Environmental Science Test

Equatorial Concentration → Polar Dispersion →Uneven Heating

Solar energy hits the equator directly → Toward the poles, the curvature of the Earth spreads the same amount of solar energy over a much larger surface area → dynamic creates a permanent global energy gradient,

The Heating Cycle:

When fluids heat up, they expand, decrease in density, and rise.

The Cooling Cycle:

When fluids cool, they contract, increase in density, and sink.

Universal Principle

Both atmospheric air and ocean water act as fluids in these convection currents. The same physical principle that produces convection deep inside the solid Earth operates in our oceans and sky.

Convection on a non-rotating Earth: Equatorial Rising → Poleward Movement → Polar Sinking

Intense heat at the equator causes warm air to rise →This rising air hits the upper atmosphere and moves toward the colder poles. →As the air cools at the poles, it becomes dense and sinks, returning along the surface toward the equator to replace the rising air

Coriolis Effect

an apparent curve in the path of anything that moves freely over the Earth's rotation + does not generate movement; it only alters the direction of fluids already in motion

Fluids are deflected to the _____ in the Northern Hemisphere and to the _____ in the Southern Hemisphere.

right, left

The Three-Cell Model for Global Circulation

he combination of convection and Coriolis breaks atmospheric circulation into the Hadley, Ferrel, and Polar cells.

Hadley, Ferrel, and Polar cells.

30° Latitude

Persistent sinking air

60° Latitude

Rising air

Poles

Sinking air

Adiabatic Cooling

Occurs when rising air encounters lower atmospheric pressure and expands, cooling without direct heat loss to the environment.

Adiabatic Cooling - Rising Air - Persistent Storms - STEPS

1. Air rises into the atmosphere

2. Atmospheric pressure decreases with altitude

3. Air expands as surrounding pressure drops

4. Temperature drops due to expansion (cooling)

5. Water vapor condenses as air cools

6. Clouds and precipitation form producing rain

Sinking Air Creates Subtropical Deserts

When atmospheric cells force air to descend, it undergoes a rapid physical transformation:

Air Sinks: Descending air from the global Hadley cell moves toward the surface.

Pressure Increases: Higher density compresses the air mass as it falls.

Temperature Rises: Compression performs work, raising the air's temperature.

Humidity Plummets: Warm air holds more moisture; relative humidity plummets.

The combination of ___________, the ___________, and the _________ ________creates distinct surface winds.

pressure differences, the three-cell circulation, and the Coriolis effect

Circulation Cells - Surface Winds - STEPS

1. Trade Winds - Flowing toward the equator from 30°.

2. Prevailing Westerlies - Flowing poleward from 30° to 60°.

3. Polar Easterlies - Flowing from the poles toward 60°.

Atmosphere-Ocean Coupling Mechanism(atmosphere and hydrosphere)

The Mechanism: Wind stress is the physical transfer of momentum from moving air to the ocean surface via friction.

Atmosphere-Ocean Coupling Chain of Events(atmosphere and hydrosphere)

Atmospheric circulation generates prevailing winds → which apply wind stress to the water → ultimately driving surface ocean movement.

Large rotating systems of surface ocean currents are known as ______

gyres

how are gyres formed?

They are formed by a combination of wind stress, the Coriolis effect, and the blocking presence of continental landmasses.

Due to Coriolis deflection, gyres rotate _______ in the Northern Hemisphere and _________ in the Southern Hemisphere.

clockwise, counterclockwise

Western Boundary Currents(Located on the western side of ocean basins)

They are narrow, fast, deep, and warm, transporting tropical water toward the poles (e.g., the Gulf Stream, Kuroshio)

Eastern Boundary Currents(Located on the eastern side of ocean basins)

They are broader, slower, and cooler, bringing polar water toward the equator (e.g., the California Current, Canary Current).

Plate Tectonics Shape Global Climate - Main 3 Steps

Geological Drivers → Ocean Pathways → Climate Shifts

Geological Drivers → Ocean Pathways → Climate Shifts

Plate tectonics determine continental positions, which in turn dictate ocean pathways and boundary currents. → These redirected ocean currents are responsible for distributing thermal energy across the globe. → Reorganizing continents over millions of years drastically alters ocean circulation, shifting regional climates and transforming ecosystems.

Oceanic Heat Redistribution:

The Heat Transfer(Ocean currents act as a global conveyor belt for thermal energy, carrying warm equatorial water across vast planetary distances.) →

Mechanism(As warm western boundary currents (like the Gulf Stream) move to cooler, higher latitudes, heat transfers directly from the warm surface waters into the cooler ambient atmosphere.) →

Climate Impact(coastal locations at identical latitudes can experience dramatically different climates depending on which ocean current flows past their shorelines.)

