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Geography - Tropical Storms and UK Landscapes

Tropical Storms

  • Definition and Types

    • Tropical storms are intense low-pressure weather systems characterized by heavy rain and strong winds.
    • Names include hurricanes, typhoons, and cyclones, which refer to the same phenomenon based on geographic location.

  • Formation of Tropical Storms

    1. Occur over oceans when sea temperatures reach 27°C or higher.
    2. Warm ocean water facilitates the rise of warm, moist air, leading to extreme precipitation.
    3. Condensation of rising warm air cools and releases energy, further powering the storm and creating low pressure that enhances surface winds.
    4. The rotation of the Earth contributes to the spinning motion of storms (
      helio transferable
      paths deflected).
    5. Energy from warm waters intensifies the storm, accelerating wind speeds.

  • Extreme Weather Conditions Associated with Tropical Storms

    1. Strong Winds:
    • Winds can exceed 250 km/h, causing severe damage to structures and natural environments.
    • The pressure difference in the center of the storm leads to destructive wind speeds.
    1. Extreme Rain:
    • Heavy precipitation can occur quickly due to the influx of warm moist air.
    • Can lead to flooding and mudslides as a direct effect of rapid rainfall.

  • Frequency and Distribution of Tropical Storms

    • Most storms occur between 5° and 30° latitude where ocean temperatures are optimal.
    • Higher occurrences in the northern hemisphere, notably in the Pacific during late summer and autumn.
    • Number of tropical storms without an overall trend over the past 130 years shows variability; Atlantic storms have increased since 1984.

The UK Landscape

  • Characterization of Landscapes

    • Landscapes represent visible features of land and can be categorized into natural (physical features such as forests and mountains) and built landscapes (human-made features such as cities).

  • Types of Landscapes in the UK

    1. Upland Areas:
    • Found in the north and west, typically formed of harder rocks like slate and granite.
    • Features steep gradients, cooler and wetter climates, with land use centered around sheep farming, quarrying, and tourism.
    1. Lowland Areas:
    • Located in the south and east, characterized by softer rocks (chalk, clay).
    • Landscape is flatter with fertile soils suitable for arable farming and urban development.
    1. Glaciated Landscapes:
    • Found primarily in the northern upland areas, shaped during the last glacial period.
    • Ice erosion has created distinct valleys and deposits.

Weathering and Erosion

  • Definitions:

    • Weathering: Breaking down of rocks; can be mechanical, chemical, or biological.
    • Erosion: Removal of rock and soil through the action of wind, water, or ice.

  • Mechanisms of Weathering

    1. Mechanical Weathering:
    • Rock breakdown without changing its chemical composition.
    • Freeze-thaw weathering prevalent in UK due to temperature fluctuations around 0°C.
    • Water enters rock cracks, freezes and expands, causing rock fragmentation.
    1. Chemical Weathering:
    • Rock breakdown through chemical reactions, such as carbonation affecting limestone.
    1. Biological Weathering:
    • Breakdown by organisms; roots of plants exert pressure on rocks, causing them to fracture.

  • Mass Movement

    • Refers to the shifting of loose material down slopes due to gravity.
    • Causes coastal retreat and is influenced by material saturation with water.

  • Processes of Erosion

    1. Hydraulic Action:
    • Pressure from waves creates fractures in rocks.
    1. Abrasion:
    • Eroded particles scrape against rocks, wearing them away.
    1. Attrition:
    • Particles collide and break into smaller fragments.
    1. Solution:
    • Dissolved minerals environmentally reacted with acidic water.

Coastal Landforms

  • Formation

    • Coastal landforms arise through erosion from waves. Example forms include headlands, bays, arches, and stacks due to differential erosion of hard and soft rocks.

  • Types of Coastal Landforms

    1. Headlands and Bays:
    • Form where different rocks erode at varying rates.
    • Bays develop in softer rock; headlands emerge from more resistant rock.
    1. Caves, Arches, and Stacks:
    • Formed from the continued erosion of headlands leading to caves that may open to form arches and ultimately stacks when arches collapse.
    1. Beaches:
    • Constructed from deposited materials; characteristics vary based on particle size (e.g. sandy vs. shingle beaches).
    1. Spits:
    • Formed when longshore drift deposits material at bends in the coastline, creating protrusions into the sea.
    • Recurved ends may form based on wave action.

River Landforms

  • River Types and Processes

    • Rivers experience erosion, transportation, and deposition, creating various landforms.

  • Landforms

    1. V-Shaped Valleys:
    • Formed through vertical erosion primarily in the upper course of rivers; shaped by weathering processes.
    1. Waterfalls:
    • Created when a river flows over hard rock followed by softer rock; eroding processes create a step and plunge pool.
    1. Gorges:
    • Formed as waterfalls retreat upstream, carving steep-sided gorges.
    1. Meanders and Ox-Bow Lakes:
    • Erosion on outer bends deepens meanders; can become ox-bow lakes when the river cuts through meanders during floods.
    1. Floodplains and Levees:
    • Floodplains develop from deposition during floods, while levees build up along riverbanks from deposited materials in flood events.

UK River Basin Case Study: River Eden

  • Characteristics

    • Located in North-West England, the River Eden flows from the Pennines to the Solway Firth.
    • Composition includes diverse landforms such as meanders and floodplains influenced by its wet climate.

  • Geomorphic Processes

    • Intense rainfall contributes to erosion and sediment transport leading to pronounced erosion patterns as defined by the geology of the area.

  • Human Impact

    • Flood walls and management schemes modify river behavior impacting natural processes, such as sediment deposition and meandering of the river channel, thus affecting local ecology and human settlement.