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Dynamic Sea Level Variability Due to Seasonal River Discharge: A Preliminary Global Ocean Model Study
Author(s) -
Piecuch Christopher G.,
Wadehra Riley
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl086984
Subject(s) - advection , climatology , environmental science , forcing (mathematics) , tide gauge , altimeter , discharge , ocean surface topography , sea level , oceanography , seasonality , scale (ratio) , geology , meteorology , drainage basin , geography , thermodynamics , physics , statistics , cartography , mathematics
River discharge R is an important driver of the coastal ocean circulation. However, the influence of variable R effects on large‐scale sea level ζ related to ocean dynamics is not well understood. We perform numerical experiments using a coarse ( ∼ 1 °) global ocean state estimate to quantify R effects on the seasonal cycle in dynamic ζ over the global ocean. Forcing by R drives substantial dynamic ζ signals ( ≳ 1 cm) on regional scales around major rivers (e.g., Amazon, Ganges, Brahmaputra, Irrawaddy, Ob, Lena, and Yenisei). Modeled ζ changes largely reflect halosteric (salinity) effects, which are partly affected by transport processes involving planetary waves and advection. The modeled ζ response to R is informative for interpreting ζ observations from satellite altimetry and tide gauges, explaining 10–20% of the regional‐scale seasonal data variance around some major rivers. Future ζ studies should consider finer‐resolution models and R forcing on nonseasonal time scales of relevance to climate.