Downward clear‐sky longwave radiation, which is related to atmospheric water vapour content, has been suggested as an important factor causing an interdecadal increase in boreal summer surface temperature over the Tibetan Plateau (TP). We reveal the relationship between the 2 m air temperature (t2m) and water vapour over the TP in boreal summer, as well as the mechanism modulating the change in atmospheric water vapour. In recent decades, spatiotemporal variations between water vapour and t2m in boreal summer over the TP have shown synchronicity at the decadal scale. Moreover, Rossby wave trains which originate over the Northwest Atlantic and trigger an anomalous anticyclone between the northeastern TP and Baikal Lake are suggested to play a crucial role in decadal warming over the TP. First, the anomalous anticyclone, with an equivalent barotropic structure, can directly heat near‐surface air across the northeastern TP. Second, it promotes net water vapour input into the northeastern TP, leading to an increase of the total water vapour content over the entire TP, ultimately contributing to warming. Finally, a linear baroclinic model experiment further indicates that the Rossby wave trains are mainly associated with interdecadal increases in sea surface temperature (SST) in the Labrador Sea, with the SST in Baffin Bay playing a secondary role.

中文翻译：

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青藏高原年代际夏季变暖可能受拉布拉多海海温异常影响

向下的晴空长波辐射与大气中的水汽含量有关，已被认为是导致青藏高原（TP）夏季北半球表面温度年代际上升的重要因素。我们揭示了北风夏季2 m空气温度（t2m）与TP上水汽之间的关系，以及调节大气水蒸气变化的机制。近几十年来，TP上北方夏季水汽与t2m之间的时空变化在十年尺度上显示出同步性。此外，建议罗斯伯波浪列车发源于西北大西洋，并引发东北TP和贝加尔湖之间的反气旋异常，在TP年代际变暖中起关键作用。首先，反气旋异常 具有等效的正压结构，可以直接加热东北TP的近地表空气。其次，它促进了向东北TP的净水蒸气输入，从而导致整个TP的总水蒸气含量增加，最终导致变暖。最后，线性斜斜模型实验进一步表明，罗斯比波列主要与拉布拉多海海温（SST）年代际升高有关，而巴芬湾（Baffin Bay）的海温则起次要作用。