'IITM project for better cloud seeding' 

Manasi Saraf Joshi
Tuesday, 14 August 2018

Reluctant to reveal any information about the data collected so far, IITM scientist and head of cloud seeding project CAIPEEX (Cloud Aerosol Interaction and Precipitation Enhancement Experiment), Thara Prabhakaran said, “These observations provide crucial inputs for the seeding project as we need to know the conditions under which the clouds grow. Actually, we need to identify what happens if the temperature increases as otherwise it will restrict the clouds. So we are noting down the observations on a daily basis.” 

Solapur: To investigate the types of clouds in the rain shadow region, the Indian Institute of Tropical Meteorology has been sending up a meteorological balloon for last one year and has completed as many as 365 flights so far from the base station developed at Sinhgad Institute campus in Solapur.

Reluctant to reveal any information about the data collected so far, IITM scientist and head of cloud seeding project CAIPEEX (Cloud Aerosol Interaction and Precipitation Enhancement Experiment), Thara Prabhakaran said, “These observations provide crucial inputs for the seeding project as we need to know the conditions under which the clouds grow. Actually, we need to identify what happens if the temperature increases as otherwise it will restrict the clouds. So we are noting down the observations on a daily basis.” 

“Clouds are different in the rain shadow area and how different they are and whether they are effective or not can be understood through this project,” she said. 

“The clouds behave in a different manner after being seeded. Sometimes, it will perform at 20 per cent or at only 5-10 per cent. So to know the effectiveness of seeding, we have to collect the data through various ways to form a scientific evidence for it,” she said. 

Interestingly, though the project was started way back in 2009, IITM so far has not seen much success. Regardless, Prabhakaran said that they started the study with minute details like studying the cloud droplets, how clouds are formed, properties of clouds and other factors. 

How does the Meteorological balloon work? 

Shivshahi Dixit, while explaining the balloon data, said, “It helps us in understanding the thermodynamic structure of the atmosphere which forms the background for the action. Through this balloon, we get the profile of quantities like pressure, temperature, humidity, wind speed and direction.” The balloon goes up to 30 kilometres and 110 kilometres horizontally during the monsoon season. 

Dixit said the balloon weighing 875 grams is made of pure rubber and is filled with hydrogen gas. It has an instrument fitted called 'Radiosonde' which actually does all the observations. 

Interestingly, there were a few cases wherein after the balloon was burst, the people in areas where it fell got scared. However, IITM cleared the doubts saying that there is a sticker fixed on it giving the information about it. So there is no need to panic. 

Role of the institute 

Sinhgad Institute in Solapur has allowed its campus to be used to install or erect the base station. The principal of the college SD Nawale said, “We are proud to have such a laboratory here which will also help us, our students and faculty to take up various research projects. In fact, we already have taken up a few projects.” 

Role of Radar, rain gauge and tower 

A radar installed at the top of the computer science department takes the observation 24x7 from a radius of 200 kilometres. The C-band Dual Polar metric radar helps to identify the clouds which can be seeded. “Thus, we can then take up the study and target the cloud at different levels,” said Prabhakaran. 

As many as 80 rain gauges installed from Karmala to Indi collects the raindrops. Mahen Konwar of IITM said they record raindrops per minute. The tip and measuring unit collect 2 mm of rainfall. Data is sent after every 15 minutes. 

The tower has been erected on land which has been leased for three years. It is 50 metres high and has 30 different levels where various instruments are installed. “The tower provides input for the moisture and heat fluxes,” said Subharathi Chaudhury, an IITM scientist. 

The ambitious project has been under continuous scrutiny from all sections of the society. However, it is claimed to be a rain enhancement experiment than an artificial rain project.

Related News