Definition of Tides
Tides refer to the cyclical ebb and flow of sea levels, primarily influenced by the Moon and the Sun's gravitational forces and the Earth's rotation. This predictable and natural phenomenon impacts coastal regions globally, creating variations in water levels and concomitant currents.
Mechanics of Tides
Gravitational Forces: Gravity serves as the pivotal force driving tides. The Moon's gravitational influence engenders a bulge in the Earth's oceans on the side nearer to the Moon, while centrifugal force, a byproduct of Earth's rotation, produces an additional bulge on the opposing side. These bulges correspond to high tides, whereas areas between the bulges encounter low tides.
Solar Influence: Despite its considerable distance from Earth, the Sun's gravitational pull plays a secondary role in tide generation. When the Sun, Moon, and Earth align during full and new moons, their gravitational forces merge to produce exceptionally high tides, termed spring tides. In contrast, during quarter phases when the Sun and Moon form a right angle with Earth, their gravitational pulls counteract one another, leading to lower than average tides, known as neap tides.
Types of Tides
Diurnal Tides: Diurnal tides, distinguished by a single high tide and one low tide each tidal day (roughly 24 hours and 50 minutes), are relatively uncommon, appearing primarily in specific areas within the Gulf of Mexico and the South China Sea.
Semi-Diurnal Tides: Semi-diurnal tides present two high tides and two low tides of nearly equal height each tidal day. Predominant along the Atlantic coasts of North America and Europe, this is the most frequently observed tidal pattern.
Mixed Tides: Mixed tides, exhibiting two high tides and two low tides of unequal heights each tidal day, are typical along the Pacific coasts of North America and Asia.
Tidal Ranges and Coastal Features
Tidal Range: Tidal range signifies the vertical distance between high and low tide at a particular location. Coastal shape, ocean floor depth, and other geographical determinants can significantly affect the tidal range.
Coastal Features: Tides substantially influence coastal features and ecosystems. Broad tidal ranges, in particular, can generate intertidal zones. These regions, exposed at low tide and submerged at high tide, foster distinct environments that accommodate diverse flora and fauna adapted to this water level oscillation.