The Birth Of An Ice Cloud Discovered For The First Time

The scientists have seen the formation of ice crystals on the individual atmospheric particles. This helps them in understanding how ice clouds shape in the atmosphere.

The study was led by researchers at the Pacific Northwest National Laboratory. They created ice clouds crystals in the laboratory. Then, they took images of the process in the microscope, which documented the first steps of cloud formation.

Science Daily reports that the process that the team used is called the ice nucleation. This process occurs when a particle attracts water vapor and forms ice crystals. When these ice crystals form together, they become a cloud. A process such as this could aid in understanding how clouds form and how clouds cool and heat the planet Earth.

Bingbing Wang, the first author of the study and a professor at Xiamen University in China, said that this process is one of the most critical but least understood parts of how cold clouds form. He further said that the fundamental process of how ice grows is relatively well understood, but ice nucleation -- that moment when the first group of molecules comes together remains a big challenge.

In the study, the researchers replicated the conditions found above the surface of the Earth with a height of 6 kilometers, in which the cirrus clouds form above the sky. The relative humidity at this height is high. Meanwhile, the temperatures are very low. This means that water vapor collects on any tiny particles found floating in the atmosphere, before freezing in place as an ice deposit.

The team then used particles of a clay mineral known as kaolinite in the process of ice nucleation. Kaolinites are minute particles with just about 2-3 microns in size, or less than one-tenth the width of the human hair.

These were placed in a highly confined climate-controlled chamber about the size of a poppy seed and could be seen through an environmental scanning electron microscope. The temperatures in ice nucleation are as low as 205 degrees Kelvin or minus 68 degrees Celsius and has a relative humidity from about 70 percent to 80 percent, according to Science Alert.

Daniel Knopf, an atmospheric chemist from Stony Brook University and one of the researchers, said that they could monitor every moment the formation of an ice crystal at a nanoscale resolution and under atmospherically relevant conditions. He further said that in doing so and knowing that this process is replicated a million times, these result in a cloud visible to the naked eye. He added that this is tremendously exciting and a huge step forward for the predictive understanding of cloud formation with important ramifications for the climate.