Waves, Tides and Currents Flashcards
What is the Beaufort scale?
A scale used to predict wave height based on the wind
What are tides mostly caused by?
The gravitational pull of the moon
What is an ebb?
A receding tide
What is a spring tide?
- The moon and sun are parallel to one another
- Their gravitational pulls are combined
- Results in the highest high tides and the lowest low tides
What is a neat tide?
- Gravitational pull of the moon and sun are working against each other
- Results in the highest low tides and lowest high tides
What is a semi-diurnal tide?
An area experiences 2 low tides and 2 high tides every day of the same magnitude
What is a diurnal tide?
An area experiences a single high tide and single low tide each day
What are amphidromic points?
Positions on the planet where there is no rise and fall of the tide, leading to a build-up of water and a rotational pattern as the moon rotates
Name the three different categories of tide range:
- Microtidal, less than 2m
- Mesotidal, 2-4m
- Macrotidal, more than 4m
What is a storm surge?
An abnormal rise in sea level caused by strong winds and low atmospheric pressure during a storm
What three things drive surface currents?
- Wind
- Land masses
- Coriolis Effect
What is the Coriolis Effect?
The apparent deflection of moving objects due to Earth’s rotation
How does the Coriolis Effect influence ocean currents?
It causes currents to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, influencing wind patterns and surface ocean circulation
What are ocean gyres?
Water motion around the ocean basin, mostly caused by equatorial winds
How many ocean gyres are there?
11
What is an upwelling?
The process where deep, cold, nutrient-rich water rises to the surface, often due to wind-driven surface water movement away from the coast
What is a downwelling?
The sinking of surface water, often carrying oxygen to deeper ocean layers and affecting thermohaline circulation.
