Mar 23, 2017, (Research Matters):
When cyclone Phailin, cruising at 200 kmph, hit the coast of Odisha on the night of October 12, 2013, India was in the eye of the storm, quite literally. Cyclones are not new to India, but what made it special was how India pulled off an enormously successful evacuation – one of the largest in history – with over 1 million people moved to safer shelters before the cyclone struck. In what could have been a tragedy to enormous lives, this evacuation resulted in just 40 deaths, in contrast to the 10,000 deaths that resulted from the cyclone of 1999. What helped save so many lives here?
Accurate weather forecasts play a significant role in saving thousands of lives around the world. Weather, defined as the state of the atmosphere around us, is very dynamic. Hot or cold, wet or dry, calm or stormy, clear or cloudy, hazy or foggy – each state has some effect on our lives. Farmers look for clouds before sowing seeds, pilots depend on visibility to take-off or land, sailors set the sails of the ship based on the wind and many sporting events are at the mercy of rains. A spell of rain can throw the traffic in Bengaluru out of gear with ease!
With so much at stake, understanding weather is imperative to our survival and has given rise to a new branch of science called ‘meteorology’. Derived from the Greek word “metéōros”, meaning “high (in the sky)", the word meteorology translates to "the study of things in the air". In the Indian context, the understanding of weather has many imperatives. “For a country like India, which is primarily an agriculture based economy, meteorology is very relevant. Monsoon rains showers that last for four months in a year, drive our agriculture and our water requirements and the ability to predict them becomes very critical”, says Prof. J Srinivasan, Professor at the Centre for Atmospheric and Oceanic Sciences (CAOS), Indian Institute of Science, Banaglore. “In my opinion, India should devote more money and resources into meteorology”, he adds.
In recognition of meteorology’s importance to humanity, the United Nations’ World Meteorological Organization has decided to observe the 23rd of March every year as World Meteorological Day (WMD) and has declared the theme for 2017 to be ‘Understanding Clouds’ - a special way to express our thanks to the harbingers of rain.
History of Meteorology
Considered the founder of meteorology, the famous Greek philosopher Aristotle’s work ‘Meteorology’ in 350 BC describes the water cycle responsible for bringing rain. But Indian knowledge about cloud formation and rain, and the seasonal cycles caused by the movement of Earth around the sun dates back to the Upanishads. Varāhamihira's classical work ‘Brihatsamhita’, written about 500 AD, provides clear evidence to the deep knowledge of atmospheric processes that existed in those times. Similar works around the world have enriched our understanding other atmospheric phenomena such as seasons, winds, thunder, lightning, snow, floods, valleys, rivers, etc.
The 15th century marked a new era in meteorology with the invention of the first standardized rain gauge by Prince Munjong of Korea, to measure rainfall. Subsequent inventions of instruments like anemometer (to measure the force of wind), thermoscope (to measure temperature), mercury barometer (to measure atmospheric pressure) and hygrometer (to measure humidity) gave us the ability to measure factors that influence weather.
In addition to these instruments, various scientific theses on the formation of snow, hydrodynamics, kinetic theory of gases, laws of thermodynamics, identification and classification of clouds and classification of wind speeds furthered our understanding on various phenomena in action in the atmosphere. A tangible outcome of these interpretations was the first International Cloud Atlas that was printed near the end of the 19th century.
In order to predict weather based on current conditions, weather observing networks were started in the 17th century where data was collected at regular intervals and sent to a processing centre miles away. The advent of telegraph enabled quick collection of weather observations from a wide area, which was used to produce maps of the state of the atmosphere for a region. In 1860, the first daily weather forecasts made it to the newspapers. In the late 19th century, many countries, including India, established national meteorological services. The India Meteorological Department (IMD), established in 1875, is today the principal government agency in all matters relating to meteorology, seismology and other allied fields.
Trends and Advances in Meteorology
The dawn of 20th century accelerated technological advancements in meteorology - weather satellites, computers and faster communication channels have opened up a new chapter in understanding and forecasting weather. “There have been three revolutionary changes in the field of meteorology in the last century – satellites, computers and communication”, remarks Prof. Srinivasan. “They have revolutionised our understanding of the atmosphere”, he adds.
The launch of the first successful weather satellite, TIROS-1 in April 1960 by NASA, put ‘an eye in the sky’. Since then, many countries like China, India, Russia and those in the European Union, have followed suite and have launched their own series of meteorological satellites. These satellites, equipped with cameras and sensors, rotate the earth in the north-south direction (polar orbiting) or remain stationary with respect to the rotating earth (geostationary).
Satellites can see more than just clouds and cloud systems - city lights, fires, effects of pollution, auroras, sand and dust storms, snow cover, ocean currents, energy flows, etc., and help us paint a picture of the atmosphere above us. “Satellite images provide a better understanding of how precipitation occurs over the oceans, how a storm is born and moves to land, comprehending which was impossible before”, says Prof. Srinivasan. “With satellites, we are now watching over every cyclone and every storm and nothing can hit us as a surprise”, he adds.
Since the beginning of the 20th century, weather forecasting was increasingly being viewed as a problem in mathematics and physics that begged a solution based on calculations and the natural laws of physics, thus giving birth to numerical weather predictions. However, the sheer number of calculations involved in solving mathematical models limited its full potential until the advent of computers. Today, most meteorological organizations use supercomputers that can process tens of trillions of calculations a second, thus increasing the accuracy of prediction.
As our understanding of the atmosphere and various factors at play increases by the day, meteorologists around the world are building robust mathematical models that consider current weather and environmental conditions like temperature, pressure and wind, to predict the future state of the atmosphere. Powered by massive computational ability, these models can now be run with increased resolutions. Simulating small-scale conditions that could catapult a routine thunderstorm or hurricane into a monster is now a simple task.
“We have moved from statistical forecasting to computer based forecasting that involves better models which assimilate data from the satellites. Since our atmosphere is very complicated, predicting major events like cyclones, which was impractical before, is now done with no difficulty”, explains Prof. Srinivasan. Now, meteorologists make accurate predictions for the next 12, 24, 36, 48 and 72 hours, and in the process, help us provide a better response to natural disasters.
The Future of Meteorology
With pioneering technologies like the Internet of Things (IoT) and Big Data what does the future of meteorology look like? “With the way things are going, I am confident that the future of meteorology would be very exciting”, opines Prof. Srinivasan. “Today, sensors are getting smaller and inexpensive, which will revolutionise data collection. The massive power of computing enables us to model complex phenomena in the atmosphere at very low resolution”, he adds.
The field of meteorology is filled with intellectually stimulating challenges like the accurate prediction of monsoon or understanding every movement of clouds at a resolution of about a kilometre from Earth’s surface. “Challenges in this field are plenty to keep one busy for the next fifty years! Solving these challenges would yield dramatic results in the future”, remarks Prof. Srinivasan.
Humanity’s quest for decoding Nature’s ways are never ending and meteorology is no exception. Our small but significant steps in understanding the enigma of weather has now armed us with information that can be the trump card against Nature’s games. What better day than today to reminisce this and hope for clues to solve a bigger challenge like the climate change.