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The interactions between surface Kuroshio transport and the eddy field east of Taiwan using satellite altimeter data

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Acta Oceanologica Sinica 2019年第4期38卷 116-125页

作者： Huizan Wang Quanhong Liu Hengqian Yan Bo Song Weimin Zhang State Key Laboratory of Satellite Ocean Environment Dynamics (SOED) Second Institute of OceanographyMinistry of Natural Resources college of Meteorology and oceanography National University of Defense Technology

Based on the daily sea surface height and absolute geostrophic velocity data from 1993 to 2015 provided by the AVISO Center of French space Agency, the surface Kuroshio transport east of Taiwan and its adjacent eddy field(sea surface height anomaly) were analyzed. Four main periods of the surface Kuroshio transport and eddy field east of Taiwan were obtained, which were used to reveal their interactions. The main conclusions are as follows:(1) Based on the wavelet analysis, the surface Kuroshio transport east of Taiwan and its nearby eddy field showed significant seasonal, annual and interannual periods. In addition to the obvious periods of 182 days(0.5 year) and365 days(1 year), there were also more obvious periods of about 860 days(2.35 years) and 2 472 days(6.8 years)for the surface Kuroshio transport. There were also four more obvious periods corresponding to the eddy field of 200 days(0.55 year), 374 days(1 year), 889 days(2.43 years) and 2 374 days(6.5 years), although there were latitudinal variations.(2) Based on both the correlation and causal analysis, the correlation between the surface Kuroshio transport and the nearby eddy field over the above four periods was analyzed, and different Kuroshioeddy interactions, with period and latitudinal variability, were revealed.

关键词： wavelet analysis causal analysis Kuroshio east of Taiwan correlation sea level anomaly

A method for extracting the preseismic gravity anomalies over the Tibetan Plateau based on the maximum shear strain using GRACE data

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Earth and Planetary Physics 2024年第4期8卷 589-608页

作者： Hui Wang DongMei Song XinJian Shan Bin Wang college of oceanography and space informatics China University of Petroleum(East China)Qingdao 266580China PCI Technology Group Co. Ltd.Guangzhou 510660China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266200China State Key Laboratory of Earthquake Dynamics Beijing 100029China

The occurrence of earthquakes is closely related to the crustal geotectonic movement and the migration of mass,which consequently cause changes in *** Gravity Recovery And Climate Experiment(GRACE)satellite data can be used to detect gravity changes associated with large ***,previous GRACE satellite-based seismic gravity-change studies have focused more on coseismic gravity changes than on preseismic gravity ***,the noise of the north–south stripe in GRACE data is difficult to eliminate,thereby resulting in the loss of some gravity information related to tectonic *** explore the preseismic gravity anomalies in a more refined way,we first propose a method of characterizing gravity variation based on the maximum shear strain of gravity,inspired by the concept of crustal *** offset index method is then adopted to describe the gravity anomalies,and the spatial and temporal characteristics of gravity anomalies before earthquakes are analyzed at the scales of the fault zone and plate,*** this work,experiments are carried out on the Tibetan Plateau and its surrounding areas,and the following findings are obtained:First,from the observation scale of the fault zone,we detect the occurrence of large-area gravity anomalies near the epicenter,oftentimes about half a year before an earthquake,and these anomalies were distributed along the fault ***,from the observation scale of the plate,we find that when an earthquake occurred on the Tibetan Plateau,a large number of gravity anomalies also occurred at the boundary of the Tibetan Plateau and the Indian ***,the aforementioned experiments confirm that the proposed method can successfully capture the preseismic gravity anomalies of large earthquakes with a magnitude of less than 8,which suggests a new idea for the application of gravity satellite data to earthquake research.

