physical geography
Geography: is the study of the spatial and temporal relationships among geographic areas, natural systems, and society Geo=earth Graphy= to write Geography= describing the earth Can add/subtrtact to find distance between locations On same side of equator you subtract but if on opposite sides of equator then add Bar scale Introduction to Physical Geography Definition: Study of spatial and temporal relationships among geographic areas, natural systems, and society. Goals: Describe patterns in the landscape. Understand the processes that create these patterns. Topographic Maps Purpose: Represent the Earth's surface variations and provide elevation data using contour lines. Key Concepts: Topography: Describes the undulations and variations of the Earth's surface. Contour Lines: Connect points of equal elevation. Closely spaced lines = steep slope. Widely spaced lines = gentle slope. Elevation can be inferred, and slope or landscape changes (e.g., glaciation) can be analyzed. Applications: Historical USGS maps reveal landscape changes. Useful for calculating slope, elevation, and geographic features. Mapping Basics Location: Defined using coordinate systems like latitude (parallels) and longitude (meridians). Important parallels: Equator (0°), Tropics of Cancer (23.5°N) & Capricorn (23.5°S), Arctic/Antarctic Circles (66.5°N/S). Maps: Scale models of Earth's surface; 3D Earth projected into 2D. Map scales: Bar, Verbal (e.g., 1 inch = 8 miles), Representative Fraction (e.g., 1:24,000). Larger scale = more detail; smaller scale = broader area. Seasons and the Sun-Earth Relationship Key Factors: Earth's Tilt: 23.5° tilt creates seasons. Elliptical Orbit: Minimal impact on seasons; Earth is closest to the Sun in winter (perihelion) and farthest in summer (aphelion). Seasonal Changes: Northern Hemisphere tilted toward Sun = Summer (long days, high Sun angles). Southern Hemisphere tilted toward Sun = Winter. Subsolar Point: Latitude where the Sun is directly overhead. Moves between Tropic of Cancer and Tropic of Capricorn annually. Solar Radiation and Energy Transfer Insolation: Incoming solar radiation; more concentrated when Sun is overhead. Diffused at lower angles due to Earth's curvature. Energy Balance: Equatorial regions: Energy surplus. Higher latitudes: Energy deficit. Drives winds, ocean currents, and global energy redistribution. Key Geographic Terms Subsolar Point: Location where the Sun is at a 90° angle overhead at noon. Solar Declination: Latitude of the subsolar point; changes daily. Circle of Illumination: Boundary between day and night, shifting with seasons. Insights on Latitude and Climate Equatorial regions: Higher energy due to direct solar angles. Supports tropical climates. High latitudes: Lower energy due to diffuse sunlight. Results in colder climates and shorter growing seasons. Week 2 The dates they acure Seasonal markers Where the subsolar point is Where do we have the longest and shortest days The great balancing act- There as been a surplus of energy coming in To remember it think of banks and deposits Daily energy Noon-peak insoliution highest point of the sun Flashlight example Atmospheric influences on isolation Energy transfer High clouds reflecting radiation Folks who have gone skiing without goggles thats radiation reflecting on the snow His shirt is green so its reflecting green to our eyes Albedi We could calculator the sun angel Urban heat island Urban areas are going to be warmer then City of bellingham is dark blue Overnight cooling patterns White roofs/ bigger trees helps cool things down Greenhouse effects linkage with this idea of absorption and radiation. Feedback loop being positive or negative Positive feedback are self sustaining Reflecting a change in a system tht can get amafied or can control or change the original change in the system Positive example-misquito bite you wanna itch but when you do ot getts worse Negative- sweating - intricate pf body heat then you sweat and your body temp will go down Clouds are questionable cuz it can act in both ways Physical Geography Notes 1. Introduction & Map Basics What is Geography? Study of spatial and temporal relationships among geographic areas, natural systems, and society. From Greek: Geo = Earth, Graphy = To write Physical Geography Focuses on physical components and natural processes in the environment. Explores "how and why" patterns occur on Earth. Coordinate Systems Latitude: Parallels measuring north/south (0° at equator to 90° at poles). Key Parallels: Equator (0°), Tropic of Cancer (23.5°N), Tropic of Capricorn (23.5°S), Arctic Circle (66.5°N), Antarctic Circle (66.5°S). Longitude: Meridians measuring east/west (0° at Prime Meridian to 180° at International Date Line). Degrees, Minutes, Seconds: 1° = 60’; 1’ = 60”; decimal degrees also used. Maps and Projections Maps are 2D representations of Earth’s surface; projections introduce distortions. Projections: Preserve either area or shape (not both). Scales: Bar scale: Visual representation. Verbal scale: "1 inch equals 8 miles." Representative Fraction (RF): e.g., 1:24,000. Topographic Maps Represent Earth's surface with contour lines. Contour Lines: Connect points of equal elevation; spacing indicates slope steepness. Allow for quick inference of elevation and slope. Example: Walking along a contour line maintains elevation; crossing lines indicates a change in elevation. Useful for tracking landscape changes over time (e.g., glaciation effects). 