World Climatic Regions PDF

WORLD CLIMATIC REGIONS  The two most significant factors in defining different climates are temperature and precipitation. A place’s location on a continent, its topography, and its elevation may also have an impact on the climate. There are five general climate regions: tropical (lo...

WORLD CLIMATIC REGIONS  The two most significant factors in defining different climates are temperature and precipitation. A place’s location on a continent, its topography, and its elevation may also have an impact on the climate. There are five general climate regions: tropical (low latitude), dry, mid-latitude, high latitude, and highland. FACTORS INFLUENCE CLIMATE Pg 62 Ngwazikazana Latitude Altitude Distribution of land and sea Location of global high and low pressure Prevailing winds Ocean currents  Latitude: with distance from the equator temperatures and sunshine hours decrease as the solar radiation is more dispersed at the poles and it has to pass through a greater amount of atmosphere Altitude: Increases in altitude lead to decreases in temperature Continentality: locations further inland heat up more quickly in the summer and cool more quickly in the winter Ocean currents: warm and cold currents circulate in the oceans either warming or cooling the adjacent land Aspect: in the northern hemisphere slopes facing south are warmer Prevailing winds: winds coming from warmer areas bring warmer air, increasing temperatures Pressure systems: areas usually affected by low pressure such as the equator have rising air, condensation and cloud formation leading to more precipitation, whereas areas affected by high pressure have dry conditions due to the sinking air  Tropical wet climates are found in Central and South America as well as Africa and Southeast Asia TROPICAL WET AND DRY This climate is called “tropical wet and dry” because the subregion has a rainy season in summer and a dry season in winter. Temperatures are cooler in the dry season and warmer in the wet season. Rainfall is less than in the tropical wet climate subregion and occurs mostly in the wet season. Tropical wet and dry climates are found next to tropical wet climates in Africa, South and Central America, and parts of Asia  DESERT Some people think a desert is nothing but sand dunes. However, deserts are categorized according to the amount of rainfall, rather than by landforms, and can be hot or cool/cold. Deserts receive less than ten inches of rain per year. Hot deserts, like the Sahara and the Arabian Desert, regularly have low humidity and high temperatures dur ing the day. At night, temperatures drop because the dry air cannot hold heat well. Cool/cold deserts are found in the mid-latitudes mostly in the Northern Hemisphere, often in the rain shadow of nearby mountain ranges. Summer temperatures are warm to hot, and winter temperatures range from quite cool to below freezing  SEMI ARID This climate subregion does receive precipitation, just not very much: about 16 inches per year. Summers are hot. Winters are mild to cold, and some semiarid locations can produce snow. The climate is found in the interior of continents, or in a zone around deserts. The region contains some of the most productive agricultural lands in the world. INTERPRETING CLIMOGRAPHS  SAVANNA CLIMATE *Climate Characteristics** - Hot and dry, with a distinct wet and dry season - Temperatures are warm to hot year-round, usually ranging from 20-35°C - Seasonal rainfall, with a wet season typically lasting 4-6 months - Annual rainfall totals are moderate, usually 500-1500 mm about October to March in the Southern Hemisphere and April to September in the Northern Hemisphere. The dry season is typically longer than the wet season, but it varies considerably, from 2 to 11 months. Mean monthly temperatures are about 10 to 20 °C in the dry season and 20 to 30 °C in the wet season.  Savannas may be subdivided into three categories—wet, dry, and thornbush—depending on the length of the dry season. In wet savannas the dry season typically lasts 3 to 5 months, in dry savannas 5 to 7 months, and in thornbush savannas it is even longer. An alternative subdivision recognizes savanna woodland, with trees and shrubs forming a light canopy; tree savanna, with scattered trees and shrubs; shrub savanna, with scattered shrubs; and grass savanna, from which trees and shrubs are generally absent. FLORA AND FAUNA Vegetation** - Dominated by grasses, with scattered drought-resistant trees and shrubs - Trees are often short, with thick bark and twisted trunks to adapt to the climate - Grasses are coarse and grow in clumps, going dormant during the dry season **Wildlife** - Home to large grazing animals like zebras, wildebeest, gazelles, and elephants - Predators include lions, cheetahs, hyenas, and wild dogs - Birds, reptiles, and insects are also abundant  *Human Activities** - Pastoralism (livestock herding) is a common livelihood, taking advantage of the grazing lands - Subsistence farming of drought-resistant crops like millet, sorghum, and yams - Limited cultivation due to unreliable rainfall, leading to a high degree of reliance on grazing animals The savanna climate is found in parts of Africa, Australia, South America, and India, covering a large area between the humid tropics and the dry desert regions. The seasonal rainfall pattern and coexistence of grasses and trees make it a highly productive ecosystem, though water availability remains a key challenge for human activities. VEGETATION PROFILE(SAVANNA CLIMATE)  PLANTS ADAPTATION is characterized by the presence of- grassland vegetation with trees and shrubs that are spaced out and widely spread. Due to this reason, the canopy of Savanna is open. They have a high density of plants, and the trees are generally few and very tall. )The plants have deep and widespread roots that allow them to absorb water from large areas and survive the dry season. 2)The plants have long, narrow leaves to decrease the amount of water loss through transpiration. 3)In few trees, the trunk is modified to act as a water-storage organ.  4)The plants are often deciduous to avoid the loss of water and moisture. 