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Circulation and fate of fresh water from river runoff

Ye. Aksenov, A. Jahn

A relatively recently published paper “Sensitivity of the thermohaline circulation to Arctic Ocean runoff” by Rennermalm et al (2006) investigates how changes in Arctic river discharge may control thermohaline circulation by a series of experiments with an intermediate complexity global climate model.  The study does not, however, study how the arctic river runoff reaches the North Atlantic and how much time it takes for this water to influence the THC. This study will fill this gap and will answer a set of scientific questions about pathways of river water and its transformations. Conditions for intercomparison experiments are outlined below.

a.     Questions :

  • What is the contribution of the Siberian and American riverine water into the FW storage in the Arctic Ocean and into the export from it.

b.     Experiments :

  • The experiments would need river tracers in models and depends on whether people are willing to include river tracers. Two following experiments will be analysed this year but we keep the door open for other simulations.
  • 1958-2006 simulations with mean annual runoff in NEMO-1/4° and river tracers for 6 major rivers, OB, Yenisey, Lena, Yana, Kolyma, Mackenzie rivers, and provisionally Yukon River, Hudson Bay rivers.
  • Fully coupled CCSM3.0 1990 equilibrium climate simulation with runoff tracers for inflow into the different shelf seas (Barents, Kara, Laptev, East Siberian, Beaufort Gyre)

c.     Which fields :

  • Tracer fields for 6 major rivers (depth range needs to be specified, in our model we see some river signal below AW layer)
  • Monthly-mean river tracer vertical distributions, monthly-mean timeseries of the river FW transport for the transects across Fram Strait at ~79°N and Davis Strait.
  • Monthly-mean timeseries of the river FW transport for the transects across Nares Strait, Jones Sound, Lancaster Sound, and Hudson Strait, provided the model resolution is high enough.