长江入河口区生源要素的浓度变化及通量估算

CONCENTRATION VARIATION AND FLUX ESTIMATION OF DISSOLVED INORGANIC NUTRIENT FROM THE CHANGJIANG RIVER INTO ITS ESTUARY

利用近几十年长江大通断面的实测流量和生源要素 (C、N、P、Si)资料 ,讨论了C、N、P、Si较长时间序列浓度的变化特征和长江入河口区的通量。结果表明 ,HCO-3 浓度比较稳定 ,波动较小 ;NO-3 、NO-2 、PO3-4 主要呈上升趋势 ;游离CO2 、NH+4和SiO2 -3 浓度表现出一定下降趋势 ;估算并研究了长江C、N、P、Si入河口区年内各月的平均通量、年际间各年的通量和多年平均的年均通量和主要变化特征 ;利用月通量序列以及相应的流量序列 ,拟合出可以利用已知的月均流量预测进入河口区的月通量的关系函数。这些研究是进行河口区生源要素收支平衡计算的重要基础。

Based upon the monthly dissolved nutrient(C?N?P?Si)concentrations and runoff discharge during the past several years at the Datong control section,which divides the Changjiang River main stream and the Changjiang River estuary,concentration variations are discussed and nutrient fluxes are estimated The concentrations of different elements showed different variation characteristics The concentration of HCO - 3 changes little while that of NO - 3?NO - 2?PO 3- 4have an increasing trend and that of CO 2?NH + 4 and SiO 2- 3 have a declining trend The monthly mean flux and annual mean fluxes C?N?P?Si are estimated Further,fitting functions between the discharge and the fluxes are obtained to predict the monthly flux with the monthly discharge