2. Seasons Sun and Earth Relationships ~99.9% of Earth's energy comes from the Sun (shortwave radiation). Earth emits longwave radiation (thermal infrared). Subsolar Point Where the Sun is directly overhead (perpendicular to the surface). Moves between 23.5°N (Tropic of Cancer) and 23.5°S (Tropic of Capricorn). Only this point receives direct insolation; other areas receive diffuse solar energy. Earth's Tilt and Seasonality Earth’s 23.5° tilt drives seasons. Summer: Hemisphere tilted toward the Sun. Winter: Hemisphere tilted away. Elliptical orbit has minimal effect on seasons. Perihelion (closest to Sun): Occurs during Northern Hemisphere winter. Aphelion (farthest from Sun): Occurs during Northern Hemisphere summer. Seasonal Markers December Solstice (Dec 21/22): Subsolar point at 23.5°S; shortest day in Northern Hemisphere. March Equinox (Mar 20/21): Subsolar point at the equator; equal day/night everywhere. June Solstice (Jun 20/21): Subsolar point at 23.5°N; longest day in Northern Hemisphere. Example: In Bellingham, ~16 hours of daylight; 24 hours of daylight above the Arctic Circle. September Equinox (Sep 22/23): Subsolar point at the equator; equal day/night everywhere. Solar Angle and Energy Solar altitude (sun angle) affects energy concentration: Higher angle = concentrated energy (e.g., summer). Lower angle = diffuse energy (e.g., winter). Example: Sun is never directly overhead in Bellingham; at 15°N, sun is overhead twice yearly. Energy imbalance between equator and poles drives global circulation systems. If Earth’s tilt were 0°: No seasons; equinox conditions year-round. If Earth’s tilt were 45° or 90°: Extreme seasonal variations. Analemma Visual tool to calculate solar declination and sun angle throughout the year. Example: On September 15, subsolar point is ~3°N. At 18°N, the sun is directly overhead twice yearly (e.g., May 15 and August 1). 3. Atmosphere & Energy Balance Composition of the Atmosphere Permanent Gases: Nitrogen (78%), Oxygen (21%), Argon (~1%). Variable Gases: Carbon dioxide, water vapor, ozone, methane. Variable gases make up tiny proportions but have large effects. Example: Carbon dioxide varies due to natural and human activities; critical for climate regulation. Water Vapor: Most abundant variable gas; moderates temperature by retaining energy. Example: Desert climates experience extreme temperature swings due to low water vapor. Clouds, condensed water vapor, reflect incoming solar radiation and trap heat. Example: Clear nights are colder without cloud cover retaining heat. Ozone: In the stratosphere: Protects Earth by absorbing UV radiation (e.g., ozone layer). At the surface: Pollutant from industrial and vehicle emissions, contributing to urban heat islands. Example: The ozone hole caused by CFCs has been recovering since regulatory measures were implemented. Daily and Seasonal Temperature Patterns Daily Cycle: Sunrise: Coolest time due to lack of incoming solar radiation overnight. Local noon: Peak insolation; sun is highest in the sky. Mid-afternoon (~3 PM): Warmest time as energy accumulates. Nighttime: Cooling as outgoing longwave radiation exceeds incoming energy. Example: Clear nights cool faster than cloudy nights due to lack of retained longwave radiation. Latitudinal Variation: Equatorial regions receive more direct solar radiation, leading to energy surplus. Polar regions experience energy deficit; surplus energy redistributed by winds and ocean currents. Albedo Measurement of reflectivity (%). High albedo: Reflects more radiation (e.g., snow reflects 60–90%). Low albedo: Absorbs more radiation (e.g., asphalt reflects 5–10%). Example: Darkened snow from pollutants melts faster due to increased absorption. Urban Heat Island Effect Urban areas are warmer than surrounding rural areas due to: Dark surfaces (e.g., asphalt, rooftops) with low albedo. Increased surface area for radiation absorption. Reduced vegetation and water retention. Example: Paris has seen a 9°F difference between urban and rural areas due to these factors. Mitigation strategies: White roofs, urban trees, reflective materials. Energy Transfer Mechanisms Radiation: Heat transfer via electromagnetic waves (e.g., feeling warmth from a stove). Conduction: Direct heat transfer through contact (e.g., pot on a burner). Good conductors: Metals (e.g., cast iron, stainless steel). Poor conductors: Insulating materials (e.g., foam). Example: Touching metal feels cold due to rapid heat transfer. Convection: Vertical movement of heat in fluids (e.g., boiling water). Example: Convective loops in boiling water distribute heat throughout. Advection: Horizontal transfer of heat (e.g., wind). Example: Coastal advection fog forms when warm air moves over a cooler surface. Latent Heat: Hidden heat involved in phase changes (e.g., liquid to vapor). Energy absorbed during evaporation or released during condensation. Example: Sweating cools the body as energy is absorbed to evaporate sweat. Example: Thunderstorms release latent heat during rapid condensation, fueling vertical development. Greenhouse Effect Greenhouse gases (e.g., CO2, water vapor) trap thermal infrared radiation, warming the atmosphere. Enhanced greenhouse effect due to human activities intensifies warming. Example: Similar to adding blankets; more heat is retained within the atmosphere. Climate change is fundamentally an energy balance problem: More radiation enters the system than leaves. 