Filmy Weather (9): Tum Mile, Love in the Time of Rain

The Mumbai rain event of 26 July 2005 spawned several investigations by meteorologists, particularly modellers, to find out the reasons behind this most extreme of extreme events, and to attempt to somehow predict it even in hindsight. It is now the turn of moviemakers to take up this event and make a different kind of story out of it.

“Tum Mile” is a new Hindi movie based upon the Mumbai rain event of 26 July 2005. It was to be released on its fourth anniversary but the release got postponed to 13 November 2009. As chance would have it, while I am writing this blog on 11 November, Mumbai is under the threat of a cyclone and is already experiencing heavy rains! So the postponed movie release is also well-timed!

“Tum Mile”, directed by Kunal Deshmukh, stars Emraan Hashmi and Soha Ali Khan in lead roles. The story is about two ex-lovers who meet again after a gap of six years. They happen to be on the same flight back to Mumbai, and get there only to see the city going through its worst times, with the highest rainfall in history, and they are forced to stick together in this time of crisis. As the metropolis copes with its nightmare, they also struggle with their own situation, and come to terms with their own lives.

R. R. Kelkar

11 November 2009

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

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.

Forecasting Hurricanes and Tropical Cyclones

The American Meteorological Society, on 5 June 2007, issued a policy statement that outlines the state of science of hurricane forecasting in the United States, including hurricane-related hazards, observations, forecasting skills, and continuing challenges. The AMS is a professional body that is not under the U. S. National Weather Service, and it has an independent and authoritative voice. The AMS statement on U. S. hurricanes makes several important points, some of which are applicable to tropical cyclones in general, and are therefore noteworthy for countries like India, which are regularly visited by such storms.

1. Track forecasts: The most heartening aspect of the AMS statement is that there has been a significant improvement in U. S. hurricane track forecasting in recent years. During the 5-year period 2001-2005, the hurricane track forecasts issued by the National Hurricane Center (NHC) of the U. S. National Weather Service had an average error of 65 nautical miles (120 km) for the 24-hour forecast and 118 nautical miles (269 km) for the 48-hour forecast. These errors are about half of what they used to be in 1990.

2. Intensity forecasts: The AMS statement, however, admits that forecasting of hurricane intensity still remains a challenge to forecasters. During the past 30 years, there has not been any noticeable improvement in the forecasts of storm intensity. Large errors typically occur when storms strengthen or weaken rapidly.

3. Warning and over-warning: The statement notes that although the forecasting of hurricane tracks has improved, hurricane warnings continue to be issued for large coastal areas of the U. S. However, the average length of the coastline warned has come down to 510 km in the current decade from 730 km in the preceding one. While only one-fourth of the warning area may actually experience hurricane conditions, some over-warning is justified in the interest of safeguarding life and property. Over-warning ensures that unexpected rapid increases in storm strength prior to landfall or unanticipated changes in the distribution of damaging winds, do not take under-prepared populations by surprise.

4. Rainfall: Prediction of rainfall from landfalling hurricanes is yet another illusive factor, particularly because of the effects of terrain.

5. Storm surge: The highest loss of life due to a hurricane continues to be attributed to the storm surge, which can be as high as 6 m when a strong hurricane strikes a coastline with shallow water offshore. The statement notes that in recent decades, large losses of life due to storm surge had become less frequent in the U. S. However, the rapid growth of the coastal population and related infrastructure, and the increasing complexity of evacuation have led to a greater vulnerability of the coastal communities. This became evident in the case of Hurricane Katrina in 2005, in which the loss of life in Louisiana and Mississippi was estimated to be 1700.

6. Storm surge modelling: Given a sufficiently accurate forecast of the hurricane’s track and surface wind structure, and the required topographic and bathymetric data, numerical models should be able to make a precise prediction of the inundation by storm surge. However, the AMS statement cautions that because of the uncertainty in hurricane forecasts, evacuation decisions should not be made on the basis of individual runs of a single storm surge model.

7. Seasonal prediction: The statement acknowledges the low confidence associated with seasonal predictions of hurricane activity in the Atlantic basin, particularly when applied to smaller areas of the basin.

8. Preparedness measures: The statement says that in order to build up a higher resilience to the hurricanes, there is a need for greater involvement of other disciplines including engineering, ecology, biology, the social, behavioral, and economic sciences, and public policy. A comprehensive framework is also essential for ensuring public understanding of the hurricane threat and the ability to take appropriate action to mitigate the loss of life and property that links the entire process — from data collection to forecast to communication of the societal impact.

9. New technology and modelling: According to the statement, the forecasts would benefit from continuing improvements in the observational systems such as Doppler radars and satellites that can effectively observe the details of the storm core, data assimilation techniques and modelling capabilities on both the global and regional scale, particularly in ocean–atmosphere interactions. More effective remote sensing of ocean surface winds can also improve the initial detection of storms and their further analysis and forecasting.

