Glen MacDonald (email@example.com), University of California, Los Angeles
Richard Lammers (firstname.lastname@example.org), University of New Hampshire
Terrestrial freshwater runoff plays a significant role in the thermohaline circulation and sea-ice production of the Arctic Ocean. About 85% of terrestrial runoff to the Arctic Ocean is generated from the Russian Federation. Recently, a number of researchers have noticed that flows in the major Arctic Russian rivers are changing, most notably as a pronounced increased in discharge as measured at the mouths of these rivers over the past 65 years. Linear extrapolation of this trend suggests that Arctic thermohaline circulation could be disrupted within 200 years (Peterson, et al. 2002), a controversial idea that received much attention at the recent ARCSS All-Hands Meeting (20-23 February 2002, Seattle).
The proposed research seeks to (1) identify when and where the discharge increases of the past 65 years are coming from; and (2) place these trends into a longer-term (century to millennium scale) temporal context. The first objective would be achieved through quantitative analysis of daily discharge records, collected at numerous gauging stations throughout the major high-latitude Russian river basins for nearly a century. An important first phase of this project would provide "data rescue" of paper-format records for at least 150 of these stations. These daily-resolution discharge time-series will be translated, digitized, checked for quality assurance, and incorporated as a special data subset in the R-ArcticNET pan-Arctic hydrologic database (http://arcss/colorado.edu/data/arcss062.html) for electronic distribution to the public. The second objective would be achieved through modeling of paleo-discharge from tree-ring width and density data, a method that has already proved successful in other high-latitude biomes and Mongolia. Tree-ring data now exist for over 70 well-distributed sites across Arctic Russia and are publicly available for this purpose.
The proposed research is guided by a core set of five working hypotheses designed to shed light on some fundamental questions about the recent discharge increases, namely "are they unprecedented?" "where is the water coming from?" and "what are the physical processes driving them?" The first question will be addressed through construction of paleo-discharge time-series extending back several centuries with annual resolution. The others will be addressed through quantitative study of daily discharge records, including baseflow recession analysis, wavelet transformation and spectral analysis, summer-flood frequency/magnitude statistics, and trend-testing of the timing and magnitude of the annual spring flood. The end products of the proposed research will be a substantially improved understanding of spatial and temporal runoff patterns across the world's largest Arctic landmass, and a historical context by which to evaluate their contemporary trends. Broader impacts include graduate education, important participation of Russian scientists from the State Hydrologic Institute, St. Petersburg, establishment of new partnerships between institutions, and provision of two unprecedented river discharge databases to the Arctic and hydrologic research communities.
Science Management Office
Role of the Arctic-CHAMP Science Management Office