Meteorological Science

Compilation of  Q & A format of the book Science and Technology for Civil Services Examinations, Tata McGraw Hill Publication

Chapter 34 Meteorological Science

1 . Weather forecasting is not an exact science. It’s primarily based on observation. But attempts are being made to make  it as scientific as possible. Comment 50 words  page 482
It is prediction of weather through application of the principles of Physics and gathering of meteorological statistical data. It is difficult to gather this data and this data keeps changing with changes in atmospheric conditions. The best of predictions may be vaid for two or three days after which predictions have to be revalidated.

2. What is synoptic meteorology? 483
It characterises the weather over a large region at exactly the same time in order to organise information about prevailing conditions. Synchronised observations for a specific time are plotted on a map for a broad area from which a general view of the weather in that region is gained.

3 . Describe the techniques adopted to gather meteorological data 100 words 484
Technological advance since the 1960s have led to a growing reliance on remote sensing, particularly the gathering of data with specially instrumented weather satellites as well as observations from ships, aircrafts, radiosondes and Doppler radar. This information is sent to meteorological centres where the data are collected, analysed and made into a variety of maps and charts.

To predict the weather by numerical means, atmospheric models have been developed by using mathematical equations to describe how atmospheric pressure, temperature and moisture will change over time. The equations are programmed into a computer which determines how different variables will change with time.

4. What is the window of meteorological deduction? 484
Weather forecasts made for 12 and 24 hours are typically quite accurate. Forecasts made for two to three days are good. Beyond about 5 days, the forecast accuracy falls off sharply.

5 . Describe the practical applications of weather forecasting. 100 words 484
Agriculture is a major area for use of weather forecasting. Planting and harvesting can be planned better if weather patterns are estimated. It is important in India due to the dependence of the agricultural sector on the monsoon. It has also become important for aviation and sea transport.

Many ocean going vessels as well as military ships use optimum ship routing forecasts to plan their routes in order to minimise lost time, potential damage and fuel consumption in heavy seas. Airlines carefully consider atmospheric conditions when planning long flights so as to avoid the strongest head winds and ride with the strongest tail winds.

Marketing stores require weather forecasts to help with the timing of sales and products ranging from snow tyres to summer clothes. International trading of foodstuffs such as sugar, wheat, corn and coffee can also be severely affected.

6 . How many regional centers  of Meteorological observation are there 485
There are 6 at New Delhi, Mumbai, Kolkata, Chennai, Nagpur and Guwahati.

7 . What s the significance of INSAT? 485

India was the first developing country in the world to have its own geo-stationary satellite, INSAT, for continuous weather monitoring of this part of the globe and particularly for cyclone warning.

8 . Describe the major achievements  of  the (IMD) Indian Meterological Department. 100 words. /486
It has Doppler weather radars installed for more accurate weather forecasting; installation of 100 Digital Cyclone Warning Dissemination systems along the Andhra coast; a Mountain Meteorology Centre was established at Delhi for prediction of avalanches, flash floods and landslides; a new long range prediction model that gives July rainfall for helping Kharif crop sowing; lowering of detection and response times by upgrading the seismic monitoring system.

An Earthquake Risk Evaluation Centre was established at Delhi for seismic micronization. There are also customised forecasts for various other important applications like power distribution, water resources, defence, emergency response and adventure sports.

9 . What are the Agro Advisory services rendered by the IMD 486
It has developed a new long range prediction model that gives more lead time as well as July rainfall as an additional forecast for helping Kharif crop sowing.

10 . What s NCMRWF? Describe it’s vision 50 words 486
The NCMRWF (National Centre for Medium Range Weather Forecasting) was established as the premier institution in India to provide medium range weather forecasts and to render agro advisory services to farmers.

its vision is to become the preferred choice for NWP (Numerical Weather Prediction) guidance over the Indian monsoon region , to develop an earth weather modelling and assimilation system, especially for the monsoon system, to develop newer applications and reach out to society at large, and constantly striving to improve accuracy and consistency.

