ESS 17 Final Review

picks up from where midterm content ended - final cumulative of all content

The Atmosphere

What is electromagnetic radiation? What emits electromagnetic radiation?

• waves that move at the speed of later, regardless of amplitude/wavelength

  • shorter wavelengths = higher energy

  • longer wavelengths = lower energy

• everything with mass emits radiation

  • hotter bodies emit shorter wavelengths with high energy

What is luminosity? What is albedo? What is the greenhouse effect?

• luminosity: sun’s power output, often measured in Watts

• albedo: fraction of solar energy reflected away

  • larger albedo = larger reflection

  • smaller albedo = smaller reflection

• greenhouse effect: natural process where atmospheric gases (ex. carbon dioxide, methane) trap heat from sun

  • ozone traps high intensity shortwave radiation (“ozone layer”) → why we have life on earth

How do Earth’s mechanics explain the global distribution of heat on the planet?

• geometry of heating

  • the Earth is a sphere so sun rays strike equator perpendicularly (concentrates intense heat into small area)

  • at higher latitudes (closer to poles) the same amt of solar energy strikes globe at oblique angle & spreads heat over larger surface area

• atmospheric & oceanic redistribution

  • unequal heating → massive convection currents

  • warm air rises at equator, cools & drops around 30 degrees latitude → creates global trade winds & major deserts

  • Coriolis Effect: earth’s rotation deflects moving air/water to…

    • RIGHT in Northern hem

    • LEFT in Southern hem

  • ocean currents

    • warm currents move massive amts of heat from tropics → higher latitudes

• energy balance

  • occurring atmospheric gases trap portion of outgoing heat, ensuring planet remains warm enough to support life

How does the tilt of the Earth explain the seasons? Be able to identify the seasons given a diagram.

• Earth’s axis is tilted at 23.5 degrees

  • Obliquity (41,000 year cycle) determines how tilted the earth’s axis is

    • the higher the tilt the warmer the summers & cooler the winters (extremities)

  • without tilt everywhere would have exactly 12hrs of daylight

• tilt affects the amount of solar energy reaching diff locations on earth' throughout the year (influences period of daylight)

  

  • summer = tilted toward the sun

  • winter = tilted away from the sun

What is the difference between perihelion and aphelion?

• perihelion = point of earth’s orbit nearest the sun

  • happens in early January ~2 weeks after December (winter) solstice

• aphelion = point of earth’s orbit furthest away from sun

  • happens in early July ~2 weeks after June (summer) solstice

What is pressure, and what causes changes of air pressure on our planet?

• air pressure = weight of air molecules in atmosphere pressing down on surface below

• causes in changes of air pressure

  • warm air molecules move faster & spread further apart → air less dense & lighter → rising warm area creates LOW pressure area

  • cool air molecules pack close together → dense & heavier → sinks toward earth creating HIGH pressure area

  • higher altitudes = pressure drop

  • humid moist air is less dense than dry air → low pressure

  • low pressure systems associated with rising air (clouds, storms)

  • high pressure systems associated with sinking air (clear, fair weather)

What are the winds, and which way would they flow on a non-rotating planet?

• winds are horizontal movements of air across a planet’s surface, driven by sun heating atmosphere unevenly

• on a non-rotating planet winds would flow straight from the poles to the equator at the surface then back from equator to the poles high in the atmosphere

Predict how the coriolis effect may impact the movement of a parcel of air.

• Coriolis effect causes moving air to CURVE due to earth’s rotation

  • in Northern hem = deflects to right

  • in Southern hem = deflects to the left

• results in major global wind belts, cyclonic rotations, jet streams

What are the ways in which we can measure atmospheric moisture?

• relative humidity = ratio of water vapor currently in air to the max amount the air could hold at specific temp (%)

• dew point temp = temp to which air must be cooled to become fully saturated (100% RH)

  • how air “feels”

• absolute humidity = mass of water vapor in specific volume of air

• specific humidity = mass of water vapor relative to total mass of air parcel

• total precipitable water = total depth of liquid water if all water vapor in atmospheric column were condensed

Be able to draw and utilize the saturation vapor pressure graph to determine the dew point temperature and relative humidity of a parcel of air.

