Pollen is known to be a major annoyance for people with seasonal allergies as spring has come and summer is coming. Though, according to a new study by teams of researchers from Texas A&M University (TAMU) and the University of Michigan (UM), pollen particles can also influence cloud formation and cause heavy rainfall. The study is published in the latest issue of the journal Geophysical Research Letters
Allison Steiner, an associate professor of atmospheric science at UM, and one of her researchers studied two grams of pollen from allergy-inducing plants, including cedar, oak, and birch trees and ragweed. They mixed the samples with water for around one hour and then converted the mixture into a spray-like substance using an atomizer.
According to Steiner, scientists have thought that little grains of pollen were too large to make an atomized spray out of them. However, Steiner stated in this new study that when pollen particles encounter any type of precipitation or moisture they disintegrate, making them thousands of times smaller. The study shows that pollen is also composed of hygroscopic carbohydrates and proteins. Hygroscopic carbohydrates are like sponges — the suck up moisture in the air when it evaporates to form clouds.
Athanasios Nenes, an atmospheric chemist and climate scientist at the Georgia Institute of Technology, explained the study shows that there could be a way to manufacture the pollen spray to alter the properties of clouds and their make up to change the amount of rainfall in a specific area. The next step in the process is to test the spray to find out what impact it would have on clouds and weather patterns.
Even though the study was conducted under laboratory-controlled conditions, scientists believe that the results will be similar when tested in nature. Nenes stated that pollen is most likely, “involved in cloud formation in specific areas at specific times of the year.” Therefore, she hopes to quantify how often those certain areas receive rainfall.
One of the theories behind the formation of clouds from pollen is that trees and other pollen-releasing plants could be influencing the process to produce more rainfall. When a cloud becomes thicker and larger, the more rain that is in the cloud. However, Nenes said pollen could actually delay the rainfall. As clouds become larger, they do not release rain until they reach their size using all moisture in the air. Larger clouds produce heavier rainfall than small, thin clouds. The study shows that the pollen could alter cloud formation to delay a heavy rainfall so that it does not flood the plants and form white clouds for shade.
“What happens in clouds is one of the big uncertainties in climate models right now,” Steiner said. The researchers at UM and TAMU believe that further studies on pollen particles could help them unearth the causes of seasonal allergies. Furthermore, scientists could find a way to create artificial clouds to produce more rain or to provide shelter from the Sun’s rays to protect crops or other types of plants.
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