Wednesday, November 9, 2011

Future Perfect: Cloud seeding to end freshwater woes

Cloud seeding Cloud seeding technique to end the drought

What’s happening right now?
With the growing levels of deforestation and global warming, incidences of drastic weather changes and droughts have been on the increase. Naturally, the sufferings are numerous and the losses immense. The focus thus is to somehow eradicate the water hassle and hurdle and present a prosperous environment. The best way to achieve this is by cloud seeding, better explained as a way to cause rainfall artificially. This method is still in the nascent stages of its application and is largely dependent on natural conditions.

There is a particular kind of clouds that can be artificially seeded in order to fasten the process of rainfall and they are thunder clouds. Naturally, it rains only when the rain drops are large and heavy enough to induce a shower. Generally, the densing of these drops takes place by the accumulation of water droplets around an ice nucleus or a tiny particle of ice.

Artificially, this process can be induced by spraying silver iodide over clouds. The gush of the gas induces the freezing of water, even when naturally; the process is simply not possible. When ice crystals are formed, they attract the surrounding water droplets and convert them into drops. These drops collide with each other a make an artificial shower.

However, there is a limitation. Only thunder clouds can be artificially made to rain. The challenge is to do so since during droughts, when water is most needs, these types of clouds seem to have gone for a long hibernation and return when not much in need.

1. China overdoes cloud seeding to end drought

China Cloud SeedingChina Cloud Seeding
China has been one of the nations that have experimented with this technique. In order to overcome the pounding drought conditions in 2009. 500 sticks of silver iodide, the size of a cigarette stick each were sprayed into clouds, inducing artificial precipitation. The result? Beijing was covered by snow due to excess application of silver iodide and thus an excessive freezing of water particles in the clouds.

2. Cloud Seeding in India

Cloud Seeding in IndiaCloud Seeding in India to end drought
Similar as the case in China, India also had felt the crunch of extreme drought conditions in 2009. In order to free the population of the threatening conditions, the Indian government had set out to build up its own cloud seeding methods. But ritualistically, silver iodide was used to induce rainfall.

The concept
As already discussed in the first section, cloud seeding is the artificial process of inducing rainfall. Going into further depths, the method is traditionally used for two separate purposes. The first motive is to cause artificial rainfalls in order to increase precipitation so as to eradicate drought conditions and protect crops from utter dryness that droughts bring with themselves. The second motive is to reduce the incidence of hail attacks on crops. Hails are destructive for vegetation and they can be stopped by inducing the showering of cloud water before the troposhperic temperature conditions induce the formation of hail.

As of the factors on which the successful process of cloud seeding depends, well, there are two of them, the temperature in the clouds and the time when the chemical is being sprayed into them. The temperature has to be appropriate. At temperature lower than -25 degree Celsius inside the clouds, the spraying of silver iodide would induce the formation of snow rather than rain, a similar case to that of China. If, however, the temperature is well above -10 degrees, then the situation does not encourage the sufficient freezing of water to form bigger droplets of water.

Time is important because, if the winds are fast blowing, the natural process of precipitation does not have enough time to occur sufficiently. As such, artificial seeding is an appropriate method. If, however, the winds are slow, it is better to let the natural process take over.

The advantages
As a highly preferred method must have, this method also has considerable advantages, the foremost among them being that seeding lets man overcome drought conditions. Secondly, crops are protected leading to relief to governments and to all individuals who are connected t agriculture in some way or the other. Natural induction of rainfall reduces the requirement of an elaborate irrigation facility which often claim a whole lot of energy input, thus demanding huge fuel consumption.

The impact
The most potent drawback is that all forms of clouds are not possible to induce to shower by using this method. Secondly, even this artificial method is highly dependent on the natural traits of rainfall, hence it is not of much use during droughts when getting clouds to seed artificially is a challenge in itself.

There is no potent damage that silver iodide causes to the environment, so that is not a concern according to some. This point however remains debatable since some researchers believe in the long term effect of silver iodide on the existence of species. The further development in this method through extensive research would also be used to combat super storms and hurricanes by altering the precipitation in the clouds involved.

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