THE KOPPEN CLIMATE CLASSIFICATION SYSTEM

INTRODUCTION

The concepts of devising climate classes that combine temperature and precipitation characteristics, but of setting limits and boundaries fitted into known vegetation and soil distributions were actually carried out in 1918 by Dr. Wladimir Koppen of the University of Graz, in Austria. Koppen was both a climatologist and a plant geographer, so his main interest lay in finding climate boundaries that coincided approximately with boundaries between major vegetation types. Although he was not entirely successful in achieving his goal, his climate system has appealed to geographers because it is strictly empirical and allows no room subjective decisions.
The classification was subsequently revised and extended by his students to become the most widely used of climatic classifications for geographical purposes.

BASIS FOR THE CLASSIFICATION

The Koppen system is strictly empirical. This is to say that each climate is defined according to fixed values of temperature and precipitation, computed according to the averages of the year or of individual months. In such a classification, no concern whatsoever is given to the causes of the climate in terms of pressure and wind belts, air masses, fronts, or storms. It is possible to assign a given place to a particular climate sub-group solely on the basis of the records of the temperature and precipitation of that place, provided, of course, that the period of record is long enough to yield meaningful averages. Air temperature and precipitation are the most easily obtainable surface weather data, requiring only simple equipment and a very elementary observer education. A climate system based on these data has a great advantage, in that the area covered by each sub-type of climate can be delineated (outlined, profiled) for large regions of the world.

LIMITATIONS

As with any regional classification, this system is not universally applicable. It utilizes, for example, only the data or mean monthly temperature and precipitation. There is not provision for variations in the strength or constancy of winds, temperature extremes, precipitation intensity and range, amount of cloud cover, or the net radiation balance. Its greatest inadequacies perhaps lie in its application to humid dry boundaries, and it should not be considered for land management and planning purposes, where more precise and varied factors should be utilized.

ADVANTAGES

Despite these and other disadvantages, this system has been used mainly because of four reasons that have special value.
1. It has precise definitions that can be applied easily to standardize data that are available for locations throughout the world.
2. There is a reasonable correlation globally with major vegetation regions.
3. It requires a minimum amount of calculation.
4. It is widely used in educational circles throughout the world.

DESIGNATION OF VARIOUS TYPES

The Koppen features a short hand code of letters designating major climate groups, sub-groups within the major groups and further sub-divisions to distinguish particular seasonal characteristics of temperature and precipitation.

Major Groups

Five major climate groups are designated by capital letters as follows:

A–Tropical Rainy Climate: Average temperature of every month is above 64.4oF (18oC). These climates have no winter season. Annual rainfall is large and exceeds annual evaporation.

B–Dry Climate: Potential evaporation exceeds precipitation on the average throughout the year. No water surplus; hence no permanent streams originate in B Climate Zones.

C–Mild, Humid (Mesothermal) Climates: Coldest month has an average temperature under 64.4oF (18oC), but above 26.6oF (-3oC); at least one month has an average temperature above 50oF (10oC). The sea climates have both a summer and a winter season.

D– Snowy Forests (Microthermal) Climates: Coldest month has an average temperature under 26.6oF. Average temperature of warmest month is above 50oF.

E–Polar Climates: The average temperature of warmest month is blow 50oF. The climates have no true summer.

Four of these five groups (A, C, D and E) are defined by the temperature averages, whereas one (B) is defined by the precipitation to evaporation ratios. This procedure may seem to be of fundamental inconsistency. Groups A, C and D have sufficient heat and precipitation for both of high trunk trees, e.g., forest and woodland vegetation.

Sub-Groups

Sub-groups within the five major groups are designate by a second letter, according to the following codes:-

S – Steppe Climate: A semi-arid climate with about 15-30 inches (38-76 cm) of rainfall annually at low latitudes.

W – Desert Climate: Arid climate. Most regions included have less than 10 inches (25 cm) of rainfall annually.

The letters S and W are applied only to the dry B climates, yielding two combinations – BS and BW.

f:- Moist. Adequate precipitation in all months. No dry season. This modifier is applied to A, C and D groups, yielding combinations – Af, Cf and Df.

w:- Dry season in the winter of the respective hemisphere (low sun season). This modifier is applied to A, C and D groups, yielding combinations – Aw, Cw and Dw.

s:- Dry season in the summer of the respective hemisphere (high sun season).

m:- Rainforest climate. Despite short, dry season in monsoon type of precipitation cycle. Applies to only A climates (Am).

Types of Climates

From the combination of the two letter groups, twelve distinct climates emerge as follows:

Tropical Rainforest Climate (Af): Rainfall of the driest month is 6 cm or more.

Monsoon variety of Af (Am): Rainfall of the direst month is less than 6 cm. The dry season is strongly developed.

Tropical Savanna Climate (Aw): At least one month has rainfall less than 6 cm. The dry season is strongly developed.

Steppe Climate (BS): A semi-arid climate characterized by grasslands. It occupies an intermediate position between the desert climate “BW” and the more humid climates of A, C and D groups.

Desert Climate (BW): An arid climate with annual precipitation usually less than 40 cm.

Mild Humid Climate with no dry season (Cf): Temperate rainy climate, moist in all seasons. Precipitation of the driest month averages more than 3 cm.

Mild Humid Climate with a dry winter (Cw): Temperate rainy climate with dry winter. The wettest month of summer has at least 10 times the precipitation of the driest month of winter or 70% or more of the mean annual precipitation falls in the warmer six months.