11 . What is global modeling? 487
NCMRWF runs 2 global spectral models (T-80, T-170) which produce daily global forecasts. The horizontal resolution of these models are 150km and 75km respectively. The atmospheric system they attempt to predict is chaotic. An ensemble prediction system, which involves generation of multiple forecasts as a function of the uncertainty has been developed.

12 . What is Mesoscale modelling? 487
They are essential for accurate prediction of high impact weather such as severe thunder storms, mountain weather forecasts, cloudbursts and cyclones. The mesoscale models (MM5 & ETA) are run up to 72 hours on real-time for high impact weather prediction using initial and boundary conditions from the global forecast model.

13 . What are extended range forecasts? 50 words 488

Currently, the dynamic approach is used for extended range (monthly) prediction based on simulations from the global atmospheric model. Probability of occurrence of excess, normal or deficient rainfall for 6 homogenous regions of the country is calculated.

A more accurate couples system is being developed to understand and predict the monsoon environment a season in advance. Experiments are being conducted to reduce model systematic errors and uncertainties.

14 . What  are Ocean State forecasts? 488
They are in great demand for ship routing, fisheries, tourism, oil exploration and port and naval operations. Ocean surface parameters form global and mesoscale models derive most of the ocean and wave models in the country in both real time and research mode. NCMRWF runs a daily global ocean wave model to predict significant wave heights, peak wave direction and wave period.

15 . What are the goals of NCMRW?

It hopes to develop crop model based application tools for agro-advisories, use of remote sensing products to address variability within the agro-climatic zones, and precision farming using GIS.

16 . What s cloud seeding?

It involves seeding clouds with tiny particles to bring more precipitation from them. There two ways to seed clouds. The first uses the coalescence process of rain formation. Small water drops are injected into the base of a cloud, which grow in size by collision with other particles until they are heavy enough to fall down.

The second method employs the ice crystal process of rain formation where small particle of silver iodide are injected into a cloud. These particles act as ice crystals. Water vapour from the surrounding liquid droplets evaporates and freezes onto the iodide particles, which grow larger. The growing crystals eventually become heavy enough to fall as precipitation.


Earth Sciences in India

Compilation of  Q & A format of the book Science and Technology for Civil Services Examinations, Tata McGraw Hill Publication

Chapter 33. Earth Sciences in India

1. Describe India’s coast line, economic zone and continental shelf.  How far does the maritime belt , economic, belt and Fisheries belt extend.   Page (470, and 480)

India’s coastline sprawls over a distance more than 7500 km long, and its territory includes 1256 islands. Its exclusive economic zone covers about an area of 20 lakh and the continental shelf stretches up to 350 nautical miles from the coast.

The continental shelf comprises of the sea bed and sub-soil of the submarine areas that extend beyond its territorial sea throughout the natural prolongation of its land territory to the outer edge of the continental margin, or to a distance of 200M from the baselines from which the breadth of the territorial sea is measured, where the outer edge of the continental margin does not extend up to that distance.

Territorial waters, or a territorial sea, as defined by the 1982 United Nations Convention on the Law of the Sea ]is a belt of coastal waters extending at most 12 nautical miles (22 km; 14 mi) from the baseline (usually the mean low-water mark) of a coastal state. The territorial sea is regarded as the sovereign territory of the state, although foreign ships (both military and civilian) are allowed innocent passage through it; this sovereignty also extends to the airspace over and seabed below.

If the distance between two States is less than 24 miles, a line drawn midway is the Fisheries belt. Within this restricted territorial belt, the littoral state (adjacent state) has exclusive rights to fish)

An exclusive economic zone extends from the outer limit of the territorial sea to a maximum of 200 nautical miles (370.4 km) from the territorial sea baseline, thus it includes the contiguous zone. A coastal nation has control of all economic resources within its exclusive economic zone, including fishing, mining, oil exploration, and any pollution of those resources. However, it cannot prohibit passage or loitering above, on, or under the surface of the sea that is in compliance with the laws and regulations adopted by the coastal State in accordance with the provisions of the UN Convention, within that portion of its exclusive economic zone beyond its territorial sea. Before 1982, coastal nations arbitrarily extended their territorial waters in an effort to control activities which are now regulated by the exclusive economic zone, such as offshore oil exploration or fishing rights .Indeed, the exclusive economic zone is still popularly, though erroneously, called a coastal nation’s territorial waters.

