Different wave types and what influences them

Factors of wave formation

Strength +direction of wind

• strong , swash aligned waves are the largest and most damaging

Duration of the wind

• as time passes wave increase in height and power

Water depth

• The deeper the water the less frictional drag

• As a wave approaches the shore the depth decreases and slows it down, causing the wavelength to become shorter and and increases its height

Wave fetch

• The distance of open the sea the wind blows

• The longer the fetch, the greater the potential for destructive waves

• E.g. Cornwall with 4000km waves from Florida

Features of constructive waves

• distant weather systems generate them

• Low, surging waves

• Long wavelength

• Strong swash, weak backwash

• Beach profile goes from gentle to steep over time

• 6-8 waves per minute

Features of destructive waves

• local storms are responsible

• High, plunging waves

• Short wavelength

• Weak swash, strong backwash

• Goes from steeper to flatter overtime

• 13-15 waves per minute

Seasonal variation

Summer

• steeper (more constructive waves)

• Strong swash so berms form due to deposition

• Sediment is organised in size order (small sediment at backshore)

Winter

• destructive waves lower angle of the beach

• Shingle beaches

• Sediment randomly dispersed

Daily variation

• storm events change profile in a few hours

• Calm, anticyclonic conditions in winter produces constructive waves that rebuild the beach profile pre storm

• Destructive waves go to constructive when the wind drops

• Storm beaches are high at the backshore due to high energy deposition of very course sediment

How are tides formed and what do they do

• formed by the gravitational pull of the mon acting on the earth

• The can also influence but the moon has 2.2x more gravitational influence

• This pulls the water towards them causing high and low tides 2x a day

• This can cause large tidal ranges (sand dunes)

• When storms occur at spring (high) tide this can cause coastal flooding and erode the coast

when do spring sides occur?

• full moon

• New moon

• Causes high tide

When do neap tides occur ?

• first quarter moon

• Last quarter moon

• Low tide

How do rides influence beach morphology?

• high tides create berms

• Spring tides aes associated with the formation of storm beaches

• A high tidal range is required to form sand dunes