Large‐Scale Signals in the South Pacific Wave Fields Related to ENSO. Issue 10 (25th October 2021)

• Record Type: Journal Article
• Authors: Li, Rui; Wu, Kejian; Li, Jingkai; Akhter, Shaila; Dong, Xianghui; Sun, Jian; Cao, Tonggang
• Is Part Of: Journal of geophysical research. Volume 126:Issue 10(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-25
• Subjects: swell -- ACW -- wave transport -- El Niño; Oceanography -- Periodicals; 551.4605
• DOI: 10.1029/2021JC017643
• Languages: English
• ISSNs: 2169-9275

Abstract

Abstract: Surface waves play an important role in oceans. By using 40 years of reanalysis data from the European Centre for Medium‐Range Weather Forecasts, CERA‐20C, we get the signal of the Antarctic Circumpolar Wave (ACW) in the Southern Ocean wave filed. In addition, this signal with a 5‐year period, can be transmitted to low latitudes by northward swells. The swells from the Southern Ocean, which link the high and low latitudes, have been proved to affect the tropical ocean by analyzing swell height with the empirical orthogonal function (EOF) analysis. This paper also shows the relation between El Niño and northward wave transport from the Southern Ocean. After El Niño outbreaks, the northward wave transport increases abnormally. The highest correlation coefficient is located around 12°S, with values around 0.79 and northward wave transport lags the Niño3 index by 1–2 months. With the decrease in latitudes, the lag time is longer and correlation coefficient increases. The cold water transport induced by waves from higher latitudes has a cooling effect on the decline of El Niño. There is an inextricable link between wave transport and El Niño. Plain Language Summary: The Southern Ocean encircles the Antarctic continent and is unbounded to the north. For the wind above the Southern Ocean, scientists found the signal of the Antarctic Circumpolar Wave (ACW). By analyzing the monthly means of significant height of waves in the Southern Ocean, this signal with a 5‐year period in the wavefield was also found. Due to the continental block, some northward swells can take with the signal from the Southern Ocean to lower latitudes ocean. Then, it can be speculated that the ACW can be found in the whole South Pacific, which is validated by analyzing the swells as well. Connecting the Southern Ocean and lower latitudes ocean, waves transport water mass (heat) in the process of propagation. It is also found that an increase in sea surface temperature (SST) is accompanied with an increase in wave transport. Cold water from higher latitudes transported by waves would have a cooling effect on lower latitudes ocean. During the period of El Niño, wave transport may play a positive role in maintaining the stability of low latitudes SST by transporting more (less) cold water to tropical oceans. It can be regarded as a way of self‐regulation of the ocean. Key Points: The signal of the Antarctic Circumpolar Wave has been shown in the Southern Ocean wavefield Monthly means of significant height of swell from the Southern Ocean has a 5‐year period in the South Pacific The northward wave transport in the South Pacific plays a positive role in the process of El Niño recession