Contiguous zone

The contiguous zone is a band of water extending from the outer edge of the territorial sea to up to 24 nautical miles (44 km; 28 mi) from the baseline, within which a state can exert limited control for the purpose of preventing or punishing “infringement of its customs, fiscal, immigration or sanitary laws and regulations within its territory or territorial sea”.

2. Describe the organization of Ministry of Earth Sciences. What areas are covered by it? 470/ 100 words
it was created in 2006 after merger of India Meteorological Department (IMD), National Centre for Medium Range Weather Forecasting (NCMRWF), Indian Institute of Tropical Meteorology (IITM), and Earth Risk Evaluation Centre (EREC) with the then ministry of Ocean Development.

The ministry’s mandate is to look after atmospheric sciences, ocean science and technology and seismology in an integrated manner. It has to formulate and implement programmes relating to long term economic and technological development. It seeks to create a framework for understanding the complex interactions among key elements of the earth system.

3. What services does the Ministry of Earth Sciences provide? 471
it provides the nation with services in forecasting the monsoon, ocean state, earthquakes, tsunamis and other phenomena related to earth systems. It also deals with science and technology for exploration and exploitation of ocean resources and play a nodal role for Antarctic/Arctic research.

4. Write a note in hundred words on the Antarctica Treaty
It came into force in 1961 after ratification by 12 countries then active in Antarctic science. The treaty covers the area south of 60 degree south latitude. Its objectives are to demilitarise Antarctica, to establish it as a zone free of nuclear tests and disposal of radioactive materials, and to ensure that it is used for peaceful purposes only; to promote international scientific cooperation in Antarctica; and to set aside disputes regarding territorial sovereignty.

The treaty remains in force indefinitely. 44 countries have acceded to it. 27 nations, including India have consultative status. They have adopted over 200 recommendations and negotiated 5 separate international agreements, collectively, these are known as the Antarctic Treaty System (ATS).

5 . What is the significance of Antarctic Research? 100 words 471-472
Antarctica provides great scope for the conduct of scientific research for the benefit of mankind. It is an impressive, pristine laboratory which has enabled scientists and researchers to detect and monitor global environment phenomena such as depletion of the ozone layer, global warming, and sea level changes. It has supplied data crucial to weather forecasting in the southern hemisphere.

Glaciological research provides important data about the heat exchange budget. The earth’s geomagnetic field renders Antarctica especially suitable to the study of polar terrestrial interactions and cosmic rays that travel from outer space.

The continent’s environment provides unique opportunities to study the specialised adaptations of organisms. Human biology and medicine provides information on the physiological adaptation of man to extreme climates and isolation.

6 . Describe in hundred words the Indian Antarctic Research Programme.
It began in 1981, when the first Indian expedition was flagged off from Goa. Subsequently, 25 expeditions have been undertaken, including one to the
Wedell sea and another one to the Southern Ocean for krill ( a kind of fish) exploration.

MAITRI, the Indian station is situated in the Schirmacher Oasis. It has all modern facilities to carry out research in various disciplines such as biology, earth sciences, glaciology, atmospheric sciences, meteorology, cold region engineering, communication, human physiology and medicine. It has a capacity to accommodate 25 people in the winter.

India was admitted to the Antarctic treaty in 1983. It was admitted as a member of the Scientific Committee in Antarctic Research (SCAR) in 1984. India became a member of the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) in 1986 and built its second permanent station ‘Maitri’ in 1988-89.

7 . Describe the activities of the National Centre for Antarctic and Ocean Research (NCAOR)  473

It was established as an autonomous institution in 1998. It is designated as the nodal organisation for the co-ordination and implementation of the Indian Antarctic Programme, including the maintenance of India’s permanent station in Antarctica, Maitri.