Mild Humid Climate with a dry summer (Cs): Temperate rainy climate with dry summer. Precipitation of the direst month of summer is less than 3 cm. Precipitation of the wettest month of winter is at least 3 times as much as that of the driest month of summer or 70% or more of the mean annual precipitation falls in the six months of winter.

Snowy Forest Climate with a moist winter (Df): Cold snowy forest climate with moist in all seasons.

Snowy Forest Climate with a dry winter (Dw): Cold snowy forest climate with dry winter.

Tundra Climate (ET): Mean temperature of the warmest month is above 0oC, but below 10oC.

Perpetual Frost Climate (EF):Ice-sheet climate. Mean monthly temperatures of all months are below 0oC.

Further Variations

To differentiate more variations in temperature or weather elements, Koppen added a third letter to the code group. Meanings are as follows:
a: With hot summer; warmest month over 71.6oF. Used for C and D climates.
b: With warm summer; warmest month below 71.6oF. Used for C and D climates.
c: With cold, short summer; less than 4 months over 50oF. Used for C and D climates.
d: With very cold winter; coldest month below –36.4oF. Used for D climates only.
h: Dry, hot; mean annual temperature over 64.4oF. Used for B climates only.
k: Dry, cold; mean annual temperature under 64.4oF. Used for B climates only.

REGIONS
The Equatorial Climate, as its name implies, occurs as a belt on either side of the equator, normally extending roughly between 5o North and South. On the windward margins of the continents, this type of climate may spread to even 10o or 25o latitudes. Its representative regions are the Amazon Basin, the Congo Basin, the Guinea Coast, East Indies and some portions of the coastlands of tropical Asia. In other words, we can say that those parts of South America, Africa, West Malaysia and Indonesia which lie close to the equator, experience equatorial climates.

TEMPERATURE
This climatic region is the area of greatest insolation, and due to cloudy atmosphere the loss of heat is very small. Therefore, there is a uniformly high temperature and the seasonal variation/range is practically nil. The mean annual temperature is between 26oC (78oF) and 27oC (80oF); the range between the hottest and the coldest months is typically less than 5oF. The sun is always shinning vertically overhead, but the daily range of temperature is from 10o to 25oF, which is far greater than the annual range of temperature. The nights are quite cool and the lowest temperatures in equatorial zones are experienced during the nights so that they are often termed as the winter of the tropics. Rapid cooling during the nights bring out fog and dew. The heat of this region is damp and steamy.

WINDS
In the absence of powerful gradient of pressure, there is very little air movement and this combined with high relative and absolute humidity (over 80%), brings about oppressive and sultry (hot & humid) weather conditions. Near the sea, land and sea breezes bring a great relief and the cool “Harmattan Wind”, blowing on the Guinea Coast, is significantly called the “Doctor”.

RAINFALL
The rainfall is heavy and well distributed throughout the year. The average rainfall is in the neighborhood of 60-100 inches. It is more on the oceans than on the continents, and more in the afternoon than in any other part of the day. It is convectional in nature and the cloudiness is as high as 58%. It is accompanied with thunder and lightening. In this region, the rainfall follows the sun and accordingly, there are two maximas (April & October – Equinoxes) and two minimas (June & December – Solstices) in a year.
The double rainfall peaks coinciding with the equinoxes are a characteristic feature of equatorial climates. However, this pattern may be upset by local conditions. Going from equator to north or south leads to a monsoonal pattern with the heaviest rainfall coming in summer months in the north and winter months in south.

SOIL
Soils of these regions are generally infertile LATERITES (large concentrations of iron, manganese or aluminum minerals occurring as lenses or layers in the soil). Considerable rainfall causes leaching of the soil, while due to intense heat, the rock material does not decay well. At the prevailingly warm temperatures, bacteria in the upper soil layer are usually vigorous and consume virtually all dead vegetation. Thus humus (fertilizer) is almost entirely absent on well-drained sites.
Leaching out of all soluble constituents of the deeply decayed rocks results in a distinctive type of soil termed as “LATOSOL”. Reddish or yellowish, and often containing irregular nodules (lumps) of reddish iron hydroxides, this soil is specially rich in hydroxides of iron, manganese and aluminum.

NATURAL VEGETATION
The prevailing high temperatures, heavy rainfall and high humidity, all contribute to the distinctive vegetation of this region – the Equatorial Rainforest or SELVAS. The plants are hygrophytic, and occupy vast regions in the Basin of Amazon in South America and in that of Congo in Africa.
These regions contain some of the largest areas of purely natural vegetation left in the world. The trees are deciduous (trees that loose their leaves every year) but all do not shed their leaves at the same time. The lack of distinct seasons induces a peculiar regime of flowering, fruiting, budding and shedding of leaves, because all are going on at the same time on adjacent trees. Each tree has its own growth cycle.
There are many different kinds of trees in every square kilometer of Equatorial Rainforest. Stands of single species do not occur naturally, as they do in Temperate Forests. Equatorial Forests are dense and the trees are tall, often rising to more than 60 meters. There is little undergrowth except in clearings and along the banks of the rivers. Parasitic plants, such as Orchids grow on trees as do creepers, like the long rope-like Lianas, which may reach down the ground.
The root system of the trees is shallow, but many of the tallest trees have buttress roots to give them additional support. Most of the trees are hard wood, such as Mahogany (chestnut), Ebony (black tropical wood), and the Rubber Tree, though the well-known softwood, Balsa also comes from the Equatorial Forest.

