Earth-Sun Relationship and Seasons

Introduction to Physical Geography

• Physical Geography is the study of spatial and temporal patterns of Earth's physical environment. It encompasses the study of energy, air, water, weather, climate, landforms, soils, animals, plants, and the Earth itself.

Earth's Four Spheres

• Lithosphere: This sphere includes the solid Earth features like mountains, soils, tectonic plates, volcanoes, and faults.
• Atmosphere: This sphere encompasses weather, climate, greenhouse gases, aerosols, and water.
• Hydrosphere: This sphere includes oceans, rivers, lakes, streams, glaciers, snow, and ice.
• Biosphere: This sphere includes all living things like plants, animals, bacteria, humans, carbon, and agriculture.

Interactions Between the Spheres

• Volcanic eruptions (lithosphere) impact atmospheric chemistry, temperature, and precipitation (atmosphere & hydrosphere).
• Climate changes can affect ecosystems and biodiversity (biosphere).
• Water cycles shape landscapes and influence climate patterns (hydrosphere & lithosphere).

Important Entities

• Water shapes the landscape; influences species distribution and regulates the climate.
• Alexander von Humboldt (1769–1859) mapped climate and vegetation across different regions and developed early theories on Earth's physical variations.
• Latitude measures the distance north or south from the Equator, while Longitude measures the distance east or west from the Prime Meridian.
• The earth is divided into Northern, Southern, Eastern, and Western Hemispheres .
• Great Circles defines the shortest distance between two points on Earth.

Spherical Earth, Solar Energy, and the Seasons

• The sun is Earth's primary source of energy, which shapes the climate and physical environment. Energy is a property of every physical system, including matter (anything with mass and occupies space).
• The energy the sun provides originates from Electromagnetic Radiation.
• The Sun generates energy through nuclear reactions, Hydrogen combine to form heavier elements (Helium).
• Photons leave solar objects and travel through space in waves at the speed of light.
• The Sun is approximately 150 million kilometers (~90 million miles) away from Earth at the center of our Solar System.

Important Units

• Joule (J) measures energy, where 1 J is required to lift a small 100g apple vertically 1 meter.
• Watt (W) measures rate, where 1 W equals 1 J per second, describes energy entering or leaving a system.

Poles vs Eqautor

• The equator receives direct sunlight, while polar regions receive sunlight at a lower angle, spreading the energy (less intense solar radiation overall).
• Solar altitude angle is the angle between the sun and the horizon.
• The angle becomes smaller at higher latitudes where the sun appears on the horizon, higher angles equals more direct sunlight and higher temperatures.
• Planets revolve counter-clockwise around the sun.
• Earth's axis is tilted 23.5° off from being perpendicular to the plane of the ecliptic, varying how directly sunlight hits the planet throughout the year.

Solstices/Equinoxes

• June 21-22 is the Summer Solstice in the Northern Hemisphere (longest day, sun over 23.5°N, the start of summer) and the Winter Solstice in the Southern Hemisphere (shortest day, colder temps, the start of winter).
• December 21-22 represents the opposite; Winter Solstice in the Northern Hemisphere (shortest day, sun over 23.5°S, the start of winter) and Summer Solstice in the Southern Hemisphere (longest day, warmer temps, the start of summer).
• March and September 21-22 represent the start of the Spring and Autumn Equinoxes, day/night time is equal

Winter vs Summer

• The sun's rays reduces heat intensity. During summer, a larger solar angle warms the concentrated area.
• The latitude with the highest solar altitude angle on Northern Hemisphere Summer Solstice is 23.5°N b/c 90° solar angle.
• Solar Declination Latitude is the latitude where the sun is directly overhead at noon.

Latitudinal Facts

• The solar declination latitude on December 21-22, which is Northern Hemisphere Winter Solstice/ Southern Hemisphere Summer Solstice is 23.5°S, 66.5°S at the Antarctic Circle.
• On June 21-22, the Northern Hemisphere Summer Solstice/ Southern Hemisphere Winter Solstice solar declination latitude is 23.5°N.
• Latitudes 23.5°N to 23.5°S (Tropics) receive the most intense solar radiation year-round.
• During the month of June, the North Pole receives the most solar radiation with a maximizing 24hrs of daylight.

Extreme Latitutdes

• Regions 66.5°N Artic Circle, and 66.5°S (Antarctic Circle) need to travel north or south to see 24 hours of sunlight on the Summer Solstice.
• Permafrost is permanently frozen ground due to low solar angle in the Arctic resulting in cold, frozen soil with important carbon composition.

Earth's Energy Balance, the Greenhouse Effect, and Global Warming

• The Electromagnetic Spectrum includes Shortwave, which is the most intense, and Longwave, with the least intensity. Photons travel at the speed of light.
• Wavelength measures the distance between two waves of electromagnetic radiation (μm); only a few wavelengths are visible.
• Bodies emit electromagnetic radiation depending on temperature. Hottest objects emit the shortest wavelengths=the more radiation.
• Sun emits shortwave radiation (visible light, ultraviolet), while the Earth emits longwave radiation (infrared).
• Transparent in the infrared, but not other wavelengths, applies to greenhouse gases.

Factors Influencing Temeprature

• If the earth is constantly bombarded by solar radiation, it does not overheat because it emits energy (longwave radiation) to maintain an equilibrium temperature. The rate of receiving photons equals rate of emitting.
• Earth must send radiation to outer space as fast as it comes in. To remain stable, Shortwave radiation reflects to outer space and Long wave radiation is emitted to outer space
• Radiative equilibrium requires the amount of solar (shortwave) radiation entering our atmosphere equals the amount of radiation (reflection+ longwave emission).

