Dryland Landscapes | OCR A-Level Geography (H481)

Dryland Landscapes

255 questions
18 subtopics
Component 01: Physical systems, one landscape of three plus the compulsory life support systems
Component 01

Dryland Landscapes is examined in Component 01, Physical systems.

It covers dryland landscape systems: inputs, stores, flows and outputs, aridity, the water balance and the UNEP aridity index, rainfall, pressure belts and the global pattern of aridity, rock type and structure in dryland landscapes, relief, aspect and desert microclimates, sediment supply and the dryland sediment budget, polar drylands and the cold deserts, hot deserts of the low and mid latitudes, semi-arid environments and the desert margins, weathering and mass movement in dryland landscapes, fluvial and aeolian processes in the desert, wadis, canyons, pedestal rocks, ventifacts and desert pavements, barchans, linear dunes, star dunes, alluvial fans and bajadas, the Mojave and the Sahara as desert landscape systems, inselbergs, pediments and relict landforms of past pluvials, frost-shattered debris, nivation hollows and solifluction deposits, water supply, dams and landscape change and tourism, off-road vehicles and landscape change.

Sample questions from Dryland Landscapes

Answer each one closed book first, then open the answer.

Dryland landscape systems: inputs, stores, flows and outputs

Give four sediment stores found in a desert landscape.

Show the answer
Dune fields, alluvial fans, playa deposits and the regolith mantling hillslopes are all sediment stores.
Rainfall, pressure belts and the global pattern of aridity

Which two latitude bands contain most of the world's hot deserts?

Show the answer
Most hot deserts lie roughly between 15° and 30° north and between 15° and 30° south of the Equator.
Relief, aspect and desert microclimates

How does slope angle influence runoff and infiltration in a dryland?

Show the answer
Steep slopes shed water rapidly as overland flow with little time for it to soak in, so both moisture and sediment become concentrated at the foot of the slope.
Polar drylands and the cold deserts

Define the term katabatic wind.

Show the answer
A katabatic wind is one produced when cold, dense air drains downslope under gravity from a high ice surface towards lower ground.
Semi-arid environments and the desert margins

Define the term desertification.

Show the answer
Desertification is the degradation of land in dry areas so that its biological productivity falls, brought about by a combination of climatic variation and human activity.
Fluvial and aeolian processes in the desert

What are transmission losses, and why do they matter in a desert?

Show the answer
They are the water lost from a channel by seepage into the dry bed and by evaporation, and they can be so great that discharge falls downstream and the flood dies out before reaching any lake or sea.
Barchans, linear dunes, star dunes, alluvial fans and bajadas

What wind conditions produce a linear dune?

Show the answer
Two prevailing wind directions separated by a wide, obtuse angle produce linear dunes, because sand is driven along the resultant line rather than piled across the flow.
Inselbergs, pediments and relict landforms of past pluvials

What is an inselberg?

Show the answer
An inselberg is an isolated, steep-sided hill of resistant rock rising abruptly from a surrounding plain.

The 18 subtopics

One subtopic is one session. Work down the list.

