Prof. R. R. Kelkar was recently interviewed by the OPEN Magazine, a weekly published from Mumbai. An article by Madhavankutty Pillai, entitled “So you were afraid of global warming” based on that interview, among other things, has been printed in the 24-30 January 2012 issue of the magazine. To read it online click here:

http://www.openthemagazine.com/article/nation/so-you-were-afraid-of-global-warming

For a pdf view of the article click here

1. “Pyar hua ikrar hua” (Film: Shree 420, 1955)

This song without doubt ranks topmost among all my favourite rain songs. I was very young when I first saw the movie in a theatre. Now when I watch it on dvd or youtube, the song still makes me feel young! It is a classic, will-never-be-forgotten song, filmed in black-and-white.

Shree 420 was about country boy Raj (Raj Kapoor) who comes to the city of Bombay in search of a job, with dreams of making it big in life. He finds life bewildering and unfair, but he also meets a simple and honest girl Vidya (Nargis) and the two fall in love. The storyline of the film gets complicated as Raj climbs the ladder of success but this love story remains at its core. And at the heart of the love story is the song Pyar hua ikrar hua sung by Lata Mangeshkar and Manna Dey under the music direction of Shankar-Jaikishan.

The beginning of this rain song is heralded by thunder and rain. It is a dark night and we see Raj Kapoor and Nargis meeting on a lonely street. They have only one umbrella and they share it throughout the song sequence, mostly standing under it. Sometimes they walk a few steps down the road with whatever protection the umbrella is able to provide. In that day and age, life was simple and love was marked by restraint. The two lovers just stand close, looking intently into each other’s eyes. They hardly touch each other, but tightly clasp the handle of the umbrella. The song has its interludes of laughter and entertainment with Raj Kapoor playing the fiddle for Nargis.

It is easy to see that the entire setting is a studio construction. The roads, buildings and night lights are obviously artificial, even the mist floating around. But the dreams that the lovers see under the leaking umbrella are real and they point to three kids wearing proper raincoats walking past smartly!

2. “Jo haal dil ka” (Film: Sarfarosh, 1999)

Sarfarosh was a film that dealt with the issue of cross-border terrorism. The plot was woven around the lives of police officer Ajay (Aamir Khan) and his girl-friend Seema (Sonali Bendre). One of the songs in the film, Jo haal dil ka, is my second favourite rain song, primarily so because of its authenticity. It was sung by Alka Yagnik and Kumar Sanu and the music was set by Jatin-Lalit.

The song begins at a surprise party arranged by Seema to celebrate Ajay’s birthday. As Ajay blows off the candles on the cake, the smoke transforms softly into the mist of a faraway monsoon and the couple is sent out of the party crowd to a dream world just of the two of them. They soak themselves in the monsoon rains and in each other’s love as well. Both Aamir Khan and Sonali Bendre wear dresses of identical colours, first red, then yellow and then blue, for each of the three stanzas of the song. The colours provide photographic contrast with the green grass and grey background of the pouring rain. It is a passionate scene. Aamir and Sonali are shown drenched to the skin, and a lot of it is indeed revealed. The close-ups show rain dripping down hair, nose and chin. If the monsoon was supposed to make you romantic, then here is the proof! When the dream sequence ends, it is back to the party for some serious business. Jo haal dil ka was said to have been filmed on location in Khandala.

3. “Taal se taal mila” (Film: Taal 1999)

My third favourite rain song also has authenticity but I like it more because of its delicate and sensitive handling. The film Taal had a complex storyline beginning in picturesque Himachal Pradesh. Mansi (Aishwarya Rai), is the beautiful daughter of a spiritual singer and Manav (Akshaye Khanna) is the son of his close friend.

In the song, Taal se taal mila, we see Mansi’s two sisters in the open countryside when it begins to rain. Mansi extends her hands to collect the first raindrops in her palms, while her sisters run for shelter which is not to be found. The three girls not only listen, but sing, clap and dance to the rhythm of the falling rain. The music is A. R. Rahman’s and the singers are Alka Yagnik and Udit Narayan.

