Possible influences of spring Barents Sea ice shrinking on Chinese heat wave events

Abstract

Heat waves have a catastrophic impact on ecosystems, economy, society and human health. Revealing the underlying physical drivers of heat waves is essential for improving extreme event forecasts and disaster prevention capabilities under climate change. Thus, this study provides an analysis of the maximum temperature, and heat wave frequency and duration during July–August in China from 1961 to 2022. Significant upward trends of different heat wave indexes were observed and broke the historical record in 2022. The influence of large-scale circulation on heat waves illustrates that the eastward South Asia High (SAH) and anomalously westward Western Pacific Subtropical High (WPSH) are closely associated with increased heat wave events, especially in 2022. We further demonstrate using reanalysis data that the Barents Sea ice shrinkage is associated with increased heat waves in China by modulating favourable atmospheric circulations. In addition, the North Atlantic Oscillation (NAO), which is closely linked to Arctic Sea ice, can provoke large-scale Rossby waves, which in turn can cause extreme heat events in China. In particular, the reduced sea ice coupled with NAO strengthens the anomalous eastward SAH and anomalous westward WPSH of their position and intensity especially in 2022 and provides favourable atmospheric circulation patterns for the occurrence of heat waves.