• find RH

  • locate air temp (x axis)

  • move vertically up until you reach curve

  • move left to y axis to find saturation vapor pressure (max moisture air can hold)

  • locate actual vapor pressure on y axis

  • RH = actual/saturation x 100%

• find dew point temp

  • locate actual vapor pressure on y axis

  • follow value until it reaches SVP curve

  • move straight down to x-axis (temp is dew point)

Calculate relative humidity

• RH = actual/saturation x 100%

Explain adiabatic cooling and heating.

• adiabatic cooling = air cools down as it expands without any heat being added/removed from outside environment

• adiabatic heating = air warms up as it compresses without heat added/removed

Explain how clouds form

• as unsaturated air rises, temp drops at dry adiabatic lapse rate = 10 C/km

• relative humidity increases

• air becomes saturated (dew point)

• condensation starts at altitude

• condensation releases altent heat

• heat released decreases rate of cooling = saturated adiabatic lapse rate = 5 C/km

Weather/Thunderstorms

What are the similarities and differences between weather and climate?

• weather = state of atmosphere at a given time & place

• climate = average weather over a long period of time

• both involve describing events taking place in our atmosphere

Predict how cold and warm fronts impact severe weather events

• cold fronts

  • trigger sudden & violent severe weather

  • wedges UNDER warm air to create rapid updrafts

• warm fronts

  • drive less explosive but prolonged severe weather

  • overrides cold air → generates extensive stratiform clouds & ocassional thunderstorms

Describe the formation of a thunderstorm, be able to draw a diagram of a thunderstorm.

• cumulus/developing stage

  • sun heats earth’s surface → creates pockets of warm buoyant air

  • warm air rises (updraft) into the atmosphere, causing moisture in air to cool and condense into cumulus cloud

  • as water vapor condenses it releases latent eat which keeps air warming that surroundings (rises higher and faster)

• mature stage

  • updrafts feed storm but heavy rain falls, dragging cool air down with it (downdraft)

  • as precipitation falls it cools surrounding air more

  • moisture extends high into atmosphere were temps drop below freezing

• dissipating stage

  • storm weakens when downdrafts become stronger than updrafts

  • without warm moist updraft to feed storm the moisture condenses less, precipitation decreases, cloud evaporates from bottom up

Describe the formation of a lightning bolt

• charge separation = rising ice crystals gain positive charge while heavier hair/slush/droplets gain negative charge

  • positively charged upper cloud, negatively charged lower cloud

  • negative region induces buildup of positive charge on ground below

• stepped leader = once charge difference becomes too great for insulating air to hold back, channel of negative charge (stepped elader) rushes down from cloud in zigzag steps

• upward streamers = stepped leader approaches surface so positive charges gather on tall objects on the ground

  • ground charges “reach up” toward approaching electrical current through channels called streamers

What is thunder and how quickly does it travel compared to lightning?

• thunder: acoustic shockwave caused by lightning superheating the surrounding air

• it travels much slower at the speed of sound compared to lightning (speed of light)

What is the difference between an air mass thunderstorm and a severe thunderstorm?

• air mass thunderstorm: brief, isolated storm fueled by local daytime heating

  • less than 50 mph

  • significant moisture in air

  • unstable air mass

• severe thunderstorm: intense, long lasting storming

  • requires wind shear (changing wind speed/direction with altitude) to sustain

  • 58+ mph

  • very moist lower atmosphere

What are the different types of severe thunderstorms?

• squall line (linear)

  • form bands up to 500km long

  • usually ahead of a cold front

• mesoscale convection complexes (MCCs) (circular)

  • squall lines that develop into larger systems (up to 10,000 km²

• supercell

  • 20-50km diameter

  • single cloud

  • violent & large scale rotation (mesocyclone)

Tornadoes

Describe the formation of a supercell thunderstorm and the steps required to form a mesocyclone

• supercell formation

  • warm moist air at surface becomes unstable and rises rapidly by pushed upward

  • strong winds change speed & direction with height → creates shearing environment where rising air twists

  • wind shear tilts updraft tower, allowing downdraft to fall SEPARATE from warm rising air (storm is long lived)

• mesocyclone formation

  • vertical shear of winds cause air to rotate horizontally (spinning cylinder)

  • powerful updraft acts as massive vacuum → brings horizontally spinning air into storm

  • updraft tilts vortex from horizontal to vertical orientation

  • once rotation is vertical it forms a deep spinning column of air within updraft → mesocyclone

What are the steps required to form a tornado?

