Deserts as natural systems Flashcards
What are systems concepts, and how are they applied to the development of desert landscapes?
Systems concepts involve understanding inputs (energy and materials entering the system), outputs (energy and materials leaving the system), energy, stores/components (elements within the system), flows/transfers (movement of energy and materials within the system), positive/negative feedback (mechanisms that amplify or dampen changes), and dynamic equilibrium (a balanced state over time). These concepts help explain how various factors interact to shape desert landscapes.
How do inputs and outputs influence desert landscapes?
Inputs like solar energy and sediment influx, and outputs like heat radiation and sediment loss, affect the formation and change of desert landscapes.
What role does energy play in desert systems?
Energy, primarily from the sun, drives processes like weathering, erosion, and transportation of sediments, shaping desert landforms.
What are stores/components in desert systems, and how do they interact?
Stores/components include elements like sand, rock, and water. Their interactions, such as sediment storage in dunes or water in wadis, influence landscape development.
What are flows/transfers in desert systems, and why are they important?
Flows/transfers involve the movement of energy and materials, such as wind transporting sand or water eroding rock. They are crucial for shaping landforms.
What is negative feedback in desert systems, and how does it occur?
Negative feedback dampens changes, such as vegetation growth stabilizing sand dunes, reducing further erosion.
What is positive feedback in desert systems, and how does it occur?
Positive feedback amplifies changes, such as increased erosion leading to more sediment transport, further enhancing erosion.
What is dynamic equilibrium in desert systems, and why is it important?
Dynamic equilibrium is a balanced state where inputs and outputs are equal over time, maintaining a stable landscape despite ongoing processes.
What are the concepts of landform and landscape, and how do related landforms combine to form characteristic landscapes?
A landform is a natural feature on the earth’s surface, like a dune or wadi. A landscape is an assemblage of related landforms that create a characteristic region, such as a desert with dunes, wadis, and rocky outcrops.
Where are mid and low latitude deserts located globally, and what are their margins?
Mid latitude deserts (e.g., the Gobi Desert) and low latitude deserts (e.g., the Sahara) are found between the tropics and mid-latitudes. Their margins include arid (extremely dry) and semi-arid (moderately dry) regions.
What are the climate characteristics of hot desert environments and their margins?
Hot deserts have extreme temperatures, low rainfall (less than 250mm), and high evaporation rates. Margins may experience slightly more moisture and milder temperatures.
What are the soil characteristics of hot desert environments and their margins?
Desert soils are often sandy, rocky, low in organic matter, and have poor water retention. Margins may have slightly richer soils with some vegetation.
What is the vegetation like in hot desert environments and their margins, and how do they interact with the climate and soils?
Vegetation in deserts is sparse, drought-tolerant, and includes species like cacti and shrubs. In margins, vegetation is more diverse and interacts with the soil by stabilizing it and reducing erosion.
What is the water balance in hot desert environments, and what is the aridity index?
Water balance in deserts is the difference between precipitation and evaporation. The aridity index measures the degree of dryness, with deserts having high aridity indices.
How do atmospheric processes relating to pressure contribute to aridity in deserts?
High-pressure systems inhibit cloud formation and precipitation, leading to dry conditions.
How do winds influence aridity in desert environments?
Winds can remove moisture and transport dry air into desert regions, exacerbating aridity.
What is continentality, and how does it cause aridity in deserts?
Continentality refers to the effect of being far from oceans, resulting in limited moisture and increased temperature extremes, leading to aridity.
How does relief (topography) affect aridity in desert regions?
Mountains can block moist air from reaching deserts (rain shadow effect), causing dry conditions on the leeward side.
How do cold ocean currents contribute to aridity in coastal deserts?
Cold ocean currents cool the air above them, reducing its ability to hold moisture and resulting in dry conditions when this air moves inland.
