Journal of Earth System Science ( IF 1.9 ) Pub Date : 2021-04-09 , DOI: 10.1007/s12040-021-01553-x Imranali M Momin , A K Mitra , R Bhatla
Abstract
Simulating upper layer of Bay of Bengal through three-dimensional ocean circulation models is a challenging task. In this study, the surface current from the Nucleus European Modelling of Ocean (NEMO) based global ocean assimilation system is assessed against the high frequency (HF) radar data along the Andhra Pradesh coast on a daily scale during southwest monsoon 2016. The temporal variation of NEMO simulated surface current with HF radar data shows that the NEMO model captures the zonal current better than the meridional current. Both NEMO and HF radar show that the mean surface current average over latitude (15.8°–16.3°N) is westward for zonal surface current and southward for meridional current with maximum at 40–60 km away from the coast. Further, the monthly mean HF radar derived surface current indicates the strong south-westward flow of surface current dominated during July 2016 with speed more than 50 cm/s which is also well simulated by NEMO analysis. It also captures the cold core eddy during 15–25 July 2016 with very small north-eastward shift with respect to HF radar. The scatter plot of collocated surface zonal and meridional current average over the box (81.5–82.5°E; 15.5–16.5°N) clearly shows that NEMO analysis has the correlation of more than 0.5 for both zonal and meridional current.
Research highlights
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The simulation of upper layer of Bay of Bengal (BoB) through three dimensional ocean circulation models is a challenging task. In this study, the surface current from the high resolution NEMO based global ocean assimilation system is compared against the observed High Frequency (HF) radar data along the Andhra Pradesh Coast during the southwest monsoon 2016.
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NEMO analysis captures the mean and variability of surface current very well with HF radar. However, it underestimates the mean surface current which may be due to coarser model resolution and complex non-linear processes in the coastal region.
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The strong cold core eddy during 15–25 July 2016 is observed along the coast which is well simulated in NEMO model with small north-eastward shift with respect to HF radar.
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The scatter plot of collocated surface current from NEMO analysis and HF radar data average over the Andhra Pradesh Coast (APCO; 81.5–82.5°E; 15.5–16.5°N) clearly shows that NEMO analysis has the correlation of more than 0.5 for surface current.
中文翻译：
沿安得拉邦海岸的HF雷达对NEMO模拟地表电流的评估
摘要
通过三维海洋环流模型模拟孟加拉湾上层是一项艰巨的任务。在这项研究中，基于2016年西南季风期间每天沿安得拉邦沿海的高频（HF）雷达数据评估了基于欧洲核模型（NEMO）的全球海洋同化系统的地表电流。时间变化HF雷达数据对NEMO模拟地表电流的分析表明，NEMO模型比经向电流更好地捕获了纬向电流。NEMO和HF雷达均显示，纬度（15.8°–16.3°N）上的平均地表电流在纬向区流中向西，在子午流中向南，在距海岸40–60 km处最大。更多，HF雷达得出的月平均月地面电流表明，2016年7月期间，地面电流向西南方向强烈流动，速度超过50 cm / s，NEMO分析也对此进行了很好的模拟。它还捕获了2016年7月15日至25日的冷核涡流，相对于HF雷达，东北偏小。盒子上并排的表面纬向和经向平均电流（81.5–82.5°E； 15.5–16.5°N）的散点图清楚地表明，NEMO分析对纬向和经向电流的相关性均大于0.5。
研究重点
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通过三维海洋环流模型对孟加拉湾（BoB）上层进行模拟是一项艰巨的任务。在这项研究中，将基于高分辨率NEMO的全球海洋同化系统的地表电流与2016年西南季风期间沿安得拉邦海岸观测到的高频（HF）雷达数据进行了比较。
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NEMO分析可以很好地捕获高频雷达的表面电流的均值和可变性。但是，它低估了平均表面电流，这可能是由于沿海地区较粗的模型分辨率和复杂的非线性过程引起的。
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2016年7月15日至25日，在沿海地区观测到强烈的冷芯涡流，这在NEMO模型中得到了很好的模拟，相对于HF雷达向东北方向有很小的偏移。
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来自NEMO分析和安得拉邦海岸（APCO; 81.5–82.5°E; 15.5–16.5°N）上的HF雷达数据平均值的并置表面电流的散点图清楚地表明NEMO分析与表面电流的相关性大于0.5 。
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