Earth's Energy Balance PDF

Earth’s Energy Balance This is the balance between incoming solar radiation and outgoing radiation from the Earth. The energy balance depends on latitude and seasons. Insulation Through Absorption: Insulation is absorbed by the Earth's crust and surface. Heating The Atmosphere: Sensi...

Earth’s Energy Balance This is the balance between incoming solar radiation and outgoing radiation from the Earth. The energy balance depends on latitude and seasons. Insulation Through Absorption: Insulation is absorbed by the Earth's crust and surface. Heating The Atmosphere: Sensible heat transfer: The absorbed heat from the Earth's surface warms the air directly through conduction and convection. Latent heat transfer: Some of the absorbed heat is used to evaporate water, turning it into water vapor, which then rises into the atmosphere, carrying latent heat energy. Outgoing terrestrial radiation: The Earth's surface also emits long-wave radiation due to its temperature, which heats up the overlaying atmosphere when absorbed. KEY WORDS Insolation – incoming solar radiation falling on a unit area of the Earth’s surfaced Radiation Budget – the balance of energy gain and energy loss. Conduction – energy transfer by contact, passing from one molecule to the next. Convection – energy transfer by movement of molecules with lots of energy. Latent Heat – the heat or energy that is absorbed or released during a phase change of a substance  ALTITUDE ASPECT Height above sea level LATITUDE The angle at Natural decrease in temp Distance which the Less dense air molecules from the sun’s rays at high altitudes equator strike the Decrease in earth temp as Insolation is (insolation distance received from equator angle of incidence) UNEQUALLY increases across the earth's surface OCEAN CURRENTS Benguela (cold) Agulhas (warm) DISTANCE FROM THE OCEAN Circulate anti- COSTAL—maritime, low temperature clockwise in SH range Circulate HINTERLANDS—continental climate, clockwise in NH high temperature range Latitudinal Influence The Sun's radiation hits the Earth in parallel waves because of the vast distance between the Indirect rays Sun and the Earth combined with the Sun's immense size. LATITUDINAL FACTORS concentrated rays 1. Distance of atmosphere 2. Insolation angle of incidence Indirect rays 3. Length if day and night 4. Albedo of Earth’s surface 5. The curvature of earth KEY WORDS Albedo – the fraction of insolation reflected from the Earth’s surface back into space (1 = high albedo; 0 = low albedo). Insolation angle of incidence – the angle at which the sun’s rays strike the earth. LOWER LATITUDES HIGHER LATITUDES (0°—30°) (60°—90°) Distance of Atmosphere Distance of Atmosphere In the lower latitudes the In the higher latitudes the heat has a shorter heat has a greater distance to travel, distance to travel, therefore less insolation is therefore more insolation lost through absorption, is lost through absorption, reflection and scattering. reflection and scattering. Angle of Incidence Angle of Incidence The lower latitudes The higher latitudes receive the greatest angle receive the smallest angle of incidence and more of incidence and oblique direct rays. rays. Length of Day and Length of Day And Night Night Less annual variation—no Greater annual variation— significant change in the significant change in duration of daylight and duration of daylight and darkness darkness Remains consistent Fluctuates noticeably as throughout the year the seasons change Albedo Albedo Lower albedo Higher albedo Vegetation covered White snow and ice surfaces absorbs more reflects insolation insolation Effect & Result Effect & Result Dispersed solar rays Concentrated solar rays Absorbed by a larger Absorbed by a smaller surface area of earth surface area of earth Cooler atmospheric Hotter atmospheric temp temperature Most intense at Equator Least intense at the Poles