Subtopic	What it covers	Questions
Dryland landscape systems: inputs, stores, flows and outputs	Recall questions on the dryland as an open system: its energy and material inputs, outputs and sediment stores, why its water store is small, geomorphic processes, positive and negative feedback, dynamic equilibrium, and why drylands respond so quickly to change.	13
Aridity, the water balance and the UNEP aridity index	Recall questions on aridity and potential evapotranspiration, the UNEP aridity index and its hyper-arid, arid, semi-arid and dry sub-humid classes, the share of land that is dryland, worked index and water balance calculations, aridity versus drought, and the limits of the index.	16
Rainfall, pressure belts and the global pattern of aridity	Recall questions on desert rainfall and its unreliability, the Hadley cell and subtropical high pressure, the latitude of the hot deserts, continentality, rain shadows and the Patagonian Desert, cold currents off the Namib and Atacama, and high-altitude drylands.	15
Rock type and structure in dryland landscapes	Recall questions on lithology and rock resistance in deserts, mesas and buttes in Monument Valley, permeability, joints and bedding planes, calcrete, gypcrete and silcrete duricrusts, sandstone as a dune source, dipping strata, and faulting in the Basin and Range Province.	13
Relief, aspect and desert microclimates	Recall questions on desert microclimates, how aspect and slope angle change temperature, moisture, vegetation, weathering and runoff, orographic rain on the Tibesti Mountains, albedo, the large daily temperature range and the world's highest recorded temperature, canyon microclimates, and dew.	12
Sediment supply and the dryland sediment budget	Recall questions on the dryland sediment budget and a worked storage calculation, sediment sources, supply versus availability, the water table and aeolian transport, dune fields fed by dry lake beds and the Kelso Dunes, Saharan dust export, sediment sinks, and measuring a budget in the field.	13
Polar drylands and the cold deserts	Recall questions on why Antarctica is a desert, dry polar air, the McMurdo Dry Valleys, katabatic winds and sublimation, polar dryland landforms and weathering, permafrost, aeolian processes, and why polar drylands are sensitive to warming.	12
Hot deserts of the low and mid latitudes	Recall questions on where low-latitude and mid-latitude deserts lie, the Sahara, the Gobi and the Great Basin, their temperature regimes, sand seas or ergs, hamada and reg surfaces, and desert vegetation and soils.	13
Semi-arid environments and the desert margins	Recall questions on semi-arid vegetation and rainfall seasonality, the Sahel, soil erosion on semi-arid land, desertification and overgrazing, how vegetation loss reinforces dryness, dune reactivation and the Kalahari linear dunes, rainfall variability and farming, and playas.	12
Weathering and mass movement in dryland landscapes	Recall questions on salt weathering and sodium sulfate, tafoni, insolation weathering and the moisture debate, freeze-thaw, hydration and oxidation in deserts, desert varnish, and rockfalls, debris flows and dry ravel on desert slopes.	14
Fluvial and aeolian processes in the desert	Recall questions on desert runoff, ephemeral streams, exotic rivers and endoreic drainage, flash flood hydrographs and transmission losses, sediment loads, deflation and the Qattara Depression, wind abrasion, saltation, surface creep and suspension, and the wind speed needed to move sand.	15
Wadis, canyons, pedestal rocks, ventifacts and desert pavements	Recall questions on how wadis and canyons form and stay steep, the Grand Canyon and the Colorado River, pedestal rocks and the processes that undercut them, ventifacts and dreikanters, and the competing explanations for desert pavements.	15
Barchans, linear dunes, star dunes, alluvial fans and bajadas	Recall questions on the conditions, shape and migration of barchans, slip faces, linear dunes and star dunes, alluvial fans and their sorting, bajadas, and fieldwork methods for measuring dune shape, barchan migration, fan sorting and geo-spatial mapping.	20
The Mojave and the Sahara as desert landscape systems	Recall questions on the Mojave as a mid-latitude, transitional desert with winter rain, its Basin and Range landforms, Death Valley and Lake Manly, the Mojave River and Kelso dunes, and the Sahara's flash floods, Tibesti and Ahaggar streams, African Humid Period and Lake Mega-Chad.	18
Inselbergs, pediments and relict landforms of past pluvials	Recall questions on pluvial periods and their causes, evidence of past pluvial climates, inselbergs such as Uluru and the competing explanations for them, pediments, their gradient and formation by sheetflooding, and how inselbergs and pediments change under present and future climates.	14
Frost-shattered debris, nivation hollows and solifluction deposits	Recall questions on relict periglacial landforms in warm deserts, frost shattering and recognising its debris, relict scree slopes, nivation hollows and their aspect, solifluction and its deposits, and how warming affects periglacial features in drylands and polar deserts.	13
Water supply, dams and landscape change	Recall questions on water demand and drought in drylands, the over-allocated Colorado River, Glen Canyon Dam and sediment trapping, hungry water, Grand Canyon sandbars and controlled flood releases, the Colorado delta, effects on alluvial fans and wadis, groundwater abstraction, and the Aral Sea.	14
Tourism, off-road vehicles and landscape change	Recall questions on desert tourism, cryptobiotic crust and its functions, how off-road vehicles increase wind erosion, dune activity, runoff and gullying around Moab in Utah, loess and dust carried to distant snowpack, management of recreational damage, and slow dryland recovery.	13

Dryland Landscapes is 255 of the 3,740 questions in the guide.Get the guide, £7

How the guide is worked

Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.

Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.

Read the full method, the return schedule and the research behind it.