Decrease of river runoff in the upper waters of the Eurasian Basin, Arctic Ocean, between 1991 and 1996: Evidence from δ¹⁸O data

Abstract

Measurements of the H 2 18 O/H 2 16 O ratio of water from two sections crossing the Eurasian Basin in 1991 and 1996 show that the observed decrease in the freshwater contained in the upper waters of the Eurasian Basin during the 1990s is due to decrease in meteoric water (mainly river runoff). The decrease in meteoric water inventories between 1991 and 1996 calculated from balances of mass, salinity, δ 18 O, and PO 4 * is about 3 meters and accounts for basically the entire freshwater change inferred from salinity budgets. Climatological data are used to ensure that the two sections can be considered to belong to the same hydrographic regime. The data also suggest that in 96 the formation of sea ice from the upper waters in the Amundsen Basin was lower by about 1 meter (3 m in 1996 compared to 4 m in 1991).