The ocean has two distinct layers of circulation operating independently:

Surface Circulation(Driven by wind stress and limited higher ocean layers) vs

Deep Circulation(driven by differences in water density, operating in the deep, lightless ocean basins.)

Temperature and Salinity Drive Thermohaline Circulation STEPS

1. Ocean Density Drivers - Colder water is denser than warm water. Saltier water is denser than fresh water.

2. Deep Water Formation - Extremely cold, salty water sinks rapidly to form deep water masses.

3. Brine Rejection -When sea ice forms, it leaves salt behind in the surrounding liquid, dramatically increasing local salinity and density.

Weather Begins With Energy Differences - Basics

Uneven heating

Temperature differences

Pressure differences

Air moves

High Pressure Air

● Air sinks

● Air compresses and

warms

● Relative humidity

decreases

● Cloud formation is

suppressed

● Clearer/drier

conditions become

more likely

Low Air Pressure

● Surface air converges

● Air rises

● Air expands and cools

● Condensation

becomes more likely

● Clouds and

precipitation become

more likely

Source Regions & Characteristics(Heat and Oceans)

mT (Tropical Ocean): Warm + humid

cT (Tropical Land): Warm + dry

cP (Polar Land): Cold + dry

mP (Polar Ocean): Cold + moist

Cold Front

1. Advance: Cold, dense air advances

2. Lift: Slides beneath warmer air

3. Rise: Warm air rises rapidly

4. Cool: Rapid cooling and condensation

5. Precip: Potential for intense precipitation and thunderstorms

Warm Front

1. Advance: Warm air advances

2. Lift: Gradually rises over colder air

3. Rise: Slower uplift and cooling

4. Cool: Widespread clouds

5. Precip: Longer-lasting, steadier precipitation

A Thunderstorm Is Moving Energy

Thermodynamic Process Flow

01 Warm surface

02 Air warms

03 Air rises

04 Air expands and cools

05 Water vapor condenses

06 Latent heat is released

07 Convection strengthens

A typical thunderstorm is powered by three fundamental

elements working in tandem: ______, ______, and

________

moisture, instability, and lift

WIND SHEAR

A change in wind speed and/or direction with increasing

height.

Separation of Drafts:

By tilting the storm structure,

wind shear physically separates the rising warm

updraft from the descending rain-cooled downdraft

Sustained Energy

This separation prevents the cool

downdraft from choking the warm updraft, allowing the

thunderstorm to become highly organized, durable, and

long-lived.

How Can Air Start Rotating? 4 Phases

PHASE 1

Wind Shear

Different wind speeds and

directions at different

altitudes.

02

PHASE 2

Horizontal Rotation

Wind shear forces the lower

atmosphere to begin rolling

horizontally.

03

PHASE 3

Updraft Interaction

A strong thunderstorm

convective updraft encounters

the rotating column.

04

PHASE 4

Vertical Tilting

The updraft tilts the rotating

column vertically, and a

rotating updraft develops.

SUPERCELL

Warm, moist inflow Strong updraft Wind shear Organized

rotation

Dynamics & Behavior - Super Cell

● Wind shear prevents storm collapse by

separating updrafts and downdrafts.

● Not all supercells produce tornadoes.

Rotation Does Not Automatically Mean Tornado Steps

1. Updraft

2. Mesocyclone

3. Interaction

4. Intensification

Climate

The overarching background pattern of the atmosphere over extended timeframes.

Weather

The atmosphere's immediate response to changing conditions of energy, moisture, and pressure.

Adiabatic Warming

The physical mechanism where descending air encounters higher atmospheric pressure, compresses, and warms up.

Low Pressure System

An atmospheric system in which surface air converges and rises, leading to air expansion, cooling, condensation, cloud formation, and precipitation.

High Pressure System

An atmospheric system in which air sinks, compresses, and warms, causing relative humidity to drop and suppressing cloud formation.

Air Mass

A large body of air that develops characteristic temperature and moisture properties based on the source region over which it forms.

Maritime Tropical (mT)

An air mass originating over warm tropical oceans, characterized by warm and humid conditions.

Continental Tropical (cT)

An air mass originating over tropical land regions, characterized by warm and dry conditions.

Continental Polar (cP)

An air mass originating over high-latitude continental landmasses, characterized by cold and dry conditions.

Maritime Polar (mP)

An air mass originating over cold polar ocean waters, characterized by cold and moist conditions.

