Wind‐driven transport pathways for Eurasian Arctic river discharge

TLDR

The study maps temperature, salinity, and barium in near‑surface waters of the Laptev Sea and adjacent Arctic Ocean for 1993, 1995, and 1996, revealing that southerly to southeasterly winds drive river waters northward beyond the shelf break into the basin, while other wind regimes steer them along the inner shelf toward the East Siberian Sea. Tracer data show that fluvial discharge was confined to the Laptev shelf in 1993 but extended beyond the shelf break in 1995 and 1996, indicating two wind‑dependent pathways into the central Arctic—upper‑layer flow near the Lomonosov Ridge or along the Mendeleyev Ridge—whose dominance each summer is governed by local wind patterns.

Abstract

Distributions of temperature, salinity, and barium in near‐surface waters (depth ≤ 50 m) of the Laptev Sea and adjacent areas of the Arctic Ocean are presented for the summers of 1993, 1995, and 1996. The tracer data indicate that while fluvial discharge was largely confined to the shelf region of the Laptev Sea in the summer of 1993, surface waters containing a significant fluvial component extended beyond the shelf break and over the slope and basin areas north of the Laptev Sea in the summers of 1995 and 1996. These distributions of fluvial discharge are consistent with local winds and suggest two principal pathways by which river waters can enter the central Arctic basins from the Laptev Sea. When southerly to southeasterly wind conditions prevail, river waters are transported northward beyond the shelf break and over the slope and adjacent basin areas. These waters can then enter the interior Arctic Ocean via upper layer flow in the vicinity of the Lomonosov Ridge. Under other wind conditions, river waters are steered primarily along the inner Laptev shelf and into the East Siberian Sea as part of the predominantly eastward coastal current system. These waters then appear to cross the shelf and enter the interior Arctic Ocean via upper layer flow aligned roughly along the Mendeleyev Ridge. The extent to which either pathway is favored in a given year is largely determined by local wind patterns during the summer months, when fluvial discharge is greatest and shelf waters are at the lowest salinity of their annual cycle.