HOW TO PREPARE FOR GEOGRAPHY OPTIONAL

Paper 1 :
1. Physical Geography by Savindra Singh
2. Rupa Made Simple Series
3. Climatology by Lal
4. Human Geography by Majid Hussain
5. Models , theories by Majid Hussain
6. Geographical Thought by Majid Hussain

Paper 2 :
Geography of India by Majid Hussain and relevant portions from above quoted books.

Why Geography?

Apart from having scientific orientation , easy availability of coaching-materials and the perceived high success rate , some parts of the syllabus like economic , environmental and human geography greatly appealed to me . Besides being helpful in essays and other GS papers I found topics like Human Development , Agri issues , resources distribution very interesting and hence did not mind going the extra mile in these topics specially of Part B of both papers.

( Beginning credits go to my class X teacher Mrs. Anita Dey(St. Xaviers Collegiate School, Kolkata ) who had piqued my interest in the subject and I got a gold medal in school J. It was named Ganga Singh medal and well I got all the Ganga cleaning questions in the interview   Don’t know if that was the link though ! )

These perceptions about easy scoring , high scoring etc can change any year for instance the 2013 paper had certain bouncer questions . In the end your optional needs to be mastered by you if you want to tide over these bouncers and be in the top bracket in your optional. Overall for Geography I would say the syllabus is quite lengthy and needs quite a bit of effort but as said earlier if you have interest in the subject and are willing to work for it do choose it.

