ESS 5 Midterm Study Guide
Latent Heat Flux (heat transfer that changes phase of a substance) - i.e. temperature of the substance itself does not change but the temperature of the surrounding environment does. Be able to explain and give examples of how latent heat is important for humans and for our weather/climate
- Humans and animals need to cool down through sweating - Precipitation: formation of clouds and water vapor
5 factors which define 'weather':
- Temperature - Air Pressure - Humidity - Cloud Cover - Wind Speed and Direction
Solar spectrum (blackbody)
Hotter black bodies: 1.Have greater intensities 2.Peak at higher energy wavelengths 3.Emit more energy 4.Color (wavelength) of light can tell us temperature A black body: 1.Absorbs all light shined upon it 2.Emits a spectrum (i.e wavelength) of light that depends upon its temperature
Heat transfer can result in sensible heat flux or latent heat flux
sensible - changes temperature latent- changes phase (energy is stored or released) Specific heat - energy needed to raise 1kg of substance by 1C
Planetary Energy Balance
solar energy absorbed = terrestrial energy emitted BUT solar energy absorbed does NOT equal terrestrial energy emitted over each latitude Energy is transported from the Equator to the poles by winds and ocean currents
Electromagnetic spectrum
the range of wavelengths or frequencies over which electromagnetic radiation extends. - Gamma Rays (highest/shortest) - X-Rays - UV - Visible - Infrared - Radio
Be able to explain what processes converted the 2nd atmosphere into the 3rd atmosphere
Atm. Today: Mostly Nitrogen, Oxygen, and Argon H2O: Earth cooled, atmosphere can only hold so much water vapor emitted by volcanoes, water vapor condensed into cloud and formed oceans O2: Anaerobic bacteria (3.5 Byrs) in oceans, photosynthesis (plants and rocks oxidized), N2: released in small amts by volcanoes (chemically inert/not water soluble), only small amt removed from atmosphere, removal of CO2 - N2 became most abundant. Ar: radioactive decay in rocks, chemically inert and insoluble Lack of CO2: volcanism went down, removed by - dissolution in oceans, biosphere, chemical weathering (acid rain reacts w rock to dissolve) - carbon locked away in minerals and rocks (fossil fuels)
Definition of 'climate'
Avg. weather and variability of atmosphere
Be able to describe which gases made up the second atmosphere and where they came from
Carbon Dioxide and Water Vapor due to Volcanoes and Comets
Be able to identify whether a transfer of heat is by conduction, convection and radiation
Conduction - Energy moving through solid; material does NOT move Convection - energy moving through fluid or gas; material DOES move Radiation - energy moving between two points; does not require any material
Definitions of energy and power
Energy: Ability to do work Potential vs Kinetic Power: How quickly energy is released/used
Composition of the atmosphere today: permanent gases and variable gases (sources and sinks)
Permanent Gases: - 78% Nitrogen - 20% Oxygen - 0.1% Ar Variable Gases: - H2O - CO2 (respiration, volcanoes/dissolution in ocean, photosynthesis) - Methane (agriculture, fossil fuel extraction, decomposition) - Ozone - Nitrous Oxide
Ways of categorizing the vertical structure of the atmosphere: pressure, temperature, chemical composition, electrical conductivity
Pressure increase altitude - pressure and air density decrease Temperature Chemical composition Heterosphere - composition not uniform (thermosphere) Homosphere - composition relatively the same; lower 80 km Electrical Conductivity ionosphere - higher than 60 km; electrified region of upper atmosphere; solar radiation absorption created ions (charged particles) Aurora Borealis
Heat transfer on Earth
Radiation (energy transfer that does not require any material) Conduction (energy moves but the material itself does not) Convection (energy moves with material e.g. forced and free) - Free convection - e.g. the wind - forced convection - energy emitted from equator
Reflection and scattering (specular reflection, Rayleigh and Mie scattering)
Raleigh Scattering - scatters in every direction - by gas molecules - stronger for shorter wavelengths * blue skies and red sunsets Mie Scattering - mainly forward - by particles like aerosols - no strong wavelength preference * grey smog Specular reflection
Be able to use the mechanics of Earth's orbit around the Sun to explain why we get day/night and seasons:
Rotation - Earth spins completely once per day (24 hours) around its axis - reason why we have day and night Revolution - Perihelion (shorter distance) and Aphelion (longer distance); only small influence on seasonal heating; when they occur today? Tilt (23.5) - Principle cause of seasons!!! effects amount of solar energy (solar beam spreading and period of daylight)
Understand and be able to describe/explain/draw diagrams of the different factors which create planetary energy balance and set global temperatures
Solar Constant - suns luminosity (power) - distance from the sun Atmosphere and Albedo - absorption - reflection and scattering - albedo Outgoing long wave radiation - greenhouse effect ***atmosphere, albedo, and outgoing radiation determine temp we feel
Transmission
The amount of solar energy reaching the earth's surface.
Be able to describe and explain how the following factors cause variation in local temperatures:
Time - daily patterns and annual patterns Latitude - absolute v range in temp; e.g. Miami ( higher absolute )v New York (higher range) Altitude - troposphere up to thermosphere Local Features: - aspect, topography, vegetation Warm and cold ocean currents Surface type - heat capacity - albedo Clouds - increase avg temperature
Definition of an 'aerosol' and examples
Tiny liquid droplets or particles that remain suspended in the air. eg. smoke, ice and sea salt crystals, dust, volcanic emissions, pollution
Names and properties of the different layers i.e. troposphere, stratosphere, mesosphere, thermosphere, homosphere, heterosphere
Troposphere - lowest - temp decreases with altitude - 80% of mass - strong vert. motion - Where most weather events occur Stratosphere - most ozone - heated by UV absorption - weak vert. motion Mesosphere - little ozone to absorb UV radiation - temp decreases with altitude Thermosphere - little mass - warm air (O2 absorbs solar radiation) - low density = large temp increase
Gases that made up the first atmosphere and how were they lost
hydrogen and helium (most common in solar system) lost over 50Myrs - H and He not retained by gravity, solar wind, Earth lack of magnetic field, collisions