HR: 1330h
AN: GC12A-0147    [PDF]
TI: Drivers of Increasing River Discharge in the Eurasian Arctic: Consideration of Dam/Reservoir Construction, Permafrost Thaw, and Fire Frequency as Potential Agents of Change
AU: McClelland, J W
EM: jmcclelland@mbl.edu
AF: Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA 02543 United States
AU: Holmes, R M
EM: rholmes@mbl.edu
AF: Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA 02543 United States
AU: * Peterson, B J
EM: peterson@mbl.edu
AF: Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA 02543 United States
AU: Stieglitz, M
EM: marc@ldeo.columbia.edu
AF: Lamont Doherty Earth Observatory, Route 9W, Palisades, NY 10964 United States
AB: While long-term records of discharge from Eurasian rivers to the Arctic Ocean show significant increases from the mid 1930s to present, the mechanisms driving these changes remain unclear. Increased moisture transport from lower to higher latitudes in a warming climate has been identified as one potential mechanism. Other suggested mechanisms have emphasized local factors including permafrost thaw, changes in fire frequency, and the influence of dam/reservoir construction. Here we evaluate the potential influence of these local factors on long-term changes in discharge from the 6 largest Eurasian arctic rivers. Particular attention is given to the influence of dams/reservoirs. Detailed records of dam/reservoir construction in combination with discharge data throughout the Russian monitoring network made it possible to clearly identify effects on river discharge. Dams/reservoirs have been responsible for pronounced shifts in the seasonality of discharge from the Ob, Yenisey, Lena, and Kolyma rivers. However, there is no evidence that dams/reservoirs were responsible for long-term increases in annual discharge. In fact, our analysis revealed that increases in annual discharge from the 6 largest Eurasian rivers to the Arctic Ocean would have been even larger in the absence of dams constructed for reservoirs and associated water diversions. Lack of comprehensive historical data on fire and permafrost parameters in the Eurasian Arctic make conclusions about their effects on river discharge more tentative. Nonetheless, it appears unlikely that either permafrost thaw or changes in fire frequency can account for the long-term changes in river discharge. Thus, of the potential drivers considered here, increasing northward transport of moisture as a result of global warming remains the most viable for explaining the observed increases in Eurasian river discharge to the Arctic Ocean.
DE: 1600 GLOBAL CHANGE (New category)
DE: 1655 Water cycles (1836)
DE: 1803 Anthropogenic effects
DE: 1860 Runoff and streamflow
SC: Global Climate Change [GC]
MN: 2003 Fall Meeting