This is what they sing:

Dil ye bechain ve, raste pe nain ve…
sawan ne aaj to, mujhko bhigo diya,
Aa ja sawariya aa aa aa aa,
Taal se taal mila…

The setting of the song is absolutely natural and appropriate to the lyrics. The girls dance in angelic white dresses with flowing dupattas, prominent against the background of the lush green earth, grey monsoon skies and the blue mountainside. In a very tenderly shot scene, Mansi sheds some of her wet clothing, and abandons herself to the music of the monsoon. But out of nowhere comes Manav, protected by a raincoat and equipped with a camera. Mansi is dazed by the realization that her sawariya has in fact been there all along, watching her movements and capturing them on his camera.

4. “Tum se hi” (Film: Jab We Met, 2007)

The film Jab We Met tells the story of young but depressed businessman Aditya (Shahid Kapoor) from Mumbai who by chance meets on a train a Punjabi girl Geet (Kareena Kapoor). As the story develops, Aditya’s depression gives way to confidence and success.

Tum se hi, sung by Mohit Chauhan to Pritam’s music direction, is a song shot in a modern office environment with intervening dream sequences. Aditya is shown picking up a guitar in his office and then singing for his office staff and moving in and out of conference halls. But his mind is not really there and he sees Geet everywhere. We see him stepping out of his chauffer-driven car into the rain while brushing aside the umbrella held out for him. He imagines Geet to be on the street and he joins her in an impromptu dance. The high point of the song is when he picks her up in his arms and raises her high. The camera captures their swirling motion from above, showing raindrops falling from all sides and centering on the couple. The dream sequence ends with the beginning of a press conference in reality.

I like this rain song because of its modern setting, and imaginative camera angles, but more so because it brings out so naturally the spontaneous romantic feelings generated by the monsoon rains.

5. “Iktara” (Film: Wake Up Sid, 2009)

Wake Up Sid is a film about two young people, Sid (Ranbir Kapoor) and Aisha (Konkona Sen Sharma). Sid is a student in Mumbai and son of a rich father, and Aisha has come to Mumbai in search of a career as a writer. At their first meeting, which is in summer, Sid tells Aisha about the beauty of Mumbai’s monsoon and that she has to only wait for the monsoon to arrive to see its charm. Sid and Aisha become friends, then a bit more than just friends. Aisha soon makes her debut as a writer and Sid finds that his future is in photography. They do part ways, but only temporarily.

The sweltering summer of Mumbai comes to an end with the arrival of the monsoon. Sid stretches his arm outside the window of his luxurious home and Aisha puts her hand out of the window of her taxi. They are both touched by the raindrops of the first monsoon shower, emotions are rekindled, and they eventually meet again, at the same spot on Mumbai’s shoreline where they had first met. They both get drenched in the first downpour of Mumbai’s monsoon and at last they are able to say ‘I love you’ in their first passionate embrace. The song ‘Iktara’ plays in the background: “Je naina karun band band, beh jaye boond boond, tadpaye re, kyun sunaye geet malhar de…”

In the film Wake Up Sid, Iktara has two versions, one sung by Kavita Seth and Amitabh Bhattacharya and the second one which I have talked about here is sung by Tochi Raina. The music is by Shankar Ehsaan Loy.

I have included Iktara in my list of favourites not because it is a great rain song but because it has a message. It tells us that just as the monsoon keeps us waiting, life as a whole expects us to be patient. All things happen in the fullness of time, to use that Biblical phrase. If we could plan our life as per our own thinking and to our convenience, how boring it would be!

The countrywide averaging of rainfall over India is, therefore, done by multiplying each rainfall value by a weight that represents the area, and an area-weighted average is obtained. Otherwise, if just a simple average be calculated, localized heavy rainfall values, like say over Cherrapunji, would make it unrealistically high.

Way back in 1886, Henry F. Blanford, the first Head of the India Meteorological Department, derived the annual average rainfall of India using a most ingenious method. He used a copy of a large rainfall chart of India on the scale of 1 inch: 64 miles. He then cut it into 25 sections, for the most part following the boundary lines of the rainfall increments. Each fragment of paper was then actually weighed on a sensitive chemical balance. Its area was computed from the weight by comparison with that of a standard area on the chart. The average rainfall in each fragment was computed from the rainfall of all stations within it. The weighted average of the annual Indian rainfall was then obtained by multiplying the weights of the pieces of paper and the rainfall, and then dividing the sum of the products by the sum of the weights of all the pieces. Blanford’s average annual rainfall value turned out to be 42 inches or 106.7 cm for the Indian region including Assam but excluding the Himalayas and the Burmese peninsula. (Reference: The Rainfall of India, Indian Meteorological Memoirs, vol. III, 1886, 658 pp)

Putting it differently, one can say that the year 2011 was the coolest of the top ten warm years.

