Coastal Hazards Exam 1 Study Guide

What mainly causes ocean tides?

The Moon’s gravity and, to a lesser extent, the Sun’s gravity, combined with Earth–Moon motion.

How does gravity change with distance?

It weakens as distance increases; for point masses, force varies inversely with distance squared.

What is a tidal bulge?

A broad area of raised sea level associated with tidal forces.

What is a spring tide?

A tide with a larger-than-average range near new and full moons.

What is a neap tide?

A tide with a smaller-than-average range near first- and third-quarter moons.

What is tidal range?

High-tide height minus low-tide height.

What is a king tide?

An especially high predicted astronomical tide; weather and sea-level rise can worsen flooding.

What is a flood tide?

The incoming, rising tide; tidal flow generally moves landward.

What is an ebb tide?

The outgoing, falling tide; tidal flow generally moves seaward.

When are tidal currents often strongest?

Around mid-tide, between high and low water; slack water often occurs near high and low tide.

What is sunny-day flooding?

High-tide flooding that occurs without a storm.

What do check valves do in storm drains?

They limit seawater from flowing backward through drains while allowing runoff to drain out.

What causes most everyday ocean surface waves?

Wind transferring energy to the water.

What is wave height?

The vertical distance from a wave trough to its crest.

What is wavelength?

The horizontal distance between successive crests or successive troughs.

What is wave base?

Approximate depth where wave orbital motion becomes negligible, often about half the wavelength.

What is wave refraction?

The bending of waves as parts of a wave enter shallow water and slow at different rates.

Why do headlands often erode faster?

Wave refraction concentrates wave energy on headlands or promontories.

How do waves break?

In shallow water they slow, shorten, steepen, and become unstable as the crest outruns the wave base.

What is a rip current?

A narrow, strong current that flows away from shore, often carrying returning water through a channel.

What should you do if caught in a rip current?

Float, signal for help, and swim parallel to shore to exit the current before returning to the beach.

What is a tsunami?

A series of long-wavelength waves caused by rapid displacement of a large volume of water.

What can cause a tsunami?

Undersea earthquakes, landslides, volcanic eruptions, and rarely large impacts.

How does a tsunami change near shore?

It slows and its wavelength shortens; wave height can increase dramatically in shallow water.

How do you identify high and low tide on a graph?

High tide is a local peak; low tide is a local minimum.

How do you tell if the tide is incoming or outgoing on a graph?

Rising water level means incoming/flood; falling water level means outgoing/ebb.

How do you calculate tidal range?

Subtract the low-tide height from the high-tide height.

How can shoreline shape affect tides?

Bays, estuaries, water depth, and shelf shape can amplify, reduce, or shift tides.

What is a beach profile?

A cross-section showing beach elevation from landward areas toward the water.

Which beach areas are often more stable?

Higher, landward areas such as vegetated dunes, though storms can still change them.

Which beach areas are often more dynamic?

The foreshore and nearshore, where waves, tides, and currents frequently move sediment.

How does a beach often change in summer?

Gentler waves may move sand landward and build a berm, making the beach wider.

How does a beach often change in winter?

Storm waves often erode the upper beach and move sand offshore, narrowing the beach.

What is beach renourishment?

Adding sand to rebuild or widen an eroding beach.

What are Emery rods used for?

Measuring relative elevation changes along a beach transect.

How do you use Emery rods?

Place graduated rods along a transect, sight the difference, record distance and elevation change, and repeat.

How can an optical level measure a beach profile?

It compares staff readings from a level instrument to determine elevation differences.

How can drones measure beach profiles?

Overlapping aerial images can be processed into a 3D surface model.

What is LiDAR?

Laser-based distance measurement used to map surfaces and elevations.

What is topography?

The shape and elevation of the land surface.

What is elevation above sea level?

Height relative to a specified sea-level datum or reference surface.

What is a compass direction used for in a beach survey?

Recording the orientation or bearing of the transect.

Where does much Florida beach sand come from?

Much is carbonate material from shells and marine organisms; sources vary by region.

What is pressure?

Force divided by area.

How does pressure change with ocean depth?

It increases with depth because more water lies above the point.

How does atmospheric pressure change with altitude?

It generally decreases as altitude increases.

What is the pressure-gradient force?

A force caused by pressure differences that accelerates air from higher toward lower pressure.

How does pressure gradient affect wind speed?

A steeper pressure gradient generally produces stronger winds, all else equal.

Why does wind blow?

Uneven heating creates pressure differences, and air moves in response to pressure gradients.

How are winds named?

By the direction they come from; an easterly wind comes from the east.

What is insolation?

Incoming solar radiation.

What happens to air when it is heated?

It generally expands, becomes less dense, and may rise.

How does a sea breeze form?

Land heats faster than water; warm air rises over land and cooler air moves onshore.

How does a land breeze form?

At night land cools faster than water, so surface air can flow from land toward the sea.

How can sea breezes influence summer thunderstorms?

Converging moist air can rise along the sea-breeze front and help trigger storms.

What is specific heat capacity?

Energy needed to raise the temperature of a unit mass of a substance by one degree.

Which usually has a higher specific heat: water or sand?

Water; it warms and cools more slowly than sand.

How does high specific heat affect temperature?

The material changes temperature more slowly for the same energy input.

How does low specific heat affect temperature?

The material warms and cools more quickly for the same energy input.

Why are coastal climates often more moderate?

Water’s high specific heat slows heating and cooling, reducing daily temperature swings.

How would you test specific heat experimentally?

Heat equal masses from similar starting temperatures using equal energy input and compare temperature changes.

Which sample has higher specific heat under equal heating?

The sample with the smaller temperature increase.

What does a flatter temperature-time slope suggest under equal heating?

A higher specific heat capacity.

How do you calculate temperature change?

Final temperature minus initial temperature.

What should a graph include?

Clearly labeled axes, units, a sensible scale, and accurately plotted data.