This research evaluated the variability of current characteristics and seawater properties in the middle part of the southern shelf of the Caspian Sea. The effect of the coastal flow on marine debris dispreading was assessed in the southern Caspian Sea for the first time. The findings showed the existence of thermal stratification containing seasonal thermocline with thickness of about 40 m in the water column. Maximum monthly along-shore current velocities around 1.3 m s−1 were observed in November and December. Monthly variations were clearly found in both flow velocity and local wind components. However, no significant levels of correlation between wind and current speeds were observed during the study in the region. In some cases, the mean monthly cross-shore component velocities were measured at about 29 cm s−1 in November. The findings indicated that there was no upwelling phenomenon associated to the regional wind in the study area. In situ current measurements indicated dominant east and north-northeast directions, presumably related to the effect of general circulation in the southern basin. Current profiles in the water column displayed similarity in directions at 10, 15 and 20 m depths over the continental shelf. The field samples and analysis revealed that the soft and smaller-scale seawater litters can be carried long distances by the current along the coast. Most coastal based and marine litters originated from the tourist activities (in the middle and western parts of the shores) and waste emanated from the river (Tonekabon-Nowshahr).

中文翻译：

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里海南部沿海水域物理和动力特征的环境影响

这项研究评估了里海南部大陆架中部当前特征和海水特性的变化。海岸流对海洋垃圾扩散的影响首次在里海南部进行了评估。研究结果表明，水柱中存在厚度约为40 m的季节性温跃层的热分层。最大月沿岸流速约为 1.3 ms-1在 11 月和 12 月观察到。在流速和局部风分量中都清楚地发现了月度变化。然而，在该地区的研究过程中，没有观察到风速和当前速度之间的显着相关性。在某些情况下，月平均跨岸分量速度测量为约 29 cm s-1十一月。研究结果表明，研究区不存在与区域风相关的上升流现象。原位目前的测量表明，主要是东和北-东北方向，可能与南部盆地的大气环流的影响有关。水柱中的当前剖面在大陆架上 10、15 和 20 m 深度的方向上显示出相似性。现场样本和分析表明，软的和较小的海水垃圾可以被沿海岸的洋流带走很远的距离。大多数沿海和海洋垃圾来自旅游活动（在海岸的中部和西部）和河流产生的废物（Tonekabon-Nowshahr）。