Hsu Tien-Yiao, Mazloff Matthew R, Gille Sarah T, Freilich Mara A, Sun Rui, Cornuelle Bruce D
Scripps Institution of Oceanography, University of California San Diego, La Jolla, 92093, CA, USA.
Brown University, Department of Earth, Environmental and Planetary Sciences and Division of Applied Mathematics, Providence, 02912, RI, USA.
Nat Commun. 2024 Jun 12;15(1):5018. doi: 10.1038/s41467-024-48486-9.
Atmospheric rivers (ARs), responsible for extreme weather conditions, are mid-latitude systems that can cause significant damage to coastal areas. While forecasting ARs beyond two weeks remains a challenge, past research suggests potential benefits may come from properly accounting for the changes in sea surface temperature (SST) through air-sea interactions. In this paper, we investigate the impact of ARs on SST over the North Pacific by analyzing 25 years of ocean reanalysis data using an SST budget equation. We show that in the region of strong ocean modification, ocean dynamics can offset over 100% of the anomalous SST warming that would otherwise arise from atmospheric forcing. Among all ocean processes, ageostrophic advection and vertical mixing (diffusion and entrainment) are the most important factors in modifying the SST tendency response. The SST tendency response to ARs varies spatially. For example, in coastal California, the driver of enhanced SST warming is the reduction in ageostrophic advection due to anomalous southerly winds. Moreover, there is a large region where the SST shows a warming response to ARs due to the overall reduction in the total clouds and subsequent increase in total incoming shortwave radiation.
大气河流（ARs）是造成极端天气状况的中纬度系统，会对沿海地区造成重大破坏。虽然对两周以上的大气河流进行预报仍然是一项挑战，但过去的研究表明，通过海气相互作用适当考虑海表面温度（SST）的变化可能会带来潜在益处。在本文中，我们使用SST收支方程分析了25年的海洋再分析数据，研究了大气河流对北太平洋海表面温度的影响。我们表明，在海洋强烈变化的区域，海洋动力可以抵消超过100%原本由大气强迫引起的海表面温度异常变暖。在所有海洋过程中，非地转平流和垂直混合（扩散和夹卷）是改变海表面温度趋势响应的最重要因素。海表面温度对大气河流的趋势响应在空间上有所不同。例如，在加利福尼亚沿海，海表面温度变暖增强的驱动因素是异常南风导致的非地转平流减少。此外，由于总云量总体减少以及随后总入射短波辐射增加，有大片区域的海表面温度对大气河流呈现变暖响应。