8 . What are the activities of the National Institute of Oceanography? 100 words 474
It was established in 1966. The principal objective is to develop sufficient knowledge related to physical, chemical, and biological aspects of the seas through the study of physical process in the ocean including the monsoon, exploration of living resources of the sea, sea-farming technology, bio-active substances from marine plants and animals, development of offshore oilfields, deep sea exploration of minerals, coastal zone and harbour development, studies for effective control of marine pollution, ocean modelling, processing of satellite imagery data and acoustic topography.

The institute is also involved in R&D projects for exploration and utilisation of natural resources of the seas.

9 . What is the Coastal Zone and Islands Programme? 50 words 475
The main aim of this programme is to provide basic data and information required for the effective management of the marine environment, its conservation and develop technological aids for harnessing its resources. To address these issues, we have—

COMAPS (Coastal Ocean Monitoring and Prediction System) envisaging systematic monitoring and modelling of the marine pollution along the coastline.

SELAM (Sea Level Measurement Programme) for precision sea level measurements using modern tide gauges.

Island Development Programme- development of aquaculture techniques to improve the quality of lives in the islands.

10 . Describe India ‘s Ocean Research. 100 words 476

It is being focussed on multi-disciplinary research on the physical, chemical, geological and biological aspects of the Indian Ocean. Ocean vessels can also be used for campaigns in validating satellite oceanographic data, assessment of marine resources and for various technology demonstration activities.

Dedicated cruises were also undertaken for summer monsoon and winter monsoon coverage of the Bay of Bengal as well as the Andaman sea. A centralised FORV (Fisheries Oceanographic Research Vessel) Data and Referral center has been set up at Kochi. Survey and exploration of poly-metallic nodules is also being carried out in about 100 blocks to refine resource estimation further and to identify first generation mine sites.

With a view to protecting and preserving the marine environment, the quality of coastal waters is being continuously assessed at many locations along the coast. The two indigenously built coastal vessels- Sagar Purvi and Sagar Paschimi are being utilised for continuous monitoring of pollution levels in the coastal areas.

Sagar Kanya and Sagar sampada have been carrying in surveys for discocering economic resources of India’s exclusive economic zone.

11 . What is the National Data Buoy Programme? 100 words  476
Collection of time series observations of oceanographic and surface meteorological parameters over Indian seas are necessary to improve oceanographic services and predictive capability of short-term and long-term weather/climatic changes. The National Data Buoy Programme was started in 1997 for such observations.

These data buoys carry sensors to measure wind speed, wind direction, air pressure, air temperature, conductivity, sea surface temperature, current speed, current direction, and wave parameters. The buoys are equipped with global positioning system, beacon lights and satellite transceivers. Some buoys can measure parameters like radioactivity, light attenuation in three wavelengths and dissolved oxygen. Power to the buoys is provided by solar panels and chargeable battery packs.

Applications of this programme include Environmental impact assessment, Meteorology, oceanography, fisheries, validation of satellite data, offshore installations, ports and coastal structures, and shipping.

12. Marine organisms have attracted attention as a potential source for drugs. Explain in 100 words 477
Dozens of promising products, including cancer therapy made from algae and a painkiller taken from snails, are in development at research laboratories. Other products, such as an anti-inflammatory drug extracted from the Caribbean sea whip, and a potential antiosteoporotic drug of hexacoral origin are under review.

Among other areas of research are the discovery, development and production of drugs from marine bacteria, fungi, microalgae, sponges and opisthobranch molluscs.

After successful completion of clinical trial, the systematic collection, extraction and biological evaluation of seaweeds, mangroves, anemones, sponges, starfish, seahorses would be carried out to identify other potential drugs. Product development is on-going in 7 areas- anti-diabetic, anti-hyperlipidaemic, anti-anxiety, anti-hyperglycaemic, anti-bacterial, anti-tumour and larvicidal.

13. What is COMAPS? 478
The Coastal Ocean Monitoring and Prediction System (COMAPS) has been in operation at 82 locations for collection and analysis of 25 parameters relating to physical, chemical and biological characteristics of water and sediments. Based on this data, the areas of concern have been identified and steps are being taken to prevent and control the causes of pollution.

14 . What are submersibles? 478
A submersible is a small vehicle designed to operate underwater. A feasibility study has been carried out regarding the possibility of developing indigenous submersibles capable of operating at a depth of 600m in the first phase and 2500m in the second phase.

