Influence of estuarine tidal mixing on structure and spatial scales of large river plumes

Alexander Osadchiev, Igor Medvedev, Sergey Shchuka, Mikhail Kulikov, Eduard Spivak, Maria Pisareva, Igor Semiletov

Research output: Contribution to journalArticle

Abstract

The Yenisei and Khatanga rivers are among the largest estuarine rivers that inflow to the Arctic Ocean. Discharge of the Yenisei River is 1 order of magnitude larger than that of the Khatanga River. However, spatial scales of buoyant plumes formed by freshwater runoff from the Yenisei and Khatanga gulfs are similar. This feature is caused by different tidal forcing in these estuaries, which have similar sizes, climate conditions, and geomorphology. The Khatanga discharge experiences strong tidal forcing that causes formation of a diluted bottom-advected plume in the Khatanga Gulf. This deep and weakly stratified plume has a small freshwater fraction and therefore occupies a large area on the shelf. The Yenisei Gulf, on the other hand, is a salt-wedge estuary that receives a large freshwater discharge and is less affected by tidal mixing due to low tidal velocities. As a result, the low-salinity and strongly stratified Yenisei plume has a large freshwater fraction and its horizontal size is relatively small. The results show that estuarine tidal mixing determines freshwater fraction in these river plumes, which governs their depth and area after they spread from estuaries to coastal sea. Therefore, the influence of estuarine mixing on spatial scales of a large river plume can be of the same importance as the roles of river discharge rate and wind forcing. In particular, plumes with similar areas can be formed by rivers with significantly different discharge rates, as illustrated by the Yenisei and Khatanga plumes.

Original languageEnglish
Pages (from-to)781-798
Number of pages18
JournalOcean Science
Volume16
Issue number4
DOIs
Publication statusPublished - 3 Jul 2020

ASJC Scopus subject areas

  • Oceanography
  • Palaeontology

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    Osadchiev, A., Medvedev, I., Shchuka, S., Kulikov, M., Spivak, E., Pisareva, M., & Semiletov, I. (2020). Influence of estuarine tidal mixing on structure and spatial scales of large river plumes. Ocean Science, 16(4), 781-798. https://doi.org/10.5194/os-16-781-2020