Hot desert processes and landforms

Outline sources of sediment in hot deserts.

Figure 3 is in the insert.

Figure 3 shows mean annual precipitation and mean annual temperature in central Chile.

Using Figure 3, analyse the relationship between annual precipitation and temperature in central Chile.

Figure 4 is in the insert.

Figure 4 shows progress in the development of the Great Green Wall reforestation scheme in the Sahel region of Africa.

Using Figure 4 and your own knowledge, assess the challenges in responding to desertification.

To what extent do you agree that weathering is the most important geomorphological process shaping desert landscapes?

Outline characteristics of a pediment.

Figure 3a and Figure 3b are in the insert.

Figure 3a shows the average rainfall and current extent of the Sahara Desert and other vegetation types in central and north Africa.

Figure 3b shows the average rainfall and vegetation types in central and north Africa around 6000–10 000 years ago.

Using Figure 3a and Figure 3b, interpret the change in rainfall and vegetation patterns in central and north Africa.

Figure 4 is in the insert.

Figure 4 shows some of the factors causing desertification in selected locations.

Using Figure 4 and your own knowledge, assess the potential impact of desertification.

With reference to one or more hot deserts that you have studied, assess potential impacts of climate change on the development of landforms.

Outline weathering processes in hot deserts.

Figure 3 shows the changing size of the Sahara Desert between 1980 and 1990. A standard deviation calculation has been started.

Space for working

Complete the table and standard deviation calculation in Figure 3 and evaluate the usefulness of the technique in analysing this data.

Figures 4a, 4b and 4c are in the insert, and show information about a town in Egypt (El-Sheikh El-Shazli) which is prone to desert flash flooding.

Figure 4a shows the location of El-Sheikh El-Shazli relative to a number of wadis in the area shown on a satellite image.

Figure 4b shows sketch maps of the town and area flooded before and after increased urbanisation.

Figure 4c is a photograph of the town looking towards the hills in Figure 4b.

Using Figures 4a, 4b, 4c and your own knowledge, assess the relative importance of physical and human factors contributing to the flash flooding events in this area.

With reference to a hot desert that you have studied, assess the relative importance of different sources of energy in landscape development.

Outline the sources of water in deserts.

Figures 3a and 3b are in the insert.

Figure 3a shows annual mean temperatures in Australia in 2018 compared to historical temperature observations.

Figure 3b shows annual rainfall in Australia in 2018 compared to historical rainfall observations.

Analyse the extent of the relationships shown in Figure 3a and Figure 3b.

Figure 4 shows a landscape feature in the White Desert in western Egypt.

Note: The White Desert extends over 300 km 2 of the Egyptian Sahara Desert. Sedimentary rocks formed from oceanic deposition in an earlier geological era are now subject to hot desert conditions. Features such as those illustrated protrude above the landscape to give the White Desert its distinctive character. Mushroom-shaped formations can be as high as 4.5 metres.

Using Figure 4 and your own knowledge, assess the role of wind in the development of this landscape.

How far can an understanding of systems in physical geography help to mitigate against the expansion of deserts into semi-arid areas?

Outline the role of wind in the process of transport in hot deserts.

Figures 3a and 3b are in the insert.

Figure 3a shows average total rainfall (1979 – 2009) between November and April measured at multiple recording stations across Saudi Arabia.

Figure 3b shows average total rainfall (1979 – 2009) between June and September measured at multiple recording stations across Saudi Arabia.

Analyse the data shown in Figure 3a and Figure 3b.

Figure 4 shows a landscape in the Namib Desert in southern Africa.

Note: The landforms in this landscape are aligned approximately north-west to south-east and extend from between 16 km to 32 km in length, reaching heights between 60 metres to 240 metres. The sediment source is the Orange River, several kilometres away.

Using Figure 4 and your own knowledge, assess the relative importance of factors leading to the development of this landscape.

To what extent can an understanding of feedback systems help to reduce the problem of desertification?

Outline the role of cold ocean currents as a cause of aridity.

Figure 3 is in the insert.

Figure 3 shows desertification risk levels by landscape type in an area of Tunisia, north Africa.

Analyse the relationship between landscape type and risk of desertification shown in Figure 3.

Figure 4 shows a landscape near to Naein, central Iran.

Using Figure 4 and your own knowledge, assess the view that low precipitation is the most important factor leading to the development of this landscape.

‘Desertification trends are entirely a product of human-induced climate change as opposed to naturally occurring phenomena.’

To what extent do you agree with this view?

Outline sources of energy in hot desert environments.

Figures 3a and 3b are in the insert.

Figure 3a shows the primary productivity in five study areas of northern China which are at different stages of aeolian desertification.

Figure 3b shows the percentages of soil particle size in the same five study areas.

Analyse the data shown in Figure 3a and Figure 3b.

Figure 4 shows the landscape around and including Uluru in the Uluru-Kata Tjuta National Park, Northern Territory, Australia.

Note: Uluru is one of Australia’s most recognisable natural landmarks. The sandstone formation stands 348 m high, rising 863 m above sea level, with most of its bulk lying underground. It has a total circumference of 9.4 km. Uluru is dominantly composed of coarse-grained sandstone and other rock fragments including basalt and granite.

Using Figure 4 and your own knowledge, assess the role of weathering in the development of this landscape.

‘The fragile inter-relationship between climate, soils and vegetation in arid regions is becoming increasingly affected by human activity.’

How far do you agree with this view?

Outline the role of atmospheric processes in causing aridity in desert regions.

Figure 3 shows data on outbreaks of locust swarms (a threat to arable farming), civil unrest, drought and famine against the background of historical trends for population and rainfall in Niger between 1880 and 2005. Niger is in the Sahel region of Africa.

Analyse the data shown in Figure 3.

Figure 4 shows a landscape in the Gobi Desert near Yumenguan, China.

Note: This landscape features river and lake sand and mud beds (primarily silt, sand, clay and some gravel) which were formed, but not completely consolidated, towards the end of the last ice age.

Using Figure 4 and your own knowledge, assess the view that wind is the most important factor in the development of this landscape.

‘Climate change is on course to radically alter the role of water in deserts and their margins, affecting both human populations and the physical landscape.’

To what extent do you agree with this view?