Oceanography Lecture 15: Tides and Global Sea Level

A set of vocabulary flashcards covering key terms from Oceanography Lecture 15 on tides and global sea level.

Tide

Short-term, predictable, cyclic changes in local sea level.

Gravitational forces

Forces exerted by the Moon and the Sun that primarily cause tides.

Gravity Bulge

The bulge of water on Earth created by the Moon's gravitational pull.

Inertia Bulge

The bulge of water on the side of Earth opposite the Moon, caused by inertia in the Earth-Moon system.

Differential Gravitational Force

The difference in gravitational pull across Earth's diameter that creates tidal bulges.

Tidal Day

The duration of a complete tidal cycle, which is approximately 24 hours and 50 minutes.

Diurnal Tide

A tide pattern with one high tide and one low tide per tidal day.

Semidiurnal Tide

A tide pattern with two high tides and two low tides of approximately equal height each day.

Mixed Semidiurnal Tide

A tide pattern with two high tides and two low tides of unequal heights each day.

Bay of Fundy

Location known for having the world's highest tidal range due to its funnel-shaped bay.

Spring Tides

Tides occurring during new and full moons, characterized by the highest high tides and lowest low tides.

Neap Tides

Tides occurring during quarter moons, with the least difference between high and low tides.

Thermal Expansion

The expansion of ocean water as it warms, contributing to sea level rise.

Melting of Glaciers and Ice Sheets

The process that adds more water to oceans and contributes to sea level rise.

Tide Gauges

Devices used to measure local sea level changes over time.

Satellite Altimetry

A method of measuring sea level from satellite data, providing precise global data.

Last Glacial Maximum (LGM)

The period approximately 20,000 years ago when sea levels were significantly lower.

Meltwater Pulse 1A

A period of very rapid sea level rise approximately 14,500 years ago.

Geographic Vulnerability

The susceptibility of low-lying small island nations to sea level rise.

Future Projections

Expectations that sea level rise will continue and likely accelerate due to global warming.

Syzygy

The alignment of the Sun, Moon, and Earth during new and full moons, affecting tidal strength.

Satellite Altimetry vs Tide Gauges

Satellite altimetry shows a faster rate of sea-level rise compared to tide gauges.

Global warming

The long-term trend contributing to accelerating sea level rise.

Cyclical Forces

Short-term variations, like tides caused by the Moon/Sun.

Progressive changes

Long-term trends, such as sea level rise due to climate change.

Tidal Cycle

The rhythmic rise and fall of sea levels caused by gravitational forces.

Atmospheric pressure changes

Factors that can raise or lower sea level differently, affecting tides.