Sugar Atoms

Pileus clouds

Appearance: Resembles the top of a mushroom or a smooth cap.

Occurrence: Occasional. Found above rapidly growing cumulus or cumulonimbus clouds as a result of warm updrafts formed during a thunderstorm. 

Conditions: Caused by rapid, relatively strong, upward movements of warm moist air, which acts as a barrier. Air approaching the top of the cloud is forced to move up and around it. The air forced upward, cools and forms the cloud cap. 

Location: Pileus clouds form in conjunction with strong convective clouds and are associated with the cumulus cloud that lies beneath. These occur in areas with strong heating and lots of moisture close to the ground. This means that they commonly occur over land in areas like the eastern United States and Australia (more likely over the Great Dividing Range and in the northern parts during monsoon season) during spring and summer.

Plants have long been known as the lungs of the Earth, but a new finding has found they may also play a role in electrifying the atmosphere.

Scientists have long suspected an association between trees and electricity but researchers from Queensland University of Technology (QUT) think they may have finally discovered the link.

They found the positive and negative ion concentrations in the air were twice as high in heavily wooded areas than in open grassy areas, such as parks.

Dr Jayaratne, who is also a member of QUT’s Institute of Health and Biomedical Innovation (IHBI), said that natural ions in the air were mainly created by ionisation due to two processes - radiation from the trace gas radon in air and cosmic radiation from space.

Radon is a by-product of the radioactive decay of radium which is present in minute quantities in rocks and is continually exhaled by the ground.

“Because radium is found in rocks and radon is soluble in water, ground water is particularly rich in radon,” he said.

“Trees act as radon pumps, bringing the gas to the surface and releasing it to the atmosphere through transpiration - a process where water absorbed by the root system is evaporated into the atmosphere from leaves. This is especially prevalent for trees with deep root systems, such as eucalypts.”