Even three years after winding up the cloud-based experiments over Solapur, a comprehensive report on the key findings is still under preparation, an RTI query filed by The Indian Express has found.
The public availability of these scientific report findings are vital, as they will form the basis for local governments and district administration while planning contingency measures when faced with drought situations. These reports and findings will guide on weighing options such as cloud seeding to create artificial rain and address water shortage for drinking, reservoir, or cultivation purposes.
Given the increase in extreme and heavy rainfall events and a decrease in the number of light to moderate-intensity rainy days during the monsoon season, the rainfall distribution during the June to September season has become highly unpredictable.
For instance, the Indo-Gangetic plains — Uttar Pradesh, Bihar, Jharkhand, Bihar and West Bengal — ended with large-scale rainfall deficiencies during the monsoon season this year. Climate change, experts say, will make such events more frequent.
The Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEX) – IV was conducted at a cost of Rs 100 crore, during two consecutive monsoon seasons of 2018 and 2019 over Solapur, a rain-shadow district in Maharashtra.
The campaign aimed at constructing climatological data of clouds, aerosols and precipitation over Solapur region. This, by studying a number of parameters, including cloud and precipitation parameters like the droplet size, rain drop rate; morphological parameters such cloud depth and volume ; thermodynamics of the atmosphere — wind velocity, humidity, temperature ; aerosol size, distribution and interactions and black carbon.
Scientists at Pune-based Indian Institute of Tropical Meteorology (IITM), under the Ministry of Earth Sciences (MoES), hired an aircraft to conduct air-borne experiments during July 14 – October 5, 2018, and July 29 – October 15, 2019. Ground-based observations continue to be recorded over the locality. The total data generated, inclusive of the observations and corresponding numerical simulations, was around 200 Terabytes , the RTI response said.
The World Meteorological Organization (WMO) has set standards for conducting such experiments and producing related reports which is being followed by the CAIPEX-IV team.
However, it still remains unknown as to when the reports will be ready for publishing. On the progress of report compilation, the RTI response said, “The report, which will be released after an internationally peer reviewed publication, which is under preparation.”
On the overall experiment during the two-year campaign, the RTI response read, “There are a total of 276 cases from the two years of the randomised experiment. In each case, the aircraft executed the procedure of seeding or no-seeding on the basis of the protocols developed by the CAIPEX.”
The need for better understanding of the role and interaction of aerosols in climate and the overall cloud physics towards rain-bearing, has existed. A dedicated campaign, CAIPEX was established at IITM, which has successfully conducted four cloud-centered experiments in various parts of India, including Maharashtra and Tamil Nadu.
In the past, cloud-seeding took centre stage every time there was deficient rainfall threatening drought situations, especially over the rain-shadow regions along interior peninsular India. Multiple cloud seeding programmes have been conducted in Maharashtra, Andhra Pradesh and Karnataka in the past decade. But scientists have complained that these state government-led exercises by hiring private agencies are unscientific and may not be successful in creating artificial rain over parched regions.
In fact, in 2019, Maharashtra government sanctioned Rs 30 crore after the state received poor rainfall during many days of the monsoons season.