• needs combo of warm moist air near the ground and cooler, drier air aloft

  • makes atmosphere highly unstable & warm air to rise rapidly

• rising warm air encounters wind shear (dramatic change in wind speed/direction with incr. altitude)

  • forces rising column of air to roll horizontally

• thunderstorms develop to create strong updrafts of warm air

  • brings horizontal spinning air into storm which tilts rotation to vertically

  • creates mesocyclone

• cold dense air in downdrafts pushes rotation down to lower altitudes

  • decrease in pressure causes moisture in air to condense & create spiral funnel cloud extending from base of storm

• downdraft intensifies and spinning column meets ground

  • funnel cloud begins kicking up dust, debris → tornado

Why is “Tornado Alley” so prone to tornadoes?

• due to warm moist air coming northbound from the Gulf of Mexico meeting dry cold air coming south from Canada

What is a "rear flank downdraft"? How does it cause a tornado to form?

• mass of dry, rain-cooled air that descends on backside of supercell thunderstorm’s rotating updraft

• as cool air rushes to the ground and wraps around lower level of storm, it causes upper level rotation to surface to form a tornado

What is a "hook echo?"

• hook shaped radar signature found in supercell thunderstorms

• indicates presence of mesocyclone

  • serves as indicator that the storm is capable of producing a tornado

What scale do we use for measuring the strength of tornadoes?

• Enhanced Fujita (EF) scale

  • rates tornadoes from 0 to 5 based on est. 3 second wind gusts and the specific damage they inflict on structures/vegetation

  • not based on direct wind measurements

How does one stay safe in a tornado?

• seek shelter in basement, small windowless interior room, or lowest floor of sturdy building

• stay away from windows, exterior doors, outside walls

• find heavy cover underneath sturdy piece of furniture

• shield yourself against head injuries

• if trapped in car, pull over under an overpass and buckle your seatbelt

• if completely outdoors lie flat in low-lying area (ditch, ravine) and avoid being the tallest thing around

Hurricanes

In what regions are tropical cyclones most likely to occur and why? What are the main reasons for the global distribution of hurricanes?

• tropical cyclones (hurricanes) form in ocean basins between 5 and 30 degrees latitude north/south of equator

  • most active region is Western North Pacific

  • also occurs in eastern pacific, north atlantic, north indian, southwest indian, australian/south pacific regions

• reason for distribution

  • requires warm ocean temperatures that provide necessary moisture & latent heat to fuel storm

  • Coriolis effect (rotational force) is too weak within 5 degrees of equator

  • low wind shear in these areas won’t tear the storm apart

  • high relative humidity doesn’t cause evaporation in the storm’s clouds which would cool the updraft and weaken the system

  • intertropical convergence zone (ITCZ) initiates rotation/uplift required for the storm to form

Describe the steps necessary to form a hurricane. What processes contribute to hurricane intensification?

• warm ocean water

• atmospheric instability

• high humidity

• coriolis effect

• disturbances such as tropical wave, cluster of thunderstorms, pre-frontal boundary

• low vertical wind shear

• processes:

  • latent heat release

  • pressure drop/inflow

  • rapid intensification

  • eyewall replacement cycles

What is the positive feedback mechanism associated with hurricanes?

• warm tropical oceans heat the air above the water and evaporates massive amts of water vapor

• warm humid air forces water vapor to condense into massive thunderstorm clouds

  • process releases latent heat (warms surrounding air) and causes air to rise faster

• since so much air is pulled upward and pushed out at the top of storm, atmospheric pressure at sea surface decreases

  • causes surrounding air to rush inward at surface faster to replace rising air

• as pressure drops & air rushes in, surface wind speeds increases

  • enhances evaporation and transfers more heat/moisture into storm’s core

  • leads to more condensation, faster rising air, lower pressure, stronger winds

Be able to interpret a feedback diagram. What are positive and negative couplings? How do you connect the boxes?

What impacts are associated with hurricanes? Which one is typically the most damaging?

• storm surge: strong winds push water inland and sea levels rise rapidly (deadliest)

• flooding: prolonged rainfall can continue for days after storm passes

• high winds: 74+ mph, can uproot trees, snap power lines, etc.

• tornadoes: can be spawned in the hurricane’s outer bands

Determine which part of a hurricane is the strongest, and describe which parts of a coast will be most impacted by a hurricane.

