Rain in nature

Effect on agriculture

Precipitation, especially rain, has a dramatic effect on agriculture. All but perhaps a couple of plants need at least some water to survive, therefore rain (being the most effective means of watering) is important to agriculture. While a regular rain pattern is usually vital to healthy plants, too much or too little rainfall can be harmful, even devastating to crops. Drought can kill crops in massive numbers, while overly wet weather can cause disease and harmful fungus. Plants need varying amounts of rainfall to survive. For example, cacti need small amounts of water while tropical plants may need up to hundreds of inches of rain to survive.

Human influence

The fine particulate matter produced by car exhaust and other human sources of pollution form cloud condensation nuclei, leading to the production of clouds and increasing the likelihood of rain. As commuters and commercial traffic cause pollution to build up over the course of the week, the likelihood of rain increases: it peaks by Saturday, after five days of weekday pollution has been built up. In heavily populated areas that are near the coast, such as the United States' Eastern Seaboard, the effect can be dramatic: there is a 22% higher chance of rain on Saturdays than on Mondays.^[3]

Artificial rain

There is controversy over whether it is possible to induce artificial rain, a technique known as cloud seeding. According to this theory, when chemicals such as silver iodide or dry ice are shot into clouds they freeze individual droplets of moisture, which fall down to earth, melting as they near and so creating rain.

Culture

1. ^ http://www.ems.psu.edu/~fraser/Bad/BadRain.html
2. ^ http://www.wonderquest.com/falling-raindrops.htm
3. ^ Cerveny, R. S., and R. C. Balling. Weekly cycles of air pollutants, precipitation and tropical cyclones in the coastal NW Atlantic region. Nature. 394, 561-563.
4. ^ http://www.bom.gov.au/climate/averages/

See also