2.8C Temporal variations in costal recession

• rates of recession are impacted VIA:

  • wind direction/fetch
  • tides
  • seasons
  • weather systems
  • occurrence of storms
• wind direction/fetch:

  • rate of recession will be higher when the wind is blowing onshore
  • Dominant wind is the direction of the strongest wind
  • Prevailing wind is the direction of the most common wind
  • When wind blows from prevailing wind direction, strong winds produce large destructive waves and rapid recession
• tides:

  • Rates of recession more rapid during high tide when deeper water in the foreshore zone allows waves to maintain a higher energy when they reach the backshore.
  • Greater energy of impact on backshore increases erosion and rates of recession
  • High tides occur twice each day, about 12 hours apart
• storms:

  • Storm events are deep (very low pressure) depressions
  • They produce large, high energy destructive waves and fast rates of recession
• seasons:

  • more likely to occur in the winter when the contrast in temperature and pressure between the tropical and polar air masses is the greatest.
  • in Holderness, in winter 2-6 m of erosion is common when storms, combined with spring tides, increase erosion rates 
• weather systems:

  • Interaction between warm and cold produces high air pressure anticyclone and low air pressure depression weather systems
  • Anticyclones produce gentle winds and small waves - low rates of recession
  • Depressions - areas of rising air (low surface air pressure)