ANIMALS
Quite suitable to natural vegetation, rainforest is the home of small forest animals, of which the monkeys are perhaps the best representatives, taking advantage of the continuous forest canopy for living and traveling. Birds too are numerous and are spectacularly plumaged (ornamented with feathers). There is, also, a large number of poisonous insects. The Tse-Tse fly of Congo Basin is quite well-known.

MINERALS
There are large concentrations of iron, manganese or aluminum minerals occurring as lenses or layers in the soil and are termed as LATERITE. These minerals may be extracted as ores of commercial value.

RUNOFF SYSTEM
Stream flow tends to be fairly constant and extremely copious (extensive) because a large water surplus exists throughout much of the year and provides ample water runoff. River channels are lined along the banks with dense vegetation. Sandbars or sandbanks are not so conspicuous (noticeable) as in drier regions. Flood plains have meanders (complexities) and many swampy sloughs (swamps, lowlands) where the river channels have shifted their courses. Although water is abundant, river system such as Amazon carries relatively little material in chemical solution.

TRANSPORT
Transportation is by rivers whose broad courses can be utilized by dug-out canoes or shallow-draft river crafts. The use of light aircraft has, however, greatly simplified long distance transportation.

SLOPES
Hilly or mountainous belts have very steep slopes, on which flows, slides, and avalanches of soil and rock frequently occur, stripping away forest and soil down to the bedrock.

FOREST PRODUCTS
Of economic importance are several forest products. Rainforest lumber (timber), such as Mahogany, Ebony or Balsa wood, is a valuable tropical product. Quinine, cocaine, hemp (marijuana) and other drugs come from the bark and leaves of tropical plants; cocoa comes from the kernel (seed) of the cacao plant. Rubber, made from the sap (plant fluid) of the rubber tree is now largely an economic product. Cassava (a type flour made from the thick roots of the tropical plants), sago (hard white grains made from the soft inside of a type of palm and usually cooked with milk like pudding), kapok (substance similar to cotton) are also among the forest products of this region.

AGRICULTURE
Agriculture is generally backward and based on the method of shifting cultivation, known in the different parts of the world’s Equatorial Forests as Ladang, Milpa and Swidden Cultivation.

PEOPLE
These regions are very sparsely (thin and scattered) populated and natives of this region are stunted (not growing properly) both physically and mentally. The Pygmies of Congo Basin are the most backward and primitive. In East Indies, Guinea Coast and Tropical Asia, the clearing is easy and more population is found here. The density of population is greater on the sea coasts. Malayans, Javanese and Dykas Borneo are quite sturdy (muscular) though lazy.

IMPORTANT TOWNS
In these regions the most important towns are those which are situated on the sea and where collection of products of these areas can be done. Singapore, Colombo (Sri Lanka) and Para (Brazil) are the three most important towns in order of importance.

COMMERCIAL PRODUCTS
The chief commercial products of these regions are cocoa (Ghana & Ivory Coast), coconut palm, banana, pineapple, coffee, rice and certain kinds of millets (grains) etc.

OCCUPATION AND INDUSTRIES
Ivory collection and hunting in Congo Basin, rubber collection in the Amazon Basin, and plantation or agriculture in Indonesia (Java) and Tropical Asia (Sumatra) are the main occupation of people.
Because of certain difficulties (inaccessibility and unwholesome climate), industrialization of these areas is not possible. There is a lack of mineral wealth as well. The only two minerals so far known to exist in Asiatic Equatorial Belt are Petroleum and Tin. Copper is mined in Congo Basin. These regions are, therefore, called “Regions of Debilitation (exhaustion) and Retarded Growth”.

SAVANNA-SUDAN TYPE OF CLIMATE-TROPICAL GRASSLAND TYPE

INTRODUCTION
The desert belt of the tropics shifts south in winter and the equatorial rain belt shifts north in the summer. In between is the Savanna belt with winter droughts and summer rains. This type of climate is found on both sides of the equatorial belt and is also known as the “Sudan Type” or “Tropical Grassland Type” or “Parkland Type”. It has less precipitation and there is a distinctly dry and wet season. Accordingly, in these regions tall and dense forests are replaced by large grass interspersed with trees.

REGIONS
The Savanna, sometimes called the Sudan Climate, is to be found on the outer margins of the equatorial regions in South America and Africa, and in Northern Australia, just inland of the coast. The regions of this climate occupy a transition belt between the Desert Climates on the one side and the Rainforest Climate (Equatorial) on the other. Roughly, it extends between the latitudes of 5o and 15o around the equatorial belt. The characteristic regions of this climate are the Llanos del Orinoco Plain in Venezuela and Columbia (South America), the Campos of Brazil (East of Brazil), the Sudan of Africa, and the tropical grassland of North Australia.

TEMPERATURE
These regions have sufficiently high temperature, although in the wetter southern belts, the temperature is little low, while in the drier strip (north), the temperature is a bit higher. Average temperatures are high throughout the year, generally exceeding 25oC (77oF). The range varies from 10oF in wetter parts (forest) to 30oF in drier parts (desert). Clear skies promote intense heating during the day and rapid radiation during the night, causing a drop of temperature down to 10oC (50oF).

SEASONS
This type of climate region has three distinct regions:
1. The cool dry season, which coincides with the low sun;
2. The hot dry season, which precedes the high sun but occurs just before the start of rainy season; and,
3. The hot wet season.
During the cool dry season, the temperature often rises to 32oC (90oF) in the afternoon but humidity is low and hence the heat is very oppressive. The hot dry season has a maximum temperature in the neighborhood of 38oC (100oF). The climate is very much like that of the Equatorial Climate.