15. Describe the integrated coastal and marine area management Programme (ICMAM)? 50 words. 478
The programme has two components, namely capacity building and development of infrastructure for R&D, Survey and Training for ICMAM. The second component covers 4 activities- development of GIS (Geographic Information System) based information system for 11 critical habitats in the coastal and marine areas, determination of waste assimilation capacity at selected estuaries along the coast, development of guidelines for environmental impact assessment and preparation of model integrated coastal and marine area management plans.

16.  What are polymetallic nodules? Describe the activities in this field? 100 words
Polymetallic modules on the ocean floor are considered to be a treasure house of much needed metals. The potato shaped, largely porous modules, are found in abundance carpeting the ocean floor. The nodules are of economic importance because they contain, besides manganese and iron, nickel, cobalt, copper, lead, molybdenum, cadmium, vanadium, titanium, of which cobalt, copper and manganese are considered to be of strategic importance.

In August 1987, India became the first country to be allotted 150,000 sq. km of area in the central Indian ocean for exploration and exploitation of polymetallic nodules under certain obligations and was given the status of a Pioneer Investor. The Department of Ocean Development which has been designated as the nodal agency responsible for implementing the deep seabed mining programme, has drawn up a long term plan to fulfil these obligations.

17 . What are the important types of marine data being studied now? 481
The important types of marine data being studied now are bathymetry data, seismic reflection data, seismic refraction data, gravity and magnetic data and geological knowledge.

18 . How are Tsunami warnings given ? (482)

After the devastating Indian Ocean Tsunami, the Department of Ocean Development was given the responsibility of putting in place an early warning system for tsunami and storm surges in the Indian Ocean region with an ultimate objective of saving lives and property. The total cost of this system has been estimated at 125 crores of rupees and is expected to become operational by 3 years,

Physics and Global Environmental issues

Compilation of  Q & A format of the book Science and Technology for Civil Services Examinations, Tata McGraw Hill Publication

1 . What is Photonics? How is it different from Electronics ?  What is the use of Photonics?
Photonics is the study of light, including its generation, propagation and interaction with matter, where light includes more than just visible wavelengths. In photonics, energy and information are carried by photons rather than electrons as in electronics. Photonics use the wave/particle nature of light to create high technology optical materials. They are expected to replace electronic components with optical components

2 . How does Photonics help computers?
It could lead to much higher memory capacities and a significant increase in data processing speed.

3 . In about a hundred words explain the applications of Photonics?
It can be used for bio-medical sensors and instrumentation and capillary electrophoresis, digital multimeters, power supplies, microwave systems, detection of cracks and corrosion under paint, carrier grade data networks, high-performance internet services and telecom networking products. It can be used for Industrial Process Control, Instrumentaion and Telecom. In Industrial Process Control, we can hace accelerated component life8testing equipment, Lab on a chip etc., In Telecon we can have high performance , intelligent and value added systems. In Instrumentation systems we can detect cracks and corrosion under paint. This work led to prototype detection devices for use on airplane wqings that are in the process of being brought to the market.

4 . Explain in a hundred words the medical uses of Photoncs.
Optical sensors that use photons as sensing elements are becoming increasingly important in the field of non-invasive diagnostics. Spectroscopic techniques are used for minimally invasive early detection of cervical, prostrate, oral and gastro-intestinal cancers. Photoplethysmography (PPG) is a non-invasive method for detecting the blood volume pulse. This information is analysed afrer interfacing with a computer. The bacteria and virus detection defence technology recognises the spectroscopic signatures of bacteria and viruses. Scientists are also developing a sophisticated photonic pill called the compact photonic explorer, that can perform remote diagnostics in the digestive tract and send information back to doctors.

5 . What is Laser?
Laser is a device that produces a very narrow, powerful beam of light. A laser beam can also be transmitted over long distances with no loss of power.

