[M-IS01] Environmental, Socio-Economic and Climatic Changes in Northern Eurasia

[MIS01-10] Centennial and decadal variability of Yenisei River flow assessed with the online tool TRISH - Tree-Ring Integrative System for Hydrology

*Irina P Panyushkina¹、David Meko ¹、Richard Thaxton²、Alexander I Shiklomanov ³、Alexander Prusevich³、Stanley Glidden³、Richard Lammers³ (1.University of Arizona, Laboratory of Tree-Ring Research 、2. University of Idaho, Department of Earth and Spatial Sciences、3.University of New Hampshire, Earth Systems Research Center)

キーワード：Dendrochronology , Hydrology , Arctic , Water Balance Modeling , River Discharge Modeling

To advance our understanding of the feedbacks between Arctic warming and regional hydrology, we explore the hydrological potential of historical and new tree-ring networks across the Yenisei River Basin. The Yenisei River, the largest Arctic River by annual discharge and the 5th largest globally, is 3,487 km long and drains an area of 2.5 million km² of Middle Siberia from Mongolia to the Kara Sea. We develop four tree-ring models of the annual (Oct-Sept) and winter season (Nov-Apr) flow of the Yenisei River at the Kyzyl (south) and Igarka (north) gauges for this enormous river basin. The tree-ring reconstruction shows better skill for the winter discharge than for the hydrological year: 50% explained variance versus 30%. The decadal and multi-decadal variability of the reconstructed seasonal discharge varies significantly in the space and over the last 300 years, showing a general tendency for increasing flow in the second half of the 20th and 19th centuries. The flow was high in the 1970s-1980s and low around the 1940s and 1740s. Remarkably, the recent increase of the Yenisei annual flow is higher than the long-term average estimated with the tree rings. But this trend has weakened as flows have decreased in the most recent decade. The tree-ring modeling of Yenisei River discharge reveals large seasonal changes in the flow most likely related to permafrost thaw, especially in the south, due to forest fires and a warming climate. Our modeling results highlight the undervalued potential of temperature-sensitive tree-ring networks for hydrological modeling in high-latitude watersheds. The reconstruction was done with the Tree-Ring Integrated System for Hydrology (TRISH), a new online tool for analyzing tree-ring data in a spatial framework via the University of New Hampshire EarthAtlas Map Server, Map Data Calculator, and Water Balance Model (WBM). The tool helps researchers to access, analyze and visualize hydro-climatic signals in tree-ring networks using historical observations and reanalysis products and WBM outputs. We discuss challenges in application of 1) historical networks of temperature- and moisture-sensitive tree rings to hydrological modeling in high-latitude watersheds, and 2) water balance simulations of flow to tree-ring river flow reconstruction.