Coal-type source rocks include both coal and terrigenous marine source rocks. By studying the distribution of secondary depressions, uplifts, as well as the characteristics of peat formation and accumulation in the northern marginal sea basin of the South China Sea, and combining them with coal formation characteristics observed in other basins, five genetic theories on the relationship between peat accumulation and dispersed organic matter accumulation are proposed. The northern marginal sea basin of the South China Sea is characterized by “disadvantageous coals formation and favorable terrigenous marine source rocks formation.” This paper provides a distribution map of coal seams and terrigenous marine source rocks in the Qiongdongnan Basin and determines their distribution patterns. Research shows that the migration of sedimentary facies in the basins and inner depressions led to the formation and migration of the peat accumulation centers. In addition, the vertical migration of the peat accumulation centers led to planar migration, which is actually a type of coupling relationship.Previous research results have revealed that the formation of coal-type source rock is multi-phased. The marginal sea basin is composed of several fault-depression basins, with each basin developing a second order of depression and uplift. There is no unified basin center or depositional center to be found. As a result, the concentration centers of coal-forming materials also vary greatly. Based on the distribution characteristics of coal-type source rocks in different basins within the marginal sea basins of the South China Sea, the research results have practical significance and provide guidance for exploring coal-type oil and gas reservoirs in this area.
{"title":"Genetic relationship between formation, accumulation and migration and dispersion of peat materials in Paleogene–Take the Qiongdongnan Basin as an example","authors":"Xiaojing Li, Zengxue Li, Dongdong Wang, Guangzeng Song, Pingli Wang, Haiyan Liu","doi":"10.1007/s13131-024-2334-7","DOIUrl":"https://doi.org/10.1007/s13131-024-2334-7","url":null,"abstract":"<p>Coal-type source rocks include both coal and terrigenous marine source rocks. By studying the distribution of secondary depressions, uplifts, as well as the characteristics of peat formation and accumulation in the northern marginal sea basin of the South China Sea, and combining them with coal formation characteristics observed in other basins, five genetic theories on the relationship between peat accumulation and dispersed organic matter accumulation are proposed. The northern marginal sea basin of the South China Sea is characterized by “disadvantageous coals formation and favorable terrigenous marine source rocks formation.” This paper provides a distribution map of coal seams and terrigenous marine source rocks in the Qiongdongnan Basin and determines their distribution patterns. Research shows that the migration of sedimentary facies in the basins and inner depressions led to the formation and migration of the peat accumulation centers. In addition, the vertical migration of the peat accumulation centers led to planar migration, which is actually a type of coupling relationship.Previous research results have revealed that the formation of coal-type source rock is multi-phased. The marginal sea basin is composed of several fault-depression basins, with each basin developing a second order of depression and uplift. There is no unified basin center or depositional center to be found. As a result, the concentration centers of coal-forming materials also vary greatly. Based on the distribution characteristics of coal-type source rocks in different basins within the marginal sea basins of the South China Sea, the research results have practical significance and provide guidance for exploring coal-type oil and gas reservoirs in this area.</p>","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141573091","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 : 2024-07-10DOI: 10.1007/s13131-024-2342-7
Jing Ma, Wanyin Wang, Hermann Zeyen, Yimi Zhang, Zhongsheng Li, Tao He, Dingding Wang
The distribution of oil and gas resources is intricately connected to the underlying structure of the lithosphere. Therefore, investigating the characteristics of lithospheric thickness and its correlation with oil and gas basins is highly important. This research utilizes recently enhanced geological–geophysical data, including topographic, geoid, rock layer thickness, variable rock layer density, and interface depth data. Employing the principles of lithospheric isostasy and heat conduction, we compute the laterally varying lithospheric thickness in the China seas and adjacent areas. From these results, two pivotal parameters for different types of oil and gas basins were statistically analyzed: the minimum lithospheric thickness and the relative fluctuation in lithospheric thickness. A semiquantitative analysis was used to explore the connection between these parameters and the hydrocarbon abundance within the oil and gas basins. This study unveils distinct variations in lithospheric thickness among basins, with oil and gas rich basins exhibiting a thicker lithosphere in the superimposed basins of central China and a thinner lithosphere in the rift basins of eastern China. Notably, the relative fluctuations in lithospheric thickness in basins demonstrate significant disparities: basins rich in oil and gas often exhibit greater thickness fluctuations. Additionally, in the offshore basins of China, a conspicuous negative linear correlation is observed between the minimum lithospheric thickness and the relative fluctuation in lithospheric thickness. This study posits that deep-seated thermal upwelling results in lithospheric undulations and extensional thinning in oil and gas basins. Concurrently, sustained deep-seated heat influences sedimentary materials in basins, creating favorable conditions for oil and gas generation. The insights derived from this study contribute to a quantitative understanding of the intricate relationships between deep lithospheric structures and oil and gas basins. These findings provide valuable guidance for future oil and gas exploration in the studied areas.