4. Atmospheric Circulation & Global Winds Pressure Zones and the Subsolar Point The subsolar point, which moves between 23.5°N (Tropic of Cancer) and 23.5°S (Tropic of Capricorn), has a profound effect on Earth's pressure zones throughout the year. As the subsolar point shifts north and south, it causes the intertropical convergence zone (ITCZ) to move as well, creating seasonal shifts in pressure. Summer: The ITCZ moves north, causing the low-pressure zone to move north as well. This brings a zone of wet, rainy conditions to areas such as the Indian subcontinent. Winter: The subsolar point drips south, and the zones of low and high pressure move with it, spreading out and causing a dry winter in regions that had wet summers. The Role of Land and Ocean Land heats up faster than water, so large land masses like Eurasia experience more intense surface heating than the oceans. This creates a strong zone of rising air, which is crucial in shaping the atmospheric pressure systems. For example, the summer monsoon in Asia is influenced by the landmass's ability to heat up and create low-pressure areas that draw in moist air from the ocean. Pressure Systems and the Jet Stream Pacific High: In the winter months, the Pacific High pressure system sits off the Southern California coast, bringing dry conditions to the region and creating a strong pressure system near 30°N. This pressure system is part of what drives the relatively dry conditions found in Baja California in the winter. Aleutian Low: The Aleutian Low pressure system develops over the North Pacific, which is a well-developed pocket of low pressure, steering storms onshore, particularly along the west coast of North America. Jet Stream: The jet stream is a fast-moving band of upper-level winds that moves from west to east. It plays a key role in directing storm systems and other weather patterns. These winds are important for understanding how different atmospheric systems interact. 5. Wind Patterns and Coriolis Effect Coriolis Deflection The Coriolis effect describes the deflection of winds due to Earth's rotation. In the Southern Hemisphere: Winds are deflected to the left. In the Northern Hemisphere: Winds are deflected to the right. This effect is crucial in determining wind patterns and helps create the global circulation cells that drive the prevailing winds. For example, winds flowing from high-pressure zones towards low-pressure zones will turn due to Coriolis deflection, forming distinct wind patterns. Prevailing Winds Trade Winds: In the tropics, near the equator, the prevailing winds are known as the trade winds. These winds flow from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere. These winds are historically significant for oceanic trade routes. Westerlies: In the mid-latitudes (about 30° to 60° north and south), the prevailing winds are westerlies, which blow from the west toward the east. Polar Easterlies: Near the poles, the winds blow from the east toward the west, known as the polar easterlies. Global Wind Circulation Hadley Cells: The rising air at the equator creates low-pressure zones and the associated trade winds. Air that rises at the equator travels toward the poles and sinks at about 30° latitude, creating high-pressure systems. Ferrel Cells: In the mid-latitudes, winds are deflected by the Coriolis effect, creating the westerlies. These winds drive weather systems and storms across the mid-latitudes. Polar Cells: Near the poles, cold air sinks and moves toward the equator, creating the polar easterlies. 6. Shifts in Wind Patterns & Climate Implications Seasonal Shifts Throughout the year, the subsolar point’s movement causes a shift in the wind patterns: Summer: The ITCZ shifts north, bringing wetter conditions to tropical regions, while high-pressure systems dominate the mid-latitudes, resulting in dry conditions. Winter: The ITCZ moves south, and the high-pressure systems move north, leading to cooler, drier conditions in the tropics. Impact on Climate and Vegetation The prevailing wind patterns greatly influence the climate of regions. For instance: Monsoons: The monsoon seasons in Asia are driven by the shifting of the ITCZ and the large landmass's ability to heat up and create low-pressure zones. Continental Climates: Large landmasses like Eurasia experience extreme temperature variations due to the lack of moderating influence from oceans. Winds and their patterns have a significant impact on regional climates. Vegetation and Soils: The location of prevailing wind belts can influence the type of vegetation and soils in an area. For example, regions influenced by westerlies tend to have more temperate forests, while areas affected by trade winds may have tropical rainforests or deserts. 7. Application of Wind Patterns: Understanding Global Geography By understanding the prevailing wind patterns and their seasonal shifts, we can predict weather and climate conditions: Example: If a location is near the equator and experiences trade winds, it will likely have a tropical climate. Conversely, regions affected by the westerlies or polar easterlies will experience more temperate or cold climates, respectively. Shifting Wind Zones Understanding these wind zones also explains the geography of regions. For example, a shift in wind patterns or pressure systems could result in dramatic changes in climate. This understanding is crucial for fields such as agriculture, urban planning, and environmental science.What are maps?
