Detection and Attribution of Changes in the Hydrologic Regimes of the Mackenzie, the Kuparuk and the Lena River Basins
We seek to understand how the Arctic hydrologic cycle has varied over the past 50 years and how it may change over the next 50 years. An understanding of the Arctic hydrological cycle is now recognized as critical to understanding both the earth's climate and the ocean's thermohaline circulation. Research sites will include the Kuparuk River in Alaska, the MacKenzie River in Canada, and the Lena River in Russia. Within each watershed, we will study two sub-watersheds in a detailed, process-scale approach: one underlain by continuous permafrost and another underlain by discontinuous permafrost. Field measurements obtained from ongoing collaborative projects will be used within a previously developed, process-based Arctic hydrological model (WaterWERCs, a newly-reconstructed form of ARHYTHM) run at high spatial resolution (up to 5 m posting) both to help elucidate the processes involved and to allow extrapolation up to a coarser spatial resolution. This same model will then be run at 100 m posting using locally-derived numerically-extrapolated meteorological data for the entire watershed, the results aggregated into 10 km posting, and this output compared to WaterWERCs output created using meteorological data output from a version of the MM5 atmospheric model that will be adapted to Arctic conditions on 10 km postings. Results of these comparisons will be used to assess our modeling reliability and create a reduced-form combined atmospheric/hydrological model which minimizes CPU time such that it can be used to assess scenarios across the entire Arctic for the next 50 years.
The Polar Climate and Meteorology Group at the University of Colorado, in collaboration with researchers at Iowa State University will contribute to this project through the development and application of an Arctic specific atmospheric model based on the widely used mesoscale model MM5. Future scenarios will be analyzed based on output from the Arctic version of MM5 and detailed hydrologic modeling using a statistically based reduced form model.