WINDS
This climate region lies in the Trade Wind Belt and constant, strong winds are the rule in many areas. The north-east trade winds, infact, reach the Guinea Coast as dry, dust-laden winds called the Harmattan (Doctor).

RAINFALL
Trade winds bring rain to coastal areas. Interiors or western coasts receive little rain The amount of rainfall is between 70 to 80 inches on the forest side, while it is 10 to 15 inches only on the desert side. Mostly the rain falls during the spring and the summer months, while the winter months remain absolutely dry. On the equatorial margins, the rain remains for almost the whole year and the dry season is very short. But as we move towards the desert border, the dry season goes on becoming longer.

SOILS
Soils of the Savanna Climate are mostly yellowish or reddish LATOSOL. Excessive leaching is the result of the heavy rainfall and high temperatures. In general, these soils are not fertile and are little cultivated in South America and Africa.

RUNOFF
From flood conditions with extensive low-lying areas under water in the rainy season, the streams pass to a region of little or no flow in the dry season, when the channel bottoms of land and gravel are exposed and mud flats dry.

VEGETATION
The vegetation changes gradually from the SELVAS (Equatorial Rainforest) of equatorial regions, to become thinner and more open as a dry season becomes apparent. Trees only grow along the banks of water courses and on the windward slopes of the hills. Elsewhere, there is coarse grassland, which merges into scrub and eventually into desert. The vegetation is known as TREE SAVANNA where trees are dotted evenly over a grassland area.
Typically, the Savanna is made up of coarse, tropical grass with scattered trees and damp areas. At the end of the dry season, the vegetation is brown and the soil is parched (dried out). With the first rains of the wet season, new grass grows rapidly, sometimes to a height of over 2 meters. Trees come into leaf and flowers bloom.
At the end of the wet season, the trees begin to loose their leaves and the land again dries out. The only trees able to survive in this climate are those which are, in varying degrees, Xerophytic. The Baobab, Acacia (long roots) and Australian Gum Trees are typical examples of such vegetation.
Away from the equator, where the wet season becomes shorter and the annual rainfall is scarce, trees disappear and even grass becomes short and touchy. Bunch grass appears, with areas of bare rock or dry soil between the tufts (bunch, lumps) of vegetation.

ANIMALS
Closely related to the vegetation and climate is the natural animal life of the Savanna grassland and woodland. These are the regions of carnivorous game animals and a vast multitude of grazing animals on which they feed.
The grasslands of Africa are the natural home of such herbivores such as gazelle (a small antelope), deer, antelope, buffalo, rhinoceros, zebra, giraffe, and elephant. On them feed the lion, leopard, hyena and jackal.
The Indian Savanna woodland and thorn forest have a somewhat similar assemblage. Deer and antelope are specially abundant, with some water buffaloes and a few rhinoceroses. The tiger replaces the lion as the principal carnivore. The Indian elephant is, however, largely restricted in natural habitat to the rainforest coastal strips of Burma, the Malabar Coast, and Sri Lanka. The giraffe is a peculiar adaptation to Savanna woodlands; its long neck permits browsing upon the higher foliage of scattered trees. National parks have also been established around these regions.

HUMAN LIFE
Many tribes either rear cattle or are nomads.
The Masai – Cattle Pastoralists
1. Nomadic in Kenya and Tanzania
2. Move up and down the east African Plateau, according to the conditions
3. Circular huts, fences for cattle
4. Cattle called ZEBU – kept for milk and blood
5. Reluctantly trade their cattle for millet, bananas, groundnuts and vegetable
The Hausa – Settled Cultivators
1. Northern Nigeria (Kano), settled and advanced
2. Land clearing for agricultural crops like; maize, millet etc.
3. Rotation of crops
4. Cattle and goats for milk and meat; chicken

DEVELOPMENT
1. The Savanna with annual rainfall of 30 inches should be able to support many tropical crops.
2. Immense potential for plantation of cotton, sugarcane, coffee, oil palms, ground nuts fruits.
3. Kenya, Uganda, Tanzania have started large scale production of cotton and sisal hemp. Other crops are ground nuts, cocoa, oil palm etc.
4. Temperate crops in cooler highlands.

PROBLEMS
1. Leaching due to torrential heavy rains
2. Poor laterite soil
3. Cattle fall victim to NGANA or sleeping sickness due to tsetse fly
4. Animals are bony so export of beef or milk is not possible
5. Long and tiring droughts
6. Conservative Masai people

ECONOMIC ACTIVITIES
Cattle rearing is an important activity in many areas of Savanna. Commercial cattle herding is found in parts of South America – the Llanos del Orinoco of Venezuela and the Campos of Brazil – and also in Northern Australia. Subsistence cattle farming is important in parts of Africa – Mali, Niger, Chad, Sudan, Kenya, Tanzania and Zambia – but large areas are infested with Tse-Tse Fly and cannot, therefore support cattle. Some areas of Savanna are highly suitable for coffee growing or for the cultivation of sugarcane and ground nuts.

PROSPECTS
1. Counter measures like adequate irrigation, improved crop varieties, scientific techniques
2. Conservation of soil; through regular maneuvering, weeding and careful maintenance
3. Introduction of temperate cattle, such as English Short Horn to cross with tropical Zebu
4. A better network of communication
5. Scientific cattle breeding and disease control

INTRODUCTION
The monsoon regions occupy eastern coast within the latitudes of Savanna type. The climate of these regions is dependent on and is an outcome of the change in prevailing wind system in rainy season. The most important season of this climate is the rainy season and the general characteristic of the climate is very much the same as the that of the Tropical Savanna Type, except that the rainfall is caused in a different manner. The warm wind season coincides with the period of onshore winds, while the period of offshore winds is the cold, dry season.
The typical monsoon lands are the sub-continent of Indo-Pakistan, peninsula of Indo-China and southern parts of China, central and Northern China and Japan are often called “Monsoon Lands”.

