1. On earth most deserts are in 30 degrees latitude due to the warm air, calm winds and virtually constant areas with higher pressures that form in the atmosphere above. Throughout the year, deserts experience dry and hot conditions and plenty of sunlight, very little precipitation and little wind. This mostly occurs in the latitude 30 degrees north to 30 degrees south of the equator.
2. Deserts are areas that receive less than 10 inches of average annual rainfall. They are also characterized by high water loss from the ground and through plants through the process of transpiration. Another factor in the desert is the uneven and unpredictable nature of the little precipitation that occurs.
3. The warm air cools after rising at the equator. Precipitation at the equator is typical since cold air holds less water. The air mass moves 30 degrees north and south; the dry air warms as it sinks.
4. As the warm moist air rises to higher land elevations and drops its water along the way, the rain shadow effects occur. A region on the far side of the mountain is created that is relatively void in precipitation to the extent of forming a rain shadow desert.
5. The regions having little precipitation of below 25 cm annually are referred to as deserts and consequently, have hostile conditions for survival of plant and animal life.
6. An alluvial fan is a triangular-shaped deposit of gravel, sand, and smaller pieces of sediments as silt. They are formed when flowing water interacts with mountains, hills and steep slopes of canyons.
7. Every stream has the elevation below where it cannot flow known as a base level. The ultimate base level for all stream actions is the sea level.
8. Leos refers to a layer of fine, mineral-rich material from the wind-blown dust off from glaciers.
9. The flat-floored bottom of undrained desert basin that sometimes turns into a shallow lake is a playa.
10. The pavements are formed through gradual clearance of dust, sand and other fine-grained materials. The clearances are enhanced by intermittent rainfall and the wind that leaves the large fragment behind.
11. The removal of vegetation leads to desertification, since the soil would remain unprotected and would be more prone to wind erosion. This result to a serious impact as it would reduce the land’s fertility since the top soil layers, rich in nutrients, would be blown away by the wind. This would also have devastating effects on the land and its overall productivity.
12. Ranching and farming practices contributed to the Dust Bowl of the 1930s as the area had low rainfall, high winds, light soil, a combination that was potentially destructive. The soil lacked the root system that was strong to act as anchor like that of grass. The winds therefore easily picked up the loose topsoil and moved it into dense clouds of dust.
13. Modern technology contributes to the desertification of sub-Sahara Africa. This is due to the rise in infrastructure and modernization of agriculture practices which have led to the intensive use of the land to the extent that all the soil has been loose. The modern technology and industrial waste disposal result in environmental degradation. The two factors have also steered desertification in the Sub-Sahara Africa.
14. To effectively prevent desertification there is the need for both approaches of macro policy and local management that would enable sustainability of ecosystem service. It would be wise to focus on prevention due to it being costly to rehabilitate desertified areas. Major policies and management changes are required to reverse and curb desertification. The initiatives to create a culture that prevents and protects the land should also be established.
15. Desert lands are so fragile due to lack of and limited amount of moisture that is prone to evaporation due to the strong winds.
. As a glacier retreats, the ice melts away from beneath the moraines; hence they leave long, narrow ridges showing where the glacier used to be. Moraines are not always left behind by glaciers because sometimes the material is washed away by glacier’s melt water.
In summer melting of snow and ice removes glacier forms, with less than the amount added by winter snowfalls. Progressively the excess snow is buried deeper year-by-year and is converted to blue glacial ice.
A little pressure can lower the melting point of ice at normal atmospheric pressure at 0° C resulting to snow being packed into a dense snowball.
A glacier where it comes in contact with the ground is slowest.
Glaciers advance and retreat. When more ice and snow are added, the would be much lose through melting and advancement in calving.
The act of a glacier sliding over the bed due to melting water under the ice acting as a lubricant is termed basal sliding.
An ice sheet is a mass of glacial ice more than 50,000 square kilometers. They are sometimes called continental glaciers and contain up to 99% of freshwater. They convert into ice shelves as they enlarge to the coast.
The part also known as firn limit is the area between the upper region of névé and the lower region of solid ice above which ablation occurs.
Striations mean a series of ridges, furrows and linear marks.
Till is material that is unsorted deposited by glacial ice and has no stratification. It is sometimes referred to as boulder clay because it is made up of intermediate size boulders and clay.
The sediments and the mass of rocks deposited by glacier are carried down typically at its extremity.
When the glaciers are in motion, they erode the land around and beneath them. They carry huge amounts of clay, rock and soil. They also carry boulders as big as houses.
This time, more CO2 going into the atmosphere comes from carbon sources that had been sequestered in fuels previously such as gas. The sea-level therefore rises in the past and gets attributed to the melting glaciers and changes in the Earth Orbit cause thermal expansion. Today sea-level rise and melting are driven by anthropogenic CO2.
The Pleistocene Epoch is simply the period that started 1.8 years ago and until about 11,700 years ago. The last Ice Age that took place then, as planet Earth was covered by glaciers.
Loess is an aeolian sediment created by the coming together of silt that is wind-blown, normally between 20-50 micrometer in size, around 20% clay, silt and sand loosely cemented by calcium carbonate. It is highly porous and homogenous as well as vertical capillaries traversing it.