6 . What are the components of Lasers?
A typical laser contains 4 primary components-The active medium may be solid crystals such as ruby. They contain atoms whose electrons may be excited to an elevated energy level by an external energy source. The excitation mechanism or energy source pumps energy into the active medium .A high reflectance mirror at the ends of the optical cavity reflects essentially 100% of the laser light. There is also a mirror that reflects less than 100% of the laser light and transmits the remainder.

7 . Why is laser called coherent light?
A laser produces a thin, intense beam of light which is highly directional. Hence, it is also referred to as coherent light.

8 . What is class 1 laser? 412
A class 1 laser is considered safe for humans. This class includes all laser systems which cannot emit levels of optical radiation above the exposure limit for the eye under any conditions inherent in the design of the laser product.

9 . What is class 2 laser? When is it hazardous?
A class 2 laser system must emit a visible laser beam. Because of its brightness, it will be too dazzling to stare into for extended periods. Momentary viewing is not considered hazardous as the upper radiant power limit of this type is less the MPE (Maximum Permissible Exposure) for an exposure of 0.25 second or less. Intentional extended viewing is however harmful.

10 . What is class 3 laser? Is it harmful to the skin? When does it cause harm?
A class 3 laser system can emit any wavelength, but it cannot produce a diffuse (not mirror-like) reflection hazard unless focussed or viewed for extended periods at close range. It is also not considered a serious skin hazard or fire hazard.

11 . How is laser useful in IT? 100 words
Lasers are particularly useful in recording, storing and transmitting information. The most common use is recording of music and motion pictures on compact disks. Bursts of laser light record such information on the disks in patterns of tiny pits. The laser beam’s tight focus allows much more information to be stored on a CD or DVD . Lasers can also read and play back information stored on these disks. In a CD or DVD, the laser beam reflects off the pattern of pits as the disk spins. Other devices in the player change the reflection into electrical signals and decode them as music.

12 . What is holography?
Laser beams can produce three-dimensional images in a photographic process called holography. Holography is a method for storing and displaying a three-dimensional image, usually on a photographic plate or any light-sensitive material. The exposed plate is called a hologram. Some credit cards contain holograms to prevent counterfeiting,

13 . How does a Laser printer work?
Laser printers use a scanning laser beam to produce copies of documents. Scanning involves movement of a laser beam across a surface. In a supermarket, what looks like a line of light is actually a rapidly moving laser beam scanning a bar code. A bar code consists of a pattern of lines and spaces that identifies a product.
14 . How are lasers useful in Medicine? 100 words
In medicine, the heating power of laser is often used in eye surgery. Highly focussed beams can close off broken blood vessels on the retina. It can also reattach a loose retina. Laser beams pass through the cornea but cause no pain or damage because the cornea is transparent and does not absorb light. Lasers are also used to treat skin disorders, remove birthmarks and shatter gallstones. Lasers can replace the scalpel, in some operations. They reduce bleeding and damage caused to nearby healthy tissues.

15. How are laser light shows created?
Laser light shows are created with scanning laser beams. The beams move so rapidly they produce what looks like a stationary picture. They can thus produce very colourful visual effects.

16 . How are lasers useful in ophthalmology?
The heating power of laser is often used in eye surgery. Highly focussed beams can close off broken blood vessels on the retina. It can also reattach a loose retina. Laser beams pass through the cornea but cause no pain or damage because the cornea is transparent and does not absorb light.

17 . What is a miniature hydrogen bomb explosion? 
In nuclear research, scientists use lasers to create controlled, miniature hydrogen bomb explosions. They focus many powerful laser beams onto a pellet of frozen forms of hydrogen. The intense beams compress the pellet and heat it to millions of degrees. This causes the nuclei to fuse and release energy.

18 . What is a pico second or femto second ?
A pico second is 10-12 seconds. A femto second is 10-15 seconds.

19 . What is line width and how  are lasers relevant here?
By careful design of the laser components, the purity of the laser light (measured as the line width) can be improved more than the purity any other light source. This makes the laser very useful for spectroscopy. It also makes techniques like Raman spectroscopy possible. It can also be used to make extremely sensitive detectors of various molecules.

20 . What is spectroscopy?
Spectroscopy is the study of interaction between matter and radiated energy.