My geography strategy hitched on 3 things :
1. Coverage of entire syllabus with a mixture of coaching notes , reference books .Begin with NCERTs , GC Leong and then move onto more advanced things .
2. Regular updation of current notes on contemporary events and analyzing news from geographical point of view especially for handling part B of both papers.
3. Test series , answer writing and diagram practice.
Coaching
Well honestly it was roll of a dice between Shabbir Sir and Madam Neetu Singh . I guess it was based on certain reviews of a just successful candidate whose blog I found online that I went for Neetu Singh(NS).
NS covers about 70% of the syllabus in her class notes . Honestly this 70% formed the core of my geography preparation . After the NCERTS and GC Leong , I went through her notes repeatedly and had them committed to memory . I stuck to this one source and kept on adding information concepts from other sources like internet , test series , reference books etc . It served me well for I did not hop from one book to other and just used my time more efficiently to plug the gaps or weakness I found after having established sound knowledge in the subject . I used to consult both the syllabus , previous years papers to look out for missed out portions and covered them accordingly .
Many people get coaching notes from various coaching institutes and in the end are confused what to read what not to . About 80% all notes are repetition of each other and you will waste a lot of time .
My final take on NS coaching was this :
Pros :
 Lot of spatial examples in most topics which are helpful in maps and makes the answers more comprehensive .
 To the point coverage on topics . For me in the paper on most topics I had just enough matter for 200-300 words answers , hence did not have to give much time to sieve through my knowledge. It was there for me in a condensed form which I reproduced on paper especially for the theory based questions like mountain belts , their origin , plate tectonics etc.
 Good coverage of map pointing in class. In the map questions apart from importance of place ( which you maynot know ) use your knowledge from climate , soil structure , vegetation and physiography . 10 words on each will be sufficient.
 Good coverage of part B of both papers . I used books only for reference and adding certain points she missed or for topics like sustainable developments , disaster management which fell in the 30% she did not cover .
 I found her coverage of Indian geography comprehensive enough for mains although not so much for prelims for which I used the book by Majid Hussain.
 I am also a believer that facts supplemented with data make a more convincing case and madam provided sufficient data like census numbers , forest cover , etc well.
 Cons : ( had to work a lot to make up for them )
 Poor coverage of part A of the topic .For instance landform development theories , slope development , channel morphology , law of sea , marine pollution etc are just a few to name which was poorly covered. I had to supplement them with additional notes of Shabbir Sir , and reference from standard texts .
 No answer writing practice in my time . Right now she has weekly tests but don’t know how much of answer writing practice happens there .
 Diagram work is bordering on average-poor in most topics for which you need to refer to standard texts , online material .
 Many important topics fall in the 30% she does not cover in class. For instance Disaster Management , social forestry , major portion of environmental geography , regional development and planning amongst others .
 Her part B coverage is very good but at times she misses out or just mentions the concepts in passing instead of explaining them in detail . For instance the concept of pay , mental maps , limits to growth etc. For these I used Majid Hussain books extensively apart from Shabbir Sir notes.
Overall her guidance helped me in the exam for I did not have to go through many books to get my basics and fundamentals of geography . They just served as reference books and there is hardly any 1 book in geography that I read fully apart from NCERTS. However this does not mean that coaching is compulsory for success in the exam . Many people take guidance from standard texts and ace the examination without coaching .
3. Current affairs
I maintained a separate notebook for geography and had topics like IPCC , Flood control , HDI , Food Security etc as topics which were constantly updated .
Newspapers : The Hindu , Indian Express
Online : Google topics like IPCC , global warming , sustainable development etc .
Magazines : Kurukshetra ( Agri issues ) , Geography and You , Terra Green ,The Hindu Environment Survey
How to read current affairs with geo perspective ?
For instance a topic like food security . Apart from issues of lack of access to food and water , how climate change is affecting productivity of crops , how shift of cropping patterns away from pulses is affecting nutrition security , how poor and tribals are disproportionately affected in various parts of our country ( draw a map ) and solutions like biofortication , social forestry etc can be looked into .
In case of falling Child Sex Ratio apart from numbers and maps it may be linked to how regional development has led to falling numbers in Maharashtra ,, even Kerala whereas tribal regions show an uptick.
Make In India one can focus on the issues of manufacturing industries like iron and steel , aluminum ,how we lack sufficient silicon industry for electronics , transport issues due to poor regional development , spatial map of electricity shortage etc .
Newspapers are a rich source of maps and data as well . I remember an article in Express on Migration where they had given the source and destination of major migrations in the form of a map . Just cut and paste them in the notes and supplement them with any other information . For instance the civil wars in Africa and Middle east and ensuing crisis can be added as illegal migration , refugees and shown with a map incase a question on migration is asked .
These information will not be usually given in one article at one place . Hence the need to maintain topic wise notes and continuously add points to it . For instance after the Uttarakhand and Kashmir floods , I got to know about a new concept of critical power for floods mentioned in one of the magazines . It also mentioned about Ravi Chopra Committee whose recommendation I read and used in Himalayan Ecosystem fragility answer this year in Mains .
Moreover I used to be a regular reader of Insights Secure Mains which covered newspapers like Business Standard , Live-Mint , NYT etc. At times they take out very relevant articles for geography optional like recently livemint had an article series on water crisis of India which I found very useful . SO keep your eyes and ears open at all times !
4. Maps and answer writing
In my first attempt I was just reliant of coaching notes for I hardly had time apart from coaching between May 2013 when I passed out and December 2013 when I first appeared . I just drew 2-3 diagrams in both papers . This time around it increased to about 25-30 diagrams in total .
I maintained a separate notebook for Maps . I drew the diagram on the right side and left side was used for practice later . Often we read books , or see a good diagram but fail to catalogue it properly . GC leong , NCERTs have some excellent diagrams and since we donot revise them before exams we tend to forget them .
Hence whenever I saw a good diagram , a map , I used to cut and paste or draw then and there . Even from the reference books like Majid Hussain I remember drawing world diagrams on urbanization , forest degradation and distribution , land degradation etc.
During answer writing you would always feel that there is no time / need to make a diagram for you have said it all in the answer or draw a sketch at the end of the answer . That is a very bad strategy . Infact try and make one diagram per question and at the appropriate place for a picture speaks a thousand words . For instance coal issues make a map of distribution of coal resource and in your answer link how people in Jharkhand suffer from lung disease due to it . Always have a link to the question .
Answer writing is of essence for mains as I have told earlier . some questions like tropical vs temperate cyclones , mountain –volcano distribution , Penck-Davis cycle etc are standard questions which are often repeated in the exam . I really liked Shabbir Sir’s strategy where in the test series he made you practice a lot of these questions and corrected them . These self written , comprehensive answers with sufficient diagrams , examples data are ready made material that come very handy in exams .
5. Test series
In my first attempt I did my test series with NS as it was part of my coaching and had too less a knowledge to properly evaluate myself . However I found her questions a good mix of static and dynamic and her model answers gave a very comprehensive picture . However her feedback and discussion sessions were not very helpful as she seemed in a hurry always then .
For my second attempt I took ALS test series . Let me warn you at first that it shall not be taken by Shashank Atom Sir . I find it wrong for them to give this advertisement with him as Course Director for that gave a wrong impression including to me that he will take the test series . It will be taken by Sachin Sir or someone else , so be warned .
Pros :
Good Discussions , timely tests , few bouncer questions as well , and since number of people are less than 50 so you get personal attention as well . I appreciate Sachin Sir’s inputs where he asked me to focus on diagrams , highlighting the mains points and keeping a good mix of concepts, data in the answers .
Cons :
Unprofessional at times for we were not given model answers for as many as 3-4 tests conducted out of a total 8 ! Moreover feedback especially in the full tests is so important , but sadly we never ever received the last 3 papers despite repeated attempts which was a huge letdown for me in the end .This attitude was both unhelpful and unexpected right at the crunch time in end November .
In March 2015 I joined Shabbir Sir ( VAjiram ) Test series in anticipation of my third attempt !
Pros :
Brilliant focus on answer writing , discussion and concept clarity . He provides a question sheet , discusses the answers and asks you to submit written answers for evaluation before he conducts the test on the specific topic .His dedication towards students and inspiring words are noteworthy . He goes to great lengths to research articles , material on important topics which saves a lot of time one would ordinarily waste surfing online . Besides I used his class notes extensively for filling gaps in my preparation as specified .
Cons :
Sir goes overboard at times . I felt he covered 130% of the syllabus and the information overload at times got me all confused at times . He emphasizes case studies etc which is all good but I usually found his notes lacking in spatial examples in many topics .
The number of tests are only 5-6 with no full tests .
However Shabbir Sir test series needs quite a lot of effort and time as you need to read up well and write answers to derive benefit from it .
Overall Part A of both Papers are straight forward and can be prepared from standard texts , coaching notes and with help and guidance from someone for conceptual clarity at certain points . As stated earlier part A was not my forte and I used to attempt 3/5 questions from Part B which I prepared well from the sources listed above with a lot of focus on current affairs .
Questions like Food Security Problems in developing countries were handled by me as I had a knowledge about the Global Hunger Index 2014 in news then . I drew a map regarding the same , used my knowledge of cropping patters , land degradation , climate change to frame the core of the answer . Similarly in 2014 Government of India took out a new Agro forestry policy and in the newspaper article it covered points as to why we failed earlier and what changes have been made . So my love affair with newspapers and current affairs did prove to be a boon .
In conclusion cover the syllabus , use limited books again and again , catalogue your resources for quick revision , practice practice practice and most importantly have interest in your optional for you need to spend a lot of quality time in it !

