Glaciers and Their Dynamics

Glaciers

• Glaciers are bodies of ice that show evidence of movement due to their weight.
• Accumulation zone: Area of net mass gain from snowfall, typically at the glacier's highest point.
• Ablation zone: Area of net loss where ice and old snow are exposed.
• Equilibrium line: Where accumulation equals melting.
• Glacial movement is driven by internal flow (due to weight and ice crystal structure) and basal sliding (meltwater reducing friction).

Glacial Erosion and Deposits

• Glacial drift: All sediment deposited by glacial erosion.
• Till: Unsorted glacial drift deposited directly from ice.
• Moraines: Till deposits with various forms (e.g., ground, terminal, lateral, medial).

Types of Glaciers

• Continental glaciers (ice sheets): Largest glaciers, covering vast land areas, including Greenland and Antarctica.
• Mountain glaciers: Alpine, cirque, valley, fjord, and piedmont glaciers.

Hydrologic Cycle

• Water Distribution: Oceans contain most water (97.5%), while polar ice sheets hold 74% of fresh water. Groundwater is a significant reservoir of unfrozen fresh water.
• Streams: Ephemeral streams flow only after rainfall, perennial streams flow year-round.
• Stream flow: Consists of storm flow (from precipitation) and base flow (from groundwater).
• Load Types: Bedload (large material dragged along the bottom), suspended load (fine material within the water), and dissolved load (ions from rock and organic matter).
• Particle Movement: Velocity affects sediment distribution (lowest velocity along inside meanders, forming point bars, highest along outside meanders, creating cut banks).
• Aquifer systems: Unconfined (water table connection) and Confined (bounded by impermeable rock, with artesian aquifers having high pressure for free-flowing water).

Porosity and Permeability

• Porosity: Percentage of open spaces in rock.
• Permeability: How easily fluids pass through rock.
• Both determine water storage and movement in rocks.
• Wells in unconfined aquifers have water levels equalling the water table.

Atmospheric Layers

• The troposphere is the lowest layer, extending from Earth's surface to about 9 km at the poles and 12 km at the equator. Temperature decreases with altitude. This is where weather phenomena occur.
• Stratosphere: Temperature increases with altitude, mostly stable. Ozone is mainly found here, absorbing UV radiation.
• Mesosphere: Does not absorb solar energy.
• Thermosphere: Contains minimal gases, absorbing short-wavelength solar energy.

Temperature Changes in the Atmosphere

• Temperature variations are complex, with temperature decreasing with altitude in the troposphere (lapse rate) and inversions (temperature increasing) in the stratosphere.
• Changes create distinct layers.

Ozone Layer

• Located in the stratosphere.
• Absorbs ultraviolet (UV) radiation, protecting life on Earth.
• Ozone concentration is higher at the poles due to seasonal patterns and atmospheric circulation.

Pressure and Wind

• Air moves from high to low pressure.
• Wind patterns are influenced by temperature differences, the Earth's rotation (Coriolis effect), and topography.
• Global wind patterns form distinct circulation cells (Hadley, Ferrel, and Polar cells).

Albedo

• Reflectivity of Earth's surface.
• Average albedo is 30%.
• Higher at the poles due to ice cover.
• Oceans have lower albedo when the sun is directly overhead.

Heat Transfer in the Atmosphere

• Heat is transferred by convection (vertical air movement due to temperature differences), conduction (direct transfer between molecules), and radiation (energy transfer through electromagnetic waves).

Carbon Dioxide Cycle

• CO2 is a greenhouse gas, absorbing and re-emitting infrared radiation.
• Oceans play a role in absorbing atmospheric CO2 and regulating its concentrations.