关键词： Gravity Recovery And Climate Experiment(GRACE)data maximum shear strain offset index K preseismic gravity anomalies Tibetan Plateau fault zone

Spurious Dianeutral Mixing in a Global Ocean Model Using Spherical Centroidal Voronoi Tessellations

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Journal of Ocean University of China 2016年第6期15卷 923-935页

作者： ZHAO Shimei LIU Yudi college of Meteorology and oceanography People's Liberation Army University of Science and Technology

In order to quantitatively evaluate the spurious dianeutral mixing in a global ocean model MPAS-Ocean （Model for Prediction Across Scales） using a spherical centroidal voronoi tessellations developed jointly by the National Center for Atmospheric Research and the Los Alamos National Laboratory in the United States, we choose z＊ vertical coordinate system in MPAS-Ocean, in which all physical mixing processes, such as convection adjustment and explicit diffusion parameter schemes, are omitted, using a linear equation of state. By calculating the Reference Potential Energy （RPE）, front revolution position, time rate of RPE change, probability density function distribution and dimensionless parameter 2＂, from the perspectives of resolution, viscosity, Horizontal Grid Reynolds Number （HGRN）, Rea, and momentum transmission scheme, using two ideal cases, overflow and baroclinic eddy channel, we qualitatively analyze the simulation results by comparison with the three non-isopycnal models in Ilicak et al. （2012）, i.e., MITocM, MOM, and ROMS. The results show that the spurious dianeutral mixing in the MPAS-Ocean increases over time. The spurious dianeutral transport is proportional to the HGRN directly and is reduced by increasing the lateral viscosity or using a finer resolution to control HGRN. When the HGRN is less than 10, spurious transport is reduced significantly. When using the proper viscosity closure, MPAS-Ocean performs better than MIT6c and MOM, closely to ROMS, in the 2D case without rotation, and much better than the above-mentioned three ocean models under the condition of 3D space with rotation due to the cell area difference between the hexa- gon cell and the quadrilateral cell with the same resolution. Both the Zalesak （1979） flux corrected transport scheme and Leith closure in MPAS-Ocean play an excellent role in reducing spurious dianeutral mixing. The performance of Leith scheme is preferable to the condition of three-dimensional baroclinic eddy.

关键词： MPAS-Ocean spurious dianeutral mixing Reference Potential Energy (RPE) Leith scheme Horizontal Grid Rey-nolds Number (HGRN)

Vegetation ecological benefts index (VEBI): a 3D spatial model for evaluating the ecological benefits of vegetation

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International Journal of Digital Earth 2023年第1期16卷 1108-1123页

作者： Zhimei Zhang Yanguo Fan Zhijun Jiao Bowen Fan Junwei Zhou Zhanhao Li School of Geosciences and Info-physics Central South UniversityChangshaPeople’s Republic of China college of oceanography and space informatics China University of Petroleum(East China)QingdaoPeople’s Republic of China Center of Subtropics Remote Sensing Central South UniversityChangshaPeople’s Republic of China college of Underwater Acoustic Engineering Harbin Engineering UniversityHarbinPeople’s Republic of China

Urban population explosion may increase ecological environment discomfort,thereby affecting negatively humans’mental and physical ***,it is important to detect and monitor vegetation and predict its ecological *** complex composition of urban environment ground objects,such as steel roofs,plastic courts,and building shadows,significantly interferes with vegetation detection and *** optimized hyperspectral image-based vegetation index(OHSVI)constructed in this study effectively solves this ***,it is difficult to accurately predict the ecological benefits of vegetation based on the two-dimensional vegetation information extracted based on remote sensing images;this is related to the three-dimensional(3D)structure of vegetation and the 3D pattern of ***,wefirst proposed the vegetation ecological benefits index(VEBI)based on the 3D structure of vegetation to reveal how vegetation acts on its 3D *** method was tested in a playground,an academic building,and a parking *** results showed that the vegetation extraction accuracy of the OHSVI exceeded 93%,which is better than that of the existing *** suggest that VEBI may be efficient in predicting 3D vegetation ecological benefits combined with remote sensing and lidar datasets.

