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Chinese Journal of Aeronautics 2006年第B12期19卷 151-155页

作者： YANG fan bi Xiao-fang School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics 100083 Beijing China

The effects of the thickness of MgO and Fe on the electronic structure and magnetic properties of Fe/MgO/Fe magnetic tunnel junction was studied using the first principle method. Two series of models with MgO of different thicknesses： Fe（3）MgO（t）Fe（3）（t-=1,3,5,7） and with Fe of varied thicknesses： Fe（t）MgO（3）Fe（t）（t=3,4,5,6,7） were established. Calculated results show that in all the models the magnetic moment of Fe increases at the Fe/MgO interface and surface as compared with that of the inner layers. The mag- netic moment of each Fe layer was found to be independent of MgO thicknesses, while the spin-polarization of Fe layer at the interface shows a slight change in function of the MgO thicknesses. The tunneling magnetoresistance （TMR） ratio estimated by the Julliere model has the same change tendency as the spin-polarization has, and the largest value is obtained at the MgO thickness of 5 atomic layers. When the Fe thickness increases, the spin-polarization of interface Fe layer follows up an increase with a decrease. The highest TMR value is achieved when the Fe thickness is of 4 atomic layers.

关键词： Fe/MgO/Fe electronic structure tunnel magnetoresistance thicknesses

Wave Effect on the Ocean Circulations Through Mass Transport and Wave-Induced Pumping

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Journal of Ocean University of China 2014年第2期13卷 175-182页

作者： bi fan WU Kejian Physical Oceanography Laboratory Ocean University of China

The wave Coriolis-Stokes-Force-modified ocean momentum equations are reviewed in this paper and the wave Stokes transport is pointed out to be part of the ocean circulations. Using the European Centre for Medium-Range Weather Forecasts 40-year reanalysis data(ERA-40 data) and the Simple Ocean Data Assimilation(SODA) version 2.2.4 data, the magnitude of this transport is compared with that of wind-driven Sverdrup transport and a 5-to-10-precent contribution by the wave Stokes transport is found. Both transports are stronger in boreal winter than in summers. The wave effect can be either contribution or cancellation in different seasons. Examination with Kuroshio transport verifies similar seasonal variations. The clarification of the efficient wave boundary condition helps to understand the role of waves in mass transport. It acts as surface wind stress and can be functional down to the bottom of the ageostrophic layer. The pumping velocities resulting from wave-induced stress are zonally distributed and are significant in relatively high latitudes. Further work will focus on the model performance of the wave-stress-changed-boundary and the role of swells in the eastern part of the oceans.

关键词： Stokes transport Sverdrup transport wave pumping velocity western boundary currents

The effect of Stokes drift on Ekman transport in the open sea

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Acta Oceanologica Sinica 2012年第6期31卷 12-18页

作者： bi fan WU Kejian ZHANG Yuming Physical Oceanography Laboratory Ocean University of ChinaQingdao 266100China

By introducing the wave-induced Coriolis-Stokes forcing into ageostrophic motion equation, th1 Eulerian transport is modified by the wave-induced Stokes drift. The long-term mean contributions of the Stokes transport with remotely generated swells being included to the ageostrophic transport are analyzed using the ECMWF （European Centre for Medium-Range X,Veather Forecasts） reanalysis data. The ratio of Stokes transport to Ekman transport in north-south （N-S） direction can reach maximum of over 50% in the subtropical region. The preliminary influence of the Stokes transport on the North Pacific gyre is all year persistent, while the effect on the North Atlantic gyre is only obvious in boreal winter and early spring.

