: Earth's revolution in orbit around the sun Its daily rotation on the axis Its tilted axis The unchanging orientation of its axis Its sphericity Revolution Earth's travel around the sun Earth's speed in orbit together with Earth's distance from the sun, determines the time required for one revolution around the sun and therefore the length of the year and the duration of the seasons Rotation Earth's turning on its axis; averages slightly less than 24 hours in duration Determines day length Creates the apparent deflection of winds and ocean currents Produces the twice daily rise and fall of the ocean tides in relation to the gravitational pull of the sun to the moon Axis an imaginary line extending through the planet from the geographic North Pole to the South Pole Rotates counterclockwise West to east Circle of Illumination the diving line between day and night Plane of Ecliptic a plane touching all points of Earth's orbit Factor Description Revolution Rotation Tilt Axial Parallelism Sphericity Orbit around the sun requires 365.24 day to complete Earth turning on its axis; takes approximately 24 hours to complete Axis is aligned at a 23.5 degree angle from a perpendicular to the plane of the ecliptic Remains in a fixed alignment with Polaris directly over the North Pole throughout the year Appears as an oblate spheroid to the suns parallel rays; the geoid
Solstices specific points in time at which the sun's declination is at its position farthest north at the Tropic of Cancer (23.5 degree North) or south at the Tropic of Capricorn (23.5 degrees South) Tropic Latitude where the sun's declination appears to stnd still briefly then it "turns" and heads towards the other tropic Winter Solstice or December Solstice December 21 or 22; the circle of illumination excludes the North Pole region from sunlight but includes the South Pole region Arctic Circle the southern most parallel (in the Northern hemisphere) that experiences a 24 hour period of darkness
Vernal Equinox or March Equinox March 20 or 21; the subsolar circle of illumination passes through both poles so that all locations on Earth experience a 12 hour day and 12 hour night Summer solstice or June Solstice June 20 or 21; the subsolar point migrates from the equator 23.5 degree North latitude, the Tropic of Cancer; everything North of the Arctic Circle receives 24 hours of daylight ("The Midnight Sun") Antarctic Circle South pole is in darkness 24 hours "Midwinter's Day" Automnal equinox or September Equinox circle of illumination passes through both poles so that all parts of the globe experience a 12 hour day and a 12 hour night Dawn the period of diffused light after a sunrise Twilight the period of diffused light after a sunset Denudation (erosion) Means to denude or lay bare, includes: o Mass wasting o Mass movement o Overland flow (run off) Factors (denudation) Main force gravity Slope (gradient) Vegetation Moisture Mass Wasting 1. Consistency o Wet dry 2. Motion o A. slow-fast o B. slide- fall 3. Result (landform) o Disturbed (mixed)- undisturbed (block) Mudflow Large amounts of loose debris Excessive amounts of runoff Sparse vegetation cover Steep slopes Special example- lahar Material Strength 1. Cohesion (sand has no cohesion) 2. Internal Friction (very angular has more vs. very rounded)