Why this coolaveri di?

However, according to news reports, there are second thoughts about the venue. And the rethinking is not due to an adverse political climate but because of unfavourable weather conditions.

Delhiites are quite aware of the fact that in the last week of December, Delhi weather can be at its worst. Minimum temperatures usually drop to around 4 degrees, there is a good chance of rain, and of course there is fog.

In the heat of the moment, these cold facts were perhaps disregarded while fixing the date of Anna’s fast on 27 December at Delhi. So now, the news reports say, the venue of the fast is likely to be shifted to Mumbai’s Azad Maidan. That will be at a safe distance from a western disturbance as well as a political one. It is good to be weatherwise if not otherwise!

The now-forgotten Hindi film of 1951, Naujawan, had this can-never-be-forgotten song, sung by Lata Mangeshkar under the music direction of S. D. Burman:

Thandi hawayen, lehra ke aaye
Rut hai jawan, unko yahan, kaise bulaye

It was picturised on Nalini Jaywant, dancing sweetly to the rhythm of the cool winds while thinking of Prem Nath. The artificial flowers and branches in the studio sets were made to sway gently as if to prove that the winds were indeed there. There were a couple of dream sequences interspersed in the song.

In the 1955 Guru Dutt film, Mr and Mrs 55, there was another cool song:

Thandi hawa, kali ghata, ahi gayi jhoom ke
Pyar liye dole haseen, nache jiya ghoom ke
Kah do koi aaj ghata barase jara dhoom se
Pyar liye dole haseen, nache jiya ghoom ke

It was sung by Geeta Dutt to the inimitable music of O. P. Nayyar and picturised on Madhubala. The scene however had little to do with the beautiful words of the song. The setting was a swimming pool and Madhubala and her companions danced around it holding designer umbrellas as protection from the winter sun. There were no black clouds to be seen in the background and no evidence of chilly winds. But the song is lively and even today makes one jhoom in nostalgia.

In 1961, came this beautiful song sung by Kishore Kumar, with music set by Kishore Kumar, and picturised on Kishore Kumar, in the film Jhumroo:

Thandi hawa, yeh chandni suhani
Ae mere dil, suna koi kahani

Saare haseen nazare
Sapno mein kho gaye
Sar rakhke asman pe
Parbat bhi so gaye

Aise mein chal raha hoon
Pedon ki chhaon mein
Jaise koi sitara
Badal ke gaon mein

In the film, Kishore Kumar is shown walking through the woods, and there are intervening shots of a faraway Madhubala.

All the above songs were shot in black-and-white, but then there was this song in colour in the 1966 film, Do Badan:

Jab chali thandi hawa, jab uthi kali ghata
Mujh ko ae jaan-e-wafa, tum yaad aye

Asha Bhosle sang this song for Music Director Ravi. The song sequence was shot in the open, with a group of happy girls surrounding a sad Asha Parekh who is thinking of a distant Manoj Kumar. There are no dark clouds, but there is surely a strong winter wind as we see colourful flowers and Asha Parekh’s dupatta swaying with it.

Another lively and colourful song was this one from the Hindi film Prince (1969):

Thandi thandi hawa mein dil lalchaye
Haye jawani deewani
Pankh bina ye udti jaye
Haye jawani deewani

It was sung by Lata and the music was composed by Shankar-Jaikishan. In the film it was a vivacious dance number, shot in Kashmir, in which Vaijayantimala and other belles outwitted the wind speed in their actions. Shammi Kapoor was shown just sitting in his car and being wooed by the dancing girls.

In the more recent film, Haathi Mere Saathi (1971), came this song:

Sun ja aa thandi hava
Aha tham ja ae kali ghata

It was a Lata-Kishore duet and music was given by the duo Laxmikant-Pyarelal. The song was picturised in a rather contrived situation, in which Rajesh Khanna and Tanuja were basking in the winter sun on hammocks and were rocking throughout the long song sequence. Apparently the winter winds were pretty strong! But again there were no signs of any dark clouds.

