Pub Date : 2020-03-09DOI: 10.1080/1755876X.2020.1737345
Jiahao Wang, Xi Chen, Kefeng Mao
ABSTRACT Based on the subsurface mooring observations at 159°59′E, 14°40′N from July 2014 to May 2016, the vertical structure and variability of the North Equatorial Current/Undercurrent (NEC/NEUC) are investigated. The NEC flows westward stably from the sea surface down to 500 m and is strongest with the magnitude of approximately 40 cm/s in January 2016, while in several months, the eastward current occurs and attains the maximum of nearly 15 cm/s in April and September 2015. Beneath the NEC, the eastward NEUC is observed and its depth could reach at least 860 m. The Power Spectral Density function reveals surface-intensified signals of the currents at mooring site, and the period in the upper layer is around 30–155 days. AVISO products accurately describe the variability of the NEC and are consistent with the mooring observations. Further analysis with sea level anomaly data suggests that the mesoscale eddies, which move westward, may influence the intraseasonal variability measured by the mooring. A comparison of the results with other mooring observations at 130°E implies the phenomenon of western intensification and the existence of NEUC jets at different longitudes that they are not observed at 130°E, 15.5°N.
{"title":"Measurement of the North Equatorial Current/Undercurrent by a subsurface mooring at 160°E","authors":"Jiahao Wang, Xi Chen, Kefeng Mao","doi":"10.1080/1755876X.2020.1737345","DOIUrl":"https://doi.org/10.1080/1755876X.2020.1737345","url":null,"abstract":"ABSTRACT Based on the subsurface mooring observations at 159°59′E, 14°40′N from July 2014 to May 2016, the vertical structure and variability of the North Equatorial Current/Undercurrent (NEC/NEUC) are investigated. The NEC flows westward stably from the sea surface down to 500 m and is strongest with the magnitude of approximately 40 cm/s in January 2016, while in several months, the eastward current occurs and attains the maximum of nearly 15 cm/s in April and September 2015. Beneath the NEC, the eastward NEUC is observed and its depth could reach at least 860 m. The Power Spectral Density function reveals surface-intensified signals of the currents at mooring site, and the period in the upper layer is around 30–155 days. AVISO products accurately describe the variability of the NEC and are consistent with the mooring observations. Further analysis with sea level anomaly data suggests that the mesoscale eddies, which move westward, may influence the intraseasonal variability measured by the mooring. A comparison of the results with other mooring observations at 130°E implies the phenomenon of western intensification and the existence of NEUC jets at different longitudes that they are not observed at 130°E, 15.5°N.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"1 1","pages":"142 - 151"},"PeriodicalIF":3.1,"publicationDate":"2020-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87440512","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 : 2020-03-09DOI: 10.1080/1755876X.2020.1736748
M. Bernardino, Liliana Rusu, Carlos Soares
ABSTRACT The objective of the present study is to give a contribution to the extreme wave climate assessment in the Black Sea, as studies of extreme storm waves are of great interest for coastal protection and maritime traffic. High resolution wind wave data sets are used to investigate trends and variability of the characteristics of extreme storm waves. Two different methodologies (Eulerian and Lagrangean) are applied to 30 years of wave hindcast from 1987 to 2016, over the Black Sea to identify extreme storm waves and also to assess the extreme wave climate. Using the Eulerian methodology, it is observed that extreme storm waves are seasonal, being more frequent during the winter and almost non-existent during the summer. Also, that some areas, as the south-eastern region of the Black Sea more prone to storm generation, in particular, during winter and autumn. For the seven locations near the coast, a considerable inter-annual variability is found in extreme values, but not so much in the mean. Statistical significance in trend adjustment was only found in two locations in the north-western coast, for extreme values. Using a Lagrangean methodology, an inter-annual variability in all storm characteristics that is found, more marked in the annual number of wave storms, maximum area affected by storm waves and maximum length, and less marked for maximum Hs in the storm waves and storm lifetime.
{"title":"Evaluation of extreme storm waves in the Black Sea","authors":"M. Bernardino, Liliana Rusu, Carlos Soares","doi":"10.1080/1755876X.2020.1736748","DOIUrl":"https://doi.org/10.1080/1755876X.2020.1736748","url":null,"abstract":"ABSTRACT The objective of the present study is to give a contribution to the extreme wave climate assessment in the Black Sea, as studies of extreme storm waves are of great interest for coastal protection and maritime traffic. High resolution wind wave data sets are used to investigate trends and variability of the characteristics of extreme storm waves. Two different methodologies (Eulerian and Lagrangean) are applied to 30 years of wave hindcast from 1987 to 2016, over the Black Sea to identify extreme storm waves and also to assess the extreme wave climate. Using the Eulerian methodology, it is observed that extreme storm waves are seasonal, being more frequent during the winter and almost non-existent during the summer. Also, that some areas, as the south-eastern region of the Black Sea more prone to storm generation, in particular, during winter and autumn. For the seven locations near the coast, a considerable inter-annual variability is found in extreme values, but not so much in the mean. Statistical significance in trend adjustment was only found in two locations in the north-western coast, for extreme values. Using a Lagrangean methodology, an inter-annual variability in all storm characteristics that is found, more marked in the annual number of wave storms, maximum area affected by storm waves and maximum length, and less marked for maximum Hs in the storm waves and storm lifetime.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"48 1","pages":"114 - 128"},"PeriodicalIF":3.1,"publicationDate":"2020-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77501112","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 : 2020-01-02DOI: 10.1080/1755876X.2019.1606765
M. Sotillo, P. Cerralbo, P. Lorente, M. Grifoll, M. Espino, A. Sánchez-Arcilla, E. Álvarez-Fanjul
ABSTRACT SAMOA (Sistema de Apoyo Meteorológico y Oceanográfico de la Autoridad Portuaria) is the latest initiative of Puertos del Estado, the Spanish Public State Port Agency, to enhance the delivery of user-customised operational met-ocean information to aid Spanish Port Authorities making harbour safety, environmental management and operational decisions. This initiative provides high-resolution coastal operational prediction systems in domains such as harbours and nearby coastal waters. Forecast systems implemented are fully operational from January 2017 for nine Spanish ports in the Mediterranean, the Iberian Atlantic and the Canary Islands. This paper provides an end-to-end description of these SAMOA systems that are based on high-resolution ROMS model applications. The SAMOA systems are CMEMS downstream services, being the coastal models nested into the regional IBI forecast solution. At the surface, SAMOA systems use as forcing daily updated hourly winds and heat and water fluxes from the Spanish Meteorological Agency forecast services. Highlights from the scientific pre-operational model evaluation phase and the multi-parametric validation are shown, illustrating agreements between SAMOA products and in-situ and remoted sensed observations. To this aim, skill metrics (such as bias, errors, Taylor diagrams and correlations) are presented. Finally, a look ahead to future SAMOA developments and operational innovations is provided.
SAMOA (Sistema de Apoyo Meteorológico y Oceanográfico de la Autoridad Portuaria)是西班牙公共港口机构Puertos del Estado的最新举措，旨在加强用户定制的运营海洋信息的交付，以帮助西班牙港口当局制定港口安全，环境管理和运营决策。该计划为港口和附近沿海水域等领域提供高分辨率沿海业务预测系统。从2017年1月起，西班牙在地中海、伊比利亚大西洋和加那利群岛的九个港口实施的预报系统将全面投入使用。本文提供了基于高分辨率ROMS模型应用的这些SAMOA系统的端到端描述。萨摩亚系统是CMEMS的下游服务，是嵌套在区域IBI预报解决方案中的沿海模式。在地面，萨摩亚系统利用西班牙气象局预报服务每天更新的每小时风、热通量和水通量作为强迫。本文展示了科学的预操作模式评估阶段和多参数验证的亮点，说明了萨摩亚产品与原位和遥感观测之间的一致性。为此，我们提出了技能指标(如偏差、错误、泰勒图和相关性)。最后，展望萨摩亚未来的发展和业务创新。
{"title":"Coastal ocean forecasting in Spanish ports: the SAMOA operational service","authors":"M. Sotillo, P. Cerralbo, P. Lorente, M. Grifoll, M. Espino, A. Sánchez-Arcilla, E. Álvarez-Fanjul","doi":"10.1080/1755876X.2019.1606765","DOIUrl":"https://doi.org/10.1080/1755876X.2019.1606765","url":null,"abstract":"ABSTRACT SAMOA (Sistema de Apoyo Meteorológico y Oceanográfico de la Autoridad Portuaria) is the latest initiative of Puertos del Estado, the Spanish Public State Port Agency, to enhance the delivery of user-customised operational met-ocean information to aid Spanish Port Authorities making harbour safety, environmental management and operational decisions. This initiative provides high-resolution coastal operational prediction systems in domains such as harbours and nearby coastal waters. Forecast systems implemented are fully operational from January 2017 for nine Spanish ports in the Mediterranean, the Iberian Atlantic and the Canary Islands. This paper provides an end-to-end description of these SAMOA systems that are based on high-resolution ROMS model applications. The SAMOA systems are CMEMS downstream services, being the coastal models nested into the regional IBI forecast solution. At the surface, SAMOA systems use as forcing daily updated hourly winds and heat and water fluxes from the Spanish Meteorological Agency forecast services. Highlights from the scientific pre-operational model evaluation phase and the multi-parametric validation are shown, illustrating agreements between SAMOA products and in-situ and remoted sensed observations. To this aim, skill metrics (such as bias, errors, Taylor diagrams and correlations) are presented. Finally, a look ahead to future SAMOA developments and operational innovations is provided.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"70 1","pages":"37 - 54"},"PeriodicalIF":3.1,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75989623","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 : 2020-01-02DOI: 10.1080/1755876X.2019.1685834
A. Schiller, G. Brassington, P. Oke, M. Cahill, P. Divakaran, M. Entel, J. Freeman, D. Griffin, M. Herzfeld, R. Hoeke, Xinmei Huang, E. Jones, E. King, B. Parker, T. Pitman, U. Rosebrock, J. Sweeney, Andy J. Taylor, M. Thatcher, R. Woodham, A. Zhong
ABSTRACT The operational Australian Bluelink ocean forecast system is used to transform physical oceanographic observations into coherent analyses and predictions. These analyses and predictions form the basis for information services about the marine environment and its ecosystem, and can provide boundary data for weather predictions. Bluelink information services are available to marine industries (e.g. commercial fishing, aquaculture, shipping, oil and gas, renewable energy), government agencies (e.g. search and rescue, defence, coastal management, environmental protection), and other stakeholders (e.g. recreation, water sports, artisanal and sport fishing) who depend on timely and accurate information about the marine environment. This review highlights the last 15 years of Bluelink achievements delivering mesoscale (eddy-resolving) to sub-mesoscale and short- to medium-range (days to weeks) ocean forecasts and reanalyses. Key achievements include the development of a global ocean forecasting and reanalysis system, a relocatable ocean-atmosphere model and a littoral zone analysis and forecasting capability. Beyond the traditional short-term forecasting of physical ocean properties (temperature, salinity, surface height, currents, waves), marine activities such as water quality and habitat management as well as climate monitoring increasingly rely on operational oceanographic data and products. These are areas of active research of the Bluelink team in collaboration with national and international partners.
{"title":"Bluelink ocean forecasting Australia: 15 years of operational ocean service delivery with societal, economic and environmental benefits","authors":"A. Schiller, G. Brassington, P. Oke, M. Cahill, P. Divakaran, M. Entel, J. Freeman, D. Griffin, M. Herzfeld, R. Hoeke, Xinmei Huang, E. Jones, E. King, B. Parker, T. Pitman, U. Rosebrock, J. Sweeney, Andy J. Taylor, M. Thatcher, R. Woodham, A. Zhong","doi":"10.1080/1755876X.2019.1685834","DOIUrl":"https://doi.org/10.1080/1755876X.2019.1685834","url":null,"abstract":"ABSTRACT The operational Australian Bluelink ocean forecast system is used to transform physical oceanographic observations into coherent analyses and predictions. These analyses and predictions form the basis for information services about the marine environment and its ecosystem, and can provide boundary data for weather predictions. Bluelink information services are available to marine industries (e.g. commercial fishing, aquaculture, shipping, oil and gas, renewable energy), government agencies (e.g. search and rescue, defence, coastal management, environmental protection), and other stakeholders (e.g. recreation, water sports, artisanal and sport fishing) who depend on timely and accurate information about the marine environment. This review highlights the last 15 years of Bluelink achievements delivering mesoscale (eddy-resolving) to sub-mesoscale and short- to medium-range (days to weeks) ocean forecasts and reanalyses. Key achievements include the development of a global ocean forecasting and reanalysis system, a relocatable ocean-atmosphere model and a littoral zone analysis and forecasting capability. Beyond the traditional short-term forecasting of physical ocean properties (temperature, salinity, surface height, currents, waves), marine activities such as water quality and habitat management as well as climate monitoring increasingly rely on operational oceanographic data and products. These are areas of active research of the Bluelink team in collaboration with national and international partners.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"77 1","pages":"1 - 18"},"PeriodicalIF":3.1,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89912380","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 : 2020-01-02DOI: 10.1080/1755876X.2019.1679609
G. Gawarkiewicz, A. Plueddemann
ABSTRACT The Ocean Observatories Initiative (OOI) of the National Science Foundation in the USA includes a coastal observatory called the OOI Pioneer Array, which is focused on understanding shelf/slope exchange processes. The OOI Pioneer Array has been designed and constructed and is currently in operation. In order to fully understand the design principles and constraints, we first describe the basic exchange processes and review prior experiments in the region. Emphasis is placed on the space and time scales of important exchange processes such as frontal meandering and warm core ring interactions with the Shelfbreak Front, the dominant sources of variability in the region. The three major components of the Pioneer Array are then described, including preliminary data from the underwater gliders and Autonomous Underwater Vehicle (AUV) deployments. The relevance of the Pioneer Array to important recent scientific issues in the area, including enhanced warming of the continental shelf and increasing frequency and spatial extent of Gulf Stream interactions with the continental shelf is discussed. Finally, similar observatories in Asia are briefly described, and general conclusions regarding principles that should guide the design of shelfbreak observatories in other geographic regions are presented.
{"title":"Scientific rationale and conceptual design of a process-oriented shelfbreak observatory: the OOI Pioneer Array","authors":"G. Gawarkiewicz, A. Plueddemann","doi":"10.1080/1755876X.2019.1679609","DOIUrl":"https://doi.org/10.1080/1755876X.2019.1679609","url":null,"abstract":"ABSTRACT The Ocean Observatories Initiative (OOI) of the National Science Foundation in the USA includes a coastal observatory called the OOI Pioneer Array, which is focused on understanding shelf/slope exchange processes. The OOI Pioneer Array has been designed and constructed and is currently in operation. In order to fully understand the design principles and constraints, we first describe the basic exchange processes and review prior experiments in the region. Emphasis is placed on the space and time scales of important exchange processes such as frontal meandering and warm core ring interactions with the Shelfbreak Front, the dominant sources of variability in the region. The three major components of the Pioneer Array are then described, including preliminary data from the underwater gliders and Autonomous Underwater Vehicle (AUV) deployments. The relevance of the Pioneer Array to important recent scientific issues in the area, including enhanced warming of the continental shelf and increasing frequency and spatial extent of Gulf Stream interactions with the continental shelf is discussed. Finally, similar observatories in Asia are briefly described, and general conclusions regarding principles that should guide the design of shelfbreak observatories in other geographic regions are presented.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"48 1","pages":"19 - 36"},"PeriodicalIF":3.1,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79932096","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 : 2020-01-02DOI: 10.1080/1755876X.2019.1633236
Jan‐Victor Björkqvist, Olga Vähä-Piikkiö, V. Alari, A. Kuznetsova, L. Tuomi
ABSTRACT WAM, SWAN and WAVEWATCH III® were implemented to the Finnish archipelago with a 0.1 nmi grid. A comparison with coastal wave buoy observations showed that the models agreed on the significant wave height, with biases and root-mean-square-errors (RMSE) differing at most 0.06 m. In a general sense, WAM propagated most long wave energy into the archipelago, while SWAN generated the highest local waves. The performance of WAVEWATCH III was wind direction dependent. The model tendencies caused them to disagree on the peak period near the coast, with differences in mean values being up to 1.4 s. The large scatter (RMSE>2 s) inside the archipelago was mostly explained by the ill-defined nature of the parameter in more complex wave conditions. The mean period had less scatter (RMSE<1.5 s), but changes in the upper integration frequency from 0.6 Hz to 1 Hz affected the bias by roughly 1 s in all models. WAM and WAVEWATCH III underestimated the high-frequency wave energy for certain wind directions, possibly because of a too small friction velocity. A wind forcing taken every 3 h from a 7.4 km operational atmospheric model was found to be sufficient to force the high-resolution wave models.
{"title":"WAM, SWAN and WAVEWATCH III in the Finnish archipelago – the effect of spectral performance on bulk wave parameters","authors":"Jan‐Victor Björkqvist, Olga Vähä-Piikkiö, V. Alari, A. Kuznetsova, L. Tuomi","doi":"10.1080/1755876X.2019.1633236","DOIUrl":"https://doi.org/10.1080/1755876X.2019.1633236","url":null,"abstract":"ABSTRACT WAM, SWAN and WAVEWATCH III® were implemented to the Finnish archipelago with a 0.1 nmi grid. A comparison with coastal wave buoy observations showed that the models agreed on the significant wave height, with biases and root-mean-square-errors (RMSE) differing at most 0.06 m. In a general sense, WAM propagated most long wave energy into the archipelago, while SWAN generated the highest local waves. The performance of WAVEWATCH III was wind direction dependent. The model tendencies caused them to disagree on the peak period near the coast, with differences in mean values being up to 1.4 s. The large scatter (RMSE>2 s) inside the archipelago was mostly explained by the ill-defined nature of the parameter in more complex wave conditions. The mean period had less scatter (RMSE<1.5 s), but changes in the upper integration frequency from 0.6 Hz to 1 Hz affected the bias by roughly 1 s in all models. WAM and WAVEWATCH III underestimated the high-frequency wave energy for certain wind directions, possibly because of a too small friction velocity. A wind forcing taken every 3 h from a 7.4 km operational atmospheric model was found to be sufficient to force the high-resolution wave models.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"13 558 1","pages":"55 - 70"},"PeriodicalIF":3.1,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75346955","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 : 2019-11-20DOI: 10.1080/1755876X.2018.1523301
Ashley Miller, A. Luscher
ABSTRACT The National Oceanographic and Atmospheric Administration National Water Level Observation Network (NWLON) is the foundation of a comprehensive system for observing, communicating, and assessing the impact of changing water levels nationwide. The network also measures other oceanographic parameters in addition to water levels, including meteorological parameters. Although initially established to support navigation, NWLON is a ‘go to’ source for data and products to support coastal community decision making. Real-time water level information available 24/7 is critical to emergency managers and planners monitoring changing water levels and contributes to NOAA’s forecast model for tsunami and storm surge warnings. This article also discusses the role of NWLON in terms of addressing emerging observational needs around emergency management, tracking changes in sea level rise through persistent changes in high tide flooding, establishing new regional sea level scenarios and projections, and restoring tidally influenced habitats. Sea level trends have been computed at 142 water level stations using a minimum span of 30 years of observations at each location. Coupling present trends with projected future scenarios supports decisions that will remain relevant into the future.
{"title":"NOAA’s national water level observation network (NWLON)","authors":"Ashley Miller, A. Luscher","doi":"10.1080/1755876X.2018.1523301","DOIUrl":"https://doi.org/10.1080/1755876X.2018.1523301","url":null,"abstract":"ABSTRACT The National Oceanographic and Atmospheric Administration National Water Level Observation Network (NWLON) is the foundation of a comprehensive system for observing, communicating, and assessing the impact of changing water levels nationwide. The network also measures other oceanographic parameters in addition to water levels, including meteorological parameters. Although initially established to support navigation, NWLON is a ‘go to’ source for data and products to support coastal community decision making. Real-time water level information available 24/7 is critical to emergency managers and planners monitoring changing water levels and contributes to NOAA’s forecast model for tsunami and storm surge warnings. This article also discusses the role of NWLON in terms of addressing emerging observational needs around emergency management, tracking changes in sea level rise through persistent changes in high tide flooding, establishing new regional sea level scenarios and projections, and restoring tidally influenced habitats. Sea level trends have been computed at 142 water level stations using a minimum span of 30 years of observations at each location. Coupling present trends with projected future scenarios supports decisions that will remain relevant into the future.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"42 1","pages":"S57 - S66"},"PeriodicalIF":3.1,"publicationDate":"2019-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74126795","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 : 2019-11-08DOI: 10.1080/1755876X.2019.1684136
R. Bell, B. Kirtman
ABSTRACT The sinking of the cargo ship SS El Faro is investigated by providing a comprehensive analysis of the wind, wave and ocean currents associated with Hurricane Joaquin. Using state-of-the-art reanalyses the event is assessed in high resolution and from a long-term climate perspective. The last known location of the SS El Faro was in the north-west eye-wall of Hurricane Joaquin when it was a category four major Hurricane. The maximum individual wave height in this region was over 10 m and the Benjamin-Feir index was 0.69 indicating a high likelihood of rogue waves. As the vessel tried to outrun the hurricane it was continually impacted by strong wind and waves on its port side. This was compounded with flooding that caused a starboard list which likely eventually caused the vessel to sink.
{"title":"Extreme environmental forcing on the container ship SS El Faro","authors":"R. Bell, B. Kirtman","doi":"10.1080/1755876X.2019.1684136","DOIUrl":"https://doi.org/10.1080/1755876X.2019.1684136","url":null,"abstract":"ABSTRACT The sinking of the cargo ship SS El Faro is investigated by providing a comprehensive analysis of the wind, wave and ocean currents associated with Hurricane Joaquin. Using state-of-the-art reanalyses the event is assessed in high resolution and from a long-term climate perspective. The last known location of the SS El Faro was in the north-west eye-wall of Hurricane Joaquin when it was a category four major Hurricane. The maximum individual wave height in this region was over 10 m and the Benjamin-Feir index was 0.69 indicating a high likelihood of rogue waves. As the vessel tried to outrun the hurricane it was continually impacted by strong wind and waves on its port side. This was compounded with flooding that caused a starboard list which likely eventually caused the vessel to sink.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"1 1","pages":"98 - 113"},"PeriodicalIF":3.1,"publicationDate":"2019-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85114461","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 : 2019-11-04DOI: 10.1080/1755876X.2019.1684135
K. Maneesha, D. Prasad, K. Patnaik
ABSTRACT Cyclone Hudhud originated in the Andaman Sea on 6 October 2014. Later, it intensified into a cyclonic storm on 8 October and eventually made landfall at Visakhapatnam on 12 October as a very severe cyclonic storm. It was intensified off of Visakhapatnam by high stratified waters with a thick barrier layer that held significant heat content. In this study, we analysed the data along the cyclone track using a combination of satellite, in-situ Argo and Bio-Argo data to assess the upper oceanic changes along the Hudhud track. Notable changes were detected in the upper ocean due to its extreme intensification and prior passage through cold-core eddies. A high translation speed and persistent stratification dominated the effects caused by the cold-core eddies on the intensification of the cyclone and the same was attributed to the upwelled subsurface chlorophyll maxima. The biophysical changes in the top 150 m layer derived from Argo floats were in good agreement with the satellite and model data. Further, it was observed that the increase in lightning flash rates also influenced surface productivity during the cyclone. Subsequent to the passage of the cyclone, the ocean took two weeks to achieve its original state.
{"title":"Biophysical responses to tropical cyclone Hudhud over the Bay of Bengal","authors":"K. Maneesha, D. Prasad, K. Patnaik","doi":"10.1080/1755876X.2019.1684135","DOIUrl":"https://doi.org/10.1080/1755876X.2019.1684135","url":null,"abstract":"ABSTRACT Cyclone Hudhud originated in the Andaman Sea on 6 October 2014. Later, it intensified into a cyclonic storm on 8 October and eventually made landfall at Visakhapatnam on 12 October as a very severe cyclonic storm. It was intensified off of Visakhapatnam by high stratified waters with a thick barrier layer that held significant heat content. In this study, we analysed the data along the cyclone track using a combination of satellite, in-situ Argo and Bio-Argo data to assess the upper oceanic changes along the Hudhud track. Notable changes were detected in the upper ocean due to its extreme intensification and prior passage through cold-core eddies. A high translation speed and persistent stratification dominated the effects caused by the cold-core eddies on the intensification of the cyclone and the same was attributed to the upwelled subsurface chlorophyll maxima. The biophysical changes in the top 150 m layer derived from Argo floats were in good agreement with the satellite and model data. Further, it was observed that the increase in lightning flash rates also influenced surface productivity during the cyclone. Subsequent to the passage of the cyclone, the ocean took two weeks to achieve its original state.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"72 1","pages":"87 - 97"},"PeriodicalIF":3.1,"publicationDate":"2019-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79541545","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 : 2019-09-06DOI: 10.1080/1755876x.2019.1661564
T. Tamtare, D. Dumont, C. Chavanne
ABSTRACT Predictions of drift trajectories based on four drift models were compared with observations from drifting buoys deployed in 2014 and 2015 in the Estuary and Gulf of St. Lawrence to show the impact of the current vertical shear on the surface drift predictions. Input of ocean currents and winds are obtained from ISMER's 5 km resolution ocean circulation model and from the Canadian Regional Deterministic Prediction System, respectively. The control drift model A considers depth-averaged near-surface currents (0–5 m) provided by the top grid cell of the ocean circulation model. Model B performs a linear extrapolation assuming a constant vertical shear equal to that between the first two cells of the ocean model. Models C and D perform a dynamic extrapolation assuming an Ekman layer with a constant or linearly increasing vertical viscosity, respectively. Model performance is evaluated based on several error metrics. Drift models based on extrapolated surface currents reduce separation distances relative to the control model by 25% (model B), 31% (model C) and 35% (model D) on average, for lead times from 3 h to 72 h. We thus recommend the use of extrapolation methods of near-surface ocean currents for improving surface drift forecasting skills in support of emergency response.
{"title":"Extrapolating Eulerian ocean currents for improving surface drift forecasts","authors":"T. Tamtare, D. Dumont, C. Chavanne","doi":"10.1080/1755876x.2019.1661564","DOIUrl":"https://doi.org/10.1080/1755876x.2019.1661564","url":null,"abstract":"ABSTRACT Predictions of drift trajectories based on four drift models were compared with observations from drifting buoys deployed in 2014 and 2015 in the Estuary and Gulf of St. Lawrence to show the impact of the current vertical shear on the surface drift predictions. Input of ocean currents and winds are obtained from ISMER's 5 km resolution ocean circulation model and from the Canadian Regional Deterministic Prediction System, respectively. The control drift model A considers depth-averaged near-surface currents (0–5 m) provided by the top grid cell of the ocean circulation model. Model B performs a linear extrapolation assuming a constant vertical shear equal to that between the first two cells of the ocean model. Models C and D perform a dynamic extrapolation assuming an Ekman layer with a constant or linearly increasing vertical viscosity, respectively. Model performance is evaluated based on several error metrics. Drift models based on extrapolated surface currents reduce separation distances relative to the control model by 25% (model B), 31% (model C) and 35% (model D) on average, for lead times from 3 h to 72 h. We thus recommend the use of extrapolation methods of near-surface ocean currents for improving surface drift forecasting skills in support of emergency response.","PeriodicalId":50105,"journal":{"name":"Journal of Operational Oceanography","volume":"18 1","pages":"71 - 85"},"PeriodicalIF":3.1,"publicationDate":"2019-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90916887","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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