Book Review of “Monsoon Prediction” by R. R. Kelkar in Current Science

The 25 June 2009 issue (Vol 96, No. 12) of Current Science carries this review of the book “Monsoon Prediction” by Prof. R. R. Kelkar:

The history of monsoon prediction in India dates back to 1886. India Meteorological Department (IMD) has the distinction of being the first national weather service in the world to start the operational monsoon prediction work. It all started in 1886, when Blanford used the relationship between winter Himalayan snow cover and Indian monsoon for predicting the ensuing monsoon rainfall. Sir Gilbert Walker, in 1910s and 1920s, initiated high-quality research in understanding the monsoon variability and development of statistical models. Since then, meteorologists have been working relentlessly to understand and predict Indian monsoon variability and numerous research papers have been published on this important topic. Many reviews have also been published. Monsoon prediction is now a challenging research area with plenty of scope and opportunity. However, we did not have a good compilation of all the results pertaining to monsoon prediction research. The book under review fills this gap. The author, R. R. Kelkar, who served IMD for more than 35 years was also responsible for operational monsoon prediction in IMD. He has used his rich experience in shaping this useful book. The book also includes a critical analysis of our prediction capability and its future scope and opportunities.

The book contains six chapters, describing the major components of the monsoon, global and regional teleconnections, different methods of seasonal monsoon prediction, characteristics of intra-seasonal variations and prediction, projection of monsoon in the 21st century and finally, problems and prospects associated with monsoon prediction.

The first chapter describes different ways of defining a monsoon, monsoon regions, and major climatological features of the Indian monsoon. There are many ways of defining a monsoon. But for the Indians, it is the annual cycle of rains over the country. Monsoon theories included the simple land–sea breeze theory to a complex theory that involves the atmosphere, land and ocean. Indian monsoon variability is influenced by many components of the global climate system. They are known as teleconnection patterns, linking the Indian monsoon variability to major climate anomalies around the world such as Eurasian snow cover and snow depth, El Nino/Southern Oscillation (ENSO), sea surface temperature anomalies over the Indian and Atlantic oceans, and land surface temperature anomalies.

In the second chapter, various monsoon teleconnection patterns are discussed. Teleconnections with ENSO and snow cover are probably studied more and are discussed in detail. However, a detailed discussion on the role of Indian Ocean climate anomalies (Indian Ocean Dipole and EQUINOO) on Indian monsoon is missing. The relationship between sunspot activity and Indian monsoon is a research area with some renewed interest.

In India, statistical models are extensively used for monsoon prediction (long-range forecast). Most of these statistical models are based on the same principles used by Gilbert Walker in 1920s. IMD now uses an updated statistical model for issuing operational long range forecasts based on the ensemble technique. Chapter 3 discusses the details of these statistical models, including the parameters used in the model. The models include simple linear regression, discriminant models for probability distributions and the latest ensemble method based on projection pursuit regression.

Prediction of the quantum of rainfall during the whole season (seasonal prediction) is useful for planning purposes. However, for the farmers, prediction on intra-seasonal timescales (for example, 15–20 days) is more relevant for their day-to-day operations. Similarly, prediction of intra-seasonal activities such as onset and withdrawal, and the active–break cycles of the Indian monsoon is crucial for agricultural planning. However, little work has been done on this important area. Prediction of various monsoon intra-seasonal elements is discussed in Chapter 4. This is an emerging area of research both in India and abroad. This chapter also includes a brief discussion on the use of atmospheric and coupled general circulation models for seasonal monsoon prediction.

In the particular context of climate change due to global warming, it is important to know the future projections of the Indian monsoon. Chapter 5 discusses the projection of the Indian monsoon behaviour in the 21st century. The chapter starts with a discussion on the observed climate change over India using instrumental datasets, followed by future emission scenarios and climate projections. Even though there is no appreciable trend in the quantum of monsoon rainfall averaged over the country, there are significant trends in monsoon rainfall over different parts of the country. Also, there are temporal changes during the monsoon season. Most of the current climate models indicate that monsoon rainfall would increase in future climate. However, there are many uncertainties in the climate model projections. Most of the current climate models are unable to simulate the observed features of the Indian monsoon in their totality. It is important to understand and appreciate these uncertainties in the global climate models in interpreting and using the future climate-change projections.

