Arctic River Discharge Growing

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By Paul Homewood

AMHERST, Mass. — A civil and environmental engineering researcher at the University of Massachusetts Amherst has, for the first time, assimilated satellite information into on-site river measurements and hydrologic models to calculate the past 35 years of river discharge in the entire pan-Arctic region. The research reveals, with unprecedented accuracy, that the acceleration of water pouring into the Arctic Ocean could be three times higher than previously thought.

The publicly available study, published recently in Nature Communications, is the result of three years of intensive work by research assistant professor Dongmei Feng, the first and corresponding author on the paper. The unprecedented research assimilates 9.18 million river discharge estimates made from 155,710 orbital satellite images into hydrologic model simulations of 486,493 Arctic river reaches from 1984-2018. The project and the paper are called RADR (Remotely-sensed Arctic Discharge Reanalysis) and was funded by NASA and National Science Foundation programs for early career researchers.

  The key thing about this study is not that river flows are greater than previously estimated, but that they have increased over the period of the study, 1984-2018:

This is significant because it means the Arctic Ocean is gradually becoming fresher. Exactly the same phenomenon occurred during what was called The Great Salinity Anomaly, GSA, which began in the 1960s. As Dickson & Osterhus described in their study, One Hundred Years in the Norwegian Sea in 2007:

Though other factors were involved in the freshening of the Arctic Ocean, such as the NAO, the GSA marked a dramatic shift in the Arctic climate, putting an end to what is known as the Warming of the North between 1920 and 1960 and bringing a much colder era.

Part of the reason for this is the fact that freshwater freezes at higher temperatures than salty water, leading to an increase in sea ice. The GSA is also known to have slowed down the Atlantic meridional overturning circulation (AMOC).

HH Lamb also wrote about it, particularly how the GSA was triggered by greater run off from rivers in Canada flowing into the Arctic:

HH Lamb: Climate, History & The Modern World

And a Russian study by Viktor Kuzin shows that 11% of the world’s river water flows into the Arctic, a considerable amount.

A milder Arctic tends to be a wetter one, but a wetter climate leads to freshening of the ocean and a return to colder conditions. In other words, it is cyclical.

All of this reinforces the likelihood that the Arctic will become much colder, with sea ice expanding again in the not-too-distant future.


NOVEMBER 30, 2021