More on cloud seeding

On Monday, March 21, 2022, Minister of Energy, Pavithra Wanniarachchi, complained to reporters that all of the island’s reservoir levels are depleted, therefore reducing their ability to produce hydro-electricity, which in turn results in frequent power cuts. The next day, data produced by the National Oceanic and Atmospheric Administration (NOAA), USA, showed that skies over the catchment area were covered by cloud. (See photo).

How do these clouds form inland? Mainly by evaporation of water in the reservoirs (90%), and by transpiration from trees (10%) and agricultural plants in the area. Western studies reveal that “an acre of corn gives off about 3,000-4,000 gallons (11,400-15,100 litres) of water each day, and a large oak tree can transpire 40,000 gallons (151,000 litres) per year.” Deep roots can extract water from the water table.

A search of the Internet fails to reveal any data for Sri Lanka. Unplanned tree cutting in the past, and removal of topsoil purely for economic benefit by local ‘robber barons’, have done untold damage in the central hills.

Usually, evaporated and plant-transpirated water vapour moves upwards in the atmosphere, then expands due to low pressure and cools down in keeping with a phenomenon known as adiabatic cooling. It amounts to approximately 2 degrees Celsius per thousand feet. The water vapour then condenses around minute particles of dust, releasing latent heat in the process and making the moist air warmer than the surrounding atmosphere. This moist air is unstable and produces clouds rising to a height of 50,000 ft or more in the tropics.

Many years of research have shown that at this stage of cloud development, if the number of these minute solid particles can be artificially increased by aerial spraying a mixture of dry ice (carbon dioxide), salt (sodium chloride) and silver iodide, the volume of rain could be enhanced significantly. This is known as ‘cloud seeding’.

Two researchers, Arvind Kumar and Amitha Tripathi, confirm through mathematical analysis that cloud seeding not only increases rainfall, but also increases the agricultural crops as well as clouds in the atmospheric environment. Therefore, it is a self-sustaining cycle of nature.

Although it is now March/April and the sun is fast reaching overhead on its east/west passage, the so-called ‘inter-monsoon’ period, between the northeast and southwest monsoons, actual rainfall is scanty. In earlier times the inter-monsoons sometimes brought more rain with thunderstorms than the monsoon itself. Now, there is hardly any wind, and one feels ‘muggy’ due to high relative humidity in the atmosphere.

I am at a loss to understand why our so-called scientific community and meteorologists are slow to react. It is all a matter of timing. Drastic times need drastic actions. The Sri Lanka Air Force is equipped to carry out these activities, but seems to have got its priorities mixed up and become involved in farming instead.

First, we must have enough water for agriculture and electricity. The cost of the cloud seeding operation would be less than refurbishing their old MiG fighters in the Ukraine or Russia, for which they have reportedly obtained government permission. There is, however the ‘small matter’ of those two countries being currently engaged in a war which could postpone that project indefinitely.

Undoubtedly the SLAF is equipped with men and machines. We are repeatedly told that the authorities are so ‘pig headed’ that they don’t listen to reason. After all, the proof of the pudding is in its eating.

Guwan Seeya