21 . How are lasers helpful in measuring earthquakes and land surveys?
Laser beams directed over long distances can detect small movements of the ground. Such movements help geologists involved in earthquake warning systems. Laser devices used to measure shorter distances are called range finders. Surveyors use the devices to get information needed to make maps.

22. What are optical tweezers?
Optical tweezers involve grabbing, moving and generally manipulating, without any physical contact, micrometre-sized particles. This is based on the optical dipole or gradient force. They are based primarily on Newton’s laws and fundamental optics, and this has enabled an unprecedented insight into biological molecules such as the DNA.

23 . What exactly is Photonics?
Photonics deals with generating, controlling and detecting light and is based on a variety of materials. It also plays a major role in sensing.

24 . The human vision system is the ultimate interface between electronics and photonics. Explain
The eye and the brain work in perfect harmony. We sense others by photons, the quantised light waves that impinge on the retina. The optical information received by the retina is quickly converted into electrical impulses. These impulses travel through the optic nerve to the visual cortex of the brain.

25 .  What is EPIC?
Seamless union of electronics and photonics is the ultimate goal of the program for developing a single tiny chip of silicon that can not only manipulate and guide photons, but also convert photons into electrons and process the electrical signals. This program is called EPIC. It seeks to produce a single chip capable of emulating the eye and the brain.

26 . Describe the Photonics Development Programme in India 50 words. 417 -418
Its short term objective is to nurture photonic technologies, including those that are relevant to IT and optical communications such as optical fibres, optical amplifiers. The long term objective of the programme is to ensure that India has a presence as a technology developer in the broader application domains of photonics that include polymers used in nano-photonics and photonic crystal fibres, besides having a presence as an optical communication developer.

Chapter 31 Global Environmental issues

1 . Describe the Stratospheric  Ozone layer . 50 words
The stratospheric ozone layer is found in a broad band, generally extending from about 15 to 35 km above the earth. The profile and concentration of this layer depends on the dynamics of the winds, as well as sunlight and trace pollutants. The layer is surprisingly thin. But it is sufficient to filter out the bulk of the ultraviolet radiation that would otherwise reach the earth’s surface.

2 . What is the importance of this layer?   100 words
Life on earth evolved under the protection of an ozone layer thick enough to remove much of the UV-B radiation known to damage cellular DNA. YV-B rays are of high energy, which allows them to penetrate deeply into water, leaves and skin. It can harm metabolism of cells and damage genetic material. It could lead to increased incidence of skin cancer, eye damage and cataracts as well as inhibition of the immune system. Less stratospheric ozone also means less local heating. A weakened Ozone layer has also effects on climate. It could lea to decreased crop yields, damage to forst eco systems etc.,

3 .  What is stratospheric Ozone Destruction.? What are its consequences? 100 words
Ozone can be destroyed by chemicals that react with it directly, or by those that react with the oxygen atom temporarily freed when an ozone molecule splits. But, the only ozone destroyers of concern are those that can participate in a catalytic cycle, where one trace catalytic chemical can be responsible for destroying hundreds of thousands of ozone molecules. The detection of significant concentrations of CFCs in the lower atmosphere was coupled with the finding that photochemical and rain-out processes that usually remove most pollutants were not working for these compounds. They are extremely stable and have atmospheric lifetimes of 50 to several 100 years. Lesser stratospheric oxygen means less local heating, and that more ultraviolet light is transmitted to the earth’s surface causing skin cancer and damage to genetic material.

4. What is the Ozone Hole? What are its effects? 424
A massive continental-sized hole appeared over the continent of Antarctica in the spring of 1980. In the 1990s, this hole grew in size. The polar vortex was also responsible for the formation of the ozone hole. The winter stratospheric air over Antarctica is colder than the air elsewhere, which results in the formation of polar stratospheric clouds. This is because the strong confining winds of the polar vortex isolate this air from the warmer lower-altitude air. These cause greater chemical reactions and these chemicals are released during spring which in turn destroys the ozone. Lesser stratospheric oxygen means less local heating, and that more ultraviolet light is transmitted to the earth’s surface causing skin cancer and damage to genetic material.