REGIONS
The Monsoon Climate occurs around the Indian Ocean, specially in India and Pakistan, Bangladesh, Burma, Laos, Vietnam, Indo-China, North Western Australia and part of the East African Coast.
A monsoon effect is also found on the coastal margins of north-western South America (Pacific Coast of Columbia), eastern Brazil, and Central America, whilst much of the heavy rainfall of the Guinea Coast of West Africa might be described as monsoonal.

TEMPERATURE
The monsoon lands are characterized by hot summers and warm winters. But the rainfall affects the temperature distribution in the lands. The temperature is uniformly high throughout the year and the highest temperature is 29oC (85oF) to 35oC (95oF), just before the rainy season. There is a great annual and diurnal range. The drier areas have a greater range of temperature, e.g., Punjab (northwest India) or Lahore (40oF) than those which are wet or near the sea, e.g., Bombay (10.1oF). The Monsoon Climate is characterized by high temperatures when the sun is overhead, but lower temperatures when the sun shines from a lower angle.

SEASONS
In monsoon lands, there are three distinct seasons:
1. Cold season, with little rain, which lasts from October to January;
2. Hot season, when the land is heated up and there is no rain, which extends from February to May; and
3. Rainy season, when the heavy rain cools the atmosphere, and the temperature is lower, which lasts from June to September.
In typical monsoon areas, such as the West Coast of India, the cooler season (October to January) is dry, sunny and warm, with temperature averaging 20o to 25oC. Spring (from February to May) becomes gradually hotter as the sun’s angle in the sky increases and daytime temperatures of upto 40oC may be recorded. The heat is almost suffocating towards the end of the hot season, and everyone waits and longs for rain. The monsoon breaks sometime in June, when warm and humid air comes in from the India Ocean. Banks of heavy clouds form over the coast and become lower and thicker; the rain pours down continuously for days, even weeks. During the rainy season (June to September), the temperature drops noticeably to an average of about 20oC as the dense cloud cover excludes the direct rays of the sun.

RAINFALL
Rainfall is strongly seasonal. In the monsoon climate rainfall depends upon:
1. The direction and force of onshore winds, called Monsoons;
2. The relief of the land; the heaviest rainfall being on the coasts and slopes of mountains; and,
3. The angles at which the onshore winds reach or strike the coast.
The rainfall of the Monsoon lands comes in heavy downpours and its chief characteristic is that it is irregular and uncertain, both in time and space. Hence, famines and floods are the calamities common to these lands. It is in these places that the average rainfall at certain places is over 400 inches. But normally the rainfall distribution is such that four types or belts can be demarcated out of them:
1. over 80 inches – areas which are normally covered with evergreen forest of equatorial type;
2. those that receive between 40 and 80 inches – areas where the deciduous monsoon forests flourish, the trees loosing their leaves in the hot, dry season;
3. those that get between 20 and 40 inches – covered with scrub land and thorn forest, and
4. those that get less than 20 inches of annual rainfall – forming deserts and semi-deserts.
The rain brought to northern Australia is not as heavy as that brought by the Northern Hemisphere monsoon. This is chiefly because the Australian low pressure system is less intense than the one over Asia, but it is also the result of the flatness of the northern Australian coastlands. Rainfall is particularly heavy on high hills or mountains lying athwart (across) the onshore winds, as in the Western Ghats of the Southern India, the mountains of Burma and above all the foot hills of the Himalayas and the mountains of Assam, where they lie behind the Bay of Bengal. The highest rainfall ever recorded occurred at Cherrapunji. In one year it received 896 inches of rainfall, and its average annual rainfall is 432 inches.
Apart from these areas of high ground, rainfall normally decreases further inland: Calcutta has 64 in., Allahabad 42.5 in., Kanpur 33 in., New Delhi 25.4 in., and Lahore has 20.5 in.

LATE ARRIVAL OF MONSOONS
In most parts of these regions, there is actually a date when monsoon is expected to arrive. Occasionally it becomes late, and this is serious, not only because water supplies are exhausted, but also because the farmer is waiting to sow his crops, specially rice. Late sowing means a late and perhaps a less plentiful harvest. Hundreds of millions of peasant-farmers in India and South-East Asia await the arrival of monsoons, knowing that famine may follow if it is late. All times the monsoon fails completely, and this causes great distress and wide spread famine in the subsistence (existing) farming communities throughout South-East Asia.

PRESSURE SYSTEM
The effect of the monsoon is felt most strongly near the coast. Its cause lies in the seasonal changes in atmospheric pressure over the continental interiors of Asia and Australia. In June, with the sun overhead at the northern tropic, there are large low pressure systems over Central Asia and the Sindh Desert in northwestern India. These pressure systems attract warm, very humid air from adjacent sea areas. At the same time, a high pressure center develops over central Australia giving rise to out-blowing winds and dry conditions along the north coast. Six months later, in December, the positions are reversed because the sun is overhead at southern tropic; high pressure over Central Asia and Sindh Desert now gives rise to out-blowing winds but, with low pressure over the heart of Australia, onshore winds bring monsoon rain to the northern coastlands there.

