The central and east Siberian shelf regions represent a key area in the shelf-land environment of the Arctic region. River discharge by Lena, Indigirka and Kolyma rivers as well as sediment supply from riverine sources and coastal erosion dominate the freshwater and sediment budget of the broad, shallow shelf. Strong seasonal and interannual variability in ice formation and extent impact on the sea-ice mass balance of the Transpolar Drift, with a pronounced decline in Arctic summer ice extent to a large degree derived from recent changes in the East Siberian ice cover. New studies also indicate that formation and export of ice from this region are of disproportionate importance for the long-range dispersal of ice-rafted sediments throughout the Arctic Basin. Despite its significance, this region is not nearly as well studied and understood as other sectors of the Arctic.

This research proposal, with a well-defined Russian collaborational component, aims to further our understanding of the Siberian shelf-land system by (1) identifying links between riverine freshwater supply, sea-ice formation and sediment export by ice rafting, (2) quantifying the regional and temporal variability of the relevant processes, (3) determining the relative importance of major, catastrophic events as compared to the gradual evolutionary regime for coastal and basin-wide sediment transport, (4) identifying a set of critical processes and parameters that delimit the gradual and the catastrophic regime. Based on this analysis of present-day mean state and extremes, we furthermore hope to extend our understanding of land-ocean interaction to paleo-oceanographical time scales.

Time series of the relevant atmospheric, hydrologic and oceanic parameters will be analysed in conjunction with remote-sensing methods. From infra-red, passive microwave and synthetic-aperture-radar remote-sensing data, we will determine the dispersal of riverine freshwater and its impact on autumn ice formation. For this component, extensive ground-truth data sets from Russian hydrographic surveys and previous, ice-going research expeditions will be utilized. Sediment entrainment and export will be derived from visible-range satellite imagery based on newly developed classification and mapping techniques. Quantitative estimates of sediment dispersal and regional and temporal variability of the relevant boundary conditions will be augmented by numerical modelling to study the impact of different circulation regimes and rank the importance of extreme events versus the background signal of gradual change. Based on this analysis, the impact of linkages between hydrography, atmospheric circulation and the sea-ice regime over the Siberian shelves on decadal variability and propagation of anomalies throughout the Eurasian Arctic will be assessed.