Last Class – Global What transformations occur as energy flows through the earth system. Relationship between distance from the source and amount of energy available. This Class - Energy Balance – Earth’s Structure How does variability in the earth’s physical structure affect the transformations of energy? What is the physical structure of the atmosphere? What is the chemical structure of the atmosphere?

Energy comes to earth in these wavelengths Energy leaves the earth in these wavelengths

How do features of the earth’s surface control energy exchange - Changes in Albedo

How features of the earth’s surface control energy exchange Changes in Albedo Light colors reflect energy – they have a high albedo (e.g. snow, ice) Dark colors absorb energy – they have a low albedo (many soils and rocks) Water can be quite variable in it’s albedo (related to angle of incidence and what is in the water)

Effect of Clouds on Radiation Daytime Clear sky conditionsCloudy conditions

Effect of Clouds on IR Radiation Night time Clear sky conditionsCloudy conditions Ahrens 3rd Edition, p. 63

Energy Balance – Atmospheric Structure - Feedbacks What is the physical structure of the atmosphere? What is the chemical structure of the atmosphere?

These fluxes are related to the structure and composition of the atmosphere. They allow life to exist

Weather occurs here Ozone - UV protection here

Structure of the Atmosphere Thermosphere Mesosphere Ozone Maximum Stratosphere Troposphere Temperature

78% nitrogen 20.6% oxygen < 1% argon 0.4% water vapor 0.036% carbon dioxide traces gases: Ne, He, Kr, H, O 3 Methane, Nitrous Oxide

Absorption Spectra of Atmospheric Gases Anthes, p. 55 WAVELENGTH (micrometers)

Energy Balance – Atmospheric Structure - Feedbacks What is the physical structure of the atmosphere? - multi-layered, with little chemical interaction - most of the mass is near the surface What is the chemical structure of the atmosphere? - nitrogen by far the most common element - oxygen is second most common - greenhouse gasses are small in amount, but important!

Absorption Spectra of Atmospheric Gases Anthes, p. 55 WAVELENGTH (micrometers)

Global Water Balance Anthes, p. 47 (modified) Earth’s annual water balance, (original) units are 105 km 3 of water per year. Huge quantities of water are cycled through the atmosphere each year. On the continents, precipitation exceeds evaporation and the reverse is true for oceans. Runoff from the continents balances the deficit of the oceans. Land Ocean Precipitation Evaporation Runoff

Since the amount of energy coming from the sun varies on long and predictable time scales, we need to focus on the exchanges 1)In the atmosphere, and 2) At the earth surface