WINDS
The Monsoon Climate is characterized by seasonal reversal of wind direction associated with alternating periods of rainfall and drought. During the summer season, humid unstable air moves from the ocean. Conditions are, therefore, conducive to rainfall. In winter, a dry wind originating over the land blows towards the seas.
The monsoonal circulation system having reversal of wind direction develops in response to the differences in annual temperature variations between continents and oceans. During summer, the intense heating of Central Asia produces an area of a very low pressure, whereas in the Southern Hemisphere there exists a sub-tropical high pressure over the oceans. The south-east trades flow from the high pressure to the low pressure area and are deflected to the right and reach India and South-East Asia as onshore south and southwesterly winds. These winds are laden with moisture and, therefore, cause heavy rainfall in these parts of the Asian continent. The reversal of the winds and the arrival of the rain is known as the “Break of the Monsoon”.
During winter, the excessive cooling in Central Asia intensifies the high pressure belt and the offshore northeast trades blow over South-East Asia. Due to the presence of the Himalayas, these cold winds are prevented from descending into the Indian peninsula. Temperatures are low during this season.

SOILS
These regions are overlaid with rich alluvial soil which is renewed after every flood. Although this soil lacks humus and suffers from “Reh” in certain patches, it is quite deep and fertile. At places, soils rich in lime and phosphorous are found.

VEGETATION
The natural vegetation of the tropical monsoon climate is forest or woodland, and that the resting season is the hot, dry period of the year. It is at that time that the trees need to guard against excessive loss of temperature, and most of them do so by shedding their leaves (deciduous).
Rainfall determines the vegetation. In areas where rainfall is over 80 inches in a year, luxuriant evergreen forests are found. In regions having 40 to 80 inches annual rainfall, true monsoon forests occur. As rainfall declines further, the forest land passes into shrubby growth separated by patches of grassland.
The natural vegetation in the areas of heaviest rainfall is not unlike that of the equatorial region. But the forest is less dense than the SELVAS and the trees are of different types, because the plants have to survive a dry season in the monsoon forest. Areas with a lower rainfall have a sparser (scanty) vegetation, such as drought resistant thorn forest.
The natural monsoon forest is found in the mountains of Burma, Thailand, Laos and Vietnam, as well as along the parts of north Australian coast.
Monsoon forests present a more open tree growth than the Equatorial and Tropical Rain Forests. Consequently, there is less competition among trees for light, but a greater development of vegetation in the lower layers. Maximum tree heights range from 40 to 100 ft. Many tree species are present and may number to 30 to 40 species in a small tract (area, region). Tree trunks are massive; the bark is often thick and rough. Branching starts at comparatively low levels and produce large round crowns. Perhaps the most important feature of the monsoon forest is the deciduousness of most of the tree species present, e.g., the abundance of Tropophytes.
The shedding of leaves results from the stress of a long dry season which occurs at the time of low sun and cooler temperature. A representative example of a monsoon forest is the Teakwood tree. Other important trees are Sal and Sandalwood.
The long rope-like Lianas, which may reach down the ground and Epiphytes are locally abundant in Monsoon Rainforest but are fewer and smaller than in the Equatorial Rainforest. Undergrowth is taken as a dense shrub thicket (brush, undergrowth). Where second-growth vegetation has formed, it is typically a jungle. Clumps (bunches) of Bamboo are an important part of vegetation in climax Teakwood Forest.
Monsoon Forest is a response to a wet-dry tropical climate regime in which a long rainy season with a large total precipitation alternates a dry, rather cool season. Perhaps the type regions of Monsoon Forests are in Burma, Thailand and in Cambodia. Areas of Monsoon Forests or related types are also described in Indonesia (specially Java and Celebes), in northern Australia and in western Madagascar.

AGRICULTURE
The monsoon climate is very favorable to the growth of food crops which, like the natural vegetation, vary with the rainfall.
Rice and sugarcane are the characteristic crops of the wetter parts; millet, sesamum and cotton of drier parts, whilst wheat and barley flourish as winter crops in the cooler, drier regions. Maze and various oil seeds flourish in the intermediate areas. Sometimes two crops can be taken in a year and occasionally three.
Much of the Monsoon Forest has been cleared and the land brought under cultivation, specially in India, Pakistan and Bangladesh.

ANIMALS
The animals common to these regions are generally the vegetation-eating cattle, buffalo and elephants. But the flash eating wild beasts are also found in denser forests.

PEOPLE
The monsoon lands are amongst the most densely populated in the world. One-forth of the population of the world is found in these regions. The population tending to be largely agricultural is concentrated in those areas where the soil is richest. This is why the northern region of Australia is not so developed as India, Burma or south China.

ECONOMIC ACTIVITIES
Agriculture remains the most important occupation of the people because of the following favorable factors:
1. Fertility of the soil;
2. Suitable temperature throughout the year;
3. Facility for irrigation; and
4. Pressure of population on land.
Hence both temperate and tropical crops are cultivated. Rice, wheat, beans, cotton, sugarcane, oil seeds are the main crops, while it has a monopoly in Jute (bark of tree used to make rope or cloth) and Tea. As the soil is deep and fertile, comparatively little effort is needed to bring an abundant return in these regions; therefore these are known as “Regions of Increment”.
Forests are not an important source of timber, the only important trees being Sal, Shesham and Teak in India and Granchaco in South America. The secondary products like oils, gums, resins, lace etc. are more important.
Grasslands are not permanent, nor do they have any good quality of grass. Hence cattle rearing is not important.
These regions have vast and varied natural resources but due to skilled labor shortage, poor transportation facilities, and distance from the market, not much industrialization has been possible.

