In this study, we simulated typhoon waves in the shallow waters around the Zhoushan Islands using the WaveWatch-Ⅲ(WW3) model version 5.16, the latest version released by the National Oceanic and Atmospheric Administr...In this study, we simulated typhoon waves in the shallow waters around the Zhoushan Islands using the WaveWatch-Ⅲ(WW3) model version 5.16, the latest version released by the National Oceanic and Atmospheric Administration. Specifically, we used in-situ measurements to evaluate the performance of seven packages of input/dissipation source terms in the WW3 model. We forced the WW3 model by wind fields derived from a combination of the parametric Holland model and high-resolution European Center for Medium-Range Weather Forecasts(ECMWF) wind data in a 0.125? grid, herein called H-E winds. We trained the H-E winds by fitting a shape parameter B to buoy-measured observations, which resulted in a smallest root mean square error(RMSE) of 3 m s^(-1) for B, when treated as a constant 0.4. Then, we applied the seven input/dissipation terms of WW3, labelled ST1, ST2, ST2+STAB2, ST3, ST3+STAB3, ST4, and ST6, to simulate the significant wave height(SWH) up to 5 m during typhoons Fungwong and Chan-hom around the Zhoushan Islands. We then compared the SWHs of the simulated waves with those measured by the in-situ buoys. The results indicate that the simulation using ST2 performs best with an RMSE of 0.79 m for typhoon Fung-wong and an RMSE of 1.12 m for typhoon Chan-hom. Interestingly, we found the simulated SWH results to be relatively higher than those of the observations in the area between Hangzhou Bay and the Zhoushan Islands. This behavior is worthy of further investigation in the future.展开更多
Based on the quasi-harmonic analysis of 11 d vector ocean currents obtained from two high frequency sur- face wave radars located at Zhujiajian Island and Shengshan Island, the spatial distribution characteristics of ...Based on the quasi-harmonic analysis of 11 d vector ocean currents obtained from two high frequency sur- face wave radars located at Zhujiajian Island and Shengshan Island, the spatial distribution characteristics of surface tidal currents in the open sea area to the east of the Zhoushan Islands of Zhejiang Province, China are studied. The following conclusions are drawn from the analysis： the tidal current pattern in the open sea area to the east of Zhoushan Islands is primarily regular semidiurnal, which is significantly affected by the shallow water constituents. The directions of the major axes of tidal current ellipses of M2 lie approx- imately in the NW-SE direction. With the increasing of distance away from the coast, the directions of the tidal current ellipses gradually shift toward the E-W direction. The tidal currents are mainly reversing cur- rents. The spatial distribution of probable maximum current velocities decreases gradually from northeast to southwest which is basically in accordance with the spatial distribution of measured maximum current velocities. The residual currents near the coast are larger than those far away from the coast. The directions of the residual currents are basically north by east, and the angle to the due north increases gradually with the increasing distance away from the coast. The topography shows a certain impact on the spatial distri- bution of shallow water constituents, the rotation of tidal currents, the probable maximum currents and the residual currents.展开更多
The pollution level of diuron in seawater and sediments in the west coastal sea area of Zhoushan Island from 2011 to 2013 was investigated. Results revealed that the concentration of diuron in seawater varies from les...The pollution level of diuron in seawater and sediments in the west coastal sea area of Zhoushan Island from 2011 to 2013 was investigated. Results revealed that the concentration of diuron in seawater varies from less than (3.0 to 52.1) ng·L-1, with an average level of less than 11.1 ng.L-1. The annual average content was less than 7.9 ng.L-1, 13.9 ng.L-1, and 12.3 ng.L-1 in 2011, 2012, and 2013, respectively. The concentrations of diuron in marine sediments also varied from less than (0.3 to 3.9) ng.g-1 (dry weight), with an average concentration of less than 1.13 ng g-1 (dry weight). The annual average concentration was less than 0.851 ng.g-1, 1.328 ng.g-1, and 1.202 ng.g-1 in 2011, 2012, and 2013, respectively. The accumulation of diuron in seawater and sediments may pose a potential risk to the marine ecosystem of the investigated sea area.展开更多
