The average summer precipitation in the Yangtze River Basin over the years. Photo courtesy of Yang Yang
Nanjing, February 21 (Xu Shanshan) reporters learned from Nanjing University of Information Science and Technology on the 21st that the team of Professor Yang Yang of the School of Environmental Science and Engineering of the university united 5 units inside and outside the United Nations revealed the impact of anthropogenic emission reductions during the prevention and control of the new crown pneumonia epidemic on the record-breaking summer precipitation in China's Yangtze River Basin in 2020.
The results were recently published in the internationally renowned journal Nature Communications.
In the summer of 2020, China experienced an "ultra-long plum rainy season" that lasted for 62 days, ranking alongside 2015 as the longest since 1961, and this extreme precipitation incident was called "super violent plum" by netizens. Past studies have explored the possible causes of "super violent plums" in 2020 from the perspective of natural variability, but have ignored the possible effects of changes in human activities on extreme precipitation.
The anomalous spatial distribution of precipitation in the Yangtze River Basin in the summer of 2020 was observed. Photo courtesy of Yang Yang
This extreme precipitation occurred during the 2020 COVID-19 epidemic prevention and control period, and emissions of greenhouse gases and atmospheric pollutants have decreased significantly due to the reduction of human activities.
As the first work in the world to propose that emission changes during the epidemic prevention and control period will have an impact on global and regional climate, Professor Yang Yang's team has been cited many times in the sixth assessment report of the United Nations Intergovernmental Panel on Climate Change (IPCC), and then invited to participate in the epidemic simulation comparison plan under the framework of the Sixth International Coupled Model Comparison Plan (CMIP6) as a Chinese numerical simulation team among dozens of teams around the world, and explored the connection between the anthropogenic emission changes caused by the epidemic and the extreme precipitation in China.
The study found that during the epidemic prevention and control period, the reduction of anthropogenic emissions affected the radiation balance of the earth's gas system, strengthened the atmospheric convection in the eastern region of China, and led to a positive anomaly of sea level air pressure in the northwest Pacific Ocean, which enhanced the water vapor transport to China, and eventually led to an increase in precipitation in the Yangtze River Delta region.
"It is very important to further understand the precipitation mechanism, and our research is to take into account the important impact of anthropogenic emission reduction on precipitation, reveal the significant reduction of aerosol and greenhouse gas emissions during the prevention and control of the new crown pneumonia epidemic, and the impact mechanism of extreme precipitation in China, so as to provide scientific support for the assessment and prediction of extreme precipitation in China." Yang Yang said. (End)