Transferring Thermal Energy Earth Science Applications Objectives 4-9

Thermal Energy Thermal Energy: sum of the kinetic and potential energy of all the molecules in an object Thermal Energy increases as temperature increases Heat is thermal energy that flows from high temperatures to low temperatures Earth’s sources of heat: Sun, gravitational contraction, radioactive decay, asteroid/meteorite bombardment

How is heat transferred? Conduction Radiation Convection

Conduction Transfer of thermal energy through matter by the direct contact of particles Ex: Holding snow/ice in your hand Holding a cup of coffee Earth Science: conduction occurs at Earth’s surface as the particles in the atmosphere make direct contact with the ground.

Radiation Transfer of energy by electromagnetic waves Travel through space regardless of matter being present or not Ex: Standing by a fire to warm your hands Earth Science: Sun heating the Earth

Radiation

Convection Transfer of energy by the motion of heated particles in a fluid Energetic particles move from one spot to another, carrying energy with them Convection currents are a rising and sinking action Ex: Lava Lamp Earth Science: Convection Currents on Earth (mantle, atmosphere, oceans)

Helpful Links Atmosphere and Ocean Live Data Ventusky Live Data

Global Circulation Video Overall, the Sun heats the surface of the Earth, and Earth radiates back to space about as much energy as it receives over the course of a year. (300) Day vs. Night, Poles vs. Tropics  Balancing the budget! (301) Tropics and other places maintain fairly constant average temps bec heat energy is redistributed around the world. The continual motion of air and water reallocates heat energy among Earth’s surface, oceans, and atmosphere and brings it into balance.

Energy Transfer in Oceans: Vertically – Water Masses (397-8) – sea ice forms, salt ions are left, cold salty water becomes denser and sinks, (H – density current) arctic, salty water migrates toward the equator along the ocean floor Upwelling (405) – upward motion of ocean water, water originates from the bottom of the ocean and are cold, surface water is displaced by winds and replaced by upwelling deep water, waters are rich in nutrients which support marine life

Energy Transfer in Oceans: Horizontally – Density currents - arctic, salty water migrates toward the equator along the ocean floor, move slowly in deep ocean waters (403) Surface currents – wind driven and follow wind patterns, relatively salty midlatitude / subtropical water carried into polar regions and become colder and denser and sink (403) Gyres – closed, circular current systems, five major ones, northern hemisphere = clockwise, southern hemisphere = counterclockwise --Read page 404 and view the figure

Salinity Graph What information do we get from this graph?

Salinity Map Salinity Map Complicated due to the factors that affect salinity. Increasing Salinity  ice formation, evaporation, adding salt from volcanic eruptions or weathering of rocks Decreasing Salinity  ice melting, precipitation, salt precipitates on arid coasts, spray drops, formation of shells, bones and teeth of marine organisms

Light Absorption In general, light penetrates only the upper 100m of seawater, causing the top to be warm and the bottom to be dark and cold.

Thermocline Thermocline – rapidly decreasing temperatures with depth, caused by the inability of light to reach past ~100m

Thermohaline / Global Conveyer Belt Thermohaline: part of a large-scale ocean circulation driven by global density gradients controlled by temperature and salinity (deep ocean currents) Global E Conveyer Belt – constant motion of the ocean water transferring E. Caused by thermohaline currents (density currents) and wind currents (surface currents)

Gyres

Energy Transfer in Atmosphere: Global Wind Systems (305-6) Wind (282) – air moves in response to density imbalances created by the unequal heating and cooling of Earth’s surface, works like air conditioned building, H  L Air Masses (303) – large body of air that takes on characteristics of the area over which it forms, cP cT mP mT, air masses move transferring heat from one area to another to establish heat balance

Coriolis effect – deflects moving particles such as air & water to the right above the equator and to the left below the equator; caused by Earth’s rotation and combines with the heat imbalance found on Earth to create the trade winds (0-30 degrees N/S), westerlies (30-60 degrees N/S), and polar easterlies (60-90 degrees N/S) AND Hadley/Ferrel/Polar cells.

W/o Earth spinning, there would be no Coriolis effect and currents may look like this.

Differential Heating and the Coriolis effect cause Hadley/Ferrel/Polar Cells AND the global wind belts

Day time sea breeze Night time land breeze

Air Masses from a global perspective

FRONTS Cold (blue triangles) – clouds, showers, some storms (abrupt) Warm (red half circles) - extensive cloudiness & light precip (gradual) Stationary (both blue triangles & red half circles) – similar to warm but can stay a while Occluded (purple) – precip on both sides of the front, cold air mass catches another cold air mass and forces warm air up

On a weather map

Weather Map Ex