MEDITERRANEAN CLIMATE

INTRODUCTION
The rainy belt of prevailing westerlies shifts south in winter and the desert belt of the earth shifts north in summer. In between is the Mediterranean Belt with cool, rainy winters and hot, dry summers.
As its name indicates, it represents the climate that prevails around the Mediterranean Sea. Mediterranean Climate is one of the most distinctive climates in the world. It is named after that part of the world where it is more extensive, but it is also found on the west coasts of North and South America, in South Africa and in south-westerly parts of Australia. Thus there are regions with a Mediterranean Climate on the western sides of land masses between 30o and 40o north and south of the equator.

CAUSE OF THE CLIMATE
The cause of this climate in the regions around the Mediterranean Sea is the movement of the sun, north and south of the equator, a fact which also causes a shift in the wind belts. The result is that certain parts of the earth in summer, roughly betwe en latitudes 30o and 45o on both sides of the equator, are in the Trade Wind Belt, or more correctly in the High Pressure Belt from which the Trade Winds arise. Like the hot deserts which border them on the side nearer the equator, these regions are hot and dry in the summer, with out blowing winds. In winter, however, these regions come under the depressions of the westerly wind belt and so enjoy moist, mild winters. An important characteristic of this climate is that it is a Mid Latitude Climate and essentially cooler. Another characteristic of the Mediterranean Climate is the large amount of sunshine. Almost cloudless skies are the rule in summer, and even in winter clouds are less numerous than would be expected.

REGIONS
This climate is found along the west coasts of continents between 30o and 45o latitudes. It is bounded by Arid Steppe (grassland) on the equatorward side and the Marine West European Climate on the poleward side. The largest area of Mediterranean Climate is that found all round the Mediterranean Sea: North America (Central California), South America (Central Chile), South Africa (southwest of Cape Province), and southeastern (Victoria) and southwestern parts of Australia. But except the land surrounding the Mediterranean Sea, where this climate extends for 2,000 miles inland, nowhere else does it extend so much.

CLIMATE
It is a transition type between the hot deserts on the south and cool temperate regions on the north. Due to the shift of wind belts, these regions join with the hot deserts during summer and come under the influence of cyclones of Humid Middle Latitudes. In the summer months, these regions are hot and dry like the hot deserts that lie to their south and winds are blowing out from them. During winter months, they are under the influence of cyclones brought by westerlies and enjoy changeability that accompanies them.
The following are the chief characteristics of the climate of these regions:
1. Wet and mild winters;
2. Warm or hot and dry summers;
3. A high percentage of sunshine and a large number of cloudless days;
4. Irregularity of showers; and,
5. Variation due to proximity to sea, or location in the interior of the continent or due to the situation of mountain barrier.
In areas of this climate, which lie near the deserts, the drought period is long and more intensive, while near the poles it is much shorter. In Palestine, the dry period is of six month duration, while in Greece it is of only one month. The general characteristics are also modified by the nearness to the sea. Those having marine location have a greater rainfall, while as we move into the interior, it gets lesser and lesser.
The regions of this type of climate which are situated on or near the sea have the equable influence of the sea and offshore currents. The result is that summers are cool, fogs are frequent and the month of maximum heat is retarded to August. The waters are unusually mild and free from frost. Both the annual and diurnal range of temperature is quite small.
On the other hand, regions of the climate situated away from the shores into the interior of the continents, have extremes of temperature and although winters are still mild, the summers are better and the annual range may be 15oF or more.
The presence of mountain chains acts as a barrier which checks the influence of this climate from reaching inland and creates dry pockets on their leeward side.

TEMPERATURE
The temperature of these areas is quite irregular due to cyclonic visits and is greatly modified by nearness to desert or cool temperate regions of the sea. Temperature is also affected by the prevalent winds – cool from the poleward side as the Bora in Europe and hot from the desert margins known as Sirocco in the peninsula of Italy. The average winter temperature ranges from 2oC (35oF) to 10oC (50oF), while the summer temperature may be from 27oC (80oF) to 38oC (100oF). The annual range is in the neighborhood of 20oF to 30oF.

SEASONS
There are two seasons – a short, mild, wet winter season and a long, dry, hot summer season.
In the summer months, the days are very warm but not sultry (hot & humid). The weather is not oppressive or muggy. The sky is clear and atmosphere is dry. This favors great heating during the day and rapid cooling at night. The nights are damp and chilly and early in the morning it is quite fogy.
The winter season is generally of three months duration and although the temperatures are not very low, frosts may occur on the poleward margins. During winter months, mid day temperatures may rise from 13oC (55oF) to 16oC (60oF), but the night temperatures may be 4oC (40oF). If the region is situated in the interior of the continents, the average temperature is -12oC (10oF) to -7oC (20oF) above the freezing point.

HUMIDITY
Relative humidity is generally low but varies during the 24 hours because the temperature rises during the day and falls considerably at night.

WINDS
The regions of Mediterranean type of climate are always under the influence of variable winds and are always visited by exotic winds – cold and dry like Bora and Mistral in the winter and hot and dry like the Sirocco in the summer. Winds of this type are common to all regions of such climate, the only difference is that their strength and frequency varies from place to place.
During the summer months, the prevailing winds are from north, while during the winter, the winds are westerly and southerly, although on the approach of cyclonic storms it changes and veers (deviates, diverges). On the coasts, the land and sea breezes are very dominant.