In the final chapter, the problems and prospects of monsoon prediction are discussed. There are known limitations of the statistical models, like secular variations of correlation, choice of optimum number of predictors and training period, etc. However, in spite of these known constraints, statistical models continue to be popular for several reasons. The users, while interpreting forecasts from these statistical models, should understand and appreciate the limitations of these models. There are other issues like the definition of all-India summer monsoon rainfall (averaged over the whole country and whole season from 1 June to 30 September), changes in the global teleconnection patterns, especially with ENSO. Statistical models cannot be used for prediction on much smaller spatial and temporal scales. For this specific need, we have to use dynamical models. The future prospects of monsoon prediction are completely dependent on the skill of advanced dynamical models, which showed an improvement in the model skill over the recent years. Specifically, monsoon field experiments and Indian climate research programmes will improve our understanding of the monsoon variability and thus monsoon prediction.

This book is specifically designed on monsoon prediction as it discusses the current state-of-the-art of monsoon prediction, its problems and prospects. It provides a critical analysis on how good we are in monsoon prediction and what are its future prospects in the context of improvement in dynamical models and monsoon field experiments. The book contains a good compilation of useful and updated references at the end of each chapter. The book will be useful to meteorologists, especially operational forecasters and students in meteorology and anyone interested in knowing more about monsoon prediction.

- M. RAJEEVAN

Kalidasa – Kavee kee Shastradnya

An article in Marathi by Prof R R Kelkar entitled “Kalidasa – Kavee kee Shastradnya” was published in the Marathi newspaper “Sakal” from Pune on 23 June 2009.

Click here to read

Kalidasa: The Poet with a Scientist’s Mind

“Meghadoot”, meaning the Cloud Messenger, is a Sanskrit poem of 120 stanzas or slokas, composed by the poet Kalidasa. Briefly, the poem is about a yaksha, who is banished from Alakapuri, takes refuge in Ramgiri, shares his sorrow with a cloud, and requests the cloud to go and tell his beloved in Alakapuri that he is safe. However, Kalidasa has developed this simple theme into a great literary masterpiece of unparalleled beauty. Even after a passage of 1600 years since it was written, Meghadoot continues to captivate the minds of its readers. Rabindranath Tagore, Madhav Julian, Kusumagraj, Shanta Shelke, and many literary stalwarts have translated Meghadoot from Sanskrit into other Indian languages. Kalidasa’s descriptions are so picturesque, that artists have been inspired to paint Meghadoot sloka by sloka. Its translations into several foreign languages have been posted on the internet.

It is said that a poet can see what even the sun does not. There are no limits to a poet’s imagination. Meghadoot, however, stands a class apart from other great poetry, as Kalidasa’s flight of fantasy transcends into the realm of real science which we know today as meteorology. It would be futile to conjecture how or from whom Kalidasa might have acquired his scientific knowledge. Perhaps nature herself was his teacher!

The very first sloka of Meghadoot paints before us a picture of a yaksha, meaning a servant, exiled from his home in Alakapuri, now living in a far away place called Ramgiri, lonely, broken-hearted and worn out, pained by the separation from his beloved. He is counting the remaining days of his sentence. And on the first day of the month of Ashadha, he suddenly notices a cloud, standing alone atop the mountain peak of Ramgiri (“Ashadhasya prathama divase”…sloka 1.1).

Historians are in general agreement that the town presently called Ramtek, near Nagpur, is the location of Kalidasa’s Ramgiri, while Alakapuri might have been in north India somewhere in the Himalayan foothills. It is important to note that the average date of the arrival of the monsoon over the Ramtek region in 400 A. D. was indeed the same as it is today. This is a reassuring fact, particularly in the context of climate change and the doubts that are being expressed about the changes in the monsoon patterns.

Now imagine that Kalidasa’s solitary cloud is standing proudly over the mountain top, overlooking the region around it, announcing the arrival of the monsoon rains to a population that has been suffering from the scorching heat of the prolonged summer. This cloud is spearheading the monsoon front, making sure that the way ahead is clear for the advance of the monsoon. The yaksha looks at this cloud which has such a heavy responsibility (1.3) and pleads with him to undertake an additional task of carrying a message to his beloved (1.4).

