No Rain Without Sunshine!

The Sun Is Responsible for the Bad Weather!

It is somehow peculiar, but without sunshine there would be no rain, either. This is because the sun plays a major role in the formation of clouds. It is the energy supplier, so to speak. The sun heats the earth, so that water can evaporate and be taken up by the air as water vapour. The warm air currents ascend and cool down during the ascent. The water vapour starts to condensate, and small cloud droplets are formed. The cloud droplets are so tiny and light that they sink to the bottom only very slowly. Light updrafts are sufficient to keep them suspended or even move them into higher heights.

Many Tiny Droplets Become One Big Drop

In order to become real raindrops, these small cloud droplets have to increase their diameter by a hundredfold.

 Many hundreds of small cloud droplets are necessary for a raindrop to form..

The transformation starts in the topmost cloud layers. These layers extend into the ice-cold troposphere at a height of about 10 000 metres. There, small ice nuclei are formed, which later become the raindrops. Below minus 20?C, the supercooled cloud droplets spontaneously freeze into ice crystals on minute particles in the air. They grow and sink downwards. Thereby, the ice crystal accumulates many more cloud droplets. The crystals cake together into hailstones. As soon as the hailstones reach temperature regions above zero degrees, they start to melt and fall to the ground as raindrops.

Acid Rain

When fossil fuels (coal, petroleum, natural gas) are burned, the contained sulphur is transformed into gaseous sulphur dioxide (SO2) for the most part. Because of reactions of the nitrogen and the oxygen of the air, gaseous nitric oxides (NOx) are formed during the burning. Sulphur dioxide and nitric oxides are so-called acidifiers, i.e. they react to acids (e.g. sulphuric and nitric acid) with water and the oxygen of the air. This formation of acid is the cause of acid rain.

How Acidic Is Acid Rain?

The pH value is a measure of the amount of acid in a liquid. The lower the pH, the more acidic the solution. Without any air pollution, rainwater has a pH value of about 5.6. Peak values show a pH of 3. That is already quite acidic.

Acid Rain Is the Reason for Forest Dieback

In the case of plants, the acid rain attacks the wax layer of leaves, and often causes corrosion of the bark of trees. Continuous introduction of acid into the environment also disturbs the self-regulating neutralisation of the soil (acidification) and lakes, which results in the destruction of the ecological balance. In the lakes, numerous animal and plant species become extinct. In the soil, the sensitive acid-base balance is disturbed. The results are widespread forest dieback, and damage on facades and other buildings