{"title":"Influence of lithospheric thickness distribution on oil and gas basins, China seas and adjacent areas","authors":"Jing Ma, Wanyin Wang, Hermann Zeyen, Yimi Zhang, Zhongsheng Li, Tao He, Dingding Wang","doi":"10.1007/s13131-024-2342-7","DOIUrl":"https://doi.org/10.1007/s13131-024-2342-7","url":null,"abstract":"<p>The distribution of oil and gas resources is intricately connected to the underlying structure of the lithosphere. Therefore, investigating the characteristics of lithospheric thickness and its correlation with oil and gas basins is highly important. This research utilizes recently enhanced geological–geophysical data, including topographic, geoid, rock layer thickness, variable rock layer density, and interface depth data. Employing the principles of lithospheric isostasy and heat conduction, we compute the laterally varying lithospheric thickness in the China seas and adjacent areas. From these results, two pivotal parameters for different types of oil and gas basins were statistically analyzed: the minimum lithospheric thickness and the relative fluctuation in lithospheric thickness. A semiquantitative analysis was used to explore the connection between these parameters and the hydrocarbon abundance within the oil and gas basins. This study unveils distinct variations in lithospheric thickness among basins, with oil and gas rich basins exhibiting a thicker lithosphere in the superimposed basins of central China and a thinner lithosphere in the rift basins of eastern China. Notably, the relative fluctuations in lithospheric thickness in basins demonstrate significant disparities: basins rich in oil and gas often exhibit greater thickness fluctuations. Additionally, in the offshore basins of China, a conspicuous negative linear correlation is observed between the minimum lithospheric thickness and the relative fluctuation in lithospheric thickness. This study posits that deep-seated thermal upwelling results in lithospheric undulations and extensional thinning in oil and gas basins. Concurrently, sustained deep-seated heat influences sedimentary materials in basins, creating favorable conditions for oil and gas generation. The insights derived from this study contribute to a quantitative understanding of the intricate relationships between deep lithospheric structures and oil and gas basins. These findings provide valuable guidance for future oil and gas exploration in the studied areas.</p>","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141573071","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 : 2024-06-21DOI: 10.1007/s13131-023-2275-6
Regina Kolzenburg, Federica Ragazzola, Laura Tamburello, Katy R. Nicastro, Christopher D. McQuaid, Gerardo I. Zardi
Marine heatwaves (MHWs) caused by anthropogenic climate change are becoming a key driver of change at the ecosystem level. Thermal conditions experienced by marine organisms across their distribution, particularly towards the equator, are likely to approach their physiological limits, resulting in extensive mortality and subsequent changes at the population level. Populations at the margins of their species’ distribution are thought to be more sensitive to climate-induced environmental pressures than central populations, but our understanding of variability in fitness-related physiological traits in trailing versus leading-edge populations is limited. In a laboratory simulation study, we tested whether two leading (Iceland) and two trailing (Spain) peripheral populations of the intertidal macroalga Corallina officinalis display different levels of maximum potential quantum efficiency (Fv/Fm) resilience to current and future winter MHWs scenarios. Our study revealed that ongoing and future local winter MHWs will not negatively affect leading-edge populations of C. officinalis, which exhibited stable photosynthetic efficiency throughout the study. Trailing edge populations showed a positive though non-significant trend in photosynthetic efficiency throughout winter MHWs exposure. Poleward and equatorward populations did not produce significantly different results, with winter MHWs having no negative affect on Fv/Fm of either population. Additionally, we found no long-term regional or population-level influence of a winter MHWs on this species’ photosynthetic efficiency. Thus, we found no statistically significant difference in thermal stress responses between leading and trailing populations. Nonetheless, C. officinalis showed a trend towards higher stress responses in southern than northern populations. Because responses rest on a variety of local population traits, they are difficult to predict based solely on thermal pressures.