The yaksha knows that the cloud is made up of four ingredients: water, wind, electricity and smoke (“Dhoomra jyoti salila marutam sannipatah kva meghah…” 1.5). He is well aware of the different forms of clouds (1.6). Moreover, he also knows that the northern town of Alakapuri, where his beloved is, lies in the path of the monsoon clouds (“Gantavya te vasatiralaka…” 1.7). Today it is known that smoke consists of two types of carbon, organic and black, of which the former helps in cloud formation and the latter absorbs heat. The role of black carbon in global warming is however not yet fully understood. It is mindboggling that Kalidasa should have known about cloud processes in such detail in his times.

In today’s satellite era, it is possible to monitor globally the growth, movement and dissipation of clouds. The average life time of a typical monsoon cloud is at best a few hours. When Kalidasa’s yaksha asked the cloud to go with his message all the way from Ramgiri in central India to Alakapuri in the Himalayan foothills, he seems to be quite aware of this fact. He was sure that one single cloud would not be able to sustain itself along this long journey. So he finds a scientific solution to the problem. He advises the cloud to rest awhile over the several rivers that would have to be crossed on the way and get rejuvenated (“Neetva neelam salilavasanam muktarodhonitambam…” 1.43). The rivers mentioned are Vetravati (1.24), Shipra (1.31), Gambhira (1.42), Ganga (1.53) and others. It is obvious that Kalidasa envisaged a process in which the evaporation from the surface of these large rivers would help in cloud formation and development. Kalidasa’s poetic fantasy and scientific logic go hand in hand to help fulfill the yaksha’s desire. Little research has however been done since Kalidasa’s times till today on how the monsoon is influenced by the rivers that crisscross the Indian subcontinent.

The yaksha thereafter lays down the itinerary of the cloud. He wants the cloud to visit places like Vidisha, Ujjayini and Devgiri, which have great beauty and with which he has strong emotional bonds. He describes them in picturesque detail and entices the cloud to see them. But here again the scientist prevails over the poet and he says that the monsoon winds will surely carry the cloud to the destination (“Mandam mandam nudati pavanaschanukulam yatha twam…” 1.10). The monsoon winds will slowly turn westwards (“Kinchit paschadvraja laghugatirbhuya evottarena…” 1.16). The yaksha is acquainted with the circuitous route of the monsoon and he repeatedly cautions that the cloud must always keep moving to the north (“Vakra pantha yadapi bhavatah prasthitasyottarasham…” 1.27).

At many places, the yaksha tells the cloud to gain height in order to move faster, again suggesting that Kalidasa was aware of the fact that the monsoon winds gathered strength with height, while phenomena such as the tropical easterly jet and the low level jet were discovered by meteorologists only in the last century.

We do not yet have a precise definition of a typical monsoon cloud. But monsoon clouds over northern India are taller than those over peninsular India and are associated with thunder and lightning. At the end of the poem, the yaksha wishes that the cloud and his beloved, the lightning, may never get separated (“Ma bhudevam kshanamapi cha te vidyuta viprayogah…” 2.55).

Kalidasa’s Meghadootam is not only a poem of great beauty but an accurate scientific statement about the monsoon clouds and winds. What Kalidasa wrote about the monsoon 1600 years ago, can be said to be scientifically sound by today’s standards. In some respects, Kalidasa remains ahead of the scientists of the twentyfirst century and they can learn from him and draw inspiration for doing further research in the monsoon.

Prof. R. R. Kelkar
Kalidasa Day, 23 June 2009

Cooking on a Rainy Day

What can you do on a rainy day? Tuck yourself into a warm bed and read a book? Or watch cricket on tv? Or go out and get drenched? There are so many more options.