Climate Change & The Impact of Climate Change

Fire engulf the bone dry forests of Indonesia. Tornadooes shred parts of the US. Droughts sap the Australian outback. Floods swarm the otherwise parched Ethiopia. Deadly storms lash china's coastal provinces. Central Pacific islands receive a bumper harvest of 7 cyclones ! Fires sweep across the fragile rainforests of South America and thousands of living beings the world over fall prey to the violent mood swings of the EI-Nino.
Climate, like ant other physical phenomenon, is not state but fairly dynamic. It greater or less degree it is ever changing. Till recently, the concept of climate change was considered of academic importance. It was only during the past few decades that scientists began to recognized the inherent variability of climate on all time scales. Furthermore, now there has been an ever-growing awareness among the general public and the government of the possible variability of the earth's climate. In other words, climate change is viewed as a  matter of great concern for the future.

The Impact of Climate change :-
It has been conclusively proved that climate change is attributable to human intervention. Carbon dioxide, emitted mainly by the burning of fossils fuels, and the emission of methane, nitrous oxide, CFC's and other greenhouse gases thickens the blanket of greenhouse gases over the earth's atmosphere, upsetting the natural flow of energy from the sun. Deforestation accelerates global warming by reducing the absorption of carbon dioxide in the atmosphere.
It has been conclusively proved that climate change is attributable to human intervention. Carbon dioxide, emitted mainly by the burning of fossils fuels, and the emission of methane, nitrous of fossils fuels, and the emission of methane, nitrous oxide. CFC's and other greenhouse gases thickness the blanket of greenhouse gases over the earth's atmosphere, upsetting the natural flow of energy from the sun.
Based on current emission levels, it is estimated that the global temperature will rise by between 1 degree C and 3.5 degree C by the year 2100; that even after emission levels are stablised, climate change will continue to occur for hundreds of years.
The mean sea level may rise upto 100 cm by the year 2100, causing flooding and submergence of many island and coastal cities.

Inspite of technological change, most of the world's people will continue to be subsistence or small-scale market farmers, vulnerable to climate fluctuations. But unlike ancient societies who could migrate to where cultivation of crops was possible, the world is too crowded for ` habitat tracking'.
To conclude as any coin with two sides, environment science  has two opposite but complementary aspects. One is the impact or influence of the environment upon humans; the other is the human influence or impact upon the environment.
But we must not forget our atmosphere supports us. We have polluted it beyond all levels yet, we have a chance to redeem ourselves. Let us play the role of a protector and give one children a better air to breath.

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Greenhouse Effect ( The Rising Problem )

The Greenhouse Effect is the result of the atmosphere's absorption of long-wave radiation emitted by Earth. Among the atmosphere constituents, carbon dioxide absorbs the largest proportion of that radiation. Thus, when the carbon dioxide content of air changes, a corresponding increase or decrease in the greenhouse effect occurs. The natural supply of carbon dioxide has probably varied little over the past several million years, but over the past 200 years human beings have increasingly acquired the capacity to alter this balance.

In particular, the coming of the Industrial Revolution in the late 18th century has been accompanied by an ever greater consumption of coal, oil and natural gas. The burning of these fossil fuels products enormous quantities of carbon dioxide, and the global levels of this variable atmospheric gas have risen substantially in recent decades. Although no firm conclusions have emerged from various scientific studies on the possible climate and other environmental consequences of a heightened greenhouse effect, the evidence gathered to date suggests that higher level, the evidence gathered to date suggest that higher levels of atmospheric carbon dioxide may be linked to the increase in global temperatures.
Scientists who subscribe to the greenhouse theory of climate change have delivered forecasts of future environment conditions. Some predict an intensification of the global warming, with average temperatures steadily rising by as much as 1.0 to 4.5 degree C by 2050. Others forecast a different scenario that involves the oceans. They argue that much of the increased heat of the atmosphere today is really being absorbed and temporarily stored by the sea. Over the next few years, however, they expect that heat to be released in vast quantities, thereby causing sudden, significant climate change without warming.
These prognostications have led some to consider other implications of such greenhouse warming like dramatic alteration of weather patterns, intensification of storm systems, re-direction of ocean currents and severe coastal flooding as melting polar ice-caps can global sea levels by as much as 5 feet by 2050.

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The Sun ( The largest object in the Solar System)

The sun accounts for 99.85% of mass of the solar system. The immense gravitational pull of the Sun keeps the planets rotating around it in definite orbits.

• It continuously gives off energy in the form of visible light, infra red, ultra violet, X-rays, gamma rays, radio waves and plasma.
• The period of revolution of the Sun around centre is  250 million years. This period is called a Cosmic or Galactic Year.
• Like all other stars, the Sun is mainly composed of hydrogen and helium. Nuclear fusion in the core of the Sun is source of all its energy.
• The glowing surface of the Sun, that we see, is called the Photosphere, above the photosphere is the red coloured Chromosphere and beyond it is the magnificent Corona, which is visible during eclipses.
• The Sun is continuously emitting streams of protons in all directions either as persistent spiral streams called Solar Winds or as bouts of incandescent material called Solar Flares.
• The Constituent particles of solar wind are trapped by the earth's magnetic field and enter the earth's upper atmosphere as auroral displays described as Aurora borealis in the northern hemisphere and Aurora australis in the southern hemisphere.
• Solar flares being hot ionized gases pose danger to satellite communication.
• The surface of the sun changes continuously. Bright sports called plages and dark spots called Sunspots frequently form and disappear.
• Sunspots are cold and dark regions on the surface of the sun with a periodicity of 11 years. These spots greatly influence the the global climate.

