Atmosphere and ocean dynamics and their projections for the 21st century are assessed in the Eastern Tropical Pacific, using an ensemble of 17 models from the Coupled Model Intercomparison Project – CMIP6, under two radiative scenarios. Projections in the Panama Bight (PB) and Equatorial Pacific cold tongue (CT) are studied in more detail. In the 2071–2100 period and SSP5-8.5 scenario, referenced to the 1985–2014 period, air temperature (sea surface temperature) is expected to rise ∼3.5 °C (∼3 °C). Precipitation is projected to increase > 3 mm day−1 in the mean position of the Intertropical Convergence Zone, and decrease toward the north. A similar meridional pattern is projected in sea level atmospheric pressure and sea surface salinity (SSS) with negative anomalies toward the south. Large seasonal variations, which dominate the region, are projected to remain similar for the rest of the century. However, in January-April a weakening in the Panama wind jet and intensification of surface wind in the CT is expected, while in the June-November season, a weakening of the Choco wind jet will affect both sub-regions. Mean sea surface height (SSH) is expected to decrease, probably dominated by barotropic wind effects over SSS reduction effect on SSH. However, sterodynamic sea level (SDSL) is projected to rise (∼21 cm) driven by the global mean thermosteric contribution. For the end of the century, a mean sea level rise of ∼69 cm is estimated in the ETP, with SDSL being about half the barystatic contribution. These projections should be used with caution, as climate models have shown limitation reproducing atmospheric and ocean observations in the tropical Pacific Ocean during the last decades, due to large internal variability and systematic biases.

中文翻译：

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基于 CMIP6 模式的东热带太平洋大气和海洋预估变化


在两种辐射情景下，使用耦合模式比较项目 （CMIP6） 的 17 个模式集合，评估了东热带太平洋的大气和海洋动力学及其对 21 世纪的预测。更详细地研究了巴拿马湾 （PB） 和赤道太平洋冷舌 （CT） 的投影。在 2071-2100 年期间和 SSP5-8.5 情景中，参考 1985-2014 年期间，预计气温（海面温度）将上升约 3.5 °C （∼3 °C）。预估降水将在热带辐合带的平均位置增加 > day−1 ，并向北减少。在海平面大气压和海面盐度 （SSS） 中投影了类似的经向模式，向南为负距平。预计在本世纪余下时间里，该地区的主要季节性变化将保持相似。然而，预计在 1 月至 4 月，巴拿马风急流会减弱，CT 的地面风会增强，而在 6 月至 11 月季节，Choco 风急流的减弱将影响这两个子区域。预计平均海面高度 （SSH） 将下降，可能主要是气压风效应而不是 SSS 对 SSH 的降低效应。然而，在全球平均恒温贡献的推动下，预计立体动力学海平面 （SDSL） 将上升 （∼21 cm）。到本世纪末，ETP 估计平均海平面上升约 69 厘米，SDSL 大约是重晶静贡献的一半。应谨慎使用这些预测，因为气候模型显示，由于巨大的内部变率和系统偏差，过去几十年来在热带太平洋复制大气和海洋观测的能力有限。