What do I do on a rainy day? Put on the music system, go into the kitchen, and cook. Here is a recipe for a rainy day:

All Stir-Fry Chicken (or Paneer for vegetarians)

Ingredients:

250 gm boneless chicken
100 gm ginger garlic paste
3 cm long piece of ginger
3 large capsicums (Shimla mirch)
2 large tomatoes
1 lemon (nimboo)
1 large onion
Half packet of tomato puree
Half teaspoon garam masala
Cooking oil
Salt to taste

Cut the boneless chicken into medium-sized cubes. Marinate it in ginger garlic paste for half an hour. Skin the ginger and slice into long slivers. Cut the capsicums and tomatoes lengthwise into long narrow pieces after removing the seeds. Cut the onion so as to form rings or half-rings. Extract juice from the lemon and keep aside.

Heat a little oil in a kadhai or pan and fry the onion rings until they turn dark brown. Keep aside.

Heat oil in another kadhai or in a non-stick pan, and fry the ginger until golden brown. Put in the chicken pieces and stir-fry for 5 minutes. Add capsicum and stir-fry for 5 more minutes. Then add tomatoes and continue for another 3 minutes. Add garam masala and salt, mix well, and fry for 2 minutes. Now add tomato puree and lemon juice, and cook for 3 minutes. Finally add the crispy fried onion and cook for 2 more minutes. Serve hot with rice or roti.

The time for preparation is about 10 minutes and the time for cooking is about half an hour. For making a pure vegetarian dish, chicken can be substituted by paneer.

Book Review of “Satellite Meteorology” by R. R. Kelkar in WMO Bulletin

The April 2009 issue (Vol 58, No. 2) of the WMO Bulletin published by the World Meteorological Organization, Geneva,  carries this review of the book “Satellite Meteorology” by Prof. R. R. Kelkar:

Satellite Meteorology

R. R. Kelkar. BS Publications (2007).
ISBN 81-7800-137-3.
xix + 251 pp.
Price: US$ 26

Observing our weather from space—referred to here as satellite meteorology (SM)—has revolutionized our understanding of how the atmosphere, ocean, land and cryosphere operate and interact as part of a system. By the unique virtue of being global, satellite data have radically transformed the way meteorologists perform numerical weather prediction (NWP). Today, gigabytes of radiances from satellites are routinely assimilated into weather forecast models.

This book traces the fascinating history of satellite meteorology and its application to NWP, starting from the beginning of the space era up to the current state-of-the-art sensors, providing the reader with a comprehensive introduction to remote-sensing, climate monitoring and weather forecasting, with a particular focus on Indian meteorology. In particular, the book covers (and illustrates with nice colour figures) a variety of remote-sensing topics ranging from the orbits of the satellites, the types of radiation they sense, the physical understanding of their measurement and the retrieval of ocean, land and atmospheric parameters, up to the exploitation of their data to study tropical weather systems and constrain, validate and initialize NWP models.

The book constitutes very good material for university students planning a career in physics or Earth sciences, as well as a reference for scientists involved in Earth system research or operational weather prediction, in particular over tropical regions.

The author, R. R. Kelkar, who [was] ISRO Space Chair Professor at the University of Pune, India, has a long experience in satellite meteorology at the India Meteorological Department, and has done a very good job in synthesizing this fast growing field, highlighting its potential,as well as the related challenges and opportunities.

Reviewed by Pierre-Philippe Mathieu

Tornado over India

Tornadoes rarely occur over India, but they do occur. Recently, on 31 March 2009, a tornado with a wind speed of about 250 kmph, and accompanied by a thunderstorm, rainfall and hail, struck Rajakanika block of Kendrapara district of Orissa causing the loss of about 15 human lives and leaving several injured, apart from damage to property. A detailed preliminary report on this event is available on the web site of the India Meteorological Department at http://www.imd.gov.in/section/nhac/dynamic/tornado_orrisa.pdf.

God’s Role in Natural Disasters (2)

As we wander a little away from the busy life of the city, nature begins to present sights that we rarely see. Mountains, hills, waterfalls, lush green plains, rivers, lakes, oceans, beaches, the clear blue sky, bring peace, serenity and tranquility to the spirit within us. When we explore nature further, we begin to feel overpowered by its awesomeness. Raw nature can be disturbing and even frightening, making us think of the mighty hand of God that has shaped all creation. But at times, nature can be angry, furious, relentless and unremorseful. Cyclones, earthquakes, droughts and floods can take the lives of thousands of people and render millions homeless and destitute. And then we ask, “What is God doing?”.