Solar Statistics :-

1. Distance from Earth  -  150 m n km*
2. Diameter  -  100 Earth Diameters
3. Core Temperature  -  15 million degree C
4. Surface Temperature  -  6000 degree C
5. Rotation Time  -  25 days
6. Age  -  5 bn years
7. Composition  -  H2 71%  ;  He 26.5%  ;  others 2.5%  .

* Distance of Earth from Sun:-

Aphelion ( Max) - 152 mn km on July 4.

Perihelion ( Min) - 147 mn km on January 3 .

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River Rejuvenation

The earth's crust is far from stable and it is not surprising that, in the course of a river's development, parts may be uplifted or depressed, giving rise to certain characteristics features associated with rejuvenation, i.e. being young again.
A negative movement occurs when there is an uplift of land or a fall in sea level. This will steepen the slope so that active down-cutting is renewed. A fall in sea level leaves the flood-plain at an increased altitude above the sea level. The river with its renewed vigour cuts into the former flood-plain, leaving behind terraces on both sides of the river. There is also a break in the graded profile of the river, often marked by a series of rapids. This point where the old and rejuvenated profile meet is called the Knick Point or Rejuvenated Head.

If rejuvenation occurs in the upper-course, the river valleys are deepened and steep-sided Gorges are formed. In the middle and lower course vertical corrasion replaces lateral corrasion and the existing meanders are vertically eroded by the rejuvenated stream. A distinct new inner trench is cut in the old valley, and the river develops a deep valley with entrenched or incised meanders. The best developed incised meanders are those of the River Colorado, U.S.A., where the uplift of 7,000 feet in the tertiary period renewed down-cutting to a fantastic depth. In some parts of the Grand canyon, the depth is almost a mile. It is 10 miles wide at the top and 300 miles long. Other examples are the River Moselle in Germany, the River Wear at Durham, England and the Wye Valley, Monmouthshire.
A positive movement occurs when there is a depression of land or a rise in sea level. This submerge the lands along the coast, `drown' the valleys and weaken the erosive power of the river. The flow is checked and large quantities of sediment will be dropped. The lower course of the river may be partly in the sea and features of deposition are shifted upwards to the middle course. The upper course is little affected when there is a rise in sea level. In many areas where the sea has risen this was probably caused by the release of water locked up in the ice masses during the Quaternary Ice Ages.
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Land and Sea Breezes and Monsoons

Land and sea breezes are, in fact, monsoons on a smaller scale. Both are basically caused by differential heating of land and sea, the former in a diurnal rhythm and the latter in a seasonal rhythm.
During the day, the land gets heated up much faster than the sea. Warm air rises forming a region of local low pressure. The sea remains comparatively cool with a higher pressure so a sea breeze blows in from sea to land. Its speed or strength is between 5-20 m.p.h. and it is generally stronger in tropical than temperate regions. Its influence does not normally exceed 15 miles from the coast. It is most deeply felt when one stands facing the sea in a coastal resort.
At night the reverse takes place. As the land cools down much faster than the sea, the cold and heavy air produces a region of local high pressure. The sea conserves its heat and remains quite warm. Its pressure is comparatively low. A land breeze thus blows out from land to sea. Fishermen in the tropics often take advantage of the out-going land breeze and sail out with it. They return the next morning with the in-coming sea breeze, complete with their catch.
In the same way, monsoon are caused. rapid heating in the hot summer over most parts of India for example induces heated air to rise. The South-West Monsoon from the surrounding ocean is attracted by the low pressure over the land and blows in, bringing torrential rain to the sub-continent.
Similarly, in winter when the land is cold, the surrounding seas remain comparatively warm. High pressure is created over Indo-Pakistan and the North-east Monsoon blows out from the continent into the Indian Ocean and the Bay of Bengal.

The Tropical Marine Climate

This type of climate is experienced along the eastern coasts of tropical lands, receiving steady rainfall from the Trade Winds all the time. The rainfall is both orographic where the moist trades meet upland masses as in eastern Brazil, and convectional due to intense heating during the day and in summer. Its tendency is towards is towards a summer maximum as in monsoon lands, but without any distinct dry period. The rhythm of climate as experienced in Cairns, on the eastern coast of Queensland, under the constant influence of the South-east Trade Winds, and in summer also affected by the Tropical monsoons. Its wettest months are in January ( 15-8 inches), February ( 16-.4), March  !7.7) and April ( 12.1), which is summer in the southern hemisphere. Approximately 70% of the annual rainfall is concentrated in the four summer months. There is no month without any rainfall. The range of temperature is typical of the tropical latitudes with a maximum of 82 degree F, in January and a minimum of 70 degree F, in July a range of 12 degree F, for the year. Due to the steady influence of the trades, the Tropical Marine Climate is more favourable for habitation, but it is prone to severe tropical cyclones, hurricanes or typhoons.

