GS Paper - III
Mission Mausam, launched by the government, aims to not just improve weather forecasting in the country but also ‘manage’ certain weather events, and on demand, enhance or suppress rainfall, hail, fog and, later, lightning strikes. For effective weather modification, one of the most important areas is cloud physics, in which India will have to strengthen research. Towards this end, India is establishing a first-of-its-kind cloud chamber at the Indian Institute of Tropical Meteorology (IITM), Pune.
What is a cloud chamber?
- A cloud chamber resembles a closed cylindrical or tubular drum, inside which water vapour, aerosols, etc. are injected. Under the desired humidity and temperature inside this chamber, a cloud can develop.
- The Pune facility will allow scientists to study the seed particles that form cloud droplets or ice particles in a sustained manner.
- Many countries have basic cloud chambers, which have limited functionalities and scope to perform specific studies.
- With Mission Mausam, however, India is building a cloud chamber with convection properties, as required to study Indian monsoon clouds. Globally, there are only a handful of convective cloud chambers.
Why is India building a convective cloud chamber?
- Cloud physics basically involves the study of cloud behaviour during normal and extreme conditions; intra-particle interactions inside a cloud; the formation of rain droplets and ice particles; the influence of moisture added into the atmosphere due to cyclones or low pressure systems; and interactions between different cloud layers, among others.
- The objective of establishing a convective cloud chamber is to gain a better understanding of cloud physics under conditions commonly affecting Indian weather systems. Thereafter, this knowledge can be used for strategic planning of weather modification.
How are scientists planning to use the cloud chamber?
- With the establishment of a convective cloud chamber, scientists will have the flexibility to tailor physical and atmospheric parameters to suit environmental requirements that influence the Indian weather and climate.
- “We have certain new ideas and we wish to test them. Within a controlled-environment, wherein we can apply various temperature, humidity, convective conditions and other parameters, we plan to monitor and understand clouds to arrive at high-level scientific findings on how monsoon clouds behave,” said Thara Prabhakaran, senior IITM scientist and expert in the physics of clouds.
- Over the next 18-24 months, the Indian team will mainly focus on developing complex and highly advanced instrumentation and probes that will be deployed when the chamber is ready. The civil construction of the chamber will take place in the coming months.
- We will need highly advanced instrumentation backup, capable of monitoring the minute properties of the conditions under investigation.
- We will also have to perform seed particle injection into the chamber, which will offer us a scenario to look at different environmental conditions, Prabhakaran added.
How has India’s experience with cloud seeding been?
- One such dedicated experiment was the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) programme, which was conducted in four phases lasting more than a decade.
- In the last phase, experiments were performed over a limited geographical area along the rain-shadow regions of Maharashtra’s Solapur district from 2016-2018.
- Analysis of the experiments reaffirmed that under suitable conditions, cloud seeding was an effective strategy for enhancing rainfall over a region.
- Rainfall could be enhanced by up to 46 per cent (±13 percent at some locations and on average), and about 18 per cent (±2.6 percent) in a 100 square kilometre area in the downwind of seeding location over this rain shadow region.
- However, it has been widely recognised that cloud seeding is not a silver bullet to address rainfall problems.