Water Discharge, Nitrate Concentration and Nitrate Flux in the Lower Mississippi River
Thirty-five years of monthly lower Mississippi River water discharge, nitrate concentration and nitrate flux have been analyzed. The potential predictability of these quantities has been evaluated. Results indicate a large amplitude, long-term cycle in the nitrate concentration that is not observed in the water discharge. A decrease in average nitrate concentration from a peak in 1983 to the present confirms that this variability is more cyclic than trend-like. River-water discharge variation was greatest in association with the annual cycle. The annual water discharge and nitrate concentration cycles were similar; high nitrate concentrations usually occurred near the vernal freshet, and low concentrations usually occurred along with autumnal low-flow conditions. Nitrate flux variations exhibited a low amplitude, long-term modulation of a dominant, annual cycle. A predictor-hindcast analysis indicates that truly skilled forecasts of all three fields are feasible.
Journal of Marine Systems
(1993). Water Discharge, Nitrate Concentration and Nitrate Flux in the Lower Mississippi River. Journal of Marine Systems, 4(4), 315-326.
Available at: http://aquila.usm.edu/fac_pubs/6683