中国科学院大气物理研究所段晚锁团队在研究耦合条件非线性最优扰动及其在ENSO集合预报中的应用中取得了新进展。2024年2月26日出版的《中国科学：地球科学》杂志发表了这项研究成果。

本研究提出了一种新的方法，即耦合条件非线性最优摄动(C-CNOP)方法，该方法较好地考虑了多球相互作用。厄尔尼诺—南方涛动(ENSO)是一种典型的海洋—大气“耦合”(或“相互作用”)现象。研究人员将C-CNOP方法应用于ENSO的集合预报。结果表明，C-CNOP方法可以为ENSO集合预报产生适当考虑海洋—大气初始耦合不确定性的耦合初始扰动(CPs)。结果表明，CPs有效地提高了ENSO集合，平均预测Nino3.4海温异常的时间变异性和ENSO成熟期海温异常的空间变异性的能力。

值得注意的是，尽管热带太平洋最弱的海洋—大气耦合强度发生在北方春季和夏季，但ENSO预测在这些季节初始化时，CPs仍然捕获了这种弱耦合的不确定性。CPs的这种性能显著抑制了这些季节由于海洋—大气耦合高度不稳定而导致的ENSO预测误差的快速增加，有效延长了熟练预测ENSO的提前期。因此，C-CNOP方法是一种适合ENSO集合预报的初始摄动方法，可以描述海洋—大气耦合的初始不确定性。研究结果强调，预计C-CNOP方法在预测其他高影响气候现象，甚至未来地球系统预测中发挥重要作用。

据悉，现有的集合预报初始摄动方法在描述地球系统各球间相互作用时存在局限性。

附：英文原文

Title: Coupled conditional nonlinear optimal perturbations and their application to ENSO ensemble forecasts

Author: Wansuo DUAN, Lei HU, Rong FENG

Issue&Volume: 2024/02/26

Abstract: Limitations are existed in current ensemble forecasting initial perturbation methods for describing the interactions among various spheres of the Earth system. In this study, a new method is proposed, namely, the coupled conditional nonlinear optimal perturbation (C-CNOP) method, which incorporates multisphere interactions much appropriately. The El Nio-Southern Oscillation (ENSO) is a typical ocean-atmosphere “coupling” (or “interaction”) phenomenon. The C-CNOP method is applied to ensemble forecasting of ENSO. It is demonstrated that the C-CNOP method can generate coupled initial perturbations (CPs) that appropriately consider initial ocean-atmosphere coupling uncertainty for ENSO ensemble forecasts. Results reveal that the CPs effectively improve the ability of ENSO ensemble-mean forecasts in both temporal variability of Nino3.4 sea surface temperature anomalies (SSTAs) and spatial variability of ENSO mature-phase SSTAs. Notably, despite the weakest ocean-atmosphere coupling strength in the tropical Pacific occurring during the boreal spring and summer, CPs still capture the uncertainties of this weak coupling when ENSO predictions are initialized at these seasons. This performance of CPs significantly suppresses the rapid increase of ENSO prediction errors due to the high ocean-atmosphere coupling instability during these seasons, and thus effectively extends the lead time of skillful ENSO forecasting. Hence, the C-CNOP method is a suitable initial perturbation approach for ENSO ensemble forecast that can describe initial ocean-atmosphere coupling uncertainty. It is expected that the C-CNOP method plays a significant role in predictions of other high-impact climate phenomena, and even future Earth system predictions.

DOI: 10.1007/s11430-023-1273-1

Source: https://www.sciengine.com/SCES/doi/10.1007/s11430-023-1273-1