关键词： Urban environment vegetation ecological benefits 3D landscape pattern lidar hyperspectral image

Big Metadata,Smart Metadata,and Metadata Capital:Toward Greater Synergy Between Data Science and Metadata

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Journal of Data and Information Science 2017年第3期2卷 19-36页

作者： Jane Greenberg college of Computing and informatics Drexel University

Purpose： The purpose of the paper is to provide a framework for addressing the disconnect between metadata and data science. Data science cannot progress without metadata *** paper takes steps toward advancing the synergy between metadata and data science, and identifies pathways for developing a more cohesive metadata research agenda in data science. Design/methodology/approach： This paper identifies factors that challenge metadata research in the digital ecosystem, defines metadata and data science, and presents the concepts big metadata, smart metadata, and metadata capital as part of a metadata lingua franca connecting to data science. Findings： The ＂utilitarian nature＂ and ＂historical and traditional views＂ of metadata are identified as two intersecting factors that have inhibited metadata research. Big metadata, smart metadata, and metadata capital are presented as part ofa metadata linguafranca to help frame research in the data science research space. Research limitations： There are additional, intersecting factors to consider that likely inhibit metadata research, and other significant metadata concepts to explore. Practical implications： The immediate contribution of this work is that it may elicit response, critique, revision, or, more significantly, motivate research. The work presented can encourage more researchers to consider the significance of metadata as a research worthy topic within data science and the larger digital ecosystem. Originality/value： Although metadata research has not kept pace with other data science topics, there is little attention directed to this problem. This is surprising, given that metadata is essential for data science endeavors. This examination synthesizes original and prior scholarship to provide new grounding for metadata research in data science.

关键词： Metadata research Data science Big metadata Smart metadata Metadata capital

A new algorithm for sea-surface wind-speed retrieval based on the L-band radiometer onboard Aquarius

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Chinese Journal of Oceanology and Limnology 2015年第5期33卷 1115-1123页

作者：王进张杰范陈清王晶 college of Information Science and Engineering Ocean University of China college of Physics Qingdao University First Institute of oceanography State Oceanic Administration

Aquarius is the second satellite mission to focus on the remote sensing of sea-surface salinity from space and it has mapped global sea-surface salinity for nearly 3 years since its launch in 2011. However,benefiting from the high atmospheric transparency and moderate sensitivity to wind speed of the L-band brightness temperature(TB),the Aquarius L-band radiometer can actually provide a new technique for the remote sensing of wind speed. In this article,the sea-surface wind speeds derived from TBs measured by Aquarius' L-band radiometer are presented,the algorithm for which is developed and validated using multisource wind speed data,including Wind Sat microwave radiometer and National Data Buoy Center buoy data,and the Hurricane Research Division of the Atlantic Oceanographic and Meteorological Laboratory wind field product. The error analysis indicates that the performance of retrieval algorithm is good. The RMSE of the Aquarius wind-speed algorithm is about 1 and 1.5 m/s for global oceans and areas of tropical hurricanes,respectively. Consequently,the applicability of using the Aquarius L-band radiometer as a near all-weather wind-speed measuring method is verified.

关键词： microwave radiometer Aquarius wind speed L-band

Urban growth scenario projection using heuristic cellular automata in arid areas considering the drought impact

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Journal of Arid Land 2024年第4期16卷 580-601页

作者： TANG Xiaoyan FENG Yongjiu LEI Zhenkun CHEN Shurui WANG Jiafeng WANG Rong TANG Panli WANG Mian JIN Yanmin TONG Xiaohua college of Surveying&Geo-informatics Tongji UniversityShanghai 200092China Shanghai Key Laboratory of space Mapping and Remote Sensing for Planetary Exploration Tongji UniversityShanghai 200092China

Arid areas with low precipitation and sparse vegetation typically yield compact urban pattern,and drought directly impacts urban site selection,growth processes,and future *** simulation and projection based on cellular automata(CA)models is important to achieve sustainable urban development in arid *** developed a new CA model using bat algorithm(BA)named bat algorithm-probability-of-occurrence-cellular automata(BA-POO-CA)model by considering drought constraint to accurately delineate urban growth patterns and project future scenarios of Urumqi City and its surrounding areas,located in Xinjiang Uygur Autonomous Region,*** calibrated the BA-POO-CA model for the drought-prone study area with 2000 and 2010 data and validated the model with 2010 and 2020 data,and finally projected its urban scenarios in *** results showed that BA-POO-CA model yielded overall accuracy of 97.70%and figure-of-merits(FOMs)of 35.50%in 2010,and 97.70%and 26.70%in 2020,*** inclusion of drought intensity factor improved the performance of BA-POO-CA model in terms of FOMs,with increases of 5.50%