RAINFALL
The Mediterranean Climate is unique in being the only climate with seasonal rainfall to have summer drought. All other climates with seasonal rainfall have their wet period in high sun or summer season. This has a major influence on vegetation.
The average rainfall of these regions is quite moderate, less than 15 to 25 inches on an average. The rain falls mostly in the winter months and the summers are dry. All the rain, that comes, is cyclonic in nature and gradually increases in amount as we proceed from equator towards the poles. Snow is very rare.
Winter is, no doubt, a season of rains but the number of cloudy days is quite small and the season is rarely dull or gloomy. During summers, the days are periods of brilliant sunshine and the skies are cloudless. There are no thunder storms or storm clouds.

LAND FEATURES
The regions having Mediterranean Climate have very little low land areas. They are all narrow strips of land near the sea and hemmed (bordered) in by the chain of mountains. There are narrow river valleys and the mountains either run parallel to the sea course or at the right angles to it.

SOILS
Soils of the Mediterranean Climate are not readily subject to simple classification. The dominant soil of this region is course and sandy although alluvial patches occur here and there on coastal plains. Reddish-chestnut and reddish-brown soils, typical of semi-arid climates, are generally present. In the Mediterranean lands TERRA ROSA, a red soil formed on lime stone, occurs in various locations.

NATURAL VEGETATION
The occurrence of a wet winter and the dry summer is unique among climate types and results in a distinctive natural vegetation of hard leafed evergreen trees and shrubs, known as “SCLEROPHYLL FORESTS”.
The Mediterranean plants grow through the winter, flower in spring, fruit in early summer and remain dormant (inactive) during the intense drought which they are specially adopted to with stand.
Sclerophyll Forest, also termed as Evergreen Hardwood Forest, consists of low trees, with small hard leathery leaves. Typically the trees are low branched and gnarled (twisted) with thick bark. The formation class includes much woodland, an open forest in which the canopy coverage is only 25% to 60%. Also included the extensive areas of Scrub, a plant formation type consisting of shrubs and having a canopy coverage of perhaps 50%. The trees and shrubs are evergreen, their thickened leaves being retained despite a severe annual drought. There is little stratification (division of something into layers) in the Sclerophyll Forest and Scrub, although there may be a spring herb layer.
In Mediterranean lands the hardwood forest forms a narrow peripheral coastal belt. Here the woodland consists of such trees as Cork, Oak, Live Oak, Aleppo Pine, Stone Pine, and Olive. What may have been luxuriant forests of such trees were greatly disturbed by man over the centuries and reduced to woodland or entirely destroyed. Instead, large areas consist of dense scrub termed Maquis which includes many species, some of them very spiny (thorny).
The other Northern Hemisphere region of Evergreen Hardwood Forest is that of the California Coast Ranges. Some of this is a woodland composed largely of the Live Oak and White Oak. Much of the vegetation is Scrub “Dwarf Forest” known as “Chaparral” (undergrowth), which varies in composition with elevation and exposure. Chaparral may contain Wild Lilac, Manzanita, Mountain Mahogany, Poison Oak, and Live Oak.
The Evergreen Hardwood Forest is represented in Central Chile, and in the Cape Region of South Africa by a Maquis-like scrub vegetation which is, however, of quite different flora from those of the Northern Hemisphere. Important areas of Sclerophyll Forest, woodland and scrub are found in south-east, south-central, and south-west Australia, including several species of Eucalyptus and Acacias.

ANIMALS
According to the vegetation, the chief animals of this area are goats and sheep, which thrive better than horses and cattle. In wetter regions horse is the draft animal, while in the drier parts mule does that work. Hen and chickens also thrive very well.

AGRICULTURE
The natural vegetation has been cleared to make way for agriculture over large areas, specially in countries where there is a long history of human settlement, such as Italy and Greece. The climate is well suited to crop-growing, even in winters, because the temperature rarely falls below the critical point of 3.5oC, at which plant growth generally ceases. Fruit trees are an important cash crop, particularly the Grape-Vine, Orange, Lemon and the typical plant of the Mediterranean Region, the Olive, Cereals, mainly Wheat and Maize, are grown only as a subsistence crop by the peasant farmers.

ECONOMIC ACTIVITIES
Because of good soil, warm temperatures, and facilities for irrigation, the main occupation of this area is agriculture. While wheat and barley are the cereal crops of this region, grown for home consumption. The tree crops are more important from commercial standpoint and are meant for foreign market. Olive, Vine, Lemon, Mulberry, Figs, Oranges, Peaches and Plums are very important. The tree crops are most important in Europe and California. Besides fruit growing, vegetable gardening is also important. Drying of fruit is also practiced due to a large number of bright sunny days.
The olive tree yields oil which has led to soap making industry. The Mulberry tree and its leaves rear silk warms, which make these regions the center of silk manufacture. The grapes yield vine, which is the nucleus of vine producing industry. Except these, the industrial development of these regions is very much retarded. Italy is industrialized because it can easily get coal from the continental mines. The African and Australian regions have facilities for importing coals, but due to sparse (scattered) population, they remain backward. Hence the tree crops are exchanged for manufactured goods from outside.
The other important occupation of the people is stock-raising, which is practiced on the slopes of mountains or on the grasslands available on the deltas made by the rivers. But due to lack of urban population and want of large industrial cities, dairy or meat industry has not developed very much. Poultry raising is, however, very important and the low humidity combined with a long growing season favors it. In California it is most widely developed and poultry farms are run on the factory systems. In the southern part of California and the Mediterranean region of Australia, dairy farming has developed into one of the leading industries.

mr bhalla changa u have given the four types of climate what about the remaining ones......... how can i get that

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