The teleconnections between the tropics and the Arctic have attracted a lot of scientific interest as a result of the warming of the tropical oceans and the rapid decline of Arctic sea ice under global warming. Tropical cyclone over western North Pacific are intense tropical weather-scale systems, and most studies indicate that they will continue to intensify and expanding their generation location and range of influence towards higher latitudes. However, there is still limited understanding of the mechanisms by which typhoon activity affects Arctic sea ice.
Recently, a team from National University of Defense Technology has proposed a new mechanism of tropical-Arctic teleconnections using observational evidence and climate model simulation experiments: the tropical cyclone activity over the western North Pacific induces Rossby wave train propagation towards the Arctic, leading to anomalous cyclonic circulation over the upper troposphere of the Arctic. The circulation anomalies, on the one hand, cool and dry the lower Arctic air and reduce downward longwave radiation, and on the other hand, attenuate the prevalent cross-polar drift of Arctic sea ice, thus slowing down the reduction of Arctic sea ice in summer. Through an in-depth exploration of the impact mechanism of tropical cyclone activities over the western North Pacific on Arctic sea ice, this study reveals that tropical cyclone, as an important medium of tropical-Arctic teleconnections, modulate the physical process of Arctic sea ice change, and deepens the scientific understanding of the influence of tropical weather systems on polar climate change through the climatic feedback effect, which provides a scientific basis for the prediction of Arctic sea ice and the response to global climate change.
The research was published online in Nature Communications (IF=14.7) with the title of "Tropical Cyclone Activity over Western North Pacific Favors Arctic Sea Ice Increase" (link: https://doi.org/10.1038/s41467-024-53991-y). The College of Meteorology and Oceanography of National University of Defense Technology is the first institution to sign the paper, Ph.D. student Zeng Liangying is the first author, Associate Professor Ha Yao and Professor Zhong Zhong are the corresponding authors.
Spatial and temporal correlation between tropical cyclone energy over the western North Pacific and Arctic sea ice concentrations
Changes in atmospheric circulation, thermodynamics and dynamics associated with tropical cyclone activity over the western North Pacific
Written by: Ha Yao, Zeng Liangying
Photo by: Zhu Yimin, Yu Guang