• the EYEWALL is the strongest part of the hurricane (most intense winds and rainfall)

• the right front quadrant (Northern Hem) or left front quadrant (Southern Hem) is considered most dangerous as it couples the storm’s forward motion

  • this part of the coast relative to where the hurricane makes landfall will receive the most impact

Be able to calculate the speed of hurricane winds in different “quadrants” of the storm, depending on the average wind velocity and the direction of storm movement. Be able to do this for the northern hemisphere (counterclockwise) and southern hemisphere (counterclockwise) storms.

• Northern Hem

  • right-front (max winds)

    • rotational wind + forward speed (rotational winds blow in same direction of storm travel)

  • left-front

    • rotational wind - forward speed (rotational wind blows opposite to storm’s forward motion)

  • right-back

    • rotational wind - forward speed

  • left-back

    • rotational wind + forward speed

• Southern Hem

  • right-front (max winds)

    • rotational wind - forward speed

  • left-front (max winds)

    • rotational wind + forward speed

  • right-back

    • rotational wind + forward speed

  • left-back

    • rotational wind - forward speed

Streams and Floods

Determine how various components of the hydrologic cycle impact water cycling from the oceans to the atmosphere and back to the oceans.


• ocean to atmosphere evaporation

  • solar radiation heats ocean surface → causes liquid water to gain energy and transform into water vapor

  • 86-90% of global evaporation

• atmospheric transport

  • rising air current lift water vapor high into atmosphere

  • cooler temps cause it to condense around particles into clouds

  • wind patters and circulation transport clouds across the globe

• precipitation

  • water droplets in cloud become too heavy to be supported by rising air → fall back to earth

  • 78% falls back to ocean, rest falls on land

• runoff & infiltration

  • water falling on land infiltrates soil (groundwater) or flows over surface as runoff

  • runoff gathers into rivers, streams, lakes, etc. until it drains back into ocean

What is a watershed? 

• area of land where water falling within its boundaries drains downhill into a single common body of water

How do you determine the discharge of stream?

• discharge (Q) = area (A) x velocity (V)

• discharge (Q) = volume/time

Compare gaining streams to losing streams. What happens to a drop of rainwater in both stream types? Where does the drop of water ultimately end up?

• gaining/permanent streams

  • water flows all year

  • is at or below water table

  • humid or temperate climate

    • sufficient rainfall

    • lower evaporation

  • seasonal discharge variation

• losing/ephemeral streams

  • don’t follow all year

  • above water table

  • dry climates

    • low rainfall

    • high evaporation

  • flows mostly during flash floods

Predict which regions will be most susceptible to a flash flood and describe the outcomes of a flash flood event


• urban areas

  • impervious surfaces prevent water from absorbing into ground → high runoff = water quickly ponds in streets

• mountains/hilly terrain

  • steep slopes accelerate runoff

  • funnels fast moving water into small channels which can transform dry creek-beds into violent rivers

• deforested areas

  • no vegetation/root systems to absorb moisture & hold soil together or areas with hydrophobic conditions lead to runoff & mudslides

• low-lying areas

  • act as bottlenecks for water to pool & rise rapidly

• flash flood: arrive with little warning → immediate physical danger, widespread structural damage, power outages, contaminated drinking water, severs transportation routes

Predict how climate, human use, and soil type will impact the type of flood

• climate: as global temp rises, atmosphere holds more water vapor → intense short downpours

  • overwhelms local drainage capacities → more flash floods

• humans

  • urbanization prevents water infiltration → larger surface runoff → more flash floods

  • clearing forests/agriculture removes healthy soil to absorb water → more runoff → flash floods

• soil type

  • clay & silt have low permeability, resulting in soil to reach saturation point quickly → runoff → flash floods

Be able to reconstruct a hydrograph based on stream type.

How will climate change and human urbanization impact flood intensity in the future?

• cause dramatic increases in future flood intensity

• supercharge storms + massive surface runoff = overwhelming surrounding environment with flooding

• rising sea levels amplify storm surges

Identify hard and soft solutions to flood risk management

• hard solutions

  • build dams and reservoirs

  • levees and floodwalls

  • storm surge barriers

  • more storm drains

  • porous concrete

• soft solution

  • safety education

  • zoning

  • warning/alert systems

Climate Change

What are the 4 main reasons that climate can change? What is the timescale for each, and which are responsible for current climate change?

