What has changed in the atmospheric circulation?

It was not enough to identify the variations in atmospheric circulation as being responsible for the phenomenon. It still remained to pin down what exactly had happened. By comparing the state of the atmosphere between 2007 and 2011, they observed that the zones characterized by an increase in HCl showed a slowing down of the circulation of air and therefore an increase in the transportation times of compounds. There was therefore a direct correlation between a longer transportation time and a better conversion of source gases into HCl. The reason for this was very simple. As there was a slowing down, the CFC gases stayed at higher altitudes for a longer time. They were therefore subjected to UV rays for a longer period. A greater number of CFC molecules could be separated. A greater quantity of hydrogen chloride was produced before descending to the lower layers of the atmosphere. This is why, without a greater volume of emission of chlorine gases from the surface, the stratosphere suddenly underwent a new invasion of this destructive atom.

“We stopped there, ends the researcher. We could have gone further and tried to understand why this slowing of atmospheric circulation occurred. This is also a mystery. With regard to global warming, all the specialists tend to think that, conversely, the atmospheric circulation and air transportations of the compounds should accelerate. We therefore observed the opposite phenomenon to what was expected. Each expert should concentrate on his area of expertise. We are interested in the chemistry of the atmosphere and not its dynamics. But our research was sufficient to understand the origin of an increase of chlorine in the atmosphere in a given place while it should have gradually disappeared. Our research also made it possible to highlight a dynamics origin that was both unexpected and particular, but temporary. This was reassuring because one of our initial fears was that the phenomenon might be only the beginning, and might then spread to the rest of the globe after transportation and this homogenization of the atmosphere. But this is not on the agenda. Overall, the concentration of chlorine continues to drop”.