WHY IN NEWS?

  • Recently, a cloud seeding experiment carried out in Solapur city was able to achieve 18% relative enhancement in rainfall, which is approximately 8.67mm more rainfall.

WHAT IS CLOUD SEEDING?

  • Cloud seeding is a weather modification technique that improves a cloud’s ability to produce rain or snow by introducing tiny ice nuclei into certain types of subfreezing clouds.
  • These nuclei provide a base for snowflakes to form.
  • After cloud seeding takes place, the newly formed snowflakes quickly grow and fall from the clouds back to the surface of the Earth, increasing snowpack and streamflow.

PROCESS OF CLOUD SEEDING:

  • Experts use silver iodide because its structure is very similar to natural ice crystals.
  • When they put silver iodide in the top part of a growing cloud, the silver iodide crystal grows quickly once exposed to the cloud’s moisture.
  • Right after, the ice crystal becomes a heavy, large raindrop.
  • It will then fall through the cloud and onto the ground.
  • Just 1 gram of silver iodide can create up to 10 trillion artificial ice crystals.
  • Scientists have found two main ways to conduct cloud seeding:
  • Release silver iodide particles from below the cloud base.
  • Pyrotechnics (or flares) on the wings of planes burn silver iodide from below the clouds.
  • Drop silver iodide particles from above the cloud. Planes can also let off electrical pyrotechnics over the top of clouds.

BENEFITS OF CLOUD SEEDING:

  • Cloud seeding is used all over the world as a method for enhancing winter snowfall and increasing mountain snowpack, supplementing the natural water supply available to communities of the surrounding area.
  • The technique, which experts also call weather modification, can really help in areas that don’t have a big enough supply of natural water.
  • After cloud seeding, precipitation (rain or snow) will fall from the clouds onto the ground.
  • It does not just make rain, it also regulates water vapor that in turn prevent damages bought by destructive hails and storms.

DISADVANTAGES OF CLOUD SEEDING:

  • It uses chemicals which can harm the environment especially plants and animals.
  • Though silver iodine is not currently known to be harmful to our health today, but it might change in the future as more research is done on that.
  • The technique is mostly used on clouds that already show early signs of rainfall, so it is not known if it actually causes rain.
  • Since it modifies the weather it might change climatic pattern.
SYLLABUS: PRELIMS, SCIENCE AND TECHNOLOGY