Absorption/Emission/Reflection

• Emission; objects emit energy by sending photons outward and cool.
• Reflection bounces photons away without absorbing, energy is unaffected.
• Absorption retains photons, increasing the energy status and temperature, but not always visible light

Albedo Effects

• Albedo is an incoming solar radiation reflected back into space.
• High albedo more reflection in ice and snow.
• Low albedo more absorption in oceans and forests.
• Earth average planetary albedo is ~30%. meaning 30% of reflecting back.
• Incoming solar at atmosphere top must emit in radiation to maintain the stable temperature (Longwave radiation).

What's next?

• After solar, next is surface and atmosphere, then longwave radiation.
• Climate depends on which part of globe; different surface characteristics dictate the amount of radiation.
• Cold means less intense radiation, hotter means more long wave radiation = more emitting.
• Greenhouse gas effects = atmosphere transparent but opaque for longwave

Greenhouse Effect Explained

• Greenhouse effect: outgoing radiation absorbed/re-emitted by GHG, warming surface.
• Radiation passes through the atmosphere and surface is emitting to create GHG.
• GHG emits outer downward to space to slow cooling; bombardment warms surface/emits radiation.
• Without the Greenhouse Effect, Earth's temperature would be -15°C. the Greenhouse Effect keeps it ~18°C
• John Tyndall was one of the first to detect heat-trapping.
• Some greenhouse gases include Water Vapor (H2O, most abundant), Carbon Dioxide (CO2), Methane (CH4), and Ozone (O3).
• How does it work? Gas molecule’s radiation ability depends on vibration/frequency. Frequency makes molecules absorbers longwave radiation quickly
• Increase due to Humans and Carbon

Water, Latent Heat, Specific Heat, and Local Energy Balances

• Net Radiation (Rnet) incoming radiation minus outgoing; needs to zero to be equilibrium but green house gas not 0, +Rnet absorbed earth.
• To rid energy, Evaporation, latent heat flux, and sensible heat flux move energy into atmosphere causing surface to cool.
• Evaporation requires energy from the environment by floating water vapor into the atmosphere=cooling.
• Latent Energy is energy stored in water vapor molecules/energy associated with water phase change.
• Bonds are tough; hydrogen bonding makes the molecule want to stick. A lot for H20.
• Energy raises degree of heat for liquid water
• Locations provide continuous source for evaporation through Large amounts of energy and continuous sources.
• Deserts have low points because of little water available for evaporation during the summer, solar energy is high
• Condensation is when water vapor molecules turn back into the liquid phase, and release energy into atmosphere/warming/wind
• Flux occurs through direct contact. Sensible heat flux: exchange of energy through direct contact
• Ocean vs land temperature = different
• Positive sensible flux occurs during summer/warmer.
• heat is transferred from the surface to the atmosphere happens to cool the air.
• Energetic balance means rate of energy = outgoing.

Fluids and Evaporation

• What is a fluid? Transition of liquid to gas
• Evaporation liquid molecules vibrate allow distant for other faster liquid escape bonds
• Fast exposed= escape bonds vapor molecules entirely become water molecules Vapor phase more energy moves Vapor.
• Transition gas evaporation cools more spend bonds congeal
• Condition exceed is net condensation -Condition Saturated - Evaporation Not Saturated
• A mass Is the amount fraction vapor H2O is kg. Contribution pressure, hectopascals, hPa. - Energy, heat, molecules reduce saturation (gas)
• Pressure becomes saturated that cannot condensation. Humidity, units and measurements

Atmospheric Convection, Sea Breeze, and the ITCZ:

• Atmospheric vertical structures include; troposphere, stratosphere, mesosphere, thermosphere
• Ocean and pressure are equal
• Gases compress due to temperature or expansion.
• Convection arises heat through 1) a surface that's war, 2) molecules that heat and expand.
• Removing upwards leads - Low, winds affect pressure surface through convection .
• Pushing wind drives force sea and air during the daytime.
• High and air are wind blown from ocean Land - Wind driven at night high surface.

Additional Key Facts

• Convergence by the Sea leads to thunder which effects rates with temperature and altitude.
• Atmospheric pressure, drives ITCZ, where surface drive convention
• Warm air, high amounts lead form the ITCZ
• Demonstrate weather, energy, light. Thermal for no infrared. Body warm transfers (heat- cooling)

Wind Facts

• Sea wall over to limit flow. The force ITCZ effect deflect all latitudes equator spin rotation.
• Circulation: trades and westerlies, rapid channels. jet outflow mid- latitude
• High Subsidence leads of rising, convection opposite and Hadley cell
• Tropical rain, warming subsidence, high desert , pressure how lead force ITCZ.
• Heat, air ITCZ and cyclone

Effect of atmospheric motion on continental climate and life

• Temperate: Latitude climate - Polar storms Frontal; temperature humidity
• Rossby; storms - Smashes - Pressure area/Wind
• Circulation= conveyor Isotherms: Precipitation ocean - Specific temperature monsoon high heat

Circulation and Energy Distribution

• Trade winds warm water energy
• Heat is converted to Water- density evaporation
• Hemisphere's heat and molecules lead ITCZ
• Density differences cause high salinity Atlantic
• Warm salty currents pull moisture
• Subtropics have increased distribution linking surface winds with El Nino

Test your knowledge of Earth-Sun relationships. Questions cover the basics of solar energy, Earth's tilt, seasons, and solar altitude angle. Explore the connections between these phenomena.