Known as the Third Pole, the Tibetan Plateau (TP) significantly influences global weather and climate, but its potential for improving subseasonal-to-interannual predictions remains underexplored. Through coupled climate simulations and hindcast experiments, we uncovered interannual predictability of the 2003 European summer heatwave that persisted from June to August with devastating impacts. Hindcasts initialized from the atmosphere, land, and ocean states of a coupled simulation that assimilates soil moisture and soil temperature data over the TP show substantial skill in predicting this heatwave two years in advance. Hindcast sensitivity experiments isolated the indispensable role of the spring TP snow cover anomalies and their impact on the Atlantic and Pacific Oceans in exciting the Rossby waves that contributed to the anomalous European summer temperature. These findings highlight the dominant and remote influence of the TP and motivate research on its role in enhancing the predictability of extreme events worldwide.

青藏高原 （TP） 被称为第三极，对全球天气和气候产生重大影响，但其改善次季到年际预测的潜力仍未得到充分开发。通过耦合气候模拟和后报实验，我们揭示了 2003 年欧洲夏季热浪的年际可预测性，该热浪从 6 月持续到 8 月，造成了毁灭性的影响。从耦合模拟的大气、陆地和海洋状态初始化的后报，该模拟吸收了 TP 上的土壤水分和土壤温度数据，表明在提前两年预测热浪方面具有很强的技能。后报敏感性实验分离了春季 TP 积雪异常不可或缺的作用及其对大西洋和太平洋在激发导致欧洲夏季温度异常的罗斯比波方面的影响。这些发现突出了 TP 的主导和远程影响，并激发了对其在增强全球极端事件可预测性方面的作用的研究。