The Atmosphere

The atmosphere is made up of gases and vapour, and receives incoming solar energy from the sun giving rise to what we call climate. We actually live at the bottom of this indefinite layer of atmosphere where the air is densest. Higher up, the air thins out and it is still a matter of conjecture where the atmosphere ends. One estimate puts this limit at about 600 miles above sea level. The lowest layer, in which the weather is confined, is known as the Troposphere. It extends from the earth's surface for a height of 6 miles, and within temperature normally falls with increasing altitude. The climate elements such as temperature, precipitation, clouds, pressure and humidity within the troposphere account for the great variations in local climate and weather that play such a great part in our daily lives. From analyses taken in different parts of the globe, it is found that the lower part of the atmosphere contains a consistent proportions of certain gases : 78% of nitrogen, 21% of oxygen, 0.03 % of carbon dioxide and minute traces of argon, helium and other rare gases. In addition, it has an unpredictable proportion of water, existing either as a gas like water vapour, a liquid like rain, clouds and sleet or a solid like snow and hailstone, as well as other solid particles like smoke and dust. It is because of the variable water content of the atmosphere that we have such great contrasts in weather and climate over different parts of the world. If we were to live in a dry atmosphere, absolutely without water, there would be no weather and not even much climate.
Above the troposphere lies the Stratosphere or the upper layer of the atmosphere. It extends upwards for another 50 miles or even more. It is not only very cold, but cloudless, with extremely thin air and without dust, smoke or water vapour but there are marked seasonal temperature changes. Beyond the stratosphere is the ionosphere which goes several hundred miles up. It has electrically conducting layers which make short-wave radio transmission possible over long distances. Modern artificial satellites, launched in the upper strata of the atmosphere, as well as balloons are used to transmit back to earth information regarding the conditions of atmosphere.
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The Difference Between Weather and Climate

The term weather should not be confused with climate, though they are very closely related to each other in the study of meteorology and climatology. We don't hear people saying that the climate of the day is warm or cold, but we do talk of warm weather, a cold morning, a sunny afternoon, a rainy day or a chilly night. Any casual remarks about the atmospheric conditions of a certain place at a certain time are about weather. It is never static, and thus cannot be generalized. In the same country, even over a small area, the weather can vary tremendously. It may be sunny in one part of the district, but raining heavily a few miles away. Strong gales may be experienced along the coasts while the interior may be relatively calm. It is important to realise that any place can be subjected to haphazard changes in weather at any time.
When we speak of climate we mean the average atmospheric conditions of an area over a considerable time. For climate averages, a minimum period of 35 years is desirable. This involves the systematic observation, recording and processing of the various elements of climate such as rainfall, temperature, humidity, air pressure, winds, clouds and sunshine before any standardization of the climate means or averages can be arrived at. The climate of Malaysia is described as hot, wet, equatorial climate which is a summing up of the average everyday climate of the country throughout the year.
The degree of variability in the climate or weather of a country also differs. Generally speaking, the climate of temperate latitudes is far more variable than that of the tropics, The climate of the the British Isles is so changeable that many people have commented that ` Britain has no climate, only weather'. Conversely, the climate of Egypt is so static that it makes a good deal of sense when people say that ` Egypt has no weather, only climate'.
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Tropical Monsoon Forests

The natural vegetation of tropical monsoon lands depends on the amount of the summer rainfall. Trees are normally deciduous because of the market dry period, during which they shed their leaves to withstand the drought. Where the rainfall is heavy, e.g. in southern Burma, peninsular India, northern Australia and coastal regions with a tropical marine climate, the resultant vegetation is forest. The forests are more open and less luxuriant than the equatorial jungle and there are far fewer species. Most of the forests yield valuable timber, and are prized for their durable hardwood. Amongst these teak is the best known. Burma alone accounts for as much as three-quarters of the world's production. It is such a durable timber that it is extensively used for ship building, furniture and other constructional purposes. Other kinds of timber include sal, acacia and some varieties of eucalyptus in northern Australia. Together with the forests are bamboo thickets, which often grow to great heights.

With a decrease in rainfall in summer, the forests thin out into thorny scrubland or savanna with scattered trees and tall grass. In parts of the Indian sub-continent, rainfall is so deficient that semi-desert conditions are found. Monsoonal vegetation is thus most varied, ranging from forests to thickets, and from savanna to scrubland.

Climate Conditions in Tropical Monsoon Lands

The basic cause of monsoon climates is the difference in the rate of heating and cooling of land and sea. In the summer, when the sun is overhead at the tropic of Cancer, the great land masses of the northern hemisphere are heated. central Asia backed by the lofty Himalayan ranges is more than 15 degree F. hotter than its normal temperature and a region of intense low pressure is set up. The seas, which warm up much slower, remain comparatively cool. At the same time, the southern hemisphere experiences winter, and a region of high pressure is set up in the continental interior of Australia. Winds blow outwards as the South-East Monsoon, to Java, and after crossing the equator are drawn towards the continental low pressure area reaching the Indian sub-continent as the South-west Monsoon.

In the winter, conditions are reversed. The sun is overhead at the Tropic of Capricorn, central Asia is extremely cold, resulting in rapid cooling of the land. A region of high pressure is created with outblowing winds-the North-East Monsoon. On crossing the equator, the winds are attracted to the low pressure centre in Australia and arrive in northern Australia as the North-West Monsoon. In other parts of the world which experience a Tropical monsoon climate a similar seasonal reversal of wind directions occurs.