Maps are 2D representations of Earth's surface used to visualize geographic areas, patterns, and features.
Scale – small vs. large:
Small scale: Covers a large area with less detail (e.g., 1:1,000,000).
Large scale: Covers a small area with more detail (e.g., 1:24,000).
Projections – what they do, what they compromise:
Projections: Transform the 3D Earth onto a 2D surface, causing distortions.
Compromises: Preserve either area (equal-area projections) or shape (conformal projections) but not both.
Latitude & longitude:
Latitude: Measures north/south from the equator (0°–90°).
Longitude: Measures east/west from the Prime Meridian (0°–180°).
Both are measured in degrees, minutes, and seconds.
Contour lines:
Lines on a map connecting points of equal elevation.
Close spacing = steep slope; wide spacing = gentle slope.
Seasons
Earth-sun relationships and seasons:
Earth’s 23.5° axial tilt causes seasons.
Solstices and equinoxes mark seasonal transitions:
December Solstice (Dec 21/22): Subsolar point at 23.5°S.
March Equinox (Mar 20/21): Subsolar point at the equator.
June Solstice (Jun 20/21): Subsolar point at 23.5°N.
September Equinox (Sep 22/23): Subsolar point at the equator.
Relative amount of insolation:
Low latitudes: Receive more direct insolation year-round.
High latitudes: Receive less insolation, with extreme seasonal variations.
Subsolar point:
The location where the Sun is directly overhead.
Moves between 23.5°N and 23.5°S throughout the year.
Relationship between subsolar point, day length, sun angle, seasons:
Closer subsolar point → longer days and more insolation.
Higher sun angle → more concentrated solar energy.
Aphelion and perihelion:
Aphelion: Farthest from the Sun, occurs in July.
Perihelion: Closest to the Sun, occurs in January.
What is insolation?
Incoming solar radiation that reaches Earth.
What causes seasons?
Earth’s axial tilt and its orbit around the Sun.
Energy & The Atmosphere
What is air pressure – how does it change with elevation?
Air pressure is the force exerted by air molecules.
It decreases with elevation.
Normal lapse rate:
The rate of temperature decrease with altitude (~6.5°C per 1,000 meters).
Albedo:
Reflectivity of surfaces:
High albedo: Snow.
Low albedo: Asphalt or forests.
Urban heat island:
Urban areas are warmer due to low albedo, reduced vegetation, and heat-retaining materials.
Daily temperature pattern:
Coolest at sunrise, warmest mid-afternoon (~3 PM).
Heat transfer mechanisms:
Radiation: Sun warming Earth.
Conduction: Heat transfer through contact.
Convection: Vertical movement of heat in fluids.
Advection: Horizontal heat transfer.
6 controls on global temperatures:
Latitude, altitude, cloud cover, land-water heating differences, ocean currents, and geographic position.
Atmospheric Pressure and Winds
Global winds and pressure patterns:
Polar Easterlies, Westerlies, NE & SE Trade Winds.
ITCZ: Low-pressure zone near the equator.
High and low-pressure areas create aridity and precipitation zones.
What is high pressure?
Air descends, creating stable, dry conditions.
What is low pressure?
Air rises, leading to clouds and precipitation.
What causes winds?
Differences in air pressure.
What is an isobar?
A line connecting points of equal pressure on a map.
Three controls on wind speed and direction:
Pressure gradient force, Coriolis effect, and friction.
Local winds:
Land-sea breeze: Caused by temperature differences between land and water.
Monsoons: Seasonal wind patterns driven by temperature changes over land and ocean.