Recent changes to Arctic river discharge

Dongmei Feng,Yuta Ishitsuka,Xiao Yang,Peirong Lin,Colin J Gleason,Ming Pan

doi:10.1038/s41467-021-27228-1

Abstract

Arctic rivers drain ~15% of the global land surface and significantly influence local communities and economies, freshwater and marine ecosystems, and global climate. However, trusted and public knowledge of pan-Arctic rivers is inadequate, especially for small rivers and across Eurasia, inhibiting understanding of the Arctic response to climate change. Here, we calculate daily streamflow in 486,493 pan-Arctic river reaches from 1984-2018 by assimilating 9.18 million river discharge estimates made from 155,710 satellite images into hydrologic model simulations. We reveal larger and more heterogenous total water export (3-17% greater) and water export acceleration (factor of 1.2-3.3 larger) than previously reported, with substantial differences across basins, ecoregions, stream orders, human regulation, and permafrost regimes. We also find significant changes in the spring freshet and summer stream intermittency. Ultimately, our results represent an updated, publicly available, and more accurate daily understanding of Arctic rivers uniquely enabled by recent advances in hydrologic modeling and remote sensing.

Highlights

Arctic rivers drain ~15% of the global land surface and significantly influence local communities and economies, freshwater and marine ecosystems, and global climate
We find that Remotely-sensed Arctic Discharge Reanalysis (RADR) shows increases in total water export and acceleration across many of these comparisons, showing that RADR’s insights are not limited to its extended spatial coverage
We found that median Nash Sutcliffe Efficiency43 (NSE) and KlingGupta efficiency44 (KGE) increased by 0.16 and 0.09 across these gauges, respectively, when comparing RADR and the original model simulations (Supplementary Fig. 4a, b), and this median improvement is larger for regulated reaches (Supplementary Fig. 4c, d), showing the value of remote sensing in ‘seeing’ impacts of human regulations

Summary

Introduction

Arctic rivers drain ~15% of the global land surface and significantly influence local communities and economies, freshwater and marine ecosystems, and global climate. RADR is a record of daily discharge for 486,493 river reaches across the pan-Arctic region over the period 1984–2018. We generated RADR by assimilating approximately 9.18 million discharge observations derived from 227 million river width measurements from Landsat images (Supplementary Fig. 1) into an optimal blend of two recent global hydrologic model simulations[25,26].

Results

Conclusion