The Mesoproterozoic Baoban Group is the oldest basement in Hainan Island and has played an important role in Columbia(Nuna)supercontinent reconstructions.The Mesoproterozoic granitic intrusions in the Baoban Group are...The Mesoproterozoic Baoban Group is the oldest basement in Hainan Island and has played an important role in Columbia(Nuna)supercontinent reconstructions.The Mesoproterozoic granitic intrusions in the Baoban Group are the most widely-exposed Precambrian magmatic rocks and are the key to understanding the tectonic settings of Hainan Island and its relationship with the South China Block and the Columbia supercontinent.New LA-ICP-MS zircon U-Pb dating on three mylonitic granite samples from the Tuwaishan and Baoban areas yield ages ranging from 1447 Ma to 1437 Ma,representing the absolute timing of the emplacement of the granitic intrusions.Combined with previously published geochronological data for rocks from the Baoban Group and regional mafic intrusions,it is concluded that the Baoban Group formed at 1460-1430 Ma,coeval with the emplacement of the granitic and mafic intrusions.New in-situ zircon LuHf isotope analyses for the three mylonitic granite samples yielded positiveε(t)values,ranging from+0.49 to+8.27,with model ages(T~C)ranging from 2181 Ma to 1687 Ma,suggesting that the granitic intrusions originated from a mixed source of Paleoproterozoic crust with juvenile crust.New zircon trace element data show characteristics of high Th/U values of 0.24-1.50,steep slopes from LREE to HREE and negative Pr,Eu anomalies with positive Ce,Sm anomalies,representing typical magmatic zircons formed in continental crust.Compared with available magmatic and detrital zircon ages from Precambrian rocks in the Cathaysia Block,Yangtze Block and western Laurentia,it is inferred that Hainan Island was separated from both the Cathaysia Block and the Yangtze Block,instead being connected with western Laurentia in the Columbia supercontinent.Considering the decreasing tendency of basin deposition time along the western margin of Laurentia,it is proposed that Hainan Island was located to the north or northwest of the Belt-Purcell Supergroup,along the western margin of Laurentia,during the breakup of the Columbia supercontinent.展开更多
为保障模块化串联结构电源系统的正常运行,探讨模块化串联结构电源系统中两级分组控制的故障检测策略。该方法通过优化模块化串联结构电源的故障反馈信号接收机制,引入基于最大功率点跟踪(Maximum Power Point Tracking,MPPT)的两级分...为保障模块化串联结构电源系统的正常运行,探讨模块化串联结构电源系统中两级分组控制的故障检测策略。该方法通过优化模块化串联结构电源的故障反馈信号接收机制,引入基于最大功率点跟踪(Maximum Power Point Tracking,MPPT)的两级分组控制直流孤岛检测技术。同时,设计故障判据,并优化检测结果输出流程。通过实际案例验证,文章提出的方法能够在短时间内精准检测出故障,从而显著提升电源系统的运行稳定性。展开更多
基金partly supported by the National Key Research and Development Program of China under contract (Nos. 2017YFA0604901, 2016YFC 1401002 and 2016YFC1402000)the National Natural Science Foundation of China under contract (Nos. 41776 183, 41606024 and 41506033)
文摘In this study, we simulated typhoon waves in the shallow waters around the Zhoushan Islands using the WaveWatch-Ⅲ(WW3) model version 5.16, the latest version released by the National Oceanic and Atmospheric Administration. Specifically, we used in-situ measurements to evaluate the performance of seven packages of input/dissipation source terms in the WW3 model. We forced the WW3 model by wind fields derived from a combination of the parametric Holland model and high-resolution European Center for Medium-Range Weather Forecasts(ECMWF) wind data in a 0.125? grid, herein called H-E winds. We trained the H-E winds by fitting a shape parameter B to buoy-measured observations, which resulted in a smallest root mean square error(RMSE) of 3 m s^(-1) for B, when treated as a constant 0.4. Then, we applied the seven input/dissipation terms of WW3, labelled ST1, ST2, ST2+STAB2, ST3, ST3+STAB3, ST4, and ST6, to simulate the significant wave height(SWH) up to 5 m during typhoons Fungwong and Chan-hom around the Zhoushan Islands. We then compared the SWHs of the simulated waves with those measured by the in-situ buoys. The results indicate that the simulation using ST2 performs best with an RMSE of 0.79 m for typhoon Fung-wong and an RMSE of 1.12 m for typhoon Chan-hom. Interestingly, we found the simulated SWH results to be relatively higher than those of the observations in the area between Hangzhou Bay and the Zhoushan Islands. This behavior is worthy of further investigation in the future.