{"title":"Photosynthetic response to a winter heatwave in leading and trailing edge populations of the intertidal red alga Corallina officinalis (Rhodophyta)","authors":"Regina Kolzenburg, Federica Ragazzola, Laura Tamburello, Katy R. Nicastro, Christopher D. McQuaid, Gerardo I. Zardi","doi":"10.1007/s13131-023-2275-6","DOIUrl":"https://doi.org/10.1007/s13131-023-2275-6","url":null,"abstract":"<p>Marine heatwaves (MHWs) caused by anthropogenic climate change are becoming a key driver of change at the ecosystem level. Thermal conditions experienced by marine organisms across their distribution, particularly towards the equator, are likely to approach their physiological limits, resulting in extensive mortality and subsequent changes at the population level. Populations at the margins of their species’ distribution are thought to be more sensitive to climate-induced environmental pressures than central populations, but our understanding of variability in fitness-related physiological traits in trailing versus leading-edge populations is limited. In a laboratory simulation study, we tested whether two leading (Iceland) and two trailing (Spain) peripheral populations of the intertidal macroalga <i>Corallina officinalis</i> display different levels of maximum potential quantum efficiency (Fv/Fm) resilience to current and future winter MHWs scenarios. Our study revealed that ongoing and future local winter MHWs will not negatively affect leading-edge populations of <i>C. officinalis</i>, which exhibited stable photosynthetic efficiency throughout the study. Trailing edge populations showed a positive though non-significant trend in photosynthetic efficiency throughout winter MHWs exposure. Poleward and equatorward populations did not produce significantly different results, with winter MHWs having no negative affect on Fv/Fm of either population. Additionally, we found no long-term regional or population-level influence of a winter MHWs on this species’ photosynthetic efficiency. Thus, we found no statistically significant difference in thermal stress responses between leading and trailing populations. Nonetheless, <i>C. officinalis</i> showed a trend towards higher stress responses in southern than northern populations. Because responses rest on a variety of local population traits, they are difficult to predict based solely on thermal pressures.</p>","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551596","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 : 2024-06-20DOI: 10.1007/s13131-023-2254-y
Hafez Ahmad, Felix Jose, Md. Simul Bhuyan, Md. Nazrul Islam, Padmanava Dash
Ocean productivity is the foundation of marine food web, which continuously removes atmospheric carbon dioxide and supports life at sea and on land. Spatio-temporal variability of net primary productivity (NPP), sea surface temperature (SST), sea surface salinity (SSS), mixed layer depth (MLD), and euphotic zone depth (EZD) in the northern Bay of Bengal (BoB) during three monsoon seasons were examined in this study based on remote sensing data for the period 2005 to 2020. To compare the NPP distribution between the coastal zones and open BoB, the study area was divided into five zones (Z1–Z5). Results suggest that most productive zones Z2 and Z1 are located at the head bay area and are directly influenced by freshwater discharge together with riverine sediment and nutrient loads. Across Z1–Z5, the NPP ranges from 5 315.38 mg/(m2·d) to 346.7 mg/(m2·d) (carbon, since then the same). The highest monthly average NPP of 5 315.38 mg/(m2·d) in February and 5 039.36 mg/(m2·d) in June were observed from Z2, while the lowest monthly average of 346.72 mg/(m2·d) was observed in March from Z4, which is an oceanic zone. EZD values vary from 6–154 m for the study area, and it has an inverse correlation with NPP concentration. EZD is deeper during the summer season and shallower during the wintertime, with a corresponding increase in productivity. Throughout the year, monthly SST shows slight fluctuation for the entire study area, and statistical analysis shows a significant correlation among NPP, and EZD, overall positive between NPP and MLD, whereas no significant correlation among SSS, and SST for the northern BoB. Long-term trends in SST and productivity were significantly positive in head bay zones but negatively productive in the open ocean. The findings in this study on the distribution of NPP, SST, SSS, MLD, and EZD and their seasonal variability in five different zones of BoB can be used to further improve the management of marine resources and overall environmental condition in response to climate changes in BoB as they are of utmost relevance to the fisheries for the three bordering countries.
