The disrupted jet stream and its influence on flight time during solar proton events.

The long-chain effects of eruptive solar activities on Earth's magnetosphere, ionosphere, and the mid-to-lower atmospheric circulation are an important theoretical research topic in the fields of space weather and atmospheric science. Understanding the impact of space weather on aviation holds substantial economic value. It is well-known that flight times for polar routes may increase during solar proton events (SPEs) due to the necessity of avoiding high-energy particles. However, changes in atmospheric circulation due to SPEs and their impact on flight times have not been reported yet. This study systematically analyzed 15 pairs of representative international air routes, comprising a total of 16,037 flight records affected by the polar jet stream between 2015 and 2019. An unpaired two-sample two-tailed t-test revealed that 86.67% of westbound flights had shorter durations, while 86.67% of eastbound flights had longer durations during SPEs compared to quiet periods, with an average change of approximately 7 min. Further investigation into 42 SPEs during an entire solar cycle (11 years) indicates that the poleward shift of the polar jet stream, associated with high-energy particle precipitation, is the fundamental reason for the asymmetrical changes in flight times. This is the first report detailing the impact of SPEs on atmospheric circulation and flight times. Our findings reveal the long-chain mechanism by which SPEs directly influence the circulation of Earth's lower atmosphere. These results are also crucial for aviation, as they can help airlines optimize routes, reduce fuel costs, and contribute to climate change mitigation efforts.