Earth Science · Ocean · Climate · Water Cycle / Principles and Exploration
Albedo, greenhouse effect, and radiation balance — principles and investigation
The balance between solar energy absorbed by the Earth and infrared energy emitted is linked to temperature. Compare the equilibrium temperature and the process of reaching it by changing solar radiation, reflectance, infrared absorption rate, and heat capacity. Distinguish between conditions that change the final temperature and conditions that change the time it takes for the change to occur.
How does it work?
If the reflectivity is high, the absorbed solar radiation is reduced. When the atmosphere absorbs and re-emits infrared rays, the equilibrium surface temperature increases.
Te=[S(1−α)/(4σ)]¼ · Ts=Te·[2/(2−ε)]¼
Try this investigation
- Starting from 260 K, we calculate 1200 days. Look at the temperature curve and energy arrow and see if the difference between inflow and outflow is decreasing.
- Run and record ε=0.78 and ε=0 to distinguish between the effective radiant temperature and the ground temperature.
- Maintain solar radiation and record ε, reflectance, and heat capacity by changing them one by one. Compare the end and slope of the curve together.
Interpreting your results
If only heat capacity increases, what happens to the equilibrium temperature after enough time?
Equilibrium is when the absorbed solar radiation and the long-wave radiation going out into space are equal. C only changes dT/dt, so it does not change the final temperature.
Assumptions and limitations
It is a radiation balance model of the first layer of the atmosphere, which absorbs only infrared rays. The atmosphere is at instantaneous radiation equilibrium, and the surface is at constant heat capacity, which is integrated by RK4. ε does not correspond to a specific CO₂ concentration. Cloud, convection, water vapor feedbacks and actual climate predictions are excluded.