Higher temperature, shorter wavelength
Longwave & Shortwave Radiation
The hot sun radiates at shorter wavelengths that carry more energy, and the fraction absorbed by the cooler earth is then re-radiated at longer wavelengths.
T= 15°C (59°F)
T= –18°C (0°F)
Greenhouse effects make Earth’s surface warmer!
Surface Temperature With the Atmosphere
Surface Temperature Without the Atmosphere
Water vapor accounts for 60% of the atmospheric greenhouse effect, CO2 26%, and the remaining greenhouse gases 14%.
Water vapor (H2O)
Carbon dioxide (CO2)
Nitrous oxide (N2O)
What are they?
CO2 contributes most (55-60%) to the anthropogenic greenhouse effect, and methane is a distant second (16%).
CFCs cause the strongest greenhouse warming on a molecule-for-molecule basis.
Solar radiation passes rather freely through Earth's atmosphere.
Earth emits longwave energy, which either leaks through a narrow window or
is absorbed by greenhouse gases and radiated back to Earth.
Solar intensity, defined as the energy per area, is different at different latitude.
A sunlight beam that strikes at an angle is spread across a greater surface area, and is a less intense heat source than a beam impinging directly.
Insolation is stronger in the tropics (low latitudes) than in in the polar regions (high latitudes).
Pole-to-Equator Heating Imbalances
What controls the elevation of the Sun above the horizon?
Earth’s Tilt Primarily Determines Season
The balance is achieved locally at only two lines of latitude.