Cold Front

A weather boundary where cold, dense air advances and wedges beneath warmer air, forcing rapid uplift, cooling, and potential thunderstorm activity.

Warm Front

A weather boundary where advancing warm air gradually rises over a colder air mass, creating widespread cloudiness and steady, longer-lasting precipitation.

Stationary Front

A weather boundary between air masses where neither advances significantly, leading to persistent weather conditions over a region.

Occluded Front

A complex weather front produced when a fast-moving cold front overtakes a warm front, lifting the warm air mass entirely off the ground surface.

Wind Shear

A variation in wind speed and/or wind direction with increasing height in the atmosphere.

Mesocyclone

A broad, large-scale rotating updraft within a severe thunderstorm that is distinct from a tornado.

Supercell

A highly organized severe thunderstorm featuring a persistent rotating updraft, sustained by strong wind shear that separates rising updrafts from descending downdrafts.

Dixie Alley

A severe weather region in the Southeastern United States subject to frequent strong and violent tornadoes ($\text{EF2}$ to $\text{EF5}$), characterized by nocturnal events, fast storm movement, multi-season activity, and terrain/rain visual obstructions.

Hurricane

A massive ocean-dependent thermodynamic heat-transfer system spanning hundreds of kilometers, powered by warm sea surface temperatures ($> 26.5^\circ\text{C}$) and latent heat, and organized by the Coriolis effect.

Walker Circulation

An east-west atmospheric circulation cell across the tropical Pacific Ocean created by trade winds blowing warm surface water toward Indonesia and driving cold upwelling off South America.

El Niño

A coupled ocean-atmosphere climate phenomenon characterized by weakened trade winds, reduced upwelling off South America, and an eastward shift of warm ocean water and convective precipitation across the tropical Pacific.

La Niña

A phase of the coupled ocean-atmosphere system marked by stronger-than-normal trade winds, enhanced cold-water upwelling off South America, and an intensified east-west temperature gradient in the tropical Pacific.

Teleconnection

A climate link or relationship between environmental conditions and atmospheric shifts occurring in widely separated geographic regions of the Earth.

Trade Winds

Prevailing global surface winds in the tropics that blow toward the equator from $30^\circ$ latitude.

Prevailing Westerlies

Global surface winds blowing poleward from $30^\circ$ latitude toward $60^\circ$ latitude.

Thermohaline Circulation

Deep-ocean circulation driven by water density differences resulting from variations in temperature and salinity.

Brine Rejection

The process during sea ice formation where salt is excluded from freezing ice, increasing the salinity and density of surrounding seawater and causing it to sink.

HURRICANE

• SPATIAL SCALE

  Scale is hundreds of kilometers

• ENERGY SOURCE

  Powered by warm tropical ocean + latent heat

• ROTATIONAL DYNAMICS

  Large-scale low pressure organized by Coriolis

• OCEAN DEPENDENCY

  Requires ocean

• TEMPORAL DURATION

  Duration of days to weeks

TORNADO

• SPATIAL SCALE

  Much smaller scale

  • ENERGY SOURCE

  Powered by thunderstorm instability + moisture + lift +

  wind shear

• ROTATIONAL DYNAMICS

  Storm-scale rotating flow

  
  

• TEMPORAL DURATION

  Duration of minutes

  
  

  
  

A Hurricane Runs on Ocean Energy

01. Warm tropical ocean

02. Evaporation

03. Warm, moist air rises

04. Condensation releases latent heat

05. Convection intensifies

06. Surface pressure falls

07. Additional air moves inward

08. Coriolis organizes large-scale rotation

Weather Is the Local Expression of a Global System

The Tropical Pacific Normally Has a Pattern

Normal Conditions Sequence

1. Trade winds blow east to west

2. Push warm surface water west

3. Warm water accumulates near Indonesia/Australia

4. Increases evaporation

5. Warm, moist air rises

6. Heavy precipitation in western tropical Pacific

Meanwhile: Westward movement allows cold, nutrient-rich deep

water to upwell along South America. Sinking air in eastern Pacific.

The Pacific Doesn't Stay in the Pacific - Atmospheric Shift Sequence

1. Warm ocean water shifts

2. Evaporation shifts

3. Convection shifts

4. Pressure patterns change

5. Large-scale atmospheric circulation changes

6. Jet streams and storm tracks shift

7. Weather probabilities change far away

EL NIÑO BECOMES GLOBAL

Western South America: Wetter conditions

North America: Warmer north, wetter south

Central America: Drier conditions

Australia: Drier conditions

Indonesia: Drier conditions

Africa: Direct impacts vary by region

Atlantic Ocean: Fewer hurricanes (wind shear)