Chinese Academy of Sciences
Since 2015, Drs. LI Xingyu and PAN Yuepeng from IAP have been conducting a long-term measurement of the physical and chemical composition of freezing rain at Mount Heng, which lies in south-central China at 27°18′6″N, 112°41′5″E. The elevation of the sampling site is 1265.9 m, above the top of the atmospheric boundary layer, with temperature near 0 °C in winter favoring the occurrence of supercooled fog and freezing rain. This sampling site has also recorded the record icing thickness in China. According to the first seven-year observations, the freezing rain at Mount Heng was found to be acidic (pH
They also work with climatologists at universities and research institutes in Canada and China to explore the formation mechanisms of freezing rain and their trends in the future. They found that as the concentrations of soluble ions (especially ammonium nitrate) increase, the ambient temperatures of freezing rain show decreasing trends.
"This study presented the first chemical view on freezing rain, a physical phenomenon in traditional belief," says Prof. Ronald Stewart at the University of Manitoba of Canada, a coauthor of the study. "The higher ionic concentration may depress the temperature needed to freeze raindrops and this process prolongs the existence of freezing rain."
"Against the background of global warming, the influencing area of the freezing rain will shift northward, and the effect of freezing point depression induced by air pollution in northern China may be amplified," said Dr. ZHU Xiaying at the National Climate Center, another coauthor of the study.
/Public Release. This material from the originating organization/author(s) might be of the point-in-time nature, and edited for clarity, style and length. Mirage.News does not take institutional positions or sides, and all views, positions, and conclusions expressed herein are solely those of the author(s).View in full here.
