Tides 1.1.2

temporal variations

changes over time

how are waves caused

the surface of the sea exerting frictional drag on the lowest layer of the wind

how does the shape of constructive waves change as they approach the beach

orbital to elliptical

constructive/spilling waves

• low flat waves

• strong swash

• weak backwash

• long wave length

• 6-10 per minute

destructive/plunging waves

• large steep waves

• weak swash

• strong backwash

• short wavelength

• 11-15 per minute

what affects the height of the wave

• fetch

• strength of the wind

• duration of the wind

• sea depth

what force affects the tides

gravitational pull from the moon

what are the main three factors affecting tides

• moon

• sun

• earth

what the name of the biggest high tide

spring tide

spring tide

• sun moon and earth are aligned

• sun enhances the gravitational pull

• 2 times a month

whats the smallest high tide

neap tides

neap tides

• sun and moon are at a right angle

• sun diminishes the gravitational pull

where are the high tides

closest and furthest points from the moon, they follow the moon

semi diurnal tides

2 high and low tides per day

diurnal tides

one high and low tide per day

tidal range

difference between high and low tide

micro tidal

when the tidal range is lower than 2 metres

meso tidal

when the tidal range is between 2 and 4 metres

macro tidal

when the tidal range is higher than 4 metres

what drives ocean currents

• wind

• tides

• Coriolis effect

what are deep ocean currents

control the bottom 90% of water

what are surface currents

control the top 10% of water