The complete text of the AMS statement is available online at http://www.ametsoc.org/POLICY/2007hurricaneforecasting.html.  

A Rational View of Climate Change: (1) Tropical Cyclones

One of the pre-conditions for the formation of a tropical cyclone is that the ocean should be warm enough (27 deg C or higher). Tropical storms therefore tend to form only over certain ocean basins and in certain preferred seasons where and when this condition could get satisfied. An increase in sea surface temperature brought about by global warming should, logically speaking, lead to enhanced cyclonic activity. However, it should be remembered here that a warm ocean is only one of the pre-conditions for the formation of a tropical cyclone, and not the only one. Tropical storms do not exist by themselves but are embedded in the general atmospheric flow which does influence them a great deal. And 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. Thus statistical correlations between global warming and the frequency of occurrence of tropical storms cannot be viewed in isolation and without due regard to these other aspects.

Nowadays, whenever there is a major tropical cyclone or hurricane, heightened scientific and media attention gets focused upon global warming as a cause behind the extreme event. Thus Atlantic hurricanes like Katrina, Rita, or the recent Dean, or major typhoons elsewhere, at once result in a “we-told-you-so” stand being taken by climate change enthusiasts. In this context, it is worthwhile to take a look at what tropical cyclone experts from around the world have to say about it. An International Workshop on Tropical Cyclones (IWTC-VI) was organized by the World Meteorological Organization at San Jose, Costa Rica, in November 2006. At the end of the Workshop, the participants issued a statement on the linkage between anthropogenic (human-induced) climate change and tropical cyclones. Since there were 125 delegates from 34 different countries and regions, and since the process was overseen by a committee of the WMO Tropical Meteorology Research Programme TMRP Committee TC2, the statement can be regarded as an authoritative and consensus view of the global community of tropical cyclone researchers and forecasters. The statement is remarkably balanced in its approach and findings and it is very categorical in what it says.

First of all, the consensus statement makes it very clear that no individual tropical cyclone can be directly attributed to climate change. The increasing socio-economic impact that tropical cyclones have been making in recent years is largely because of rising concentrations of population and infrastructure in coastal regions.

Another important point that the statement makes is that as of now, no firm conclusions can be drawn about the influence of global warming on tropical cyclones as there is equal evidence both for and against it.

The statement draws attention to the various difficulties in determining accurate long-term trends in the characteristics of tropical cyclones. The observed multi-decadal variability of tropical cyclones in some regions could be natural or anthropogenic or both. Methods of estimating wind speeds associated with tropical cyclone have undergone changes in recent years and different practices are followed in different regions. In most regions there are no observations from instrumented aircraft flying into tropical cyclones.

The statement accepts that if the climate continues to warm, some increase in tropical cyclone peak wind speed and rainfall is likely to occur. There is, however, an inconsistency between models which project small changes in wind speed and some observational studies which suggest large changes. Also, how tropical cyclone tracks or areas of impact may change in the future cannot be foreseen now.

The statement also refers to the increased vulnerability of coastal areas due to cyclone-related storm surge, if the sea level were also to rise because of global warming.

The text of the Summary Statement on Tropical Cyclones and Climate Change can be read on the web site of the World Meteorological Organization at http://www.wmo.ch/pages/prog/arep/tmrp/documents/iwtc_summary.pdf and the text of the complete statement is available at http://www.wmo.ch/pages/prog/arep/tmrp/documents/iwtc_statement.pdf.

Tropical Cyclones

An article entitled “’Eye’ing the Cyclone” by Prof. R. R. Kelkar was published in the March 2006 issue of Geospatial Today. It covers various aspects like satellite monitoring of tropical cyclones, advances in satellite technology, nomenclature of weather systems, disaster management, cyclone track prediction and influence of global warming. Click here to read.

The Four Winds of the Bible (2)

Unlike the east wind of the Bible which is a distinctly powerful, dry and hot wind, the winds from the other three directions do not appear to have any particular attributes. In fact, the west wind finds a mention just once, in connection with the plague of the locusts, in which it was used to send the locusts away from Egypt (Exodus 10:19). The north wind is said to bring rain (Proverbs 25:23), and there is an instance of a windstorm coming out of the north, accompanied by brilliant flashes of lightning (Ezekiel 1:4). The north and south winds appear to go round and round in an unending course (Ecclesiastes 1:6). The north and south winds are welcome winds; when they blow on the garden, its fragrance is spread abroad (Song of Solomon 4:16). The south wind could be hot (Luke 12:55) or gentle (Acts 27:13).

The four individual winds blowing from the east, west, north and south directions are described in the Bible in the same way as a human observer would describe, even today. We get an idea of the strength of these winds, the weather phenomena associated with them, and their effects. However, the phrases ‘four winds’, ‘four winds of the earth’ or ‘four winds of heaven’ are used in the Bible in a very different manner. The four winds are referred to in the context of extraordinary events or situations as foreseen by prophets, made known to select persons by God in the form of visions, or revealed by Jesus Himself to His disciples.

