Different formation of ice in Cirrus Clouds

Cirrus clouds are major components of our climate system. They are responsible for regulating into space, the heat radiation that is emitted by Earth.  A new paper has concluded that the previously assumed mechanism for the formation of ice under humid yet unsaturated conditions is not applicable. However, there is another mechanism that explains better how the ice forms.

In our atmosphere, ice is formed on dust specks and some other materials through a process known as nucleation. Previously, the researchers were assuming that the process of nucleation in the absence of humid air, occurred because of the direct formation of water vapor molecules into ice skipping the step of liquid water in between. According to researchers, their observation and explanation did not make sense and also did not fit with the molecular models.

A hint of the correct procedure has come from the reality that particles having pores such as mini-sponges, all form ice particles that have a much greater efficiency than the ones without pores. This fact led the team of researchers to doubt that maybe the water vapors were condensing into tiny pores and the crystals of ice began growing from liquid water, and not from the vapors. The research team found out that their hypothesis was true in the experiments that included molecular simulations and the ones that were synthesized with porous particles. They concluded that even though the air was not completely saturated with water, the vapors could condense into small pores of particle and further help in nucleating the ice crystals. The authors wrote that the procedure might be active in some other processes of cloud formation as well. This made the process of Pore Condensation and freezing a major factor in the understanding of cold clouds formation.