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Hydrology - Coggle Diagram
Hydrology
Hydrological Cycle
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Intensification
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Weakening - as areas of high pressure - subtropical pressure belts - move towards the poles, places become drier
Less water vapour, so less cloud formation and rain, deserts can form
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Water Properties
Density - expands as it freezes, with molecules less densely packed in the solid lattice than as liquid
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Densest around 4C, 999kg/m3
Radiative
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Snow and clouds have high albedo, reflect shortwave
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Energy
High Specific Heat (energy needed for heating) - 4,180 Jkg-1 oC-1
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High Latent Heat
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Vaporises at any temp, even as ice, just vaporises vigorously at 100C
Land
Runoff
Ocean
Evaporation
Atmosphere
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Links water stores through evaporation, condensation, and precipitation
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Glaciers
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Valley Glacier Anatomy
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Trunk - main body where ice is being transported, along with eroded material
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Terminus - end of the glacier, where material is deposited/dispersed
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Glacial ice formation
Fresh snow is 90% air
Over time, ice thaws and refreezes around the centre of the crystal, making rounder firm snow
Compacted and pushed down by weight of snow above, with the cycle repeating over time
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Movement
Ice is brittle near the surface - fractures under tension, forming crevasses
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The top and middle of the glacier moves faster than the base and sides, due to friction from the bottom and sides
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Ice moves downwards in the accumulation zone, upwards near the terminus
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Polar glaciers are frozen to bedrock, moving more slowly (only from internal deformation)
Low sun angle warms the ice, along with longwave energy from rocks, increasing ablation on edges and maintaining vertical face
Hydrological Extremes
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API - Annual recurrence interval/flood return period - how frequently a flood of a certain size has occurred
FEP - flood exceedance probability - reciprocal of return period - probability of a flood of a certain size occurring in any given year
Floods - usually caused by rain, but can be from geological, tectonic, or glacial collapse into lakes
Prolonged heavy rain over an entire catchment, pre-existing wet ground
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Rivers
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River flow dynamics
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Gradient/slope - decreases downstream, reducing velocity and erosive capacity
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