Glacial Systems And Landforms Flashcards
How does latitude affect the distribution of cold environments?
The higher the latitude, the less solar radiation (energy/heat) the earth receives from the sun - meaning there is colder temperatures in some areas
How does altitude affect the distribution of cold environments?
The higher the altitude, the lower the temp due to lower air density
How does relief affect distribution of cold environments?
the shape and slope (relief) of the land may prevent ice accumulation
If the slope is too steep the snow and ice may slide down the peak rather than just accumulating
How does distance from moisture source affect the distribution of cold environments?
precipitation is more likely to occur near a water source.
How is solar variation a cause of ice ages?
Reduced solar variation could lead to colder winters as suns UV radiation affects atmosphere circulation. This is impacted due to earths tilt relative to the sun.
How do Milankovitch cycles cause ice ages?
The impacts of the earth’s position relative to the sun are a strong driver of the long term climate - and triggering glacial periods.
What is the quaternary period?
The latest period of geographical time, spanning the last 2 million years
What are causes of polar and tundra climates?
- low levels of insolation
- the high albedo
- high pressure systems
- coolness of the air
- Katabatic winds
What is the vegetation in tundra like?
V low levels of biodiversity due to low levels of productivity
Absence of full grown trees - short growing season
What are some plant adaptations?
Ground hugging cushion plants to avoid wind
Slow growth rates
Shallow roots - avoid permafrost
Ability to photosynthesise at low temperatures
- low albedo
What is a system?
a system is a set of interconnected parts that work together. They have a series of stores or components and have flows between them.
What is an open system?
Inputs, outputs and stores and both energy and matter can be transferred into surrounding environment
What is the glacial budget?
How much goes in and how much goes out. The total of accumulation and ablation for a glacier.
What is accumulation?
The process of building up snow and other frozen precipitation, like meltwater and firn.
What is ablation?
The process of wastage of snow or ice by melting, sublimation and calving.
What is the equilibrium line/ zone?
The line or zone on a glacier’s surface where a year’s ablation balances a year’s accumulation.
What is calving?
The process of detachment of icebergs and smaller blocks of ice from a glacier into water
What is glacier advance?
the forward movement of the snout of the glacier following successive years of positive mass balance.
What is glacier recession?
the shrinking of the snout of a glacier following successive years of negative mass balance. Also referred to as glacial retreat.
What is the snout of a glacier?
the lower part of the ablation area of a valley glacier, commonly shaped like the snout of an animal.
What is a glacier?
a mass of ice, irrespective of size, derived largely from snow, and continuously moving from higher to lower ground.
What is a valley glacier?
A glacier bounded by the walls of a valley, and descending from high mountains, from an ice cap on a plateau, or from an ice sheet
What is an ice cap?
A dome shaped mass of glacier ice, usually situated in a highland area, and generally defined as covering up to 50,000 square kilometres
What is a piedmont glacier?
A glacier that spreads out as a wide lobe as it leaves a narrow mountain valley to enter a wider area or a plain.
What is a cold-based (polar) glacier?
Occurs in polar latitudes where the temperatures of snowfall is far below freezing and glacier remains at well below freezing point
What is a warm-based (temperate) glacier?
Water is present throughout the ice mass and acts as a lubricant
What is Nivation?
annual and diurnal temperature changes lead to thaw-freeze alternation, and the conversion of snow to ice crystals.
How does a glacier form?
Snow collects in a hollow. When summer periods are cool it doesn’t melt. This mainly happens on north facing slopes. Over time, the weight of the snow compresses the snow beneath it forming a firm. This is called sintering. Nivation also helps this process by melting the snow crystals and refreezing them into ice. After 20 years of continued accumulation of snow and firn formation means all the air is squeezed out and glacier ice is formed.
What are the 5 ways the glacial ice moves in once formed?
- Internal deformation
- Rotational (movement at the start of a glacier in a corrie)
- Compressional
- Extensional
- Basal sliding
What is basal sliding?
the sliding of a glacier over bedrock, a process usually facilitated by the lubricating effect of meltwater.
What is rotational flow?
- A downhill flow of ice which, like a landslide pivot, around a point producing a rotational movement.