• greenhouse gases: changes in atmospheric gases that trap heat

  • greenhouse effect: ozone traps high intensity shortwave radiation → reason why we have life on earth

• albedo: fraction of solar energy reflected away

• changes in earth’s orbit (Milankovitch cycles) → roughly a 150k year cycle for when they all line up

What are the Milankovitch cycles? Be sure you can diagram each part of the cycle

• eccentricity (100k years): how elliptical orbit is

• obliquity (41k years): how tilted earth’s axis is

• precession (23k years): wobble of the axis

What is the difference between shortwave and longwave radiation?

• shortwave = high energy, incoming sunlight

• longwave = low energy heat radiated outward by the earth

What is the greenhouse effect? How does the Greenhouse effect increase our average planetary temperatures?

• certain gases are good at trapping heat → known as greenhouse gases

• allows shortwave sunlight to pass through atmosphere to warm the earth’s surface while absorbing & re-radiating longwave infrared heat back to ground (slows escape into space)

• this process is necessary to support life (warms earth enough)

What are greenhouse gases?

• atmospheric gases that trap heat

• carbon dioxide (most significant), methane, nitrous oxide, fluorinated gases, etc.

What is the keeling curve? Why does the keeling curve have a saw-tooth pattern?

• graph that plots ongoing change in concentration of CO2 in earth’s atmosphere (Mauna Loa University)

• has a saw-tooth pattern due to seasonal breathing of earth’s biosphere

  • drops in spring/summer as planets in northern hem grow and absorb massive amts of CO2 (decreases it in atmosphere)

  • rises in fall/winter as leaves fall and planets die → decay releases CO2 back into the atmosphere

What are the main impacts to Earth associated with our current changing climate?

• rising temperatures

  • persistent heat waves, alters growing seasons, contributes to rising CO2 levels

• extreme weather

  • warming atmospheric conditions = extreme weather (prolonged droughts, high rainfall, severe flooding, intense dry spells, etc.)

• melting ice/rising sea levels

  • erodes coastal ecosystems & polar/glacial regions experience massive ice loss

• ocean acidification

  • oceans absorb excess heat & CO2 → causes water temps to increase & water to become more acidic → threatens marine life & coral reef systems

• ecosystem/health disruptions

  • alters habitats, migration patterns, water scarcity, spread of infectious diseases

Why might climate change be considered a catastrophe?

• acts as a “threat multiplier” by accelerating extreme weather, threatening food/water security, and pushes ecosystems to extremes

• has the potential to impact ALL life on earth

What are the potential solutions to climate change?

• shift to renewable energy

• upgrade infrastructure to reduce energy consumption

• expand public transit & other forms of sustainable transportation

• protect/restore ecosystems

• shift to regenerative agriculture

• upgrade efficiency of high-emission industries

• carbon removal from air

• early warning systems/policies

Wildfires

Describe how each part of the fire triangle impacts fires specifically in Southern California.

• fuel

  • native vegetation (chaparral environment is highly flammable & thrives on consistent fires)

  • droughts reduce moisture content in plants which makes them prone to catching fire

  • dense brush allows for fires to spread quickly

• oxygen

  • santa ana winds are very fast as they move through narrow canyons → feed flames

• heat

  • radiant heat

    • dries out fuel source

    • ignites fuel source

Describe the formation of the Santa Ana Winds

• high pressure build up from Great Basin area

  • air flows CW around HP systems → pushes cool, dry air in southwest direction toward west coast

• outward pusing air is pulled to areas of low pressure over Pacific Ocean off southern CA coast

  • pressure gradient is very high → winds will blow much faster

• as air drops in elevation it is compressed by increasing atmospheric weight

  • forces temps to rise rapidly

• as air warms up it can carry more moisture -< drops relative humidity

  • “thirsty” air acts like a sponge → strips moisture from local vegetation → makes region highly susceptible to ignition

• air is squeezed through narrow canyons/mountain passes

  • results in dramatically fast moving winds

Describe the orographic effect and how it impacts regional climate

• meteorological phenomenon where a topographic barrier (ex. mountain range) forces prevailing winds to rose

• as air expands it cools and condenses moisture into preciptation, leaving windward side went and leeward side arid

• results in one side developing lush, green ecosystems and the other dry, and desert-like

How might fires be impacted by climate change?

• severe heat & drought can fuel wildfires to become more extreme and fast-moving

Impact Events

Describe the similarities and differences between asteroids and comets

Identify the problems associated with an impact event.

Identify the signs that an impact event has occurred in the past

What happened to those poor, poor dinosaurs?

Where did the dinosaur-killing asteroid originate from?

Where will likely future asteroids originate?

How might future impact events be mitigated?