Tuesday, February 2, 2016

Cloud Seeding

By Anton Antonio
February 3, 2016

I visited the University of the Philippines Open University campus in Los Baños, Laguna yesterday.  After meetings with my favourite dean, Dr. Inocencio E. Buot, Jr. and favourite mentors, Dr. Consuelo dL. Habito and Dr. Joanne V. Serrano, I decided to head back for the Big City.  However, on my way out of the main building, the headquarters of UPOU, I chanced upon a colleague and we had an interesting conversation.  After exchanging pleasantries we, as usual for environmental diehards, talked about the environment.  He expressed concern about the El Niño phenomenon which is presently wreaking havoc on agricultural activities in some parts of the country especially Mindanao.  He asked me about the possible solutions and I offered the following: (1) The planting of alternative crops to rice like soy beans which require less water and have a shorter planting-harvesting cycle; (2) Alternative livelihood opportunities for affected farmers to augment their income; and, (3) Cloud seeding.

What is cloud seeding?  Cloud seeding is a form of weather modification.  It is a microphysical process that attempts to change the amount or type of precipitation that falls from clouds through the introduction of substances into the atmosphere that serves as cloud condensation or ice nuclei.  Here is a researched material on cloud seeding… “Cloud seeding also occurs due to ice nucleators in nature, most of which are bacterial in origin.  The most common chemicals used for cloud seeding include silver iodide, potassium iodide and dry ice (solid carbon dioxide).  Liquid propane, which expands into a gas, has also been used. This can produce ice crystals at higher temperatures than silver iodide.  After promising research, the use of hygroscopic materials, such as table salt, is becoming more popular.  In mid-latitude clouds, the usual seeding strategy has been based on the fact that the equilibrium vapour pressure is lower over ice than over water.  The formation of ice particles in super cooled clouds allows those particles to grow at the expense of liquid droplets.  If sufficient growth takes place, the particles become heavy enough to fall as precipitation from clouds that otherwise would produce no precipitation.  This process is known as “static” seeding.  Seeding of warm-season tropical cumulonimbus (convective) clouds seeks to exploit the latent heat released by freezing.  This strategy of “dynamic” seeding assumes that the additional latent heat adds buoyancy, strengthens updrafts, ensures more low-level convergence, and ultimately causes rapid growth of properly selected clouds.  Cloud seeding chemicals may be dispersed by aircraft or by dispersion devices located on the ground (generators or canisters fired from anti-aircraft guns or rockets).  For release by aircraft, silver iodide flares are ignited and dispersed as an aircraft flies through the inflow of a cloud.  When released by devices on the ground, the fine particles are carries downward and upward by air currents after release.”  (Wikipedia)

If the El Niño phenomenon is an inevitable part of our weather system in the light of climate change, measures should really be on hand and available to mitigate its impact… one such solution is cloud seeding.

Thoughts to promote positive action…

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Wikipedia (2016).  “Could Seeding”.  Retrieved on February 3, 2016 from https://en.wikipedia.org/wiki/Cloud_seeding

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