SCALES IN PHYSICAL GEOGRAPHY The research process in Physical Geography (data, methodology, techniques, analysis) depends on the scale (spatial or temporal) SPATIAL SCALES IN PHYSICAL GEOGRAPHY Physical processes behave at various scales Global Continental Regional Local Individual

SPATIAL SCALES IN PHYSICAL GEOGRAPHY Regional Global Continental Sao Paulo: 238 mm in January Local Individual

TEMPORAL SCALES IN PHYSICAL GEOGRAPHY (TIME CYCLES) Daily Monthly Seasonally Annual Hundreds years Tens –hundreds of thousands years Millions of years DAILY: MONTHLY: SST Anomaly March 2005

HUNDRED YEARS: ANNUAL: SEASONAL: MILLIONS YEARS: THOUSANDS YEARS: Pangea (~225 million years ago)

SYSTEMS IN PHYSICAL GEOGRAPHY A system is a set of relationships between features, processes or phenomena Read: Strahler, Chapter2 (Systems in Physical Geography) Natural Flow system A system in which energy/matter move trough time from one location to another. Ex: Flow of energy from Sun to Earth (energy) River system (matter) Open flow systems: inputs and outputs of energy and matter Closed flow systems: NO inputs or outputs

SYSTEMS A system is a set of relationships between features, processes or phenomena linked by flows of energy and matter. Read: Strahler, Chapter 2 (Systems in Physical Geography) Ex: Hydrologic cycle

OPEN AND CLOSED SYSTEMS Open systems: inputs and outputs of energy and matter. Ex: the river system precipitation INPUT river system discharge to ocean OUTPUT

OPEN AND CLOSED SYSTEMS 2. Closed systems: NO inputs or outputs. The flowing energy and matter move endlessly. Ex: the hydrologic cycle

SYSTEM FEEDBACK When flow (of matter or energy) in one pathway acts either to reduce or increase the flow in another pathway, reinforcing or reducing the initial flow.

FEEDBACK causes Initial condition (matter/energy) Another variables changes in causes changes in Initial condition MODIFIED (matter/energy)

This feedback can create instability, disruption. POSITIVE FEEDBACK If the flow is reinforced. There is an increased response in the system. This feedback can create instability, disruption. shrubs and wood dried Wildfire More fuel available MORE fire

NEGATIVE FEEDBACK If the flow is reduced. Further production in the system decreases the growth in the system. This feedback causes a self-regulation in a natural system, stabilizing the system Warmer Earth More evaporation More cloud formation LESS warming More reflection of sunlight

SYSTEM EQUILIBRIUM The flow rates in the pathways of a system remain about the same. The amounts of energy and matter within the system are constant.

Example: Positive or negative FEEDBACK? VEGETATION REMOVED (overgrazing) TRANSPIRATION? RAINFALL ? Less or more VEGETATION?

WHY ARE MAPS IMPORTANT ? Maps are one of the most important tools in Geography. They help us: To visualize the “spherical” world on which we live To place locations

To represent physical or human features (at different scales) Ex: Physical features (precipitation distribution) Regional Global Continental

Ex: Human features (population density) Global Continental Regional

Ex: El Niño-Southern Oscillation (ENSO) impacts

IMPORTANT CONCEPTS Geographic Grid Latitude Longitude Principal lines (Equator, Prime meridian) Map projections usually given in degrees (°) GEOGRAPHIC GRID Provides a system for locating places on the Earth’s surface

LATITUDE (parallels) Define any location on Earth’s surface in terms of how far north or south it is from the Equator (0° latitude) Tells us if we are in the Northern or Southern Hemisphere (standard notation: 30° N, 55°S, max lat is 90°) 1° latitude = 111 km Equator is a Great Circle. All the other parallels are small circles

LONGITUDE (meridians) Define any location on Earth’s surface in terms of how far it is from the Prime Meridian (0° line of longitude) Tells us if we are in the Western or Eastern Hemisphere (standard notation: 100° W, 15°E, max lon is 180°) All meridians are half circles (unlike parallels) 1° longitude =111 km ONLY at the Equator (unlike latitude)

Together, latitude and longitude represent the location of any point on the earth’s surface B A

EXERCISE Locate the following points and identify the principal physical feature Lat: 40°N , Lon: 5°W Lat: 15°N, Lon: 5°W Lat: 10°S, Lon: 50°W Lat: 40°N, Lon: 50°E Lat: 20° N, Lon: 45°E Lat: 30° S, Lon: 120°E

PRINCIPAL LINES Prime Meridian Equator Tropic of Cancer Tropic of Capricorn

CONTOUR MAPS A contour map is a map of isolines Isoline: A line which connects points of equal value of a variable (temperature, precipitation, elevation , etc)

Isotherms Isohyets

CONTOUR LINES INTERPRETATION (CLIMATE VARIABLE) Closely spaced contour lines represent a large gradient, widely spaced lines indicate small gradient Gradient: the rate by which a variable changes spatially Concentric circles of contour lines indicate a maximum or minimum value

Region with highest temperature? Region with lowest temperature Region with highest pressure gradient? Region with lowest pressure gradient? Region with strongest wind? Region with lowest wind speed? Regions with rainfall probability? (low pressure centers)