Global Energy Movement - Lecture 3

These flashcards cover key concepts and vocabulary related to the global energy movement discussed in lecture 3 of ENVR 200.

Global Energy Surpluses and Deficits

• Differences in energy being absorbed between the equator and higher latitudes

• At the poles: Energy emitted as infrared radiation is greater than solar energy absorbed

where is the net energy deficit?

above 35 degrees latitude

Atmospheric Circulation

The large-scale movement of air that distributes heat and moisture across the globe.

Air parcel

• discrete area of air in any size or shape

• can be at a different temperature of pressure than the surrounding air (like a warm spot when youre swimming)

Air Pressure

The weight of air molecules pressing down on each other in the atmosphere, influencing wind patterns and atmospheric movement

the higher up in the atmosphere:

the fewer air molecules there are = less pressure

air pressure increases as …

air pressure increases as we move towards the surface of the planet

air always moves from a region of _____ pressure to ____ pressure:

air always moves from a region of high pressure to low pressure

Pressure-driven Air Movement

• Driver of the majority of the movement of air molecules and energy throughout the atmosphere

• cause: initiated by uneven solar heating on the planets surface (conduction and convection)

  • then driven: by differences in pressure

High pressure systems

warm and sunny

low pressure systems

cold and cloudy/rainy

Wind

Landform-driven air movement

• physical features in the landscape impacting air movement

• high relief of landforms forces air parcels higher into the atmosphere

  • air closer to sea level = increased pressure and density

  • air further away from ground = decrease in pressure = molecules expand = air becomes colder → water vapor may leave the air and fall as snow

Rotation-driven air movement

• as the planet rotates the movement that would normally be straight are actually curved with the rotation of the planet

  • Coriolis effect

Coriolis Effect

The curvature of air movement due to the rotation of the Earth, affecting wind patterns.

Water Vapor Transport

The movement of water vapor through the atmosphere as a result of pressure-driven and landform-driven circulation

Evaporation in water vapor transport

• conversion of liquid water to water vapor

• takes in energy

Condensation in water vapor transport

• conversion of water vapor to liquid water

• releases energy

Hadley Cell

A circulation cell of air movement that begins at the equator and descends at approximately 30°N and 30°S

Ferrel Cell

• A circulation cell that rises at 60° and falls at 30°

• driven mainly by the movement of Hadley and Polar Cells (weaker and more variable)

• moves in the opposite direction at the Hadley and Polar cells

Polar Cell

A circulation cell that begins at 60°N and 60°S and descends at the poles

Dissolved salts

• ocean water has a high concentration of them

• minerals weathered from land over time by water

• have greater mass than the hydrogen and oxygen atoms that make up water

• density in water increases as concentration of _________ increases

• lowers freezing temperature of water

ocean temperature differences

• mainly driven by differences in energy input across latitudes

salt concentration and temperature vary globally so ….

water density also differs globally (cold + salty = denser) (warm + fresh = lighter)

ocean circulation

movement of water through shallow and deep waters are necessary to transport heat from the equator to the poles

Surface ocean currents

• fast currents ~10-100m per second

• driven by surface winds

• landforms get in the way (trap and deflect currents)

  • necessary to deflect currents into different latitudes

• water at equator absorbs surplus of energy and transports it towards the poles as surface winds move the water and water is deflected by landmass

  • ex: gulf stream begins at equator and is deflected by North America and pushed northwards. travels along eastern coast of north America releasing heat as it travels. then travels to northwest of europe making northern europe warmer than is should be based on its latitude

Surface winds

• global pattern of movement of air in the atmosphere

• driven by: circulation cells and the rotation of the planet (coriolis effect)

• direction of these winds is determined by the direction of the circulation cell at that latitude

what are surface winds driven by?

circulation cells and the rotation of the planet

what determines the direction of surface winds?

the circulation cell at that latitude

Deep ocean currents / circulation

• slower circulation driven by ice formation reinforcing global differences in water density

• ice formation occurs from ocean water at the poles

  • ice excludes salt as it forms

    • leaving behind higher concentrations of salt in the water directly around the forming ice

  • this saltier water is denser than surrounding water, so it sinks below the less salty water

  • denser water sinks and pulls in new water to replace it

    • sinking water pushes along water that is already there

  • once water enters this circulation it will only exit once it warms up and becomes less dense than the surrounding water

Surface waters

• ~100 m from atmosphere

• absorb 90% of incoming solar radiation

  • heats the water (warmer water = less dense)

• water it highly oxygenated

• warmer water stays on top of colder water over the long term (stable state)

Pycnocline

• ~200 m - 1 km from the atmosphere

• region in the water column where temperature, salinity, and density of water change the most rapidly

  • warm, less dense and less salty water changes to cold, denser, saltier water

Deep Ocean

• > 1 km from the atmosphere

• very cold, dense, low in oxygen, and salty

• dramatic increase in water pressure as you go towards ocean floor (similar to air pressure on land)

Deep ocean circulation

Global Conveyer Belt

• A global system of ocean circulation that transfers heat through surface and deep ocean currents

• 1) surface currents: warm water moved by surface winds and deflected by landforms travel to the poles

• 2) deep ocean currents: at the poles the water forms ice, ice formation leave behind saltier/denser water/brine that sinks

• 3) deep ocean currents: as dense water sinks it pulls in new water from behind which pushes it further down to travel along the ocean floor

• 4) deep ocean currents: water forming deep ocean currents warms up (less dense) and rises

• 5) surface currents: rising water one again enters the surface currents and cycle repeats

Thermohaline circulation

• Drives the Global conveyer belt / large-scale ocean circulation

• differences in temperature and salinity

• It plays a crucial role in regulating global climate and redistributing heat across the planet

• thermo = temp

• haline = salt