Long-term variation of Arctic Sudden Stratospheric Warmings (SSW) and potential causes

The study is led by Prof. ShaoDong Zhang (Space Weather Committee of the Chinese Geophysical Society, Space Physics Committee of the Chinese Society of Space Sciences). Dr. QingRan Li (School of Electronic Information, Wuhan University) and other 7 researchers work together to complete the project. QingRan Li used ERA5 data to analyze the Arctic sudden stratospheric warming.

KaiMing Huang and ChunMing Huang, along with Yun Gong at the Laboratory of the Upper and Middle Atmosphere tried to find the physical reasons behind this surprising phenomenon. The team used ERA5 reanalysis data to perform statistical analyses of polar vortices and planetary waves in the same periods.

When the research team studied the Arctic vortex in the winter stratosphere, they found that the strength of the polar vortex showed trends opposite to the SSW in all three time periods (See image below), indicating a decreasing polar vortex trend appears to lead to an increase in SSW intensity and duration, and vice versa.

The researchers also calculated stationary planetary waves and 16-day waves with zonal wave number 1, the key components of planetary waves, the temperature amplitude trends of which are the same as the SSW trend in all three time periods (See image below). WenTao Tang says: "The results of planetary wave trends support the conclusion that the enhanced activity of planetary waves triggers the generation of SSW events."

"These new exciting results add to growing evidence that the Arctic SSW can be connected to polar vortices and stratospheric planetary waves over the long-term trends. We do not believe that the same trends and strong positive correlation between these long-term changes is accidental." Researcher Ma Zheng says.

These new data and the statistical results of long-term trends are highly successful not only in explaining the triggering of SSW (at least qualitatively) but also in explaining the variation in SSW duration and intensity. These evidences also provide reliable support for future statistical analyses of long-term changes in stratospheric SSW and its formation mechanism in laboratories worldwide. This team hopes their study will encourage more scientists to utilize innovative numerical modeling that can push the limits of time and data currently to improve the comprehension of the physical characteristics of SSW and its formation mechanism.

See the article:

Long-term variation of Arctic Sudden Stratospheric Warmings (SSW) and potential causes

https://doi.org/10.26464/epp2024037