Types of Coral Reefs

There are three main types of coral reefs :-

1. Fringing reefs :- A fringing reef is a coralline platform lying close to the shore extending outwards from the mainland. It is sometimes separated from the shore by a shallow lagoon. It is widest when fringing a protruding headland but completely absent when facing the mouth of a stream. The outer edge grows rapidly because of the splashing waves that continuously renew the supply of fresh food. The reefs may be about a mile wide, lying just above the level of low water and sloping steeply downwards on the seaward side to a depth of about 100 feet.
2. Barrier reefs :- A barrier reef is separated from the coast by a much wider and deeper channel or lagoon. The reef is partially submerged. Where it lies above the water level and sand can accumulate on it, a little vegetation is possible. The barrier reefs have narrow gaps at several places to allow the water from the enclosed lagoon to return to the open ocean. Such gaps are very useful for shipping and provide the only entrances for ships to enter or leave the lagoon. the best known barrier reef is the Great barrier Reef off the coast of Queensland, Australia. It is 1,200 miles long, separated from the coast by a channel 100 miles wide in places and over 200 feet deep.
3. Atolls :- Atolls are similar to barrier reefs except that they are circular in shape, enclosing a shallow lagoon without any land in the centre. The encircling ring is usually broken in a few places to allow the free flow of water. On the inside of the reefs, sand and limestone debris collect and palm trees like coconuts may grow. Such palm trees thrive well in the brackish water of the lagoons. The nuts fall into the water and are distributed widely by floating from one coral island to another. The calm waters are useful for fishing and canoeing. Some of the large atolls, e.g. Suvadiva in the Maldives, west of Ceylon, have a lagoon over 40 miles across. A number of them provide essential air bases for trans-Pacific aircraft.

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Coral Reefs

In tropical seas many kinds of coral animals and marine organisms such as coral polyps, calcareous algae, shell-forming creatures and lime-secreting plants line in a large colonies. Though they are very tiny creatures, their ability to secrete calcium carbonate within their tiny cells has given rise to a perculiar type of marine landforms. they exist in numerous species of many forms, colours and shapes. Under favourable conditions, they grow bin great profusion just below the water level. taking coral animals as a whole, the polyps are the most abundant and also the most important. each polyp resides in a tiny cup of coral and helps to form coral reefs. When they die, their limy skeletons are cemented into coralline limestone. There are also non-reef building species such as the `precious corals' of the Pacific Ocean and the `red coral' of the Mediterranean which mat survive in the colder and even the deeper waters. As a rule they thrive well only in the warmer tropical seas.
The reef-building corals survive best under the following conditions :-

• The water temperature must not fall below 68 degree F. This virtually limits the areal the tribution of corals to the tropical, and sub-tropical zones. Again they will not flourish where there are cold currents because of the upwelling of the cold water from the depths that cools the warm srface water. This explains why coral reefs are generally absent on the western coasts of the continents. On the other hand the warming effect of the warm currents e.g. the Gulf Stream, means that corals are found far to the north of the West Indies in the Atlantic Ocean. The Pacific  and the Indian Ocean, however have the most numerous coral reefs.
• The depth of the water should not exceed in fathoms or 180 feet, because beyond this depth sunlight is too faint for photosynthesis to take place. This is essential for the survival of the microscopic algae, on which the coral polyps depend. Shallow water of less than 100 feet is ideal. But there should always be plenty of water as polyps cannot survive far too long out of water.
• The water should be saltish and free from sediments. Corals therefore survive best in the moving ocean water well away from the silty coasts or muddy mouths of streams. The corals are best developed on the seaward side of the reef, where constantly moving waves, tides and currents maintain an abundant supply of cleat, oxygenated water. They also bring an adequate supply of food in the form of microscopic organisms. 

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The Circulation of the Pacific Ocean

The pattern of circulation in the Pacific is similar to that of the Atlantic except in Modifications which can be expected from the greater size and the more open nature of the Pacific.
The North Equatorial Current flows westwards with a compensating Equatorial Counter Current running in the opposite direction. Due to the greater expanse of the Pacific and the absence of an obstructing land mass the volume of water is very much greater than that of the Atlantic equatorial current. The North-East Trade winds blow the North Equatorial Current off the coasts of the Philippines and Formosa into the East China Sea as the Kuroshio or Kuro Siwo or japan Current. Its warm waters are carried polewards as the North Pacific Drift, keeping the ports of the Alaskan coasts ice-free in winters. The cold Bering Current or Alaskan Current creeps southwards from the narrow Bering Strait  and is joined by the Okhotsk Current to meet the warm Japan Current as the Oyashio, off Hokkaidi. The cold water eventually sinks beneath the warmer waters of the North pacific Drift. Part of it drifts eastwards as the cool Californian current along the coasts of the western U.S.A. and coalesces with the North Equatorial Current to complete the clockwise Circulation.
The current system of the South Pacific is the same as that of South Atlantic. The Sputh Equatorial Current, driven by the south-east Trade Winds, flows southwards along the coasts of Queensland as the east Australian Current, bringing warm equatorial waters into temperate waters. The current turns eastwards towards new Zealand under the full force of the Westerlies in the Tasman sea and merges with part of the cold West Wind Drift as the South Pacific Current. Obstructed by the tip of southern Chile, the current turns northwards along the western coasts of South America as the cold Humboldt or Peruvian current. The cold water Chilean and Peruvian coasts are practically rainless. The region is rich in microscope marine plants and animals that attract huge shoals of fish. Consequently, millions of seabirds gather here to feed on the fish. Their droppings completely whiten the coastal cliffs and islands, forming thick deposits of guano, a valuable source of fertilizer. The Peruvian Current eventually links up with the South Equatorial Current and completes the cycle of the currents in the South Pacific.
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The Movements of Ocean Currents

ocean currents are large masses of surface water that circulate in regular patterns around the oceans. Those that flow from equatorial regions polewards have a higher surface temperature and are warm currents. Those that flow from polewards regions equatorwards have a lower surface temperature and are cold currents. Their direction of movement is indicated by the arrows. But why should they follow such pattern? Some of the underlying factors are explained below :-