Afterwards, with the advent of global warming, this entire genre of cool songs vaporised into hot air. But even today, we still have these old songs to sing along.

A new dimension has now been added to the picture by recent apprehensions that in the not-so-distant future, the world will witness a new type of population migration which will be caused by climate change. It is feared that people would be forced to leave their own countries ravaged by the effects of climate change and no longer able to offer them sustainable livelihood. This idea of ‘climate refugees’ is fast catching up and there are initial estimates that by 2050 the world would have a billion climate refugees to be taken care of. Conferences are already being held and documents being compiled on how to tackle the economic, political, human rights and even religious aspects of the matter. Formal international negotiations are bound to follow.

In this context I took a quick look at a simple map of the spatial distribution of human population around the globe. What struck me most was the paradox that the population density is low in vast regions of the world where the climate is benign and the population density is highest in many large regions of hostile climate. Had salubrious climate been the first priority for the world’s inhabitants, the population distribution map of the world would have been very different from what it is today. But it is certain that there are many other factors that are important for human living which override simple considerations of climate. These are proximity to water, availability of arable land, abundance of natural resources, land elevation, access to urban facilities, opportunities for employment, and so on. These have been the prime motivating factors for human migration and climate is something that has either been accepted collaterally or prevailed upon.

What is even more notable is the fact that huge populations have continued to live for generations in places which are known to be highly vulnerable to the forces of nature, disaster-prone and even dangerous. The population density in the long coastal belt of India is high because the economic benefits of living there outweigh the occasional damage caused by tropical cyclones and coastal flooding and the potential threat of sea level rise. People in the mountain regions prefer to live there and breathe in the pure air notwithstanding landslides and cloudbursts. People living in the plains like to be near the rivers in spite of the annual monsoon floods. It is clear that millions of people prefer to strike a compromise with an unfriendly environment rather than migrate to regions where they would be safer but otherwise at a disadvantage. For example, the district of Jaisalmer in Rajasthan experiences temperatures reaching 50 C in summer, but it has a population of 6,70,000 which has increased by 32 per cent in the last ten years. Goa, which gets drenched in 300 cm of rain in a year, has a population of 14 lakhs.

Over the ages, human beings have succeeded in getting themselves acclimatized to the places they chose for habitation. They systematically evolved distinct cultures and lifestyles that would match their environment. The climate change of the future is also going to be a long and gradual process in which the temperatures would possibly rise by a degree or two over a hundred years. Going by history, there is no reason why people would not get acclimatized to this slow gradual change as it occurs in the future. This is going to be a natural reaction of the human body and mind and could occur even unknowingly.

To me, as of now, the fear of large-scale population migration due to climate change seems to be more of a myth and a far stretch of imagination. If by 2050, there are going to be a billion climate refugees in a global population of 9 billion, one out of every 9 inhabitants of this planet would be a climate refugee! What a prospect! Are we all just slaves of climate to be driven only by climate change? Climate woes seem to be more in the minds of the climate change enthusiasts and less in the minds of ordinary people.

India is a vast country with a billion-plus population and it has a variety of climates and topographical features. It depends on the monsoons for meeting all its water needs, with its major rivers either originating from the Himalayas or fed by the monsoon rains. Indian agriculture is critically linked to weather and climate. India has faced severe droughts, widespread floods and devastating tropical cyclones. The threat of climate change induced by global warming therefore looms large over India in a real sense. Although this problem has global dimensions, there are certain challenges that are specific to India. It would also like to ensure that the mitigation actions do not themselves become a stumbling block in the path of sustainable development.