关键词： Stokes transport Ekman transport ocean swell ocean gyres

The temporal and spatial variations in the Pacific wind and wave fields for the period 2002–2011

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Acta Oceanologica Sinica 2017年第3期36卷 26-36页

作者： XU Yao bi fan SONG Jinbao HE Hailun Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China North China Sea Marine Forecasting Center of State Oceanic Administration Qingdao 266061China Shandong Provincial Key Laboratory of Marine Ecological Environment and Disaster Prevention and Mitigation Qingdao 266061China Ocean College Zhejiang UniversityHangzhou 310058China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyState Oceanic AdministrationHangzhou 310012China

The temporal and spatial variations in the wind and wave fields in the Pacific Ocean between 2002 and 2011 are analyzed using a third-generation wave model（WAVEWATCH III）. The model performance for a significant wave height is validated using in situ buoy data. The results show that the wave model effectively hindcasts the significant wave height in the Pacific Ocean, but the errors are relatively large in the mid- and low-latitude regions. The spatial distributions and temporal variations in a wind speed and the significant wave height in the Pacific Ocean are then considered after dividing the Pacific Ocean into five regions, which show meridional differences and seasonal cycles. Regional mean values are used to give yearly average time series for each separate zone. The high latitude region in the Southern Hemisphere had a stronger significant wave height trend in the model results than regions at other latitudes. The sources and sinks of wave energy are then investigated. Their regional mean values are used to quantify variations in surface waves. Finally, the spectral analyses of the daily mean wind speeds and the significant wave heights are obtained. The significant wave height and the wind speed spectra are found to be connected in some ways but also show certain differences.

关键词： the Pacific Ocean wind speed significant wave height temporal and spatial variations WAVEWATCH Ⅲ

Evaluation of the simulation capability of the Wavewatch Ⅲ model for Pacific Ocean wave

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Acta Oceanologica Sinica 2015年第9期34卷 43-57页

作者： bi fan SONG Jinbao WU Kejian XU Yao Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of Sciences College of Physical and Environmental Oceanography Ocean University of China Ocean College Zhejiang University Key Laboratory of Physical Oceanography (Ocean University of China) Ministry of Education

Wave climate analysis and other applications for the Pacific Ocean require a reliable wave hindcast. Five source and sink term packages in the Wavewatch III model （v3.14 and v4.18） are compared and assessed in this study through comprehensive observations, including altimeter significant wave height, advanced synthetic aperture radar swell, and buoy wave parameters and spectrum. In addition to the evaluation of typically used integral parameters, the spectra partitioning method contributes to the detailed wave system and wave maturity validation. The modified performance evaluation method （PS） effectively reduces attribute numbers and facilitates the overall assessment. To avoid possible misleading results in the root mean square error-based validations, another indicator called HH （indicating the two authors） is also calculated to guarantee the consistency of the results. The widely used Tolman and Chalikov （TC） package is still generally efficient in determining the integral properties of wave spectra but is physically deficient in explaining the dissipation processes. The ST4 package performs well in overall wave parameters and significantly improves the accuracy of wave systems in the open ocean. Meanwhile, the newly published ST6 package is slightly better in determining swell energy variations. The two packages （ACC350 and biA） obtained from Wavewatch III v3.14 exhibit large scatters at different sea states. The three most ideal packages are further examined in terms of reproducing wave- induced momentum flux from the perspective of transport. Stokes transport analysis indicates that ST4 is the closest to the NDBC-buoy-spectrum-based transport values, and TC and ST6 tend to overestimate and underestimate the transport magnitude, respectively, in swell mixed areas. This difference must be considered, particularly in air-wave-current coupling research and upper ocean analysis. The assessment results provide guidance for the selection of ST4 for use in a backgrou

关键词： Wavewatch III evaluation Pacific Ocean source and sink term packages wave-induced flux Stokes transport

Long-term trend analysis of wave characteristics in the Bohai Sea based on interpolated ERA5 wave reanalysis from 1950 to 2020

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Acta Oceanologica Sinica 2022年第7期41卷 97-112页

作者： Jichao Wang Peidong Sun Zhihong Liao fan bi Guiyan Liu College of Science China University of PetroleumQingdao266580China National Meteorological Information Center Beijing100081China North China Sea Marine Forecasting Center of State Oceanic Administration Qingdao266061China Shandong Provincial Key Laboratory of Marine Ecological Environment and Disaster Prevention and Mitigation Qingdao266061China

Reasonably understanding of the long-term wave characteristics is very crucial for the ocean engineering.A feedforward neural network is operated for interpolating ERA5 wave reanalysis in this study,which embodies a detailed record from 1950 *** spatiotemporal variability of wave parameters in the Bohai Sea,especially the significant wave height(SWH),is presented in terms of combined wave,wind wave and swell by employing the 71 years(1950–2020)of interpolated ERA5 *** mean SWH decreases at−0.12 cm/a estimated by Theil-Sen estimator and 95th percentile SWH reflecting serve sea states decreases at−0.20 cm/***-seasonal analysis shows SWH of wind wave has steeper decreasing trend with higher slopes than that of swell,especially in summer and winter,showing the major decrease may attribute to the weakening of *** inner Bohai Sea reveals a general decreasing trend while the intersection connecting with the Yellow Sea has the lower significance derived by Mann-Kendall ***,95th percentile SWH decreases at a higher rate while with a lower significance in comparison with the mean *** frequencies of mean wave directions in sub-sector are statistically calculated to find the seasonal prevailing ***,the dominant directions in summer and winter are south and north.A similar variation concerning to SWH,the trend of the mean wave period is provided,which also shows a decrease for decades.

关键词： wave characteristic wind wave swell long-term trend Bohai Sea

Climate and extrema of ocean waves in the East China Sea

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Science China Earth Sciences 2018年第7期61卷 980-994页

作者： Hailun HE Jinbao SONG Yefei BAI Yao XU Juanjuan WANG fan bi State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyState Oceanic AdministrationHangzhou 310012China Ocean College Zhejiang UniversityZhoushan 316021China Department of Ocean and Resources Engineering University of Hawaii at ManoaHonoluluHI 96822USA School of Geographic and Oceanographic Sciences Nanjing UniversityNanjing 210023China National Marine Environment Forecasting Center Beijing 100081China North China Sea Marine Forecasting Center of State Oceanic Administration Qingdao 266061China Shandong Provincial Key Laboratory of Marine Ecological Environment and Disaster Prevention and Mitigation Qingdao 266061China

Wave climate plays an important role in the air-sea interaction over marginal seas. Extreme wave height provides fundamental information for various ocean engineering practices, such as hazard mitigation, coastal structure design, and risk assessment. In this paper, we implement a third generation wave model and conduct a high-resolution wave hindcast over the East China Sea to reconstruct a 15-year wave field from 1988 to 2002 for derivation of monthly mean wave parameters and analysis of extreme wave conditions. The numerical results of the wave field are validated through comparison with satellite altimetry measurements, low-resolution reanalysis, and the ocean wave buoy record. The monthly averaged wave height and wave period show seasonal variation and refined spatial patterns of surface waves in the East China Sea. The climatological significant wave height and mean wave period decrease from the open ocean in the southeast toward the continental area in the northwest, with the pattern generally following the bathymetry. Extreme analysis on the significant wave height at the buoy station indicates the hindcast data underestimate the extreme values relative to the observations. The spatial pattern of extreme wave height shows single peak emerges at the southwest of Ryukyu Island although a wind forcing with multi-core structure at the extreme is applied.