{"title":"Seasonal influence of freshwater discharge on spatio-temporal variations in primary productivity, sea surface temperature, and euphotic zone depth in the northern Bay of Bengal","authors":"Hafez Ahmad, Felix Jose, Md. Simul Bhuyan, Md. Nazrul Islam, Padmanava Dash","doi":"10.1007/s13131-023-2254-y","DOIUrl":"https://doi.org/10.1007/s13131-023-2254-y","url":null,"abstract":"<p>Ocean productivity is the foundation of marine food web, which continuously removes atmospheric carbon dioxide and supports life at sea and on land. Spatio-temporal variability of net primary productivity (NPP), sea surface temperature (SST), sea surface salinity (SSS), mixed layer depth (MLD), and euphotic zone depth (EZD) in the northern Bay of Bengal (BoB) during three monsoon seasons were examined in this study based on remote sensing data for the period 2005 to 2020. To compare the NPP distribution between the coastal zones and open BoB, the study area was divided into five zones (Z1–Z5). Results suggest that most productive zones Z2 and Z1 are located at the head bay area and are directly influenced by freshwater discharge together with riverine sediment and nutrient loads. Across Z1–Z5, the NPP ranges from 5 315.38 mg/(m<sup>2</sup>·d) to 346.7 mg/(m<sup>2</sup>·d) (carbon, since then the same). The highest monthly average NPP of 5 315.38 mg/(m<sup>2</sup>·d) in February and 5 039.36 mg/(m<sup>2</sup>·d) in June were observed from Z2, while the lowest monthly average of 346.72 mg/(m<sup>2</sup>·d) was observed in March from Z4, which is an oceanic zone. EZD values vary from 6–154 m for the study area, and it has an inverse correlation with NPP concentration. EZD is deeper during the summer season and shallower during the wintertime, with a corresponding increase in productivity. Throughout the year, monthly SST shows slight fluctuation for the entire study area, and statistical analysis shows a significant correlation among NPP, and EZD, overall positive between NPP and MLD, whereas no significant correlation among SSS, and SST for the northern BoB. Long-term trends in SST and productivity were significantly positive in head bay zones but negatively productive in the open ocean. The findings in this study on the distribution of NPP, SST, SSS, MLD, and EZD and their seasonal variability in five different zones of BoB can be used to further improve the management of marine resources and overall environmental condition in response to climate changes in BoB as they are of utmost relevance to the fisheries for the three bordering countries.</p>","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141553270","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 : 2024-05-25DOI: 10.1007/s13131-023-2217-3
Mukkattu Nazar Suhaana, Jaime Gómez-Gutiérrez, Paravanparambil Rajakumar Jayachandran, Punnakkal Hari Praved, Sivasankaran Bijoy Nandan
Isopod crustaceans of the family Dajidae are exclusively marine ectoparasites. The genus Notophryxus G. O. Sars, 1883 currently includes nine nominal species, which are very rarely reported as the chances for encountering these specimens are unpredictable. Our comprehension of the taxonomy, biology, ecology, and life cycle of species belonging to the Notophryxus genus is notably lacking. All nominal species of Notophryxus genus are reviewed here to obtain a comprehensive and integrative taxonomic understanding of this genus, in an attempt to address the lacunae. This paper also documents the rediscovery of an ectoparasitic isopod from the genus Notophryxus in Indian waters, after 55 years. Adult isopod specimens obtained from the outer reefs of Amini Island in the Lakshadweep archipelago, Southeastern Arabian Sea, display morphological congruence to Notophryxus globularis G. O. Sars, 1885. The only previous report on this species dates back to 1885 from G.O. Sars’ description of N. globularis as an ectoparasite on the euphausiid Thysanoessa gregaria G. O. Sars, 1883 in the North Pacific. This discovery represents a range extension of N. globularis from the North Pacific to the Arabian Sea. Two cryptoniscid larvae and three adult females of N. globularis (with dwarf males) were found attached to four adult mysid specimens of Siriella aequiremis Hansen, 1910. The present study provides an improved diagnosis of N. globularis with the aid of light microscopy images and line drawings which was not given in the original G. O. Sars, 1885 report. This research also provides a concise description of cryptoniscid larvae from the same sampling location and same host which is most likely to be N. globularis larvae.
