ISRO Lecture series (I) review...

 

Topic: The essence of climate and weather and their implications on society.

 

  Meteorological weather predictions is a subject which is taken very casually and many of us lack with the basic knowledge about the subject. Many of these  predictions are correct, but not all. However there is an improvement is seen as well as is being made in this field and many researches are being carried out.

  What is the difference between climate and weather? What are its effects on the civilisations? How is it predicted? What are the factors determining the weather? These are some basic and interesting facts, however many of us are unaware about these.

  I was indeed lucky to have attended the lecture organised by IMS-DC and ISRC-DC on the behest of Youth climate action day. The speaker Mr. Chandra Kishtawal sir, who is a senior ISRO scientist has very well defined all the basic and useful knowledge regarding the subject. I found it really inspiring and useful and hence felt to share it.  

 

  The first and the most basic thing is the difference between weather and climate.Weather is the atmospheric condition limited to hourly or daily basis, whereas climate of a place is determined as the average weather conditions over long period of time. Just for example, we say the climate at Shimla is very cold but for some day it may not so cold instead there may be bright sunlight on the day, that can be called as the weather at Shimla for that particular day.

  The effects of weather conditions seem to us to be short term, for example, whenever it rains the effect may be seen for few days, or whenever it causes floods then the effect may last for several months, but there is even beyond that. One such instance is when the Earth was formed, initially Earth was a cold planet but later there was a rapid increase in the temperature on the earth's surface. This lead to migration in areas like Africa. This changed the course of civilisation to a great extent, a book named The Long Summer by Brain Fagan describes the event.

   Another example is the war of Panipat fought between Abrahim Lodi and Babur, fought in April 1526. The army of Babur had a huge amount of gun powder and field artillery, that wouldn't be of any use if the war was fought in rainy season and hence Babur planned it in the month of April. If the war was fought in a moist weather the result of the war could have been different. The other example goes back to the birth of Bangladesh which was a result of 1970 cyclone that hid the Bangladesh which was a part of Pakistan that time and had to face a poor disaster management due to the administration centre being in western Pakistan was unable to handle the situation effectively.

 The weather affects the organisation of various sports and events like cricket. It also affects the tourism , agriculture, determines the flow of market and trends ,migration, transport power generation air business etc. The culture of a place, the festivals, rituals, dietary habits, flora and fauna, attitude of people, their costumes everything depends on climate of the place. There are many researches being made to make the weather understanding and prediction better day by day. Several books like The long summer, The great warming and the weather factor describe the effects of these phenomenon in the past. The formation and evolution of civilisations is determined by the climate. That is why it is very important to know and study the weather and climate. This generated the need to study and predict the weather. This need isn't the one which is felt in the recent years but can be seen in the past as well when the man used to depend on the primary activities like fishing and farming. Even then the fishermen would know which part of the year and climate would help them catch more into the seas. Even then the farmers know which crop was to be sown in which part of the year and this knowledge was the result of observations, long term observations.

 This ancient need to study and predict weather has further developed and has reached to a very advanced level and has developed into a separate branch of study. Some predictions for about 80- 90 years from now tell that the temperature on the Earth would rise rapidly which is of course a result of global warming and the areas like Canada which are cold now become a hub for many things. then a forecast of Indian precipitation show that the region of Gujarat would receive a relatively high rainfall and would favour agriculture conditions in future.

  Some observations also show that the air quality in India, Especially in northern India is getting worse. There is an increase in the deaths by heat strokes. The frequency and intensity of rains and tropical cyclones in India is increasing. The oceans are getting acidified.

    Now the question comes: How is this all predicted? This is done by a three steps process that includes:Observation, Understanding and Prediction.  Observe what? It includes number of factors like temperature, humidity, salinity, distance from the sea, altitude, precipitation, ocean current, winds etc. These observations were initially done manually, later some stations were set up for the purpose in various remote areas however their maintenance was challenging. The most advanced technique serving the purpose are satellites. There are two types of satellites, the first one is geostationary satellites that is used for  observing only certain part of the planets and the other is the one which revolves in the polarorbits which is able to observe different parts of the planet but only 2 or 3 times a day each. Based on the observations the experts understand and analyse the data and then they predict the weather. The one that is predicted for  few hours in advance is called now casting . The long time predictions are made using weather and climate prediction models which are the software installed in super computers.

   However various factors vary in their memory or the consistency over which it remains in the same state. For example, the memory of atmosphere is about 10  days, that of land is for several weeks, of upper ocean  it is for few months and that of the deep ocean is about several years. That's the reason why many researches are being carried out on the deep ocean  that would enable us to predict the weather in advance for several years and that would really be a great achievement!!