Ocean currents

• The planetary winds - Between the equator and the tropics blow the Trade Winds which move equatorial waters polewards and westwards and warm the eastern coasts of continents. For example the North-East Trade Winds move the North Equatorial Current and its derivatives, the Florida Current and the Gulf Stream Drift to warm the southern and eastern coasts of U.S.A. Similarly, the South-East Trade Winds drive the South Equatorial Current which warms the eastern coast of Brazil as the warm Brazilian Current. In the temperate latitudes blow the Westerlies. Though they are less reliable than the Trade Winds, they result in a north-easterly flow of water Gulf Stream is driven to the western coast of Europe as the North Atlantic Drift. In a similar manner, the Westerlies of the southern hemisphere drive  the West Wind Drift equatorwards as the Peruvian Current off southern Africa. The planetary winds are probably the dominant influence on the flow of ocean currents. The strongest evidence of prevailing winds on current flows is seen in the North Indian Ocean. Here the direction of the currents changes completely with the direction of the monsoon winds which come from the north-east in winter and south-west in summer.
• Temperatures - There is much difference in the temperature of ocean waters at the equator and at the poles. As warm water is lighter and rises, and cold water is denser and sinks, warm equatorial waters move slowly along the surface polewards,while the heavier cold waters of the polar regions creep slowly along the bottom of the sea equatorwards.
• Salinity - The salinity of ocean water varies from place to place. waters of high salinity are denser than waters of low salinity. Hence waters of low salinity flow on the surface of waters of high salinity while waters of high salinity flow at the bottom towards waters of low salinity. For example in the Mediterranean region, there is great difference in salinity between the waters of the open Atlantic and those of the partially enclosed Mediterranean Sea. the less saline water of the Atlantic flows on the surface into the Mediterranean, and this is compensated for by an outflow of denser bottom water from the Mediterranean.
• The Earth's rotation - The earth's rotation deflects freely moving objects, including ocean currents, to the right. In the northern hemisphere this is a clockwise direction ( e.g. the circulation of the Gulf Stream Drift and the Canaries Current). In the southern hemisphere it is an anti clockwise direction (e.g. the Brazilian Current and the West Drift).
• Land - A land mass always obstruct and diverts a current. For instance, the tip of southern Chile diverts part of the West Wind Drift northwards as the Peruvian Current. Similarly the `shoulder' of Brazil at Cape Sao Roque, divides the west-flowing equatorial currents into the Cayenne Current which flows north-westwards and the Brazilian Current which flows south-westwards.

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The Temperature of Ocean Water

Like land masses, oceans water varies in temperature from place to place both at the surface and at great depths. Since water warms up and cools down much more slowly than the land, the annual range of temperature in any part of the ocean is very much smaller. It is less than 10 degree F, for most of the open seas. Generally, the mean annual temperature of the surface ocean water decreases from about 70 degree F. in equatorial areas to 55 degree F. at latitudes 45 degree N and S, and drops almost to freezing-point at the poles. The reduction of temperature with latitude is however never constant, because of the interference by warm and cold currents, winds and air masses. Unlike the solid earth, ocean water is mobile and variations in temperature between different parts of the oceans can be expected. Water flowing out from the Arctic and Antarctica as cold currents, such as the Labrador Current off north-east Canada, tends to reduce the surface-water temperature. Ports of eastern Canada even at 45 degree N. are thus icebound for almost half the currents, such as the North Atlantic Drift, have their surface temperature raised. The Norwegian coast, even at latitudes 60 degree to 70 degree N. is ice free throughout the year!
The highest water temperatures are found in enclosed seas on the tropics, e.g. the Red sea which records a temperature of 85 degree to 100 degree F. The Arctic and Antarctic waters are so cold that their surface is permanently frozen as pack-ice down to a depth of several feet. In the warmer summer, parts of the ice break off as icebergs that both dilute the water and lower the surface temperature of surrounding ice-free seas.
The temperature  of the oceans also varies varity cally with increasing depth. It decreases rapidly for the first 200 fathoms, at the rate of 1 degree F. for every 10 fathoms, and then more slowly until a depth of 500 fathoms is reached. Beyond this, the drop is scarcely noticeable, less than 1 degree F. for every 100 fathoms. In the ocean deeps below 2,000 fathoms (12,000 feet), the water is uniformly cold, just a little above freezing-point. It is interesting to note that even in the deepest ocean trenches, more than 6 miles below the surface, the water never freezes. It is estimated that over 80% of all ocean waters have a temperature between 35 degree and 40 degree F.

