Abstract

This work is focused on the river plume generated by the Kodor River which is the largest river of Abkhazia and the northeastern coast of the Black Sea. Based on in situ hydrological data, quadcopter aerial images and satellite observations, hydrophysical structure and circulation in the Kodor plume was studied at different river discharge conditions. Discharge of the Kodor River, which inflows to sea from several deltaic branches forms a relatively shallow plume with large area, as compared to the Mzymta River, the largest estuarine river of the study region, at similar hydrological, meteorological, and oceanographic conditions. Due to its small vertical size and large salinity gradient at the border with the subjacent saline sea, the Kodor plume is characterized by quick response on wind forcing variability. The Kodor plume also has large spatial inhomogeneity, caused by its formation conditions (several closely located freshwater sources prone to abrupt discharge variability), as well as regional bathymetry (interaction between the plume and shoals). During low discharge period, the inflowing Kodor River has relatively low kinetic energy, which causes abrupt deceleration of the jet in the sea area adjacent to the river mouth. As a result, the inertia of the inflowing jet abruptly decreases and large velocity and salinity gradients are formed in vicinity of river estuary, which hinder formation of anticyclonic circulation at the near-field part of the plume. This feature induces transport of freshwater discharge off the river mouth and its accumulation in the far-field part of the small plume under moderate wind forcing conditions that is not typical for large river plumes. The obtained results are important for understanding general aspects of dynamics of buoyant plumes formed by rivers with small discharge rates.

中文翻译：

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科多尔河羽流的水物理结构和电流动力学

摘要

这项工作的重点是科多尔河产生的河羽，科多尔河是阿布哈兹和黑海的东北海岸最大的河流。基于原位水文数据，四轴飞行器的航空影像和卫星观测资料，研究了在不同河流排放条件下科多尔羽流的水物理结构和环流。与姆多姆塔河（研究区域最大的河口河）在类似的水文，气象和海洋条件下相比，科多尔河的流量从几个三角洲支流流入大海，形成了一个面积较大的相对较浅的羽流。由于Kodor烟羽的垂直尺寸小，且与邻近海盐海的边界处的盐度梯度大，因此其特征是对强迫风的快速响应。科多尔羽流还具有较大的空间不均匀性，这是由于其形成条件（几个位置较近的淡水源，容易产生突然的排放变化）以及区域测深法（羽流与浅滩之间的相互作用）引起的。在低排放期，流入的科多尔河具有相对较低的动能，这会导致射流在与河口相邻的海域中突然减速。结果，流入的射流的惯性突然减小，并且在河口附近形成大的速度和盐度梯度，这阻碍了在羽流的近场部分形成反气旋循环。此功能会导致在中等风力条件下淡水排出河口的过程​​，并在小羽状体的远场部分积聚，这在大河羽状体中并不常见。获得的结果对于理解由小流量的河流形成的浮羽的动力学的一般方面是重要的。