The four winds are sometimes associated with the four corners of the earth or the four quarters of heaven. This should not be considered as being suggestive of an image of a flat earth having four corners, but should be taken to mean the whole earth. Likewise, the four winds should be construed not as winds blowing literally in only four directions, but as winds blowing in all directions. Such an interpretation is indeed justified, because a wind having any speed or direction can be regarded as a combination of two north-south and east-west components.

A look at the weather charts used by today’s meteorologists would tell that the earth’s atmosphere at any given time is made up of high and low pressure areas in different regions. Winds blow out of and around an area of high pressure or anticyclone, and they would randomly scatter whatever that came in their way. On the other hand, over an area of low pressure or cyclone, intense winds would blow around and into it from all directions, and thus gather instead of scatter.

The power of the four winds of the Bible is tremendous, both figuratively and practically. It can churn the great sea, it can uproot and scatter powerful empires (Daniel 7:2, 8:8, 11:4, Zechariah 2:6). The combined power of the four winds of heaven was to be deployed against the nation of Elam, to scatter the people in all directions (Jeremiah 49:36).

On the contrary, in another situation of a positive nature, the four winds were called upon to gather together and breathe life into the slain so that they may live (Ezekiel 37:9). But of greater significance is the reference to the four winds in the events that would occur when the Son of Man returns in His glory (Matthew 24:31, Mark 13:27). He will send His angels with a loud trumpet call, and they will gather His elect from the four winds, from one end of the heavens to the other, or from the ends of the earth to the ends of the heavens.

There is a third kind of role that the four winds will be playing in the last times. John, in his vision, saw four angels standing at the four corners of the earth, holding back the four winds of the earth to prevent any wind from blowing on the land or on the sea or on any tree (Revelation 7:1). This would amount to a circulation pattern of the atmosphere in which there are no highs or lows whatever, or an atmosphere of infinite calm!

Pioneer British Meteorologists in India: (1) Henry Piddington

We are quite familiar with how a tropical cyclone looks like from space, through the images that weather satellites send down. Television news channels often present animated sequences of the images that clearly show the cloud bands swirling around the centre or the eye of the cyclone, anticlockwise in the northern hemisphere and clockwise in the southern hemisphere.

In the early nineteenth century, little was known about these violent tropical storms, except that they wrecked ships on the high seas and caused untold destruction and loss of life while crossing the coastline. But there was one man who had unravelled their structure and visualized their rotating nature. He was Henry Piddington, first a British sea captain, and then the President of the Marine Courts of Inquiry at Calcutta (now Kolkata). He had made a thorough investigation of a storm that had struck disaster on the east coast of India in December 1789, killing over 20,000 people. He presented his results before the Asiatic Society of Bengal at Calcutta in 1840, and described the storm as a ‘cyclone’, a name derived from the Greek word ‘kuklos’ meaning going around, or encircling, like the coil of a snake.

Piddington introduced this newly coined word in the books that he wrote soon thereafter on the laws that governed the tropical storms. In 1844, Piddington published a book entitled “The Horn-Book for the Law of Storms for the Indian and China Seas”. In 1848, he published an enlarged version of this book, with the title “The Sailor’s Horn-Book for the Law of Storms”. He is said to have published yet another book in 1852, entitled “Conversations about Hurricanes: for the Use of Plain Sailors”. This was written in the style of a ship’s captain training an apprentice sailor, about how to deal with storms, how to know that they are approaching, and how to take advantage of them. The book included transparent storm cards with wind arrows that could help the captain of a ship caught in a storm to sail with the wind into safer waters.  

Piddington was engaged in scientific research in varied disciplines like botany, geology, mineralogy and soil chemistry, besides of course meteorology. He published numerous papers in the Journal of the Asiatic Society of Bengal. He was also the Secretary of the Agri-Horticultural Society of India at Calcutta. At the suggestion of Rev. Dr. William Carey, of the Serampore Mission, who had similar scientific interests, he compiled the English Index to the Plants of India.

It is said that in 1854, Piddington wrote an open letter to Lord Dalhousie that the new port that he was building at Calcutta would not be able to withstand the fury of a tropical cyclone if hit by one.  Dalhousie, however, did not heed this advice. Port Canning was built, but it was indeed destroyed by a cyclone in 1867 and later abandoned.

By 1875, the name cyclone had gained the official acceptance of the international meteorological community. Today, however, tropical cyclones are called by this original name only in India and the adjoining seas, Arabian Sea, Bay of Bengal, and the Indian Ocean. Over other oceanic basins, they are now commonly known as hurricanes or typhoons.

Henry Piddington, who was born in 1797, died at Calcutta in 1858.

(This post is based upon information derived from various sources, printed and web-based, and some of the details may need to be corrected. – R. R. Kelkar, June 2007)