Geography & History Notes | KCSE, NECTA, ZIMSEC & GCSE

  Different areas in East Africa experience varying temperatures. Some areas experience extremely hot temperatures of over 30o c. They include Northeastern Uganda , Northern Kenya , the rift valley areas, and the coastal areas. Other areas experience very low/cool temperatures especially the mountainous or highland areas such as the Kenya highlands, Kigezi highlands, Mt Kilimanjaro , Mt Rwenzori, Mt Meru , and Mt Elgon among others. Several factors influence temperature or contribute to the variations in the temperature in E.Africa and they include: Altitude It refers to the height of the land above sea level. Temperatures tend to drop as altitude increases by approximately 6.5o c for every 1000 metres of ascent/rise. Due to this lapse rate effect, highland areas like Mt Rwenzori, Kenya, and Kilimanjaro experience low temperatures while low altitude areas like the rift valley region experience hot temperatures Latitude It refers to the angular distance of an area from the e...

  Temperature inversion is a condition in which the temperature of the atmosphere increases with altitude in contrast to the normal decrease with altitude. When temperature inversion occurs, cold air underlies warmer air at higher altitudes. There are four kinds of temperature inversions: ground, turbulence, subsidence, and frontal. A ground inversion develops when air is cooled by contact with a colder surface until it becomes cooler than the overlying atmosphere; this occurs most often on clear nights, when the ground cools off rapidly by radiation . If the temperature of surface air drops below its dew point, fog may result. Topography greatly affects the magnitude of ground inversions. If the land is rolling or hilly, the cold air formed on the higher land surfaces tends to drain into the hollows, producing a larger and thicker inversion above low ground and little or none above higher elevations. A turbulence inversion often forms when quiescent air overlies turbulent...

  Solar radiation refers to the energy transmitted from the sun to the earth through the atmosphere . It passes in the atmosphere in form of a beam of short wave rays (solar shortwave radiation) Solar radiation is received in a place during the day in a form of light and it is converted into heat at the earth’s surface The amount of solar radiation received in a place also varies from time to time. The air, clouds , and the ozone in the atmosphere absorb some of this energy while dust particles and clouds reflect and scatter the energy into the space. The earth, therefore, absorbs only a fraction of the energy emitted by the sun. The nature of the earth’s surface (Albedo) is used to express the ability of a surface to reflect insolation Conditions Influencing the In-coming Solar Radiation In an area: Latitude The angular distance of a place from the equator partly determines the distance from the sun to the earth’s surface. This further determines the angle of incidence at which th...