Natural Disasters - Exam 2 (SEES: 1400 UIOWA)

How are tsunami waves different than normal ocean waves?

Tsunamis have long wavelengths travel fast and move the entire water column normal waves are short wind-driven and affect only the surface

What is the fetch?

The distance wind travels across water to generate waves

What causes a tsunami generally What are some earth processes that can cause them?

Sudden seafloor displacement usually from earthquakes also landslides and volcanic eruptions

Explain the process of coastal inundation

As a tsunami reaches shallow water it slows increases in height and floods inland

Crest

The top of a wave

Trough

The bottom of a wave

Wave length

Distance between two crests

Wave height

Vertical distance from trough to crest

Wave frequency

Number of waves passing a point per time

Wave period

Time between successive waves

Reference water level

Normal sea level

Flow depth

Depth of water above ground inland during a tsunami

Tsunami height

Height of the wave at the coast

Runup height

Maximum vertical height water reaches on land

How common are tsunamis?

Relatively rare globally but frequent in the Pacific Ring of Fire

How do we predict tsunamis?

Using earthquake detection and ocean buoy systems

What three forces influence wind direction and speed?

Pressure gradient moves air high to low Coriolis effect deflects wind friction slows wind near surface

What is geostrophic wind and how does it form?

Wind that flows parallel to isobars due to balance between pressure gradient and Coriolis forces

Convective circulation

Warm air rises and cool air sinks creating circulation

What are the three circulation cells and how do they affect climate?

Hadley warm and wet tropics Ferrel variable mid latitudes Polar cold and dry

What are the three kinds of global winds and where are they located?

Trade winds tropics Westerlies mid latitudes Polar easterlies polar regions

What are Walker Circulation patterns What are they related to?

East west air circulation in the Pacific related to ocean temperatures

What is El Nino Southern Oscillation and its effects?

Climate pattern El Nino warms Pacific waters causing wetter Americas and global weather changes

What are monsoons How are they different in summer and winter?

Seasonal wind shifts summer wet winter dry

Understand mid latitude weather and pressure systems

Low pressure rising air storms high pressure sinking air clear weather

What are the five kinds of fronts and how do they differ?

Cold warm stationary occluded and dryline fronts differ by air mass movement

How do jet streams form?

From strong temperature contrasts in the atmosphere

What are the steps in forming a cyclone?

Warm air rises low pressure forms air converges and rotates

What is a thunderstorm and what are the three requirements?

Storm with lightning requires moisture instability and lifting

What is the source of moist air in thunderstorms?

Warm oceans or moist land surfaces

What are the four lifting mechanisms?

Convection frontal lifting orographic lifting convergence

What does atmospheric stability depend on?

Temperature change with altitude

What is the difference between moist and dry adiabatic lapse rate?

Dry cools faster moist cools slower due to latent heat

What are the three types of thunderstorms and which is most dangerous?

Single cell multicell supercell supercell is most dangerous

What are the four main thunderstorm hazards?

Lightning hail strong winds flooding

What is lightning and how does it happen?

Caused by charge separation and electrostatic discharge

What part of lightning kills humans?

The electrical current

What is hail?

Ice formed in strong updrafts

What is the best way to avoid thunderstorm hazards?

Seek shelter indoors avoid open areas

What is a tornado and how does it form?

Rotating column of air formed from wind shear and strong updrafts

What area experiences the most tornadoes?

Central United States Tornado Alley

Which is most dangerous regular multiple vortex or squall line tornado?

Multiple vortex tornado

How do we measure tornado intensity What are issues?

Enhanced Fujita scale based on damage not direct measurement

How do multiple vortex tornadoes form?

Smaller vortices develop within a larger tornado

Where can non supercell tornadoes form?

Along boundaries such as gust fronts

What are the best ways to protect yourself in a tornado?

Basement or interior room avoid windows

What are squall line derechos How are they different?

Long lived straight line wind storms not rotating

How do squall line derechos form?

From organized lines of thunderstorms

What is the difference between a tornado watch and warning?

Watch conditions possible warning occurring

What are most tornado injuries fatalities associated with?

Flying debris

What are hurricanes?

Large rotating tropical storms

How does spinning wind form?

Coriolis effect

Eye

Calm center of the hurricane

Eyewall

Strongest winds and rain

Spiral rainbands

Bands of storms spiraling outward

Inner core

Central intense region

Outer zone

Outer weaker storm area

What is a hurricanes forward motion?

The direction and speed the storm travels

What drives airflow in hurricanes?

Warm ocean water and pressure differences

How do hurricanes evolve over oceans?

Strengthen over warm water weaken over land or cold water

What are the different kinds of tropical storms?

Tropical depression tropical storm hurricane

What controls hurricane track?

Global wind patterns

How do we keep a hurricane going?

Warm ocean water above about 26.5 C

How do you destroy a hurricane?

Landfall cold water wind shear

Hurricane damage is produced by what?

Strong winds storm surge flooding

How can hurricane rain cause flooding and landslides?

Heavy rain saturates soil causing runoff and slope failure

What are the best ways to prepare for hurricanes?

Evacuate if needed gather supplies secure home

What are hurricane mitigation tactics?

Seawalls building codes zoning

What is climate and how is it different from weather?

Climate long term patterns weather short term conditions

Difference between long term and short term climate change

Short term years to decades long term centuries or more

Difference between direct and proxy measurements

Direct instruments proxy indirect evidence

How can oxygen isotopes and ice cores reveal past climate?

Isotopes indicate temperature ice cores trap past gases

What are natural impacts on climate?

Volcanoes solar variation orbital changes

What is the carbon cycle?

Movement of carbon through Earth systems

Short term vs long term carbon cycle

Short biosphere exchange long rocks and fossil storage

Two ways to remove CO2 long term

Burial of organic matter rock weathering

How have humans impacted CO2?

Burning fossil fuels increases CO2

What are greenhouse gases and their role?

Gases like CO2 and methane trap heat

What data are used to study climate change?

Temperature records ice cores tree rings satellites

What are floods How do they occur?

Overflow of water onto land due to excess runoff

What is a flash flood?

Rapid flooding from intense rainfall

How do we evaluate flood hazards What is recurrence interval?

Probability of flood recurrence interval is average time between events

What is flood mitigation Examples?

Reducing damage levees dams flood control

Why are floods important for ecosystems?

Deposit nutrients replenish soils support habitats

What is a watershed?

Land area draining into a stream

What is overland flow What does it create?

Water flowing over land causing erosion

What are soil erosion issues in Iowa?

Agriculture and runoff increase soil loss

What is the stream discharge equation?

Q equals velocity times area

What is channel velocity?

Speed of water flow

What are hydrographs?

Graphs showing stream discharge over time

How does urbanization affect runoff?

Increases runoff decreases infiltration

What are main stream types?

Meandering braided straight

What is a floodplain?

Flat land next to a river prone to flooding