Dajidae 科的等足类甲壳动物是专门的海洋外寄生虫。目前,Notophryxus G. O. Sars, 1883 属包括 9 个标称物种,由于遇到这些标本的机会难以预料,因此很少有报道。我们对 Notophryxus 属物种的分类学、生物学、生态学和生命周期的了解明显不足。本文对 Notophryxus 属的所有标称物种进行了综述,以便对该属的分类学有一个全面、综合的了解,从而弥补这方面的空白。本文还记录了时隔 55 年后在印度水域重新发现的 Notophryxus 属的一种外寄生等足类动物。从阿拉伯海东南部拉克沙德韦普群岛阿米尼岛外礁获得的成年等脚类动物标本显示与Notophryxus globularis G. O. Sars, 1885形态一致。此前关于该物种的唯一报道可追溯到 1885 年,G.O. Sars 将 N. globularis 描述为北太平洋中食棘皮动物 Thysanoessa gregaria G. O. Sars, 1883 的外寄生虫。这一发现标志着 N. globularis 的分布范围从北太平洋扩展到了阿拉伯海。在 Hansen, 1910 年发现的 Siriella aequiremis 的 4 个成糠虾标本上附有 N. globularis 的 2 个隐翅虫幼虫和 3 个雌性成虫(以及侏儒雄虫)。本研究借助光学显微镜图像和线条图改进了对 N. globularis 的诊断,这在 G. O. Sars, 1885 年的原始报告中没有给出。这项研究还简明扼要地描述了来自同一采样地点和同一宿主的隐翅虫幼虫,这些幼虫最有可能是 N. globularis 幼虫。
{"title":"A review on the parasitic isopod genus Notophryxus G. O. Sars, 1883 (Crustacea: Isopoda), and first report of Notophryxus globularis G. O. Sars, 1885 from Lakshadweep Sea (Amini Island)","authors":"Mukkattu Nazar Suhaana, Jaime Gómez-Gutiérrez, Paravanparambil Rajakumar Jayachandran, Punnakkal Hari Praved, Sivasankaran Bijoy Nandan","doi":"10.1007/s13131-023-2217-3","DOIUrl":"https://doi.org/10.1007/s13131-023-2217-3","url":null,"abstract":"<p>Isopod crustaceans of the family Dajidae are exclusively marine ectoparasites. The genus <i>Notophryxus</i> G. O. Sars, 1883 currently includes nine nominal species, which are very rarely reported as the chances for encountering these specimens are unpredictable. Our comprehension of the taxonomy, biology, ecology, and life cycle of species belonging to the <i>Notophryxus</i> genus is notably lacking. All nominal species of <i>Notophryxus</i> genus are reviewed here to obtain a comprehensive and integrative taxonomic understanding of this genus, in an attempt to address the lacunae. This paper also documents the rediscovery of an ectoparasitic isopod from the genus <i>Notophryxus</i> in Indian waters, after 55 years. Adult isopod specimens obtained from the outer reefs of Amini Island in the Lakshadweep archipelago, Southeastern Arabian Sea, display morphological congruence to <i>Notophryxus globularis</i> G. O. Sars, 1885. The only previous report on this species dates back to 1885 from G.O. Sars’ description of <i>N. globularis</i> as an ectoparasite on the euphausiid <i>Thysanoessa gregaria</i> G. O. Sars, 1883 in the North Pacific. This discovery represents a range extension of <i>N. globularis</i> from the North Pacific to the Arabian Sea. Two cryptoniscid larvae and three adult females of <i>N. globularis</i> (with dwarf males) were found attached to four adult mysid specimens of <i>Siriella aequiremis</i> Hansen, 1910. The present study provides an improved diagnosis of <i>N. globularis</i> with the aid of light microscopy images and line drawings which was not given in the original G. O. Sars, 1885 report. This research also provides a concise description of cryptoniscid larvae from the same sampling location and same host which is most likely to be <i>N. globularis</i> larvae.</p>","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551597","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 : 2024-05-02DOI: 10.1007/s13131-023-2203-9
Xiaolun Chen, Xiaowen Luo, Ziyin Wu, Xiaoming Qin, Jihong Shang, Huajun Xu, Bin Li, Mingwei Wang, Hongyang Wan
Understanding the topographic patterns of the seafloor is a very important part of understanding our planet. Although the science involved in bathymetric surveying has advanced much over the decades, less than 20% of the seafloor has been precisely modeled to date, and there is an urgent need to improve the accuracy and reduce the uncertainty of underwater survey data. In this study, we introduce a pretrained visual geometry group network (VGGNet) method based on deep learning. To apply this method, we input gravity anomaly data derived from ship measurements and satellite altimetry into the model and correct the latter, which has a larger spatial coverage, based on the former, which is considered the true value and is more accurate. After obtaining the corrected high-precision gravity model, it is inverted to the corresponding bathymetric model by applying the gravity-depth correlation. We choose four data pairs collected from different environments, i.e., the Southern Ocean, Pacific Ocean, Atlantic Ocean and Caribbean Sea, to evaluate the topographic correction results of the model. The experiments show that the coefficient of determination (R2) reaches 0.834 among the results of the four experimental groups, signifying a high correlation. The standard deviation and normalized root mean square error are also evaluated, and the accuracy of their performance improved by up to 24.2% compared with similar research done in recent years. The evaluation of the R2 values at different water depths shows that our model can achieve performance results above 0.90 at certain water depths and can also significantly improve results from mid-water depths when compared to previous research. Finally, the bathymetry corrected by our model is able to show an accuracy improvement level of more than 21% within 1% of the total water depths, which is sufficient to prove that the VGGNet-based method has the ability to perform a gravity-bathymetry correction and achieve outstanding results.
{"title":"A VGGNet-based correction for satellite altimetry-derived gravity anomalies to improve the accuracy of bathymetry to depths of 6 500 m","authors":"Xiaolun Chen, Xiaowen Luo, Ziyin Wu, Xiaoming Qin, Jihong Shang, Huajun Xu, Bin Li, Mingwei Wang, Hongyang Wan","doi":"10.1007/s13131-023-2203-9","DOIUrl":"https://doi.org/10.1007/s13131-023-2203-9","url":null,"abstract":"<p>Understanding the topographic patterns of the seafloor is a very important part of understanding our planet. Although the science involved in bathymetric surveying has advanced much over the decades, less than 20% of the seafloor has been precisely modeled to date, and there is an urgent need to improve the accuracy and reduce the uncertainty of underwater survey data. In this study, we introduce a pretrained visual geometry group network (VGGNet) method based on deep learning. To apply this method, we input gravity anomaly data derived from ship measurements and satellite altimetry into the model and correct the latter, which has a larger spatial coverage, based on the former, which is considered the true value and is more accurate. After obtaining the corrected high-precision gravity model, it is inverted to the corresponding bathymetric model by applying the gravity-depth correlation. We choose four data pairs collected from different environments, i.e., the Southern Ocean, Pacific Ocean, Atlantic Ocean and Caribbean Sea, to evaluate the topographic correction results of the model. The experiments show that the coefficient of determination (<i>R</i><sup>2</sup>) reaches 0.834 among the results of the four experimental groups, signifying a high correlation. The standard deviation and normalized root mean square error are also evaluated, and the accuracy of their performance improved by up to 24.2% compared with similar research done in recent years. The evaluation of the <i>R</i><sup>2</sup> values at different water depths shows that our model can achieve performance results above 0.90 at certain water depths and can also significantly improve results from mid-water depths when compared to previous research. Finally, the bathymetry corrected by our model is able to show an accuracy improvement level of more than 21% within 1% of the total water depths, which is sufficient to prove that the VGGNet-based method has the ability to perform a gravity-bathymetry correction and achieve outstanding results.</p>","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140881886","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 : 2024-05-02DOI: 10.1007/s13131-024-2345-4
Chongwei Zheng
The recognition on the trend of wind energy stability is still extremely rare, although it is closely related to acquisition efficiency, grid connection, equipment lifetime, and costs of wind energy utilization. Using the 40-year (1979–2018) ERA-Interim data from the European Center for Medium-Range Weather Forecasts, this study presented the spatial-temporal distribution and climatic trend of the stability of global offshore wind energy as well as the abrupt phenomenon of wind energy stability in key regions over the past 40 years with the climatic analysis method and Mann-Kendall (M-K) test. The results show the following 5 points. (1) According to the coefficient of variation (Cv) of the wind power density, there are six permanent stable zones of global offshore wind energy: the southeast and northeast trade wind zones in the Indian, Pacific and Atlantic oceans, the Southern Hemisphere westerly, and a semi-permanent stable zone (North Indian Ocean). (2) There are six low-value zones for both seasonal variability index (Sv) and monthly variability index (Mv) globally, with a similar spatial distribution as that of the six permanent stable zones. Mv and Sv in the Arabian Sea are the highest in the world. (3) After Cv, Mv and Sv are comprehensively considered, the six permanent stable zones have an obvious advantage in the stability of wind energy over other sea areas, with Cv below 0.8, Mv within 1.0, and Sv within 0.7 all the year round. (4) The global stability of offshore wind energy shows a positive climatic trend for the past four decades. Cv, Mv and Sv have not changed significantly or decreased in most of the global ocean during 1979 to 2018. That is, wind energy is flat or more stable, while the monthly and seasonal variabilities tend to shrink/smooth, which is beneficial for wind energy utilization. (5) Cv in the low-latitude Pacific and Mv and Sv in both the North Indian Ocean and the low-latitude Pacific have an obvious abrupt phenomenon at the end of the 20th century.
