HR: 0800h
AN: C41A-0190    [Abstracts]
TI: Mass Flux of Water, Sediments and Chemical Constituents to the Laptev Sea of the Russian Arctic via the Lena River
AU: * Armstrong, S J
EM: sarmstrong@geol.sc.edu
AF: University of South Carolina, 701 Sumter St Geological Sciences Dept., Columbia, SC 29208 United States
AU: Karabonov, E B
EM: ekarab@geol.sc.edu
AF: University of South Carolina, 701 Sumter St Geological Sciences Dept., Columbia, SC 29208 United States
AU: Karabonov, E B
EM: ekarab@geol.sc.edu
AF: Institute of Geochemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk, SC 29208 Russian Federation
AU: Styles, R
EM: rstyles@geol.sc.edu
AF: University of South Carolina, 701 Sumter St Geological Sciences Dept., Columbia, SC 29208 United States
AU: Buchinskyi, V
EM: val@igc.irk.ru
AF: Institute of Geochemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk, SC 29208 Russian Federation
AU: Williams, D F
EM: doug.williams@schc.sc.edu
AF: University of South Carolina, 701 Sumter St Geological Sciences Dept., Columbia, SC 29208 United States
AU: Kuzmin, M I
EM: makhom@igc.irk.ru
AF: Institute of Geochemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk, SC 29208 Russian Federation
AB: The Lena River, one of the world's longest rivers, stretches from southern Siberia, north of Lake Baikal and is the second largest river contributing to the freshwater budget of the Arctic Ocean. During the summer of 2003, ADCP transects of the river's currents, bathymetry and acoustic backscatter were repeated for 500km reaches and at each major tributary, covering over 3,600km of the river's length. Concurrently, multi-parameter CTD casts, water chemistry and sediment concentrations were sampled. Preliminary results show water flow through the river increased with distance from the headwaters (150m$^{3}$/s) and increased greatly with contributions from the many tributaries along the river's length, reaching a peak (over 37,000m$^{3}$/s) 64km before the delta at Stolb. Approximately 94% of the Lena's discharge through the delta was accounted for using ADCP flow calculations from transects in three primary distributaries through the delta. To determine the influence of tidal pumping at the mouth, the principle navigation distributary (Bykovskaya) was resampled at the interface with the Laptev Sea, (mouth of Neelov Bay, near Tiksi), repeatedly over a 40-hour interval revealing a lunar semidiurnal period amplitude of oscillation in flow of the same order magnitude as the `subtidal' discharge. Well-mixed thermohaline profiles were evident in the ebb discharge, but during flood, the water was thermally stratified. The net flux through the mouth accounted for only 70% of the flow to the upper reaches of the same channel (Bykovskaya). A comparison with a historic record of Lena flow places the 2003 samples in phase and approximately equal to the 60-year average. The high resolution ADCP sampling of the currents and acoustic backscatter throughout the measured cross-sections were repeated two-three times per station. Net isopleths of flux will be constructed based on the average of the repeated ADCP transects. The net isopleths will then be used to extrapolate chemistry and suspended sediment data and obtain more comprehensive estimates of mass flux. The results will then be compared with the more traditional method by taking the product of the concentration and the river discharge and will then be compared with similar historic estimates. This study will help to characterize the Lena River flow and discharge to the Laptev Sea of the Russian Arctic.
UR: http://arcticchamp.sr.unh.edu/featuredproject/index.shtml
DE: 4235 Estuarine processes
DE: 4558 Sediment transport
DE: 1806 Chemistry of fresh water
DE: 1860 Runoff and streamflow
DE: 1871 Surface water quality
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting