Pub Date : 2018-09-27DOI: 10.1080/1755876X.2018.1526462
S. Wallbridge, T. Dolphin, C. Taylor
ABSTRACT This paper reports ongoing exploration of X-band radar as an operational monitoring tool for coastal infrastructure development. Data have been continually gathered since 2013, helping a major energy developer (EDF Energy) better understand shoreline processes at a proposed new nuclear power station at Sizewell, UK, to inform considerations of engineering design. The continual coverage provided by the radar enables greater confidence in defining natural variability and therefore enhanced assurance to regulators of the integrity or suitability of the site. Sizewell is located on a low-lying, soft coast with at least 1000 years of recorded (net) retreat. The commercial X-band system deployed calculates hydrodynamic data (suitable for managing navigation and vessel access), but this paper illustrates using radar images to establish the pre-construction baseline geomorphic behaviour of the nearshore, including a steep pebbly beach-face, two shore-parallel sub-tidal sandbars, and a large sandbank, 2 km offshore, which significantly affects nearshore hydrodynamics. Data illustrate baseline geomorphic behaviours that were previously unobserved, despite beach profiling records over 20 years. The temporal and spatial scales of natural changes are compared with the potential impacts of the development, including dredging (and spoil deposition) for navigation channel maintenance and the presence of nearshore structures, all of which would affect shoreline processes and so would need to be monitored (and any impacts managed) as development proceeds. Finally, the paper considers where the utility of X-band radar as an operational monitoring tool may surmount the barriers that have limited its uptake outside of academic/research circles.
{"title":"X-band radar as a tool for monitoring natural coastal behaviour and potential development impacts","authors":"S. Wallbridge, T. Dolphin, C. Taylor","doi":"10.1080/1755876X.2018.1526462","DOIUrl":"https://doi.org/10.1080/1755876X.2018.1526462","url":null,"abstract":"ABSTRACT This paper reports ongoing exploration of X-band radar as an operational monitoring tool for coastal infrastructure development. Data have been continually gathered since 2013, helping a major energy developer (EDF Energy) better understand shoreline processes at a proposed new nuclear power station at Sizewell, UK, to inform considerations of engineering design. The continual coverage provided by the radar enables greater confidence in defining natural variability and therefore enhanced assurance to regulators of the integrity or suitability of the site. Sizewell is located on a low-lying, soft coast with at least 1000 years of recorded (net) retreat. The commercial X-band system deployed calculates hydrodynamic data (suitable for managing navigation and vessel access), but this paper illustrates using radar images to establish the pre-construction baseline geomorphic behaviour of the nearshore, including a steep pebbly beach-face, two shore-parallel sub-tidal sandbars, and a large sandbank, 2 km offshore, which significantly affects nearshore hydrodynamics. Data illustrate baseline geomorphic behaviours that were previously unobserved, despite beach profiling records over 20 years. The temporal and spatial scales of natural changes are compared with the potential impacts of the development, including dredging (and spoil deposition) for navigation channel maintenance and the presence of nearshore structures, all of which would affect shoreline processes and so would need to be monitored (and any impacts managed) as development proceeds. Finally, the paper considers where the utility of X-band radar as an operational monitoring tool may surmount the barriers that have limited its uptake outside of academic/research circles.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"30 1","pages":"S199 - S211"},"PeriodicalIF":3.1,"publicationDate":"2018-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82120368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-19DOI: 10.1080/1755876X.2018.1522717
T. Costa, Laudenor Pereira, M. Marta‐Almeida, Carlos Soares
ABSTRACT The structure and the temporal variability of modelled velocity fields at different depths are studied for the years 2002–2004 in the Northwestern Iberian Margin. The currents are simulated with the Regional Ocean Modeling System in a high resolution that is compatible with the input data from the HYbrid Coordinate Ocean Model reanalysis and the atmospheric forcing from the Climate Forecast System Reanalysis, as well as with the tidal forcing from the TPXO Global Tide Solution. After an initial validation of the numerical model results, the velocity field is mapped to identify the region's main flow characteristics and its seasonal and interannual variability, in order to find areas that have strong currents, which could be of interest for exploring tidal stream energy. There are three main regions within the numerical domain, at different levels, where velocity values reach higher values than their surroundings: (i) located at the surface flowing south around 9.5°W, related to the summer Upwelling Jet; (ii) located further offshore near the Galician Bank, flowing north at deeper water levels which is visible during most part of the year and; (iii) within Ría de Arousa, also visible all year round.
研究了2002-2004年伊比利亚西北边缘不同深度速度场的结构和时间变化。区域海洋模拟系统以高分辨率模拟海流，该系统与HYbrid坐标海洋模式再分析的输入数据、气候预报系统再分析的大气强迫以及TPXO全球潮汐解决方案的潮汐强迫兼容。在对数值模型结果进行初步验证后，绘制速度场图，以确定该地区的主要流特征及其季节和年际变化，以便找到具有强流的区域，这些区域可能对探索潮汐流能量有兴趣。数值域中存在3个不同水平的速度值高于周围的主要区域:(1)位于9.5°W左右的南向地表，与夏季上升流急流有关;(ii)位于离海岸较远的加利西亚海岸附近，以较深的水位向北流动，在一年中的大部分时间都可以看到;(iii)在Ría de awaka内，也全年可见。
{"title":"Mapping of currents off the northwestern Iberian coast with the Regional Ocean Modelling System","authors":"T. Costa, Laudenor Pereira, M. Marta‐Almeida, Carlos Soares","doi":"10.1080/1755876X.2018.1522717","DOIUrl":"https://doi.org/10.1080/1755876X.2018.1522717","url":null,"abstract":"ABSTRACT The structure and the temporal variability of modelled velocity fields at different depths are studied for the years 2002–2004 in the Northwestern Iberian Margin. The currents are simulated with the Regional Ocean Modeling System in a high resolution that is compatible with the input data from the HYbrid Coordinate Ocean Model reanalysis and the atmospheric forcing from the Climate Forecast System Reanalysis, as well as with the tidal forcing from the TPXO Global Tide Solution. After an initial validation of the numerical model results, the velocity field is mapped to identify the region's main flow characteristics and its seasonal and interannual variability, in order to find areas that have strong currents, which could be of interest for exploring tidal stream energy. There are three main regions within the numerical domain, at different levels, where velocity values reach higher values than their surroundings: (i) located at the surface flowing south around 9.5°W, related to the summer Upwelling Jet; (ii) located further offshore near the Galician Bank, flowing north at deeper water levels which is visible during most part of the year and; (iii) within Ría de Arousa, also visible all year round.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"29 1","pages":"71 - 83"},"PeriodicalIF":3.1,"publicationDate":"2018-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75272714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-24DOI: 10.1080/1755876X.2018.1489208
K. von Schuckmann, P. Le Traon, N. Smith, A. Pascual, P. Brasseur, K. Fennel, S. Djavidnia, S. Aaboe, E. Fanjul, E. Autret, L. Axell, Roland Aznar, M. Benincasa, A. Bentamy, F. Boberg, R. Bourdallé-Badie, B. Nardelli, V. Brando, C. Bricaud, L. Breivik, R. Brewin, A. Capet, Adrien Ceschin, S. Ciliberti, G. Cossarini, M. de Alfonso, Álvaro de Pascual Collar, Jos de Kloe, J. Deshayes, C. Desportes, M. Drévillon, Y. Drillet, R. Droghei, C. Dubois, Owen Embury, H. Etienne, C. Fratianni, J. G. Lafuente, M. Sotillo, G. Garric, F. Gasparin, R. Gerin, S. Good, J. Gourrion, M. Grégoire, E. Greiner, S. Guinehut, E. Gutknecht, F. Hernandez, Olga Hernandez, J. Høyer, L. Jackson, Simon Jandt, S. Josey, M. Juzà, J. Kennedy, Z. Kokkini, G. Korres, M. Kõuts, P. Lagemaa, T. Lavergne, B. Le Cann, J. Legeais, B. Lemieux-Dudon, B. Levier, V. Lien, I. Maljutenko, F. Manzano, M. Marcos, V. Marinova, S. Masina, E. Mauri, M. Mayer, A. Melet, F. Mélin, B. Meyssignac, M. Monier, Malte Müller, S. Mulet, C. Naranjo, G. Notarstefano,
Si listano le singole sezioni in cui S.Simoncelli ha contribuito. Ogni sezione puo' essere citata separatamente dal report 1.1 Ocean temperature and salinity S. Mulet, B. Buongiorno Nardelli, S. Good, A. Pisano, E. Greiner, M. Monier E. Autret, L. Axell, F. Boberg, S. Ciliberti, M. Drevillon, R. Droghei, O. Embury, J. Gourrion, J. Hoyer, M. Juza, J. Kennedy, B. Lemieux-Dudon, E. Peneva, R. Reid, S. Simoncelli, A. Storto, J. Tinker, K. von Schuckmann, S. L. Wakelin. 2.1. Ocean heat content ..K. von Schuckmann, A. Storto, S. Simoncelli, R. P. Raj, A.Samuelsen, A. de Pascual Collar, M. Garcia Sotillo, T Szerkely, M. Mayer, K. A. Peterson, H. Zuo, G. Garric, M. Monier. 3.4 Water mass formation processes in the Mediterranean Sea over the past 30 years S. Simoncelli, Nadia Pinardi, C. Fratianni, C. Dubois, G. Notarstefano. 3.5 Ventilation of the Western Mediterranean Deep Water through the Strait of Gibraltar S. Sammartino, J. Garcia Lafuente, C. Naranjo, S. Simoncelli. 4.4 Unusual salinity pattern in the South Adriatic Sea in 2016 Z. Kokkini, G. Notarstefano P-M Poulain, E. Mauri, R. Gerin, S. Simoncelli
它列出了S.Simoncelli贡献的各个部分。可分开报告提到每节1。1和S . salinity Mulet海洋温度,B .你好Nardelli, S . Good A . E .号文件,M . Monier E . L . Axell, Autret F . S . Ciliberti博格,M的,或Embury, J . R . Droghei Gourrion, J . M . Juza,霍耶J . Kennedy), B . Lemieux-Dudon, E . R . Peneva, Reid, A . S . Simoncelli退步,J . K . von Schuckmann Tinker, S . L . Wakelin。2 . 1。海洋热内容K。von Schuckmann,出了问题,S . Simoncelli, R . P . Raj,萨缪尔森。A . de Pascual Collar, M . Garcia Sotillo, T Szerkely, M . Mayer, K . A . Peterson, M . H . G . Garric, Zuo Monier。3.4 - Water大众formation - the past 30岁以上在the Sea地中海Nadia Pinardi, C . S . Simoncelli长达两年Fratianni C . Dubois, G . Notarstefano。3。5 Ventilation of the Deep西部地中海水通过the Strait of S .直布罗陀Sammartino J . Garcia - C。纳兰霍,2016年亚得里亚海南部非常规盐度模式Z. Kokkini, G. Notarstefano P-M Poulain, E. Mauri, R. Gerin, S. Simoncelli
{"title":"Copernicus Marine Service Ocean State Report","authors":"K. von Schuckmann, P. Le Traon, N. Smith, A. Pascual, P. Brasseur, K. Fennel, S. Djavidnia, S. Aaboe, E. Fanjul, E. Autret, L. Axell, Roland Aznar, M. Benincasa, A. Bentamy, F. Boberg, R. Bourdallé-Badie, B. Nardelli, V. Brando, C. Bricaud, L. Breivik, R. Brewin, A. Capet, Adrien Ceschin, S. Ciliberti, G. Cossarini, M. de Alfonso, Álvaro de Pascual Collar, Jos de Kloe, J. Deshayes, C. Desportes, M. Drévillon, Y. Drillet, R. Droghei, C. Dubois, Owen Embury, H. Etienne, C. Fratianni, J. G. Lafuente, M. Sotillo, G. Garric, F. Gasparin, R. Gerin, S. Good, J. Gourrion, M. Grégoire, E. Greiner, S. Guinehut, E. Gutknecht, F. Hernandez, Olga Hernandez, J. Høyer, L. Jackson, Simon Jandt, S. Josey, M. Juzà, J. Kennedy, Z. Kokkini, G. Korres, M. Kõuts, P. Lagemaa, T. Lavergne, B. Le Cann, J. Legeais, B. Lemieux-Dudon, B. Levier, V. Lien, I. Maljutenko, F. Manzano, M. Marcos, V. Marinova, S. Masina, E. Mauri, M. Mayer, A. Melet, F. Mélin, B. Meyssignac, M. Monier, Malte Müller, S. Mulet, C. Naranjo, G. Notarstefano, ","doi":"10.1080/1755876X.2018.1489208","DOIUrl":"https://doi.org/10.1080/1755876X.2018.1489208","url":null,"abstract":"Si listano le singole sezioni in cui S.Simoncelli ha contribuito. Ogni sezione puo' essere citata separatamente dal report 1.1 Ocean temperature and salinity \u0000S. Mulet, B. Buongiorno Nardelli, S. Good, A. Pisano, E. Greiner, M. Monier \u0000E. Autret, L. Axell, F. Boberg, S. Ciliberti, M. Drevillon, R. Droghei, O. Embury, J. Gourrion, J. Hoyer, M. Juza, J. Kennedy, B. Lemieux-Dudon, E. Peneva, R. Reid, S. Simoncelli, A. Storto, J. Tinker, K. von Schuckmann, S. L. Wakelin. \u0000 \u00002.1. Ocean heat content \u0000..K. von Schuckmann, A. Storto, S. Simoncelli, R. P. Raj, A.Samuelsen, A. de Pascual Collar, M. Garcia Sotillo, T Szerkely, M. Mayer, K. A. Peterson, H. Zuo, G. Garric, M. Monier. \u0000 \u00003.4 Water mass formation processes in the Mediterranean Sea over the past 30 years \u0000S. Simoncelli, Nadia Pinardi, C. Fratianni, C. Dubois, G. Notarstefano. \u0000 \u00003.5 Ventilation of the Western Mediterranean Deep Water through the Strait of Gibraltar \u0000S. Sammartino, J. Garcia Lafuente, C. Naranjo, S. Simoncelli. \u0000 \u00004.4 Unusual salinity pattern in the South Adriatic Sea in 2016 \u0000Z. Kokkini, G. Notarstefano \u0000P-M Poulain, E. Mauri, R. Gerin, S. Simoncelli","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"1 1","pages":"S1 - S142"},"PeriodicalIF":3.1,"publicationDate":"2018-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89645128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-03DOI: 10.1080/1755876X.2018.1505028
S. Verrier, P. Le Traon, E. Rémy, J. Lellouche
ABSTRACT Satellite altimetry provides essential sea level observations to constrain ocean analysis and forecasting systems. New generation of nadir altimeters now provides enhanced capability thanks to a SAR mode that allows reducing the 1 Hz (7 km) measurement noise level from about 3 to 1 cm RMS. A first assessment of the impact of SAR altimetry for global ocean analysis and forecasting is carried out using Observing System Simulation Experiments (OSSEs) with the global Mercator Ocean high resolution 1/12° system. OSSEs are used to quantify the impact of assimilating multiple altimeter missions with and without a SAR mode. A simple twin experiment set up that only takes into account initialisation errors and impact of altimeter random noise is used. Results are analysed in high eddy energy regions where initialisation errors are the most important ones. Both sea surface height and surface velocity analyses and 7-day forecasts are improved. Compared to conventional altimetry, SAR altimetry sea surface height variance errors for both analyses and forecasts are typically reduced by 20% in western boundary currents. This suggests that use of SAR multiple altimeter missions with high-resolution models will significantly improve the capability of the ocean analysis and forecasting systems in the near future.
卫星测高为约束海洋分析和预报系统提供了必要的海平面观测。由于SAR模式，新一代的最低点高度计现在提供了增强的功能，可以将1 Hz (7 km)的测量噪声水平从大约3到1 cm RMS。利用全球墨卡托海洋高分辨率1/12°系统的观测系统模拟实验(OSSEs)，首次评估了SAR测高对全球海洋分析和预报的影响。osse用于量化同化有或没有SAR模式的多个高度计任务的影响。采用了一个简单的双实验装置，只考虑了初始化误差和高度计随机噪声的影响。结果分析在高涡能区，其中初始化误差是最重要的。海面高度和海面速度分析和7天预报都得到了改进。与传统的测高方法相比，SAR测高方法在分析和预报海面高度时的误差通常比西部边界流减少20%。这表明，在不久的将来，使用具有高分辨率模式的SAR多高度计任务将显著提高海洋分析和预报系统的能力。
{"title":"Assessing the impact of SAR altimetry for global ocean analysis and forecasting","authors":"S. Verrier, P. Le Traon, E. Rémy, J. Lellouche","doi":"10.1080/1755876X.2018.1505028","DOIUrl":"https://doi.org/10.1080/1755876X.2018.1505028","url":null,"abstract":"ABSTRACT Satellite altimetry provides essential sea level observations to constrain ocean analysis and forecasting systems. New generation of nadir altimeters now provides enhanced capability thanks to a SAR mode that allows reducing the 1 Hz (7 km) measurement noise level from about 3 to 1 cm RMS. A first assessment of the impact of SAR altimetry for global ocean analysis and forecasting is carried out using Observing System Simulation Experiments (OSSEs) with the global Mercator Ocean high resolution 1/12° system. OSSEs are used to quantify the impact of assimilating multiple altimeter missions with and without a SAR mode. A simple twin experiment set up that only takes into account initialisation errors and impact of altimeter random noise is used. Results are analysed in high eddy energy regions where initialisation errors are the most important ones. Both sea surface height and surface velocity analyses and 7-day forecasts are improved. Compared to conventional altimetry, SAR altimetry sea surface height variance errors for both analyses and forecasts are typically reduced by 20% in western boundary currents. This suggests that use of SAR multiple altimeter missions with high-resolution models will significantly improve the capability of the ocean analysis and forecasting systems in the near future.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"1 1","pages":"82 - 86"},"PeriodicalIF":3.1,"publicationDate":"2018-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89688529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-03DOI: 10.1080/1755876X.2018.1505069
Chen Xi, Hu Dong, Mao Kefeng, Li Yan
ABSTRACT The Kuroshio Extension Region (KER) has the most active oceanic mesoscale eddies within the North Pacific Ocean, nevertheless, there is a lack of observations on the three-dimensional (3D) fine structure of these eddies. Satellite altimeter data and underway observations were used in combination to conduct a fine-scale characterisation of the 3D thermohaline structure and circulation of a mesoscale cyclonic eddy within the KER during June, 2014. The results showed that isotherms in the six in situ sections consistently exhibited enhanced upward bending and negative temperature anomalies were distinct. At locations closer to the centre of the eddy, the negative temperature anomalies became more significant and the intensity of the cold core became more pronounced. The isohalines also trended upwards, with the upper and lower levels having negative and positive anomalies, respectively. The isohalines at the various layers similarly exhibited a clear eddy-like structure from the subsurface down to 1,000 m. Both the actual flow field measured by the Acoustic Doppler Current Profiler (ADCP) and the geostrophic flow field based on thermohaline data indicated a significant asymmetric cyclonic circulation structure. By comparing with the in situ data, the HYbrid Coordinate Ocean Model (HYCOM) is capable of depicting the mesoscale eddy while the magnitude and eddy location deviate from in situ observations.
{"title":"Detailed investigation of the three-dimensional structure of a mesoscale cold eddy in the Kuroshio extension region*","authors":"Chen Xi, Hu Dong, Mao Kefeng, Li Yan","doi":"10.1080/1755876X.2018.1505069","DOIUrl":"https://doi.org/10.1080/1755876X.2018.1505069","url":null,"abstract":"ABSTRACT The Kuroshio Extension Region (KER) has the most active oceanic mesoscale eddies within the North Pacific Ocean, nevertheless, there is a lack of observations on the three-dimensional (3D) fine structure of these eddies. Satellite altimeter data and underway observations were used in combination to conduct a fine-scale characterisation of the 3D thermohaline structure and circulation of a mesoscale cyclonic eddy within the KER during June, 2014. The results showed that isotherms in the six in situ sections consistently exhibited enhanced upward bending and negative temperature anomalies were distinct. At locations closer to the centre of the eddy, the negative temperature anomalies became more significant and the intensity of the cold core became more pronounced. The isohalines also trended upwards, with the upper and lower levels having negative and positive anomalies, respectively. The isohalines at the various layers similarly exhibited a clear eddy-like structure from the subsurface down to 1,000 m. Both the actual flow field measured by the Acoustic Doppler Current Profiler (ADCP) and the geostrophic flow field based on thermohaline data indicated a significant asymmetric cyclonic circulation structure. By comparing with the in situ data, the HYbrid Coordinate Ocean Model (HYCOM) is capable of depicting the mesoscale eddy while the magnitude and eddy location deviate from in situ observations.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"42 1","pages":"87 - 99"},"PeriodicalIF":3.1,"publicationDate":"2018-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90800958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-05DOI: 10.1080/1755876X.2018.1479571
S. Mandal, S. Sil, A. Gangopadhyay, T. Murty, D. Swain
ABSTRACT First results from a systematic harmonic analysis of HF radar (HFR) derived ocean surface current observations in the northwestern Bay of Bengal (BoB) during 2010 is presented. The daily-averaged HFR currents compared reasonably well to composite daily surface currents from multiple satellites with correlation coefficient of 0.90 (0.69) for zonal (meridional) component. A set of sequential daily currents demonstrated sustained northward (southward) alongshore flow during February–April (October–December) with peak magnitude of about 1.8 (1.2) m/s. On tidal scales, harmonic analyses of zonal and meridional components at nearshore and offshore locations indicated that among semi-diurnal tidal components, M2 dominates over S2 and N2; time-scales of which were verified from available coastal tide gauges nearby. Amplitudes of semi-major axis for M2 and K1 tidal ellipses are 7.16 (6.13) and 4.02 (3.30) cm/s in nearshore (offshore) location indicating relatively stronger tidal currents in nearshore location. Finally, significant shallow water constituents S4, MS4 and M3 (M4, 2SM6 and M6) at nearshore (offshore) location are identified, which are due to non-linear interaction of tidal currents with bathymetry. Both semi-diurnal and shallow water tidal currents show dominance along isobaths in offshore region, which turn progressively across-isobath as they move nearshore.
{"title":"On extracting high-frequency tidal variability from HF radar data in the northwestern Bay of Bengal","authors":"S. Mandal, S. Sil, A. Gangopadhyay, T. Murty, D. Swain","doi":"10.1080/1755876X.2018.1479571","DOIUrl":"https://doi.org/10.1080/1755876X.2018.1479571","url":null,"abstract":"ABSTRACT First results from a systematic harmonic analysis of HF radar (HFR) derived ocean surface current observations in the northwestern Bay of Bengal (BoB) during 2010 is presented. The daily-averaged HFR currents compared reasonably well to composite daily surface currents from multiple satellites with correlation coefficient of 0.90 (0.69) for zonal (meridional) component. A set of sequential daily currents demonstrated sustained northward (southward) alongshore flow during February–April (October–December) with peak magnitude of about 1.8 (1.2) m/s. On tidal scales, harmonic analyses of zonal and meridional components at nearshore and offshore locations indicated that among semi-diurnal tidal components, M2 dominates over S2 and N2; time-scales of which were verified from available coastal tide gauges nearby. Amplitudes of semi-major axis for M2 and K1 tidal ellipses are 7.16 (6.13) and 4.02 (3.30) cm/s in nearshore (offshore) location indicating relatively stronger tidal currents in nearshore location. Finally, significant shallow water constituents S4, MS4 and M3 (M4, 2SM6 and M6) at nearshore (offshore) location are identified, which are due to non-linear interaction of tidal currents with bathymetry. Both semi-diurnal and shallow water tidal currents show dominance along isobaths in offshore region, which turn progressively across-isobath as they move nearshore.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"1 1","pages":"65 - 81"},"PeriodicalIF":3.1,"publicationDate":"2018-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82941095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-05-13DOI: 10.1080/1755876X.2018.1470454
A. Bento, N. Salvação, C. Guedes Soares
ABSTRACT An operational wave forecast system for the area of Galway Bay is presented. Three numerical models are implemented: Weather Research and Forecasting (WRF), Wavewatch III (WWIII) and Simulating Waves Nearshore (SWAN). GFS (Global Forecast System) winds, from NCEP (National Centres for Environmental Prediction), are used to force the WWIII model, while WRF winds are used to force the SWAN model. Bathymetries for WWIII and SWAN were obtained from NOAA’s GEODAS (Geophysical Data System) data base and from GEBCO (General Bathymetric Chart of the Oceans), hosted by BODC. The wave generation model, WWIII, is used to simulate waves for the whole North Atlantic, whereas the SWAN model runs for the Irish west coast, with a nested grid for Galway Bay. Forecast products of 7 days are produced daily, with a warm up of 4 days. The validations of the forecast system were made for both wind and wave parameters with data from buoys located in the Irish coast and inside Galway Bay. Comparisons in the time domain as well as a statistical analysis were performed. Overall, the wave forecast system gave good results closely reproducing the real data, with a low error.
摘要:介绍了高威湾地区的海浪预报系统。采用了三种数值模式:Weather Research and Forecasting (WRF)、Wavewatch III (wiii)和simulation Waves Nearshore (SWAN)。来自NCEP(国家环境预测中心)的GFS(全球预报系统)风被用来驱动第三次世界大战模型，而WRF风被用来驱动SWAN模型。第三次世界大战和SWAN的水深测量数据来自NOAA的地球物理数据系统(GEODAS)数据库和由BODC托管的GEBCO(海洋一般水深图)。第三次世界大战的波浪产生模型用于模拟整个北大西洋的波浪，而SWAN模型用于模拟爱尔兰西海岸，并为戈尔韦湾设置了嵌套网格。每天预报7天，预热4天。预报系统的风和浪参数是用位于爱尔兰海岸和戈尔韦湾内的浮标的数据进行验证的。在时域上进行了比较和统计分析。总体而言，该系统的预报结果较好，与实际数据接近，误差较小。
{"title":"Validation of a wave forecast system for Galway Bay","authors":"A. Bento, N. Salvação, C. Guedes Soares","doi":"10.1080/1755876X.2018.1470454","DOIUrl":"https://doi.org/10.1080/1755876X.2018.1470454","url":null,"abstract":"ABSTRACT An operational wave forecast system for the area of Galway Bay is presented. Three numerical models are implemented: Weather Research and Forecasting (WRF), Wavewatch III (WWIII) and Simulating Waves Nearshore (SWAN). GFS (Global Forecast System) winds, from NCEP (National Centres for Environmental Prediction), are used to force the WWIII model, while WRF winds are used to force the SWAN model. Bathymetries for WWIII and SWAN were obtained from NOAA’s GEODAS (Geophysical Data System) data base and from GEBCO (General Bathymetric Chart of the Oceans), hosted by BODC. The wave generation model, WWIII, is used to simulate waves for the whole North Atlantic, whereas the SWAN model runs for the Irish west coast, with a nested grid for Galway Bay. Forecast products of 7 days are produced daily, with a warm up of 4 days. The validations of the forecast system were made for both wind and wave parameters with data from buoys located in the Irish coast and inside Galway Bay. Comparisons in the time domain as well as a statistical analysis were performed. Overall, the wave forecast system gave good results closely reproducing the real data, with a low error.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"7 1","pages":"112 - 124"},"PeriodicalIF":3.1,"publicationDate":"2018-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78515083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-05-07DOI: 10.1080/1755876X.2018.1470892
Diego Pereiro, C. Souto, J. Gago
ABSTRACT Predicting the transport of marine floating litter requires a detailed understanding of the processes involved in the dispersion of floating materials in the ocean. The restraining effect of a near-coastal boundary or shallow bottom topography may affect the drift response to local wind forcing. The aim of this work is to develop a particle-tracking model for the north-west Iberian waters that allows for spatial variations in the effect of winds on the transport of marine floating litter. Observational data from 23 drifters were used, in conjunction with wind and ocean current data from atmospheric and ocean models. The drifter locations were grouped into three separate zones based on the bathymetry and the orientation of the coastline. Response matrices for each of these areas were computed using a 2-D vector regression approach. The maximum drift response to local wind forcing is alongshore in inner shelf waters, whereas an isotropic drift response to winds is observed in outer shelf waters. The wind drag coefficient ranges from 0.5 × 10−2 to 1.2 × 10−2, depending both on the wind direction and the drifter position.
{"title":"Calibration of a marine floating litter transport model","authors":"Diego Pereiro, C. Souto, J. Gago","doi":"10.1080/1755876X.2018.1470892","DOIUrl":"https://doi.org/10.1080/1755876X.2018.1470892","url":null,"abstract":"ABSTRACT Predicting the transport of marine floating litter requires a detailed understanding of the processes involved in the dispersion of floating materials in the ocean. The restraining effect of a near-coastal boundary or shallow bottom topography may affect the drift response to local wind forcing. The aim of this work is to develop a particle-tracking model for the north-west Iberian waters that allows for spatial variations in the effect of winds on the transport of marine floating litter. Observational data from 23 drifters were used, in conjunction with wind and ocean current data from atmospheric and ocean models. The drifter locations were grouped into three separate zones based on the bathymetry and the orientation of the coastline. Response matrices for each of these areas were computed using a 2-D vector regression approach. The maximum drift response to local wind forcing is alongshore in inner shelf waters, whereas an isotropic drift response to winds is observed in outer shelf waters. The wind drag coefficient ranges from 0.5 × 10−2 to 1.2 × 10−2, depending both on the wind direction and the drifter position.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"56 1","pages":"125 - 133"},"PeriodicalIF":3.1,"publicationDate":"2018-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78904509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-05-03DOI: 10.1080/1755876X.2018.1465337
L. Zedel, Yanan Wang, F. Davidson, Jinshan Xu
ABSTRACT Oceanographic data collected during seismic surveys have potential to provide a significant resource for oceanographic research. In this paper, acoustic Doppler current profiler (ADCP) data collected during the Chevron 2011 North East Grand Banks survey are analysed. The survey took place in a 32,000-km2 area in the North East Grand banks, Orphan Basin region in water depths ranging from 100 to 1500 m and notably, the survey area is crossed by the offshore branch of the Labrador current. Data quality is evaluated by comparing velocities before and after ship turns where we find no significant velocity bias. The ADCP data are compared to data products from the CONCEPTS global ice ocean prediction system operational ocean model. ADCP data and model output agree qualitatively with the model reproducing the long-term fluctuations seen in the data. At higher frequencies between 0.3 and 2.0 cycles/day, the model tends to under-represent the current velocities by about 20%, but the spectral peak associated with inertial oscillations is well resolved. Comparisons of drift track predictions based on the ADCP observations and model output show rms displacement differences of 8 km after 24 h and ∼10 km separations for drift tracks with length under 50 km.
{"title":"Comparing ADCP data collected during a seismic survey off the coast of Newfoundland with analysis data from the CONCEPTS operational ocean model","authors":"L. Zedel, Yanan Wang, F. Davidson, Jinshan Xu","doi":"10.1080/1755876X.2018.1465337","DOIUrl":"https://doi.org/10.1080/1755876X.2018.1465337","url":null,"abstract":"ABSTRACT Oceanographic data collected during seismic surveys have potential to provide a significant resource for oceanographic research. In this paper, acoustic Doppler current profiler (ADCP) data collected during the Chevron 2011 North East Grand Banks survey are analysed. The survey took place in a 32,000-km2 area in the North East Grand banks, Orphan Basin region in water depths ranging from 100 to 1500 m and notably, the survey area is crossed by the offshore branch of the Labrador current. Data quality is evaluated by comparing velocities before and after ship turns where we find no significant velocity bias. The ADCP data are compared to data products from the CONCEPTS global ice ocean prediction system operational ocean model. ADCP data and model output agree qualitatively with the model reproducing the long-term fluctuations seen in the data. At higher frequencies between 0.3 and 2.0 cycles/day, the model tends to under-represent the current velocities by about 20%, but the spectral peak associated with inertial oscillations is well resolved. Comparisons of drift track predictions based on the ADCP observations and model output show rms displacement differences of 8 km after 24 h and ∼10 km separations for drift tracks with length under 50 km.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"5 1","pages":"100 - 111"},"PeriodicalIF":3.1,"publicationDate":"2018-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85858535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-01-02DOI: 10.1080/1755876X.2018.1438341
S. Majumder, T. M. Balakrishnan Nair, K. Sandhya, P. G. Remya, P. Sirisha
ABSTRACT In this study, we focus on the improvement of wave forecast of the Indian coastal region using a multi-model ensemble technique. Generally, a number of wave forecast are available for the same region from different wave models. The main objective of this study is to merge the wave forecasts available at Indian National Centre for Ocean Information Services from different wave models to obtain an improved wave forecast using a multi-model super-ensemble method [Krishnamurti et al. 1999. Improved weather and seasonal climate forecasts from multi-model super-ensemble. Science. 285:1548–1550] during extreme weather conditions and to modify Krishnamurthy’s techniques and validate with observations for a better prediction. Here, Multi-grid WAVEWATCH III, Simulating WAves Nearshore and MIKE 21 Spectral Waves are used for the generation of wave forecast. We propose a modification of Krishnamurthy’s linear regression-based ensemble model. By using both of these ensemble techniques, we perform a multi-model ensemble forecasting of significant wave height up to 24-h lead time in the Indian Ocean for three different cyclones (Nilofar, Hudhud and Phailin) and during the southwest monsoon. A comparison of ensemble predictions and individual model predictions with the actual observations showed generally satisfactory performance of the chosen tools. At the time of severe cyclones such as Hudhud and Phailin, our modified technique shows significantly better prediction than the linear regression-based ensemble technique.
{"title":"Modification of a linear regression-based multi-model super-ensemble technique and its application in forecasting of wave height during extreme weather conditions","authors":"S. Majumder, T. M. Balakrishnan Nair, K. Sandhya, P. G. Remya, P. Sirisha","doi":"10.1080/1755876X.2018.1438341","DOIUrl":"https://doi.org/10.1080/1755876X.2018.1438341","url":null,"abstract":"ABSTRACT In this study, we focus on the improvement of wave forecast of the Indian coastal region using a multi-model ensemble technique. Generally, a number of wave forecast are available for the same region from different wave models. The main objective of this study is to merge the wave forecasts available at Indian National Centre for Ocean Information Services from different wave models to obtain an improved wave forecast using a multi-model super-ensemble method [Krishnamurti et al. 1999. Improved weather and seasonal climate forecasts from multi-model super-ensemble. Science. 285:1548–1550] during extreme weather conditions and to modify Krishnamurthy’s techniques and validate with observations for a better prediction. Here, Multi-grid WAVEWATCH III, Simulating WAves Nearshore and MIKE 21 Spectral Waves are used for the generation of wave forecast. We propose a modification of Krishnamurthy’s linear regression-based ensemble model. By using both of these ensemble techniques, we perform a multi-model ensemble forecasting of significant wave height up to 24-h lead time in the Indian Ocean for three different cyclones (Nilofar, Hudhud and Phailin) and during the southwest monsoon. A comparison of ensemble predictions and individual model predictions with the actual observations showed generally satisfactory performance of the chosen tools. At the time of severe cyclones such as Hudhud and Phailin, our modified technique shows significantly better prediction than the linear regression-based ensemble technique.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"144 1","pages":"1 - 10"},"PeriodicalIF":3.1,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74940575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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