灌河口盐、悬沙通量的分解及时空特征

灌河是江苏省北部目前唯一没有在干流建闸的入海河流，拥有广阔的滩涂和优良的航运条件。河口通量是河口治理和河口环境保护中的关键要素。为研究灌河口的盐及悬沙的输运，基于实测资料利用通量分解方法对灌河的盐及悬沙通量的空间分布、大-小潮与潮内的时间变化特征进行了探讨。研究认为：在口门以内的弯曲河段，盐通量在凸岸浅水区一般指向下游，在凹岸深槽处则指向上游。大、小潮期间悬沙通量则基本上为左侧指向上游、右侧指向下游；口外盐通量方向为NNE-NE，而且随径流量大小而稍有改变，口外悬沙通量方向在远岸区域表现为WNW-NNE，近岸G2测点的悬沙通量则指向口门；口门内外盐和悬沙通量的组成均基本以T1、T2和T4为主导，通量组成的总体特征在大、小潮期间基本类似。涨落潮流速最大时刻的悬沙通量不一定与流速方向一致，最大落潮流速时刻由于悬沙浓度可能小于平均值而导致悬沙净输运指向上游。

Decomposition of salinity and sediment fluxes and their spatial-temporal characteristics in the Guanhe estuary

The Guanhe River has wide shoals and excellent waterways,which is unique in the north Jiangsu Province that has no dam in its main stream.Estuarine flux is the key parameter in estuarine regulation and environment protection.In order to investigate the transport of salt and suspended sediment,the spatial distribution of salinity and suspended sediment and the temporal variation of spring-neap tide and intra-tide were discussed using a flux decomposition method on the basis of field data.The results show that the fluxes of salinity points to downstream in the shallow zones near the convex bank and to upstream in the channels near concave bank in the curve segments.The suspended sediment fluxes points to upstream near the left bank and to downstream near the right bank during the spring and neap tide.The directions of the flux of salinity are NNE-NE and changes slightly with different river discharge in outer zone.The suspended sediments are transported along WNW-NNE in remote area,while upstream at G2 near the river mouth.T1,T2and T4 are the dominate components of salinity and suspended sediment fluxes,and the characteristics of flux composition is similar between spring and neap tide.The direction of net suspended sediment flux is not always as same as the tidal velocity at maximum ebb or flood.Net upstream flux might be induced at maximum ebb due to sediment concentration is lower than its tidally-averaged value.