India has reason to be concerned about the likely impacts of climate change on at least six major fronts:

1) Change in the amount and distribution pattern of monsoon rainfall, which is India’s only source of water

2) Effect of temperature rise and change in the rainfall pattern on agricultural production and its impact on food security

3) Possible increase in the frequency and intensity of tropical cyclones over the Bay of Bengal and Arabian Sea, which cause heavy losses of life and property in the coastal regions

4) Threat of sea level rise to India’s 7,500 km long coastline including the Andaman, Nicobar and Lakshadweep islands

5) Retreat of Himalayan glaciers and its effect on the Indian rivers which originate in the Himalayas

6) The possible effect on the health of the population arising from the growth of vector-borne diseases due to rising temperatures

Monsoons: Many investigations have addressed the above concerns using global climate models. Since India is a country of sub-continental dimensions and phenomena like the Indian monsoon are a major component of the global atmospheric circulation system, it is not illogical to use global models for this purpose and many significant results have indeed been obtained about likely climate change over India. However, it has to be accepted that global models have a coarse resolution of 250 to 500 km and the results cannot bring out the finer features such as orography-induced rainfall. Moreover, monsoon processes show up quite differently in different climate models. In fact, several global models have not even been able to capture the basic climatology of the Indian monsoon on either spatial or temporal scales or both. This casts a shadow of doubt on the projected anomalies of temperature and rainfall when the mean values are themselves uncertain. Paradoxically, many models indicate a weakening of the monsoon circulation but an intensification of the rainfall and an extension of the monsoon season. The projected increase in monsoon precipitation has a wide difference across models, ranging from 3 to 17 %.

The only regional model used in climate change assessments over India is the Hadley Centre’s high-resolution (50 km) regional climate model, PRECIS (Providing Regional Climates for Impact Studies). The results that have become available as recently as in August 2011 are again not free from uncertainty. They provide more of a qualitative direction than a quantitative estimate, and the experiments need to be repeated with multiple emission scenarios and multiple models. The indications are that the summer monsoon precipitation over India may be 9 to 16% more in the 2080s compared to the 1970s, but the rainfall may in fact decrease over some regions of the country. Also, the rainfall distribution in terms of the number of rainy days in the monsoon season is likely to change.

The results of the climate model runs, both global and regional, have to be viewed against the observed fact that the all-India summer monsoon mean rainfall has not show any statistical trend whatever over since at least 1875. Today, when even seasonal scale monsoon predictions are difficult to make and often go wrong, like in 2009, making climate scale monsoon predictions over the next 50 or 100 years remains a formidable challenge. There are only a few global models that can be trusted with this job and there is no single climate model currently available nationally or internationally that can be truly relied upon from all angles pertaining to the monsoon for purposes of policy making.

Agriculture: There have many investigations into the likely effects of climate change on Indian agriculture. However, many of them have considered only baseline shifts in temperature and rainfall, while it is well-known that Indian agriculture is extremely sensitive to the timing of wet and dry spells, heat and cold waves, etc. The incidence of crop pests and diseases is a major weather-dependent imponderable and it can very adversely impact the crop yields. Simplistic models often give rise to alarmist results and what are required are very robust models that would incorporate the diverse inputs that determine crop production.

Tropical cyclones: Tropical cyclones over the Bay of Bengal and the Arabian Sea are much fewer in number than those in the Pacific and Atlantic basins, but they have been responsible for comparatively much heavier losses of life and property in the countries of the south Asian region. One of the pre-conditions for the formation of a tropical cyclone over the ocean is that the sea surface temperature (SST) should be 26.5 °C or higher. Tropical storms therefore tend to form only over certain ocean basins of the world and in certain preferred seasons where and when there is a possibility of this condition being satisfied in the first place. The primary effect of global warming, logically speaking, would be to cause the climatological SST isotherm of 26.5 °C to spread out and so favour the formation of tropical cyclones over a larger oceanic area than at present. However, it should be remembered here that a warm ocean is just one of the many pre-conditions for the formation of a tropical cyclone, and not the only one. Further, it is not only the number of tropical storms that is important, but also the peak intensity that they reach, and the length and orientation of the tracks that they follow. Hence, statistical correlations between global warming and the frequency of occurrence of tropical storms cannot be derived or viewed in isolation without due regard to these other aspects.

The number of cyclonic storms over the north Indian Ocean constitutes a small statistical sample, the number of severe cyclonic storms is still smaller and the instances of storms developing into supercyclones are just a few. Further, the number of landfalling systems varies widely across different sectors of the Indian coastline making some states more cyclone-prone than others. Therefore, it is difficult to draw robust conclusions from a statistical analysis of historical data and derive periodicities or trends. Although there is some evidence of an increasing trend, it cannot be extrapolated simplistically into the future. A lot of modelling effort is required to be put in, including factors such as projections of the sea surface temperature so that more credible and realistic conclusions can be drawn.