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Factors Affecting Salinity of Oceans and Seas

The variations of salinity in the various sea and oceans is affected by the following factors :-

• The rate of evaporation - The water fringing the High Pressure Belts of the Trade Wing Deserts, between 20 degree and 30 degree N and S, have salinity because of the high rate of evaporation caused by high temperature and low humidity. The temperate oceans have lower salinity due to the lower temperature and a lower rate of evaporation.
• The amount of fresh water added by precipitation streams and icebergs - Salinity is lower than the average 35% in equatorial waters because of the heavy daily rainfall and high relative humidity. Oceans into which huge rivers like the Amazon, Congo, Ganges, Irrawaddy and Mekong frain, have much of their saltness diluted and have a lower salinity. The Baltic, Arctic and Antarctic waters have a salinity of less than 32% because of the colder climate with little evaporation and because much fresh water is added from the melting of icebergs, as well as by several large poleward-bound rivers, e.g. Ob, Lena, Yenisey, and Mackenzine.
• The degree of water mixing by currents - In wholly or partially enclosed seas such as the Caspian Sea, Mediterranean Sea, Red Sea and Persian Gulf, the waters do not mix freely with the ocean water and they are not penetrated by ocean currents. Salinity is high, often over 37%. In areas of inland drainage without links with the oceans, continuous evaporation under an almost cloudless sky causes the accumulation of salts around the shores. In the open oceans where currents freely flow, salinity tends to be near the average 35% or even a little lower. The range of salinity is negligible where there is free mixing of water by surface and sub-surface currents.

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Salinity of the Ocean

Almost every known chemical element can be found in varying proportions in the oceans whose most characteristic feature is their salinity, in contrast to the fresh water of lakes and streams. All sea water contains large amounts of dissolved mineral matter of which sodium chloride or common salt alone constitutes more than 77%. The other more important compounds include magnesium, calcium and potassium, while the rest are distinguishable only in traces of very minute quantites. Due to the free movement of ocean water, the proportions of different salts, remain remarkably constant in all oceans and even to great depths. But the degree of concentration of the salt solution in oceans does vary appreciably in different areas. This is expressed as salinity, the degree of saltness of water, either as a percentage or more often in parts per thousand. Variations are shown in salinity distribution maps by isohalines lines joining places having an equal degree of salinity.
Generally speaking, the average salinity of the oceans is 35.2%, about 35 parts of salt in 1,000 parts of water. In the Baltic Sea, where there is much dilution by fresh water and melting ice, the salinity is much lower, only about 7%. In the Red sea where there is much surface evaporation and fewer rivers to bring in fresh water, the average salinity increases to 39%. In enclosed seas, which are areas of inland drainage, such as the Caspian Sea, the salinity is very high, 180%, and in the Dead Sea of Palestine, a salinity of 250 % has been recorded. The highest salinity is perhaps, that of Lake Van, in Asia Minor, with 330%. It is a salt lake,k and salts are collected from its shores. The density of the water is so high that in Lake Van or the Dead Sea, it is almost impossible to sink. Beginner-swimmers will find it much easier to float here than anywhere else!

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The Oceanic Deposits of the Ocean Floor

Materials eroded from the earth which are not deposited by rivers or at the coast are eventually dropped on the ocean floor. The dominant process is slow sedimentation where the eroded particles very slowly filter through the ocean water and settle upon one another in layers. The thickness of the layer of sediments is still unknown. Its rate of accumulation is equally uncertain. Generally speaking, we may classify all the oceanic deposits as either muds, oozes or clays.

• The muds - These are terrigenous deposits because they are derived from land and are mainly deposited on the continental shelves. the muds are referred to as blue, green or red muds; their colouring depends upon their chemical content.
• The oozes - These are pelagic deposits because they are derived from the oceans. They are made of the shelly and skeletal remains of the marine micro-organisms with calcareous or siliceous parts. Oozes have a very fine, flour-like texture and either occur as accumulated deposits or float about in suspension.
• The clays - These occur mainly as red clays in the deeper parts of the ocean basins, and are particularly abundant in the Pacific ocean. Red clay is believed to be an accumulation of volcanic dust blown out from volcanoes during volcanic eruptions.

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The Continental Shelf

This is, in fact, the seaward extension of the continent from the shoreline to the continental edge marked, approximately, by the 100 fathom (600 feet) isobath (isobaths are contours marking depths below sea level). The continental shelf is thus a shallow platform whose width varies greatly, from a few miles in the north Pacific off the continent of North America , to over 100 miles off north-west Europe. In some places where the coasts are extremely mountainous, such as the Rocky Mountain and Andean coasts, the continental shelf may be entirely absent. Off broad lowland coasts like those of Arctic Siberia, a maximum width of 750 miles has been recorded! A width of 20 to 100 miles is generally encountered. The angle of the slope is also variable, and is normally least where the continental shelf is widest. A gradient of 1 in 500 is common to most continental shelves.
Many regard the continental shelf as part of the continent submerged due to a rise in sea level, e.g. at the close of the Ice Age, when the ice in the termperate latitudes melted and raised the sea level by several hundred feet. Some smaller continental shelves could have been caused by wave erosion where the land is being eroded by the sea. Conversely such shelves might have been formed by the deposition of land-derived or river-borne materials on the off-shore terrace.

The continental shelves are of great geographical significance for the following reasons :-

• Their shallowness enables sunlight to penetrate through the water, which encourages the growth of minute plants and other microscope organisms. They are thus rich in plankton on which millions of surface and bottom-feeding fishes thrive. The continental shelves are therefore the richest fishing grounds in the world, e.g. the grand banks off Newfoundland, The North Sea and the Sunda shelf.
• Their limited depth and gentle slope keep out cold under-currents and increase the height of  tides. This sometimes hinders shipping and other marine activities since ships can only entre and leave port on the tide. Most of the world's greatest seaports including Southampton, London, Hamburg, Rotterdam, Hong kong and Singapore are located on continental shelves.

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