{"title":"A positive trend in the stability of global offshore wind energy","authors":"Chongwei Zheng","doi":"10.1007/s13131-024-2345-4","DOIUrl":"https://doi.org/10.1007/s13131-024-2345-4","url":null,"abstract":"<p>The recognition on the trend of wind energy stability is still extremely rare, although it is closely related to acquisition efficiency, grid connection, equipment lifetime, and costs of wind energy utilization. Using the 40-year (1979–2018) ERA-Interim data from the European Center for Medium-Range Weather Forecasts, this study presented the spatial-temporal distribution and climatic trend of the stability of global offshore wind energy as well as the abrupt phenomenon of wind energy stability in key regions over the past 40 years with the climatic analysis method and Mann-Kendall (M-K) test. The results show the following 5 points. (1) According to the coefficient of variation (<i>C</i><sub>v</sub>) of the wind power density, there are six permanent stable zones of global offshore wind energy: the southeast and northeast trade wind zones in the Indian, Pacific and Atlantic oceans, the Southern Hemisphere westerly, and a semi-permanent stable zone (North Indian Ocean). (2) There are six low-value zones for both seasonal variability index (<i>S</i><sub>v</sub>) and monthly variability index (<i>M</i><sub>v</sub>) globally, with a similar spatial distribution as that of the six permanent stable zones. <i>M</i><sub>v</sub> and <i>S</i><sub>v</sub> in the Arabian Sea are the highest in the world. (3) After <i>C</i><sub>v</sub>, <i>M</i><sub>v</sub> and <i>S</i><sub>v</sub> are comprehensively considered, the six permanent stable zones have an obvious advantage in the stability of wind energy over other sea areas, with <i>C</i><sub>v</sub> below 0.8, <i>M</i><sub>v</sub> within 1.0, and <i>S</i><sub>v</sub> within 0.7 all the year round. (4) The global stability of offshore wind energy shows a positive climatic trend for the past four decades. <i>C</i><sub>v</sub>, <i>M</i><sub>v</sub> and <i>S</i><sub>v</sub> have not changed significantly or decreased in most of the global ocean during 1979 to 2018. That is, wind energy is flat or more stable, while the monthly and seasonal variabilities tend to shrink/smooth, which is beneficial for wind energy utilization. (5) <i>C</i><sub>v</sub> in the low-latitude Pacific and <i>M</i><sub>v</sub> and <i>S</i><sub>v</sub> in both the North Indian Ocean and the low-latitude Pacific have an obvious abrupt phenomenon at the end of the 20th century.</p>","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140881892","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 : 2024-05-02DOI: 10.1007/s13131-023-2202-x
Hongxia Chen, Lina Lin, Long Fan, Wangxiao Yang, Yinke Dou, Bingrui Li, Yan He, Bin Kong, Guangyu Zuo, Na Liu
During the 10th Chinese Arctic scientific expedition carried out in the summer of 2019, the surface current in the high-latitude areas of the Arctic Ocean was observed using a self-developed surface drifting buoy, which was initially deployed in the Chukchi Sea. The buoy traversed the Chukchi Sea, Chukchi Abyssal Plain, Mendeleev Ridge, Makarov Basin, and Canada Basin over a period of 632 d. After returning to the Mendeleev Ridge, it continued to drift toward the pole. Overall, the track of the buoy reflected the characteristics of the transpolar drift and Chukchi Slope Current, as well as the inertial flow, cross-ridge surface flow, and even the surface disorganized flow for some time intervals. The results showed that: (1) the transpolar drift mainly occurs in the Chukchi Abyssal Plain, Mendeleev Ridge, and western Canada Basin to the east of the ridge where sea ice concentration is high, and the average northward flow velocity in the region between 79.41°N and 86.32°N was 5.1 cm/s; (2) the average surface velocity of the Chukchi Slope Current was 13.5 cm/s, and while this current moves westward along the continental slope, it also extends northwestward across the continental slope and flows to the deep sea; and (3) when sea ice concentration was less than 50%, the inertial flow was more significant (the maximum observed inertial flow was 26 cm/s, and the radius of the inertia circle was 3.6 km).
