Unit 5 Flashcards
What is the First Law of Thermodynamics? .
Energy cannot be created or destroyed, only transferred or transformed (conservation of energy). In climate science, this means Earth’s energy budget must balance: incoming solar radiation must equal outgoing radiation over the long term
What is the Second Law of Thermodynamics?
Energy naturally flows from regions of higher temperature to lower temperature, increasing entropy (disorder). This governs how heat is transferred within Earth’s climate system.
What is a blackbody object?
A blackbody is an idealized object that absorbs and emits all radiation perfectly at all wavelengths. The Sun and Earth approximate blackbodies.
What are sparkling surfaces? .
Sparkling surfaces (e.g., ice, snow, metals) have high reflectivity (albedo) and reflect most of the incoming radiation
What are clear surfaces? .
Clear surfaces (e.g., water, forests) have low reflectivity and absorb more energy
Why are high-albedo surfaces important?
High-albedo surfaces (e.g., polar ice) help regulate Earth’s temperature by reflecting sunlight.
What is temperature?
A measure of the average kinetic energy of molecules.
What is energy?
The capacity to do work (e.g., radiation, thermal energy).
What is the relationship between energy and wavelength?
Shorter wavelengths = higher energy (e.g., UV, X-rays); Longer wavelengths = lower energy (e.g., infrared, radio waves).
What is heat?
The transfer of thermal energy due to a temperature difference.
What does the Stefan-Boltzmann Law state?
E = σ T^4, where E is the total energy emitted, T is temperature, and σ is a constant. Hotter objects emit exponentially more energy.
What is shortwave radiation?
Emitted by hotter objects (e.g., the Sun) at high energy (visible & UV).
What is longwave radiation? .
Emitted by cooler objects (e.g., Earth) at lower energy (infrared)
What is Earth’s Greenhouse effect
Earth’s surface absorbs shortwave solar radiation and emits longwave infrared radiation. Greenhouse gases trap outgoing infrared radiation, warming the planet.
What are major greenhouse gases?
CO₂, CH₄, H₂O vapor, N₂O, O₃. They regulate Earth’s temperature by absorbing and re-emitting infrared radiation.
What is the Goldilocks Zone
Earth is just right for liquid water, but the greenhouse effect plays a key role.
What is global radiative equilibrium?
With GHGs, a balanced climate with a stable temperature; without GHGs, Earth would be ~33°C colder.
What are anthropogenic contributions to greenhouse gases?.
Human activities (fossil fuels, deforestation) increase CO₂, CH₄, and N₂O, enhancing the greenhouse effect and warming Earth.
What is Global Warming Potential (GWP)?
GWP compares the warming effect of GHGs over time. CO₂ = baseline (1), CH₄ = ~28x CO₂ over 100 years, N₂O = ~265x CO₂.
How do greenhouse gases interact with radiation?
They interact only with longwave radiation, absorbing and re-emitting it.
What are the fates of incoming solar radiation?
Scattering (redirection by particles), Reflection (bounced back into space), Absorption (converted into heat).
What is the global radiation budget?
Helps track energy flow (solar in, thermal out). Changes (e.g., GHGs, albedo shifts) can disrupt climate balance.
What factors affect radiation distribution?
Latitude (equator gets more direct sunlight than poles), Clouds and aerosols (reflect or absorb energy), Seasonality (Earth’s tilt changes sunlight distribution).
How does Earth’s orbit affect seasons?
Tilt (23.5°) determines seasons; Revolution around Sun causes variations in daylight length.
What are the mechanisms of energy transfer?
Radiation (transfer via electromagnetic waves), Conduction (direct heat transfer via molecular contact), Convection (heat transfer via fluid movement).
