FACTORS THAT INFLUENCE THE TEMPERATURE OF AN AREA
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 equator. Temperatures tend to reduce as one moves away from the tropics towards the Polar regions. Given that E.Africa lies astride the equator, temperatures are uniformly hot with no big variations
Prevailing winds
They have a modifying effect on the temperature of the places where they blow depending on their origin. The Northeast trade winds which blow from the Arabian desert bring hot temperatures in Northeastern Uganda (Karamoja) and Turkanaland while the Southeast trade winds and the Westerlies cause moderate temperatures around the Central plateau of E.Africa because they originate from the Indian ocean and the Atlantic ocean respectively
Continentality
It refers to the distance of a place from the sea. It is responsible for the temperature variations between places near the coast and those in the interior.
The Southeast trade winds transfer warm conditions to the coastal areas of E.Africa and this explains why Mombasa is relatively warmer than the interior of Kenya and E.Africa in general.
Water bodies also have a modifying effect on temperature through the land and sea breezes
Vegetation cover
Thick vegetation cover has a modifying effect on the temperature of the surrounding areas through evapotranspiration.
Forested areas have high humidity and relatively low temperatures for instance Mabira and Budongo forest.
On the other hand, areas with limited vegetation cover tend to experience hot temperatures e.g Northeastern Uganda and Turkana land in Northwestern Kenya
Ocean currents
They are defined as streams of surface seawater moving on a large scale in a defined direction. They are sub-divided into two (2) categories i.e warm and cold ocean currents.
They have a modifying effect on the temperature of the adjacent areas.
Warm ocean currents such as the Warm Mozambique currents raise the temperatures of the winds blowing around hence causing warm and/or hot temperatures to the adjacent lands such as Mombasa and Dar es Salaam
Cloud cover
It also determines the temperature of a place. Thick clouds control the amount of solar insolation reaching the earth’s surface and at the same time trap the escaping radiation from the earth’s surface. For this reason, areas with thick cloud cover like the Lake Victoria basin experience a small diurnal range of temperature than areas like Turkana land with limited cloud cover
Apparent movement of the overhead sun
The position of the sun influences seasonal variations in temperature. Temperatures are higher in regions where the sun is overhead.
When the sun is overhead in the northern hemisphere between June and July, hot temperatures are experienced in the northern hemisphere and low temperatures in the southern hemisphere.
When the sun is overhead in the southern hemisphere in December and January, temperatures are high in the southern hemisphere and low in the northern hemisphere
Humidity
The amount of water vapour in the atmosphere determines the atmospheric temperature of a place. High amounts of humidity absorb heat and prevent heat loss from the earth’s surface.
This explains why areas with high humidity e.g equatorial regions experience hot temperatures during the day and at night than areas with low humidity which experience cool temperatures during the night due to excessive heat loss
Nature of the earth’s surface (Albedo)
Surfaces covered by water or ice are bright so they reflect much of the heat (solar radiation) back into the atmosphere leading to low (cool) temperatures over the water surface during the day while solid dark coloured land surfaces absorb heat faster during the day leading to warm / hot temperatures
Aspect
It refers to the direction of a hill slope in relation to the position of the sun.
It influences temperature in the temperate/polar regions where the south-facing slopes in the northern hemisphere experience warm temperatures than the north-facing slopes.
In the southern hemisphere, on the other hand, the north-facing slopes are warmer than the south-facing slopes.
In the tropics, however, the influence of aspect is not experienced due to the effect of the overhead sun
Human activities
The various activities of man such as deforestation, bush burning, overgrazing, mining and industrialization result into hot temperatures due to the destruction of natural vegetation, depletion of the ozone layer, and the subsequent increase in carbonic emissions (gases) into the atmosphere which absorb solar radiation thereby causing hot temperatures.
On the other hand, afforestation reduces carbon concentrations in the atmosphere since plants absorb carbon dioxide leading to moderate temperatures