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Satellite Evidence for Strengthened M2 Internal Tides in the Past 30 Years
  • Zhongxiang Zhao
Zhongxiang Zhao
University of Washington

Corresponding Author:zzhao@apl.uw.edu

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Satellite altimetry sea surface height (SSH) measurements from 1993 to 2022 are used to show the strengthened mode-1 M2 internal tides in the past 30 years. Two mode-1 M2 internal tide models M9509 and M1019 are constructed using the data in 1995-2009 and 2010-2019, respectively. The results show that the global mean M2 internal tides strengthened by 6.6% in energy. However, the internal tide strengthening is spatially inhomogeneous. Significantly strengthened internal tides are observed in a number of regions including the Aleutian Ridge and the Madagascar-Mascarene region. Weakened internal tides are observed in the central Pacific. On a global average, M1019 leads M9509 by about 10o (20 minutes in time), suggesting that the propagation speeds of M2 internal tides increased. M9509 and M1019 are evaluated using independent altimetry data in 1993-1994 and 2020-2022. The results show that M9509 and M1019 perform better for the data in 1993-1994 and 2020-2022, respectively.
02 Aug 2023Submitted to ESS Open Archive
04 Aug 2023Published in ESS Open Archive