5 . What is the Montreal  Protocol?424
As evidence emerged on the extent of the threat to the ozone layer, the international community agreed to control ozone-depleting substances and schedule a time-table for completely phasing them out. This agreement is known as the Montreal Protocol.

6 . What are the threats to the Ozone Layer apart from those caused by industry? 50 words  425
The solid rocket strap-on motors used in the most powerful launch systems, such as Ariane, produce copious amounts of HCL. A significant fraction of their exhaust gases is deposited in the stratosphere.. The plume from each launch causes a temporary mini ozone hole.

The chemicals that are replacing CFCs are HCFCs and HFCs. Though they have less chlorine in them as compared to CFCs, they are still ozone-depleting substances.

7 . What are the present threats to bio-diversity?
The present threats are overexploitation of resources such as hunting, introduction of foreign species including predators and diseases and environmental pollution. The most common threat is loss of habitat, due to deforestation, pollution of wetlands and ploughing up of Prairies.

8 . Describe the extent of Massive extinction of modern times.  426-427/50 words
Massive extinctions have occurred 5 times in the earth’s history, most notably 65 million years ago, when 15% of the species including dinosaurs were wiped out. There is strong evidence that we are in the opening phase of the 6th massive extinction. This extinction is unprecedented in both its breadth and speed. In the past 10,000 years, and especially in the last 500, the rate of extinction of species has increased to somewhere between 100 and 1000 times what it was before human history began.

9. What are the benefits of Biodiversity  to  humans? 100 words. 427-428
We derive many benefits from biodiversity. We get useful products from the wild. Nearly 25% of the drugs used today originally came from plants. One famous example is the anti-cancer drug taxol which was originally extracted from the Pacific yew. Other well-known discoveries from plants include quinine, penicillin and aspirin. It is also important to conserve genetic diversity within individual species. The breeding of new strains of pest-resistant crops and livestock is critically dependent on the supply of new genetic variability. This variability has been provided to scientists by wild relatives of domesticated plants and animals.

10 . Benefits of biodiversity conservation come from ecosystems and services. Comment 428
Soil nitrogen, a key element for agricultural productivity, depends on bacteria such as rhizobium, which live in the roots of leguminous plants. Micro-organisms also have the ability to carry out chemical reactions. A major breakthrough in genetic engineering- the polymerase chain reaction technique used to make copies of DNA- was possible because of the discovery of heat-stable enzymes in bacteria living in hot springs.

11. What is the value of Diverse Ecosystem?
Wetlands such as swamps, marshes and mangroves filter large quantities of pollutants from the water. They also serve as breeding grounds for fish, and are thus vital to the productivity of lakes and oceans. Forests and grasslands also absorb pollutants from industries and help purify the air. Plants too need a variety of micro-organisms to grow: bacteria and algae for nitrogen and fungi for phosphorus.

12 . What is the future of biodiversity? 100 words429
Steps have to be taken to stem the tide of the sixth extinction. An international treaty called CITES (convention on international trade in endangered species of flora and fauna) went into effect in 1975 to outlaw the trade of endangered animals and animal parts.

One of the key agreements adopted in Rio in 1992 was the Convention on Biological diversity. It established 3 main goals: the conservation of biological diversity, the sustainable use of its components, and the fair and equitable sharing of the benefits from the use of genetic resources. Preserving endangered eco-systems is an important way to protect the endangered species within them.

13 . What is Green House Effect? 430
Greenhouse effect is the warming of the lower atmosphere and surface of a planet. When the radiation from lands and seas strike certain gases, these substances absorb the heat and become heated. They are then cooled by sending out infrared rays of their own. Some of these rays come back to the earth’s surface, adding to the warming of the earth and the lower atmospheric levels.

14 . What is the relation between Green House Gases and Climate Change?  50 words
Since the 19th century, the amount of carbon-dioxide has increased by 25%, chiefly due to burning of fossil fuels. This and other greenhouse gases absorb the radiation from the earth’s surface, most of which is reflected back to the earth. This increases the temperature of the earth. This could lead to rising sea levels, greater severity of storms, and changing ocean and wind patterns. This affects agriculture, forestry and wildlife.