Sea level rise: The sea level at a given place is influenced by several local factors such as coastal ocean temperature, salinity, wind, atmospheric pressure and ocean currents. The sea level is also affected by the changes in coastal geometry resulting from sedimentation, coastal erosion, storm surges and the action of waves. Tide gauge observations are available for some Indian coastal stations since the mid-nineteenth century and they have shown that mean sea level along the east coast of India is higher than that along the west coast. Sea level trends derived from historical tide gauge records are sensitive to the choice of stations and the data period analyzed but there is no evidence of a monotonic rising trend at any of them.

The prime advantage of satellite altimetry over tide gauge measurements is that satellite-derived sea level data are available across the oceans and not just on the coast. Satellite measurements have shown that over the Arabian Sea and the Bay of Bengal, sea level rise in recent years has been negligibly small and the sea level has in fact exhibited a fall in some parts.

Different sectors of the long Indian coastline have different physiographic and environmental characteristics. Problems such as erosion, flooding, subsidence, salinization and deterioration of local ecosystems like mangroves already prevail in the coastal regions. Anthropogenic factors also play a role in the deterioration of the environment of the coastal zone. There is, however, a growing tendency to attribute all sea level rise observed anywhere on the coast entirely to global warming, which needs to be curbed and a balanced view taken considering other possible reasons as well.

Himalayan glaciers: The Himalayas, including the Karakoram range, constitute the largest glacier system in the world outside of Antarctica and Greenland. Scientific observations of Himalayan glaciers were started about a hundred years ago. The snout of the Gangotri glacier in Uttarakhand was mapped in detail way back in 1935 and it had shown signs of retreat even at that time. After the 1970s remote sensing satellites have made it possible to carry out glacier mass balance investigations on a large spatial scale. The retreat of glaciers has assumed great importance in recent years as it is being projected as an indicator of the current global warming. In the case of Himalayan glaciers, however, the issue is also of great practical concern as India’s three major river systems, Ganga, Yamuna and Brahmaputra have their origins in the Himalayas.

Observational evidence indicates that the Himalayan glaciers have been exhibiting a continuous secular retreat since the earliest recording began in the mid-nineteenth century, and the retreat in the recent years in not unusual. Another interesting and important point is that not all of the Himalayan glaciers have been retreating. Making high quality and reliable measurements of glacier retreat at remote and inaccessible locations in the Himalayas is difficult but is greatly desirable. Otherwise one can very easily arrive at wrong and threatening conclusions. In fact many studies have shown that it is premature at the present time to say with certainty that the retreat of the Himalayas glaciers is attributable to the current global warming. Glaciers are known to be influenced by several geophysical features and local climate fluctuations and it is particularly difficult to correlate individual snout movements to large scale global warming.

Vector-borne diseases: The PRECIS model has been used recently for malaria incidence investigations and updated results under the A1B scenario have now become available for many parts of India. By the 2030s, compared to the 1980s, the Himalayan region and northeastern states of India are likely to be adversely affected by an increase in the transmission window, while the effect may be minimum over the Western Ghats and even beneficial over the east coast. Here again, such results have to be considered with due care and caution, since the incidence and spread of malaria is governed not just by temperature and humidity but by several other socioeconomic factors not related to climate such as urbanization, population migration, health infrastructure and intervention practices. For proper preparedness planning, there is a great need to construct comprehensive models which can envisage how these factors will evolve over time, with global warming being one of the inputs and not the only one.

Since 1982, the Indian Space Research Organisation has launched a series of geostationary satellites that have provided a continuous meteorological coverage of the Indian region and the surrounding land and Indian Ocean regions. Four satellites in the INSAT-1 series, three in the INSAT-2 series, the dedicated Kalpana-1 satellite, and the current INSAT-3A satellite, have carried a total of nine VHRR instruments so far, besides the CCD cameras on the more recent satellites. The next satellite, INSAT-3D, to be launched soon, will have an advanced 6-channel imager and a 19-channel sounder. However, these satellites have primarily been designed towards meeting the requirements of operational meteorology in India.

