2025-08-06 中国科学院（CAS）
＜関連情報＞
- https://english.cas.cn/newsroom/research_news/earth/202508/t20250811_1049938.shtml
- https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024EF005561
土壌水分フィードバックが、2023年に中国北部で発生した記録的な3日連続熱波の早期発生を強化した Soil Moisture Feedback Amplified the Earlier Onset of the Record-Breaking Three-Day Consecutive Heatwave in 2023 in North China
Kexin Gui, Tianjun Zhou
Earth’s Future Published: 17 July 2025
DOI;https://doi.org/10.1029/2024EF005561
Abstract
A record-breaking heatwave swept North China in the summer of 2023, with a regional average of daily maximum temperature exceeding 35°C on June 23, which was the hottest day since 1959. We use the dynamical adjustment approach to assess the contributions of atmospheric circulation and Soil moisture (SM) to this heatwave and find that they contributed 69.8% and 39.5%, respectively. The anomalous anticyclone that caused this heatwave was influenced by upstream signals. Easterly winds on the southern side of the anticyclone led to anomalous subsidence, which heated the air over North China. While such anomalous anticyclones over North China are not uncommon due to atmospheric circulation variability, the 2023 heatwave still broke records because the SM-temperature coupling during the heatwave was unprecedented, with a strength four times that of typical years. The dry soil conditions during the heatwave stemmed from a lack of precipitation beforehand, with cumulative rainfall in North China being the lowest since 1979. The early dryness of the soil provided favorable conditions for land-atmosphere feedback, and under the trigger of subsidence-induced warming from the early summer anticyclone, the strong SM-temperature coupling significantly amplified the intensity of this heatwave. For future projections, numerical experiment analysis shows that temperatures currently considered extreme during 2023 heatwave event will become commonplace in the future due to SM-atmosphere coupling. However, by the end of the century, the impact of land-atmosphere coupling on extreme high temperatures in North China will diminish compared to historical period, owing to increased SM.
Key Points
- Summer heatwave in North China in 2023 was record-breaking and occurred earlier than in previous years
- Anomalous anticyclone, combined with significantly stronger-than-usual soil moisture-atmosphere coupling, jointly amplified the heatwave
- The impact of land-atmosphere coupling on extreme high temperatures will be reduced by the end of the 21st century in North China
Plain Language Summary
Heatwave is a period of consecutive days with temperatures exceeding a specific threshold, having severe impacts on the environment, production, and human health. Anomalous high-pressure centers typically correspond to descending air, which heats up as it is compressed, increasing its internal energy. Dry soil, by reducing latent heat loss through lower evaporation, allows excess energy to heat the near-surface air in the form of sensible heat. In this study, we explore the characteristics and formation mechanisms of the record-breaking 2023 heatwave in North China. Our results show that this unprecedented heatwave was caused by the combined effects of an anomalous high-pressure system and strong soil moisture-temperature coupling. Additionally, we project that the probability of extreme heat events similar to the intensity of the 2023 heatwave will significantly increase in the future.
