People are also questioning why an extreme weather incident like a cloud burst at the Amarnath cave can't be forecast by the meteorological experts when the government is spending so much on getting new technology to compare it with the best in the world. These are valid questions up to a certain extent which needs an answer. Although the IMD has categorically clarified that its prediction is the best in the given circumstances, mistakes in predicting smaller weather developments like light rains and drizzles should not be a scale to measure the magnitude of failure.
Lack of Data to predict accurately through the Numerical Weather Model
The weather prediction models massively depend on the data gathered by highly specialised kinds of equipment. Different tools like Doppler radars, satellite data, Radiosondes, surface observation centers, computing tools, and advanced weather processing systems are needed to predict and forecast weather developments. Although India has added capacity in a few of these areas, it is lagging by a distance from the advanced countries in Europe and America.
Speaking to India Today, IMD Director General Mrutyunjay Mohapatra claimed that there are only 34 radars present in the country as of now. The number has increased by just 6 in the last 5 years. At the same time, the United States of America (USA) does a weather prediction with almost 200 doppler radars. According to the official website of the National Oceanic and Atmospheric Administration (NOAA), the USA has 159 doppler radars across its area.
J P Sharma from Skymet said, "The Numerical Weather Model depends on how much data you have given and what the quality of data is. If you provide the wrong information, then it will get rejected. Hence, the quality of data is quite important. We are adding networks but the speed we are adding is very slow and hence we are not getting the required amount of quality data for a pinpointed prediction."
Ground networking is still poor
For getting good quality data, one requires a good network of machines and stations across the country. The data gathering machine is required at a denser level in areas which are critical for extreme weather developments. Last week, there was a cloud burst at Amarnath Cave in Jammu and Kashmir, but there is no local radar system to predict the weather developments locally for a shrine where lakhs of pilgrims visit every year during the Monsoon season.
Skymet's J P Sharma explains that "there are radars at places like Jammu, Srinagar and Kufri but there is hardly any radar at Amarnath or Kullu. Now the radar system is so developed that a small localized radar can be established in such areas."
Sources say that although the Met department claims that there is a good working system all over the place, but 2 out of 4 radars in Mumbai, one in Hyderabad and another in Bhuj are not working properly. There is no radar coverage in big cities like Bengaluru and the very critical Andaman, from where many of the cyclonic systems start. For the last 20 years, there has been planning that a Doppler radar will be placed on Kar Nicobar island for this purpose, but nothing could be done so far.
IMD's senior scientist R K Jenamani has other views. "Delhi has 3 radars. Name me a city where there are three radars except cities like New York or Hongkong. We have radio meters and balloons also to predict the weather developments," he said.
IMD DG Mohapatra said, "We are going to increase the number of radars. By 2025, the total number of radars in the country will be 65. In the next few years, we have decided to place 4 more radars in the Western Himalayan region, 10 in the Northeastern region, and 11 additional radars in the plains of North India."
IMD's public interface missing
In the last 5 years or so, the IMD has invested massively in cities like Delhi, Mumbai, Kolkata, and Chennai. The manpower has increased and several new weather stations have been established to predict the weather developments in these cities. Earlier, Delhi used to have only two radars at Safdarjung and Palam, but now one more radar has been added to outer Delhi's Aya Nagar, which is located at the Delhi-Gurugram border. The distribution of these radars is not equitable for the different regions like east and north Delhi, which have different important localities. Experts say that the recent problem with inaccurate weather predictions in Delhi is due to a significant data gap in different parts of the capital.
A scientist explains that "If we are collecting the wrong data on the first day itself, it will only increase on the second day and thereafter. Therefore, if we are predicting the day 5 weather based on these sets of data, the prediction is bound to fail. That problem is happening in metro cities where despite multiple stations, the forecast is not coming true for many times in a year."
But rebuking this allegation, IMD's Jenamani said, "We are more focussed on predicting big weather developments in the country, like massive rains in Gujarat and Madhya Pradesh. Light rains and drizzles can't be predicted and we cannot use our resources in such forecasts, which have hardly any impact on the public."
However, contradicting Janamani's views, Skymet's J P Sharma said, "Big cities like New York and London have 24-hour weather channels so that they can keep the public updated about the developments every hour. Delhi and other Indian metro cities do not have any such kind of public interface. Even if the weather forecast is going wrong, IMD should inform the citizens about it as these cities have a population of crores and even a small development has an impact on people's lives."
Tropical climate makes it hard to predict the conditions accurately.
India has a vast land mass and a peculiar kind of geographical position as it is a mix of coastal, plain, and mountainous regions. The weather prediction is more challenging in the tropical region as compared to higher altitudes. If we compare it to the tropical region of the northern hemisphere, then it is also different from the tropical region of the southern hemisphere. In the Northern hemisphere, there is more land and through this, the continuity of sea stretch is also disrupted. This results in a high variation in the weather pattern. India has almost seven thousand kilometers of coastline, which has a very large impact on activities. Local factors like the land breeze and sea breeze play a very important role in the post-Monsoon situation. As we move from south to north, the equatorial region gives space to higher latitudes in the Himalayas. India also faces different kinds of weather extremes, like Cyclones, Western disturbances, Easterlies, and even westerlies. We have a cycle of longer seasons.
If it is compared to the European countries, which are in middle altitude, the seasonal variations are quite less. Even if those areas are facing some extreme weather conditions, it will be there for just a few days. The weather system is largely sea-related and hence those systems are more predictable. Therefore, with a more stable system and good ground coverage, even the long-term weather prediction in Europe and the US is even right on the money. IMD's R K Jenamani says, "India is in a tropical zone. It is surrounded by sea and oceans and the weather is quite warm, humidity increases with high temperatures. There are several papers, tropical weather is less predictable than middle altitudes like Europe, and the US. The weather patterns in India, Bangladesh, and Pakistan are less predictable."
Why India needs a different solution
The radar system on which the weather forecasting depends, works on the line of sight. The line of sight in the oceans is clear and hence a single radar can cover almost 500 km. Hence, by putting the radar at a few critical positions, cyclonic prediction has improved in the country. But in terrain like Amarnath where the line of sight is quite restricted due to mountains, the same radar can't work for a long range of distance.
Skymet's Sharma adds: "In the Himalayan region, for covering 500 km we will require at least 20 radars. These day technology has improved so much that even a highly localized radar can be put in place at such places. For that, there are different bands of radars available in the market." In this context, extreme weather conditions can be predicted with high accuracy with such a system.
Experts claim that in the Indian situation, the Radiosondes can work wonders. Using the radiosondes with a balloon can provide information on the direction of wind, humidity, temperature, and pressure. The vertical range of this equipment can go vertically up to 10-12 km. But in the last few years, the radiosondes have hardly been added by the IMD, and hence weather prediction related to these aspects fails. So far, IMD works with 6 models but it is planning to add two additional models in the time to come.
As per Director-General Mohapatra, remodeling is being worked out. "One model will be for the thunderstorm, through which sudden rainfall can be predicted by very high-resolution models. The name of this model is the high-resolution repeat reflex model. This is for north-east, east and peninsular regions and the experimental basis work has started already. Another model will be the lightning-specific high-resolution model which is also being developed. All these models are in the experimental stage."
Apart from this statistical help, artificial intelligence and machine learning are also being used. IMD is developing these collaborations with the IITs and IIITs, different universities, and even Google.
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