Ellen Liu
China Tibet Online
October 29, 2014
The APEC Climate Change Symposium，under the theme of “Extreme weather and hydrological disaster control: Forecasting and Early Warning” was held at the Nanjing University of Technology and Information in Nanjing，capital city of Jiangsu Province on Oct.27, reported Modern Express.
The presentation “Frequent smog is somewhat related to the Qinghai-Tibet Plateau” by Professor Zhao Tianliang of Atmospheric Physics College of the university drew the attention of plenty of participants. According to Zhao, it is difficult to disperse pollution on the Qinghai-Tibet Plateau because of the presence of weak winds. As a result, the melting of snow and glaciers on the Plateau is on the rise.
Is frequent smog, therefore, due to natural conditions on the Qinghai-Tibet Plateau?
As the plateau becomes warmer, natural winds are becoming weaker, which makes it more difficult to drive smog away.
The Qinghai-Tibet Plateau is a vast portion of China’s land area, with an average elevation of 4,000 meters, according to Zhao. And the central and eastern part of China is located in an area with lower elevation toward which wind blows down and causes a “haven” effect, which can in turn affect climate change in the east.
Zhao also said that the much warmer Qinghai-Tibet Plateau has reduced the temperature difference between the sea and land, which leads to weaker winds. And if the temperature is the same, there will be no wind, which will result in a “static climate” and the pollutants in the air cannot be expelled.
How strong should winds be in order to disperse smog?
Judging from smog levels in the last three years，there’s an 84.1 percent chance of a smoggy day with a Level 3 wind and only a 3.3 percent chance with a Level 4 wind, said Zhao.
“But the fundamental reason for the presence of smog is due to human activity,” Zhao said.
Where does the smog blow to?
According to Zhao，it remains on earth. The moving and turbulence of cold air in the atmosphere will not only disperse pollutants but also play a self-cleaning role.
The atmosphere can also move both horizontally and vertically. Vertical airflow will bring the pollutants into the atmosphere on a high altitude, where it will be diffused. Furthermore, the atmosphere can adjust itself. Some pollutants can be dissolved through physical and chemical reactions such as rain or snow and fall onto the land or into the sea.
