Recent Trends in Freshwater Influx to the Arctic Ocean from Four Major Arctic-Draining Rivers

Water, Journal Year: 2020, Volume and Issue: 12(4), P. 1189 - 1189

Published: April 21, 2020

Runoff from Arctic rivers constitutes a major freshwater influx to the Ocean. In these nival-dominated river systems, majority of annual discharge is released during spring snowmelt period. The circulation regime salinity-stratified Ocean connected global earth–ocean dynamics through thermohaline circulation; hence, variability in input flowing has important implications for climate system. Daily data each four largest Arctic-draining watersheds (Mackenzie, Ob, Lena and Yenisei; herein referred as MOLY) are analyzed identify historic changes magnitude timing with emphasis on freshet. Results show that total increased by 89 km3/decade, amounting 14% increase 30-year period 1980 2009. A distinct shift towards earlier melt also indicated proportional increases fall, winter discharges (by 2.5%, 1.3% 2.5% respectively) followed decrease 5.8%) summer percentage mean flow. This seasonal pulse onset dates indicates general flatter, broad-based hydrograph peak discharges. study reveals increasing trend not solely due freshet discharge, but combination all seasons except summer.

Language: Английский

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River Freshwater Flux to the Arctic Ocean

Springer eBooks, Journal Year: 2020, Volume and Issue: unknown, P. 703 - 738

Published: Aug. 28, 2020

Language: Английский

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Mercury Export from Arctic Great Rivers

Environmental Science & Technology, Journal Year: 2020, Volume and Issue: 54(7), P. 4140 - 4148

Published: March 2, 2020

Land–ocean linkages are strong across the circumpolar north, where Arctic Ocean accounts for 1% of global ocean volume and receives more than 10% river discharge. Yet estimates riverine mercury (Hg) export constrained from direct Hg measurements remain sparse. Here, we report results a coordinated, year-round sampling program that focused on six major rivers to establish contemporary (2012–2017) benchmark export. We determine exported an average 20 000 kg y–1 total (THg, all forms Hg). Upscaled pan-Arctic, estimate THg flux 37 y–1. More 90% occurred during peak discharge in spring summer. Normalizing fluxes watershed area (yield) reveals higher yields regions greater denudation likely enhances mobilization. River discharge, suspended sediment, dissolved organic carbon predicted concentration with moderate fidelity, while sediment water yield high fidelity. These findings face rapid warming intensifying hydrologic cycle, which will accelerate cycling tandem changing inputs thawing permafrost industrial activity.

Language: Английский

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Arctic Hydrology, Permafrost and Ecosystems

Springer eBooks, Journal Year: 2020, Volume and Issue: unknown

Published: Aug. 28, 2020

Language: Английский

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Permafrost Promotes Shallow Groundwater Flow and Warmer Headwater Streams

Water Resources Research, Journal Year: 2020, Volume and Issue: 57(2)

Published: Dec. 12, 2020

Abstract The presence of permafrost influences the flow paths water through Arctic landscapes and thereby has potential to impact stream discharge thermal regimes. Observations from 11 headwater streams in Alaska showed that July temperatures were higher catchments with more near‐surface permafrost. We apply a fully coupled cryohydrology model investigate if on path depth could cause same pattern groundwater discharging hillslopes streams. simulates surface energy balances, snow, subsurface balances for two‐dimensional hillslope cases varying extent. find continuous have shallow twice as high rates evapotranspiration, compared no For our simulated cases, 6.7% horizontal flux moves top organic soil layers when there is permafrost, while only 0.5% without deeper permafrost‐free simulations buffer seasonal temperature extremes, so summer are highest Our results suggest thawing alters can lead decreases reductions evapotranspiration catchments. These changes importance biotic components ecosystems, however, full remains unknown.

Language: Английский

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