State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, 100029, Beijing, China.
University of Chinese Academy of Sciences, 100049, Beijing, China.
Nat Commun. 2022 May 10;13(1):2552. doi: 10.1038/s41467-022-30106-z.
The Afro-Asian summer monsoon (AfroASM) sustains billions of people living in many developing countries covering West Africa and Asia, vulnerable to climate change. Future increase in AfroASM precipitation has been projected by current state-of-the-art climate models, but large inter-model spread exists. Here we show that the projection spread is related to present-day interhemispheric thermal contrast (ITC). Based on 30 models from the Coupled Model Intercomparison Project Phase 6, we find models with a larger ITC trend during 1981-2014 tend to project a greater precipitation increase. Since most models overestimate present-day ITC trends, emergent constraint indicates precipitation increase in constrained projection is reduced to 70% of the raw projection, with the largest reduction in West Africa (49%). The land area experiencing significant increases of precipitation (runoff) is 57% (66%) of the raw projection. Smaller increases of precipitation will likely reduce flooding risk, while posing a challenge to future water resources management.
非洲-亚洲夏季季风（AfroASM）为居住在包括西非和亚洲在内的许多发展中国家的数十亿人提供了支持，这些人容易受到气候变化的影响。目前的先进气候模型预计未来 AfroASM 降水将会增加，但存在较大的模型间差异。本研究表明，这种预测差异与当前半球间热对比（ITC）有关。基于耦合模式比较计划第六阶段的 30 个模型，我们发现，在 1981-2014 年期间，ITC 趋势较大的模型往往会预测出更大的降水增加。由于大多数模型高估了当前的 ITC 趋势，新兴的约束表明，受约束的预测中的降水增加减少到原始预测的 70%，在西非减少最多（49%）。经历显著降水（径流量）增加的陆地面积为原始预测的 57%（66%）。降水的少量增加可能会降低洪水风险，同时对未来水资源管理构成挑战。