基金The National High Technology Research and Development Program of China(863 Program)under contract No.2012AA091701the Fundamental Research Fund for the Central Universities of China under contract No.2012212020211
文摘Based on the quasi-harmonic analysis of 11 d vector ocean currents obtained from two high frequency sur- face wave radars located at Zhujiajian Island and Shengshan Island, the spatial distribution characteristics of surface tidal currents in the open sea area to the east of the Zhoushan Islands of Zhejiang Province, China are studied. The following conclusions are drawn from the analysis： the tidal current pattern in the open sea area to the east of Zhoushan Islands is primarily regular semidiurnal, which is significantly affected by the shallow water constituents. The directions of the major axes of tidal current ellipses of M2 lie approx- imately in the NW-SE direction. With the increasing of distance away from the coast, the directions of the tidal current ellipses gradually shift toward the E-W direction. The tidal currents are mainly reversing cur- rents. The spatial distribution of probable maximum current velocities decreases gradually from northeast to southwest which is basically in accordance with the spatial distribution of measured maximum current velocities. The residual currents near the coast are larger than those far away from the coast. The directions of the residual currents are basically north by east, and the angle to the due north increases gradually with the increasing distance away from the coast. The topography shows a certain impact on the spatial distri- bution of shallow water constituents, the rotation of tidal currents, the probable maximum currents and the residual currents.
文摘The pollution level of diuron in seawater and sediments in the west coastal sea area of Zhoushan Island from 2011 to 2013 was investigated. Results revealed that the concentration of diuron in seawater varies from less than (3.0 to 52.1) ng·L-1, with an average level of less than 11.1 ng.L-1. The annual average content was less than 7.9 ng.L-1, 13.9 ng.L-1, and 12.3 ng.L-1 in 2011, 2012, and 2013, respectively. The concentrations of diuron in marine sediments also varied from less than (0.3 to 3.9) ng.g-1 (dry weight), with an average concentration of less than 1.13 ng g-1 (dry weight). The annual average concentration was less than 0.851 ng.g-1, 1.328 ng.g-1, and 1.202 ng.g-1 in 2011, 2012, and 2013, respectively. The accumulation of diuron in seawater and sediments may pose a potential risk to the marine ecosystem of the investigated sea area.
基金funded by the Chinese Geological Survey Program(Grant Nos.DD20160035,DD20190047)the National Nonprofit Institute Research Grant of IGGE(AS2022P03)the Chinese Scholarship Council(File No.201606400032)Scholarship to Liu Yuheng。
文摘The Mesoproterozoic Baoban Group is the oldest basement in Hainan Island and has played an important role in Columbia(Nuna)supercontinent reconstructions.The Mesoproterozoic granitic intrusions in the Baoban Group are the most widely-exposed Precambrian magmatic rocks and are the key to understanding the tectonic settings of Hainan Island and its relationship with the South China Block and the Columbia supercontinent.New LA-ICP-MS zircon U-Pb dating on three mylonitic granite samples from the Tuwaishan and Baoban areas yield ages ranging from 1447 Ma to 1437 Ma,representing the absolute timing of the emplacement of the granitic intrusions.Combined with previously published geochronological data for rocks from the Baoban Group and regional mafic intrusions,it is concluded that the Baoban Group formed at 1460-1430 Ma,coeval with the emplacement of the granitic and mafic intrusions.New in-situ zircon LuHf isotope analyses for the three mylonitic granite samples yielded positiveε(t)values,ranging from+0.49 to+8.27,with model ages(T~C)ranging from 2181 Ma to 1687 Ma,suggesting that the granitic intrusions originated from a mixed source of Paleoproterozoic crust with juvenile crust.New zircon trace element data show characteristics of high Th/U values of 0.24-1.50,steep slopes from LREE to HREE and negative Pr,Eu anomalies with positive Ce,Sm anomalies,representing typical magmatic zircons formed in continental crust.Compared with available magmatic and detrital zircon ages from Precambrian rocks in the Cathaysia Block,Yangtze Block and western Laurentia,it is inferred that Hainan Island was separated from both the Cathaysia Block and the Yangtze Block,instead being connected with western Laurentia in the Columbia supercontinent.Considering the decreasing tendency of basin deposition time along the western margin of Laurentia,it is proposed that Hainan Island was located to the north or northwest of the Belt-Purcell Supergroup,along the western margin of Laurentia,during the breakup of the Columbia supercontinent.
文摘为保障模块化串联结构电源系统的正常运行,探讨模块化串联结构电源系统中两级分组控制的故障检测策略。该方法通过优化模块化串联结构电源的故障反馈信号接收机制,引入基于最大功率点跟踪(Maximum Power Point Tracking,MPPT)的两级分组控制直流孤岛检测技术。同时,设计故障判据,并优化检测结果输出流程。通过实际案例验证,文章提出的方法能够在短时间内精准检测出故障,从而显著提升电源系统的运行稳定性。