{"title":"Observation of Arctic surface currents using data from a surface drifting buoy","authors":"Hongxia Chen, Lina Lin, Long Fan, Wangxiao Yang, Yinke Dou, Bingrui Li, Yan He, Bin Kong, Guangyu Zuo, Na Liu","doi":"10.1007/s13131-023-2202-x","DOIUrl":"https://doi.org/10.1007/s13131-023-2202-x","url":null,"abstract":"<p>During the 10th Chinese Arctic scientific expedition carried out in the summer of 2019, the surface current in the high-latitude areas of the Arctic Ocean was observed using a self-developed surface drifting buoy, which was initially deployed in the Chukchi Sea. The buoy traversed the Chukchi Sea, Chukchi Abyssal Plain, Mendeleev Ridge, Makarov Basin, and Canada Basin over a period of 632 d. After returning to the Mendeleev Ridge, it continued to drift toward the pole. Overall, the track of the buoy reflected the characteristics of the transpolar drift and Chukchi Slope Current, as well as the inertial flow, cross-ridge surface flow, and even the surface disorganized flow for some time intervals. The results showed that: (1) the transpolar drift mainly occurs in the Chukchi Abyssal Plain, Mendeleev Ridge, and western Canada Basin to the east of the ridge where sea ice concentration is high, and the average northward flow velocity in the region between 79.41°N and 86.32°N was 5.1 cm/s; (2) the average surface velocity of the Chukchi Slope Current was 13.5 cm/s, and while this current moves westward along the continental slope, it also extends northwestward across the continental slope and flows to the deep sea; and (3) when sea ice concentration was less than 50%, the inertial flow was more significant (the maximum observed inertial flow was 26 cm/s, and the radius of the inertia circle was 3.6 km).</p>","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140881785","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 : 2024-04-30DOI: 10.1007/s13131-023-2284-5
Lina Cai, Jie Yin, Xiaojun Yan, Yongdong Zhou, Rong Tang, Menghan Yu
Mussel aquaculture and large yellow croaker aquaculture areas and their environmental characteristics in Zhoushan were analyzed using satellite data and in-situ surveys. A new two-step remote sensing method was proposed and applied to determine the basic environmental characteristics of the best mussel and large yellow croaker aquaculture areas. This methodology includes the first step of extraction of the location distribution and the second step of the extraction of internal environmental factors. The fishery ranching index (FRI1, FRI2) was established to extract the mussel and the large yellow croaker aquaculture area in Zhoushan, using Gaofen-1 (GF-1) and Gaofen-6 (GF-6) satellite data with a special resolution of 2 m. In the second step, the environmental factors such as sea surface temperature (SST), chlorophyll a (Chl-a) concentration, current and tide, suspended sediment concentration (SSC) in mussel aquaculture area and large yellow croaker aquaculture area were extracted and analyzed in detail. The results show the following three points. (1) For the extraction of the mussel aquaculture area, FRI1 and FRI2 are complementary, and the combination of FRI1 and FRI2 is suitable to extract the mussel aquaculture area. As for the large yellow croaker aquaculture area extraction, FRI2 is suitable. (2) Mussel aquaculture and the large yellow croaker aquaculture area in Zhoushan are mainly located on the side near the islands that are away from the eastern open waters. The water environment factor template suitable for mussel and large yellow croaker aquaculture was determined. (3) This two-step remote sensing method can be used for the preliminary screening of potential site selection for the mussels and large yellow croaker aquaculture area in the future. the fishery ranching index (FRI1, FRI2) in this paper can be applied to extract the mussel and large yellow croaker aquaculture areas in coastal waters around the world.
{"title":"The environmental analysis and site selection of mussel and large yellow croaker aquaculture areas based on high resolution remote sensing","authors":"Lina Cai, Jie Yin, Xiaojun Yan, Yongdong Zhou, Rong Tang, Menghan Yu","doi":"10.1007/s13131-023-2284-5","DOIUrl":"https://doi.org/10.1007/s13131-023-2284-5","url":null,"abstract":"<p>Mussel aquaculture and large yellow croaker aquaculture areas and their environmental characteristics in Zhoushan were analyzed using satellite data and <i>in-situ</i> surveys. A new two-step remote sensing method was proposed and applied to determine the basic environmental characteristics of the best mussel and large yellow croaker aquaculture areas. This methodology includes the first step of extraction of the location distribution and the second step of the extraction of internal environmental factors. The fishery ranching index (FRI1, FRI2) was established to extract the mussel and the large yellow croaker aquaculture area in Zhoushan, using Gaofen-1 (GF-1) and Gaofen-6 (GF-6) satellite data with a special resolution of 2 m. In the second step, the environmental factors such as sea surface temperature (SST), chlorophyll <i>a</i> (Chl-<i>a</i>) concentration, current and tide, suspended sediment concentration (SSC) in mussel aquaculture area and large yellow croaker aquaculture area were extracted and analyzed in detail. The results show the following three points. (1) For the extraction of the mussel aquaculture area, FRI1 and FRI2 are complementary, and the combination of FRI1 and FRI2 is suitable to extract the mussel aquaculture area. As for the large yellow croaker aquaculture area extraction, FRI2 is suitable. (2) Mussel aquaculture and the large yellow croaker aquaculture area in Zhoushan are mainly located on the side near the islands that are away from the eastern open waters. The water environment factor template suitable for mussel and large yellow croaker aquaculture was determined. (3) This two-step remote sensing method can be used for the preliminary screening of potential site selection for the mussels and large yellow croaker aquaculture area in the future. the fishery ranching index (FRI1, FRI2) in this paper can be applied to extract the mussel and large yellow croaker aquaculture areas in coastal waters around the world.</p>","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140829406","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}