5)The plants are specialized to have underground storage of starches. 6)The plants have specialized structures called thorns and scale leaves, which help them to prevent themselves from the herbivores. They also grow very tall to avoid being consumed by animals.  The thicker bark of many tree species indicates fire resistance than other biome forests. With frequent wildfires, savanna biome plants are more resilient to the warming future. One exciting characteristic of savanna grassland plants is to shed their leaves or not develop leaves at all. As foliage is the main exit point of moisture, eliminating it helps them conserve water.  ANIMAL ADAPTATION The animals have developed high stamina that helps them to save energy and function only when it is necessary. 8)Various animals have specialized structures that help them to cope up with dry conditions and heat. They have an increased surface area. Often, they take alternative pathways (use of mud) to keep them cool. 9)Various animals cope up with the dry day conditions by simply avoiding them by hibernating. They sleep during the entire day and perform functions during the night when the conditions are cool.  10)Many animals have developed fast running to protect themselves from predators. They even camouflage with the surrounding to avoid being hunted. 11)Many animals have adapted their body to run and survive in low water conditions and moisture. 12)A few animals migrate to other humid areas to avoid the dry season. Note: The vegetation of Savanna mostly contains grasses and has very few trees. The animals found here are mostly herbivores and extensively use the abundant food supply.  EQUATORIAL CLIMATE Equatorial rainforests contain an enormous variety of plants and animals – approximately 90 per cent of all of the world's species. rainforests are located in the equatorial climate region. They are hot and wet all year round – this creates a humid climate. The annual rainfall is high as it rains almost every day. The temperatures are constant all year round – the temperature range is usually only a few degrees. There are no seasons. The climate graph shows average rainfall and temperatures in Manaus, located in the Amazon rainforest in Brazil. The highest monthly rainfall is in March with over 300 mm and the lowest rainfall occurs in August with under 50 mm. Temperatures vary little throughout the year. The highest monthly temperature is 29°C which occurs in September. The lowest monthly temperature is 26°C which occurs in December and January. The annual temperature range is 2°C.  Equatorial or tropical rainforests are found near the equator. Places which experience an equatorial climate include parts of: Central America, eg Costa Rica South America, eg Brazil Central Africa, eg Kenya South-East Asia, eg Borneo  The forest floor/shrub layer This area is dark as trees block out most of the sunlight. The forest floor is covered in a thick blanket of dead and decaying roots and leaves, known as humus A little vegetation can grow between the trees if it is able to trap sunlight. This area is prone to flooding during torrential rainfall. The under canopy is the layer above the forest floor. This area is shady and cooler. As there is very limited sunlight, seedlings lie dormant until larger plants and trees die. The gap that is left in the canopy is quickly filled as new plants grow into it. Lianas, or vines, take root in the ground and climb up trees to reach the sunlight.  The canopy is the continuous layer of tree tops that is more sheltered The trees are normally 20 to 40 metres tall. This leafy location with fruit all year round is the habitat for most wildlife including insects, tree snakes, birds and some mammals, eg howler monkey, jaguar and sloth.  The emergent layer It consists of the tallest trees in the rainforest and they can grow up to 60 metres. They are higher because they are able to trap more sunlight to help them make more food to grow. Emergent trees are supported by buttress roots which prevent them from blowing over in high winds.  Emergents – tallest trees emerge through the main canopy layer (Main) canopy layer – most animals live here Lower/Under canopy layer – small trees and saplings grow in shady, humid conditions Shrub layer – smaller trees and ferns grow in deep shade Ground layer – leaf and animal remains cover the ground  Structure of the tropical rainforest The TRF has five distinct layers Ground layer (0m) Shrub layer (3-4m) Under canopy (15m) Canopy (30m) Emergents (45-55m) TROPICAL RAINFOREST STRUCTURE PLANTS ADAPTATION Fan palms have large, fan-shaped leaves. This feature is good for trapping sunlight and water. The leaves have segments, so excess water can drain away preventing its weight from breaking them. Many tropical rainforest trees have developed huge buttress roots These extend from the forest floor to two metres or more up the trunk and help to anchor the tree to the ground.  Buttress roots are essential as rainforests have a shallow layer of fertile soil, so trees only need shallow roots to reach the nutrients However, shallow roots can't support huge rainforest trees, so they have grown buttress roots to support them. Lianas are vines that grow up from the forest floor and use trees to climb up to the canopy, where they spread from tree to tree to get as much sunlight as possible.  Drip-tip leaves – pointed tips and glossy leaves to remove water quickly Epiphytes – these plants live on the surface of other plants, mostly tree trunks and branches. This allows them to make the most of the sunlight in the canopy layer Stilt roots – In a similar way to buttress roots, these provide tall rainforest trees with support as they are anchored in the shallow rainforest soils  Sloth - algae grow in the fur of the sloth helping to camouflage it Toucan - has a large bill to reach and cut fruit from the branches of trees Primates - have prehensile tails to help them climb trees Geckos - have large, flattened toe pads with sticky scales which allow them to grip the smooth tree trunks Stick Insects - their stick and leave shapes help them to be camouflaged IMPORTANCE OF THE TROPICAL RAINFOREST