Our long-term goal is to understand the disposition of river borne pollutants on the Russian Arctic shelves. Ultimately we want to be able to predict the fate of pollutants spilled into one of the Russian rivers. Specifically we wish to determine how much of the pollutant would escape the waters and sediment near the mouth of the river and enter the Arctic Ocean, where it could be carried to the far reaches of the basin. (Show_Outline_Map_in_Separate_Window)
If one of the Russian rivers becomes polluted with nuclear waste, the outcome may be difficult to predict. The contaminant will come down the river dissolved in the water and bound with the suspended sediment. How the contaminant is then divided between the sea water, sea ice, and offshore sediments will be dependent on the season, weather, and other parameters. The major question concerning river pollution is how a river borne pollutant will be partitioned between sea-ice, sea water at various depths, and sediment on the shelves. Our objective is to answer this question. In doing so, we are examining the geographic distribution of the river plume and how the river water mixes on the shelves with the other water types of the Arctic Ocean. We aim to learn how much of the pollutant is in solution and how much is bound with suspended sediment. The pollutant dissolved in the water will be carried by the ocean currents to other regions so we must determine the current patterns on the shelves. The pollutant bound to sediment may be incorporated in the ice and be made available for ice transport. Ice transport is being investigated by a related ANWAP project, but we must predict the amount of sediment contamination. Finally we must determine how much contaminated sediment will be deposited on the bottom near the river mouth and how much contaminated sediment will remain in suspension to be carried around the ocean.
Our approach under the current Arctic Nuclear Waste Assessment Program grant from the Office of Naval Research is a coordinated effort of data analysis and modeling. The work is being done cooperatively with colleagues at the Arctic and Antarctic Research Institute (AARI) in St. Petersburg, Russia and at Texas A&M University.
Under an ANWAP subcontract, AARI has produced a database describing the bathymetry, currents, sea level variations, river discharge, gridded winter and summer temperature and salinity fields, ice observations, and meteorological observations in the Kara, Laptev, and East-Siberian Seas for three-year periods in the late-1970's. We are presenting the temperature, salinity, and river discharge data in an ANWAP - PSC/AARI web page here at the Polar Science Center.
Separate from ANWAP, other international scientific work is offering intimations of the significance of this research and possibilities for filling in the coastal oceanographic record from earlier decades.
The TRANSDRIFT Experiments (I, II, III, and IV) are Russian-German cooperative efforts studying the Laptev Sea System. Determining the distribution of anthrophogenic radionuclides is one particular focus of these experiments. GEOMAR is a major German partner.
Investigators from AARI have recently presented measurements of radionuclide concentrations from the Kara Sea in 1992 and the Laptev Sea in 1993.
Historical records of water transparency and color hint at the patterns of water circulation and sediment transport during previous decades. Here is a peek at the Kara Sea in 1959.
Joint modeling efforts with AARI are aimed at developing an observation based model that can be expanded to larger domains with minimal computer requirements. This will allow the model to be run in Russia and the U.S. Presently we are concentrating on modeling the Kara Sea because it is most critical to the spread of pollutants from the Ob and Yenisey Rivers. The block diagram of Figure 1 illustrates the main components of the model. We divide the model into three main parts.
Part A is the diagnostic component of the AARI circulation model. It is now operational. It uses hydrographic climatology, river inflow, tidal forcing and atmospheric pressure to estimate the velocity field. It is diagnostic in that the hydrographic structure is not affected by the simulated circulation. Apart from the wind and tidal response, the velocity is an expression of climatology. Presently we are improving the time and spatial resolution and applying higher frequency forcing to resolve critical high energy current events.
Part B is also part of the existing AARI model. It uses the velocity field from Part A and determines the advection and diffusion of contaminants. It already accounts for radioactive decay but new code is being applied to account for sediment transport and settling.
Part C is being developed at PSC, primarily by Miles McPhee, as a 1-D model of sediment flux and the fractionation of radionuclides between contaminant bound to the ice and in solution. Initially a sediment transport model was developed. It accounts for the surface and bottom boundary layers, and stratification by fresh water input and sediment suspension. Bottom sediment erosion rate is dependent on bottom stress. The model is capable of tracking concentrations for several different classifications of sediment, each with critical bed stress and settling velocity parameters.
We present here output from recent model runs of water circulation in the Kara Sea by Dr. Vladimir Pavlov of AARI.
For further information, please contact Principal Investigator James Morison
To learn more about who we are, you are invited to visit -
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Last Revised on February 28, 1997