Observations of Newark Bay, a sub-estuary network characterized by multiple junctions, reveal that fronts are generated by tidal flow through transitions in channel geometry. All fronts substantially contribute to along-channel estuarine heterogeneity, and most are associated with both changes in channel geometry and tidal velocity phase-shifts. A lift-off front forms at the mouth of the sub-estuary during ebb tide in response to the abrupt seaward channel expansion. While forming, the front is enhanced by a tidal velocity phase-shift; flood tide persists in the main estuary until 90 min after the start of ebb tide in the sub-estuary. A second lift-off front forms during ebb tide at a channel–side-channel junction and is enhanced by a lateral baroclinic circulation induced by baroclinic and barotropic tidal velocity phase-shifts between the main channel and side channel. The lateral circulation also bifurcates the along-channel ebb flow at the surface, generating a surface front above the lift-off front. At the head of Newark Bay, a second surface front forms during ebb tide at the confluence of two tributary estuaries. This confluence front is rotated across the mouth of the primary fresh water source by high velocities from the adjacent tributary estuary and is maintained through much of ebb tide by lateral straining and mixing. Although the overall stratification of Newark Bay would categorize it as a partially mixed estuary, the fronts divide the density structure of the sub-estuary into a series of nearly homogeneous segments—a characteristic that is more often associated with fjords.

中文翻译：

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河口交汇处的前生

纽瓦克湾（Newark Ba​​y）是一个以多个路口为特征的河口网络的观测结果，表明锋面是由潮汐流通过通道几何形状的过渡而产生的。所有前沿都对河道沿河口异质性做出了重要贡献，并且大多数都与河道几何形状的变化和潮汐速度相移有关。在退潮期间，响应突然的向海河道扩张，在河口的口形成抬升锋。成形时，潮汐相移增强了前缘。潮汐在主要河口一直持续到次河口退潮开始后的90分钟。在通道-侧通道交界处的退潮期间，形成了第二个抬升锋面，并且由于主通道和侧通道之间的斜压和正压潮汐速度相移而引起的侧斜压循环增强了第二压升锋。横向循环还会使沿通道的起伏流在表面处分叉，从而在提离前端上方产生一个表面前端。在纽瓦克湾的顶部，在两个支流河口汇合处的退潮期间形成了第二个海面锋面。该汇合锋面通过邻近的支流河口的高速流过初级淡水水源的口而旋转，并通过侧向拉力和混合而在大部分退潮期间得以维持。尽管纽瓦克湾的总体分层将其归类为部分混合的河口，