关键词： Wave climate East China Sea Extreme value analysis WaveWatch-lll

A forecasting model for wave heights based on a long short-term memory neural network

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Acta Oceanologica Sinica 2021年第1期40卷 62-69页

作者： Song Gao Juan Huang Yaru Li Guiyan Liu fan bi Zhipeng Bai North China Sea Marine Forecasting Center of State Oceanic Administration Qingdao 266061China Shandong Provincial Key Laboratory of Marine Ecological Environment and Disaster Prevention and Mitigation Qingdao 266061China Mailbox 5111 Beijing 100094China

To explore new operational forecasting methods of waves,a forecasting model for wave heights at three stations in the Bohai Sea has been *** model is based on long short-term memory(LSTM)neural network with sea surface wind and wave heights as training *** prediction performance of the model is evaluated,and the error analysis shows that when using the same set of numerically predicted sea surface wind as input,the prediction error produced by the proposed LSTM model at Sta.N01 is 20%,18%and 23%lower than the conventional numerical wave models in terms of the total root mean square error(RMSE),scatter index(SI)and mean absolute error(MAE),***,for significant wave height in the range of 3–5 m,the prediction accuracy of the LSTM model is improved the most remarkably,with RMSE,SI and MAE all decreasing by 24%.It is also evident that the numbers of hidden neurons,the numbers of buoys used and the time length of training samples all have impact on the prediction ***,the prediction does not necessary improve with the increase of number of hidden neurons or number of buoys *** experiment trained by data with the longest time length is found to perform the best overall compared to other experiments with a shorter time length for ***,long short-term memory neural network was proved to be a very promising method for future development and applications in wave forecasting.

关键词： long short-term memory marine forecast neural network significant wave height

Improving the estimate of wind energy input into the Ekman layer within the Antarctic Circumpolar Current

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Acta Oceanologica Sinica 2013年第3期32卷 19-27页

作者： ZHANG Yuming WU Kejian ZHANG Xiaoshuang bi fan SONG Zhaoyang LIU Shouhua Physical Oceanography Laboratory Ocean University of China Key Laboratory of Marine Environmental Information Technology State Oceanic AdministrationNational Marine Data and Information Service National Marine Data & Information Service

Based on the data and method offered by Liu et al. （2009）, the direct wind and Stokes drift-induced energy inputs into the Ekman layer within the Antarctic Circumpolar Current （ACC） area are reestimated since the results of the former have been proved to be underestimated. And the result shows that the total rate of energy input into the Ekman-Stokes layer within the ACC area is 852.41 GW, including 649.75 GW of direct wind energy input （76%） and 202.66 GW of Stoke drift-induced energy input （24%）. Total increased energy input, due to wave-induced Coriolis-Stokes forcing added to the classical Ekman model, is 52.05 GW, accounting for 6.5% of the wind energy input into the classical Ekman layer. The long-term variability of direct wind and Stokes drift-induced energy inputs into the Ekman layer within the ACC is also investigated, and the result shows that the Stokes drift hinders the decadal increasing trend of direct wind energy input. Meanwhile, there is a period of 4-5 a in the energy spectrums, as same as the Antarctic circumpolar wave.

关键词： energy input Ekman-Stokes layer Coriolis-Stokes forcing Antarctic Circumpolar Current

Density Functional Theory Study on La Complex with Schiff-base as Building Block

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Chinese Journal of Structural Chemistry 2006年第2期25卷 197-203页

作者： XIA Shu-Wei XU Xiang SUN Ya-Li fan Yu-Hua bi Cai-Feng ZHANG Dong-Mei YANG Li-Rong Department of Chemistry Ocean University of China Qingdao 266003 China

Quantum density functional theory （DFT） results are reported for the building block [LaL^1（NO3）] of La complex [LaL^1（NO3）]NO3·5H2O （L^1 = （CH3）2CHCH2CH（NCHC4H3O）COO^-）. The structure was optimized and the calculation results show that the lanthanum ion is coordinated by one nitrogen atom and three oxygen atoms of L^1 and two oxygen atoms of nitrate ion. The bond length of La-N is 0.2637 nm and the average length of La-O is 0.2526 nm, which are consistent with the literatures. In addition, the stabilities, electronic structural characteristics and IR spectra of the complex have been analyzed, which describe the coordination of lanthanum ion with other atoms in detail.

关键词： rare-earth Schiff-base lanthanum complex density functional theory