Megha-Tropiques is the first satellite of the Indian space programme that makes a welcome departure from this philosophy. It is going to make systematic observations of parameters related to climate studies and its sensor configuration is entirely different from the INSAT payloads. Geostationary satellites, because they have to be parked at a height of 36,000 km above the earth’s surface, are not suited for microwave remote sensing as the radiance reaching them is very weak. Megha-Tropiques being in a low altitude orbit is designed to make microwave measurements and it carries two microwave payloads.

Megha-Tropiques is a joint India-France (ISRO-CNES) mission with a shared responsibility for development of payloads as well as launch. The spacecraft was launched by ISRO with its Polar Satellite Launch Vehicle (Flight PSLV-C18) from Shriharikota on 12 October 2011. The expected mission life is 3 years.

The main scientific objectives of the Megha-Tropiques mission are:

(a) To collect a long-term set of measurements with a good sampling and coverage over tropical latitudes to understand better the processes related to tropical convective systems and their life cycle.

(b) To improve the determination of atmospheric energy and water budget in the tropical region on various time and space scales.

(c) To study tropical weather and climate events like monsoon variability, droughts, floods, and tropical cyclones, and their predictabilty.

Megha-Tropiques carries a rare combination of three state-of-art payloads, MADRAS, SAPHIR and ScaRaB designed for measurements of radiative fluxes, precipitation, humidity profiles and cloud properties.

MADRAS (Microwave Analysis and Detection of Rain and Atmospheric Structures), is a passive imaging radiometer operating at five frequencies of 18.7, 23.8, 36.5, 89 and 157 GHz in both H and V polarizations except the 23.8 GHz which has only V polarization. Data from the first three channels has applications in the retrieval of rain over oceanic regions, liquid water content in clouds and vertical integrated water vapour. Their spatial resolution is 40 km. The 89 GHz channel is useful for retrieving convective rainfall over both land and ocean at a resolution of less than 10 km. The 157 GHz channel is meant for measuring the concentration of ice particles in clouds at a resolution as high as 6 km.

SAPHIR (Sounder for Atmospheric Profiling of Humidity in the Inter-tropics by Radiometry) is a microwave sounding instrument. It has six channels in the frequency region of 183 GHz, all having 10 km ground resolution. SAPHIR data will be used to retrieve atmospheric humidity profiles at six levels up to a height of 12 km. After INSAT-3D is launched, SAPHIR soundings will complement the temperature and humidity profiles that will be derived from the INSAT-3D sounder.

ScaRaB (Scanner for Radiation Budget Measurement) is the third Megha-Tropiques payload. It has four channels: Sc1 – Visible (0.5-0.7 µ), Sc2 – Solar (0.2-4.0 µ), Sc3 – Total (0.2-100 µ), and Sc4 – IR Window (10.5-12.5 µ). Sc2 and Sc3 are the main channels of the ScaRaB instrument. ScaRaB will measure fluxes at the top of the atmosphere with a ground resolution of 40 km. Longwave irradiance can be calculated from the difference between Sc3 and Sc2 measurements. Images from Sc1 and Sc4 channels will be used for scene identification and will provide the necessary compatibility with operational satellites like INSAT which have radiometers with similar spectral channels.

The MADRAS payload has been developed jointly by ISRO and CNES France, while SAPHIR and ScaRaB have been developed by CNES. ROSA (GPS Radio Occultation Sensor) is another payload that Megha-Tropiques is flying. This has been procured by ISRO from Italy. ROSA operates at L1 and L2 frequencies of 1575.42 and 1227.60 MHz and will be used for retrieving temperature and humidity profiles in the atmosphere by the GPS occultation method.

India launched the Oceansat-2 satellite on 23 September 2009, which has an on-board Ku-band scatterometer for measurement of surface winds and is already providing useful data on the global oceans. The launch of INSAT-3D with its advanced imager and sounder, is now eagerly awaited. A synergistic utilization of the data gathered from all these satellites is certainly going to lead to a great advancement of the current knowledge of the role of the tropical atmosphere and oceans in the global weather and climate.

The progress of the Megha-Tropiques mission can be seen on the web sites http://meghatropiques.ipsl.polytechnique.fr/ and http://www.isro.org/