God’s role in natural disasters is clarified in the Bible in the Old Testament, the First Book of Kings, Chapter 19. Here we read about the persecution that the prophet Elijah was suffering under the regime of Queen Jezebel who believed in a god named Baal and King Ahab who did whatever the queen wanted. Jezebel sent Elijah a message that she would get him killed within a day. He was scared and ran for his life towards the faraway land of Horeb. When he was tired, he rested under a tree and asked God to bring an end to his torment by taking his life. But God had other plans for Elijah. He arranged for an angel to give him nourishment every day so that he could continue on his journey.

Strengthened by that food, Elijah travelled forty days and forty nights until he reached Horeb, the mountain of God. There he went into a cave and spent the night. And the word of the Lord came to him: “What are you doing here, Elijah?” He replied, “I have been very zealous for the Lord God Almighty. The Israelites have rejected your covenant, broken down your altars, and put your prophets to death with the sword. I am the only one left, and now they are trying to kill me too.” The Lord said, “Go out and stand on the mountain in the presence of the Lord, for the Lord is about to pass by.”

Then a great and powerful wind tore the mountains apart and shattered the rocks before the Lord, but the Bible says that “the Lord was not in the wind.”

After the violent wind storm there was a powerful earthquake, but the Bible again says that “the Lord was not in the earthquake” either.

There was a third catastrophic event that followed the earthquake. This came in the form of a raging fire, but then again the Bible says that “the Lord was not in the fire.”

So where was God?

The Bible narrative continues to tell us that after the fury of all the three violent natural calamities had abated, came a gentle breeze. When Elijah heard it, he pulled his cloak over his face and went out and stood at the mouth of the cave. Then a voice said to him, “What are you doing here, Elijah?” Some Bible versions translate it as “a gentle whisper”, others as “a still, small voice”.

I Kings Chapter 19 tells us clearly that God may not choose to speak to people through violent nature. He can talk to us directly through our hearts in a still, small voice that we should train ourselves to hear.

Radhanath Sikdar: Through the Haze of Time and Neglect

An article on Radhanath Sikdar entitled “Through the Haze of Time and Neglect” by Ajana Choudhury, R. R. Kelkar and A. K. Sen Sarma was published on the Statesman Online edition of 1 March 2009. Click on the following link to read it.
http://www.thestatesman.net/page.news.php?clid=30&theme=&usrsess=1&id=245496

Alternatively, to read a pdf version, click here.

Kalidasa’s Meghadoot and Monsoon Meteorology

I had delivered a lecture at the Marathi Department of the University of Pune on 9 February 2009 in which I had presented a meteorologist’s view of the poetic fantasies of fourth century Sanskrit poet Kalidasa in his ‘Meghadoot’ and the modern day Marathi monsoon poems of Mangesh Padgaonkar.

Abhijit Ghorpade who attended my lecture, has reviewed and paraphrased my talk in an article in the Marathi newapaper ‘Loksatta’ published from Pune on 22 February 2009.

Click here to read the article.

R. R. Kelkar

U. S. National Weatherman’s Day

According to the U. S. National Oceanic and Atmospheric Administration (NOAA) web site (http://www.crh.noaa.gov/lsx/?n=wxmanday) Thursday, 5 February was celebrated as National Weatherman’s Day in the U. S., commemorating the birth of John Jeffries in 1744. Jeffries, one of America’s first weather observers, began taking daily weather observations in Boston in 1774 and he took the first balloon observation in 1784. “This is a day”, says NOAA, “to recognize the men and women who collectively provide Americans with the best weather, water, and climate forecasts and warning services. Many of us take weather information for granted. Turn on a light switch, you get light. Turn on your television or radio, or check a web site and you get the weather forecast. It’s easy to forget that around the clock, dedicated meteorologists and weathercasters are vigilantly creating forecasts to help you plan your day, and issuing warnings to help keep you safe.”

It is nice to hear some one speaking a kind word about the weathermen, and weatherwomen of course! – R R Kelkar