印度洋偶极子预报技巧在多模式中的对比研究

本文采用北美多模式集合产品数据，分析了印度洋偶极子指数在不同模式中实际预报技巧和潜在可预报性的差异，并进一步探究其可能的原因。结果表明，印度洋偶极子的有效预报时效在不同模式中差别较大，从2个月到4个月不等。其中东极子海温异常在不同模式中预报技巧的差别较西极子海表面温度异常更明显，表明模式误差和初始误差对东极子海表面温度异常演变的影响更为显著。另外，印度洋偶极子的实际预报技巧和潜在预报技巧存在明显的线性关系，潜在预报技巧高的模式，其实际预报技巧也高。最后，本文诊断、分析了厄尔尼诺对印度洋偶极子预报技巧的影响，发现在厄尔尼诺和印度洋偶极子相关性较高的气候模式中，印度洋偶极子实际预报技巧也较高。

A comparison of Indian Ocean dipole prediction skill in a multi-model ensemble

In this work, we compare the actual prediction skills and potential predictability of the Indian Ocean Dipole (IOD) index among different models, using the North American Multi-Model Ensemble dataset. If defined by a 0.5 anomaly correlation skill, we find that skillful predictions of the IOD strongly vary among models, ranging from 2- to 4-month leads. The diversity in the prediction skills of Sea Surface Temperature Anomalies (SSTA) over the east pole of the IOD is more obvious than that over the west pole, suggesting the model errors and the initial errors have more significant effects on SSTA over the east pole region. Also, there is a significant linear relationship between the actual prediction skills and potential predictability of the IOD. Finally, we find the actual prediction skills diversity is due to the El Niño/Southern Oscillation (ENSO) influences onto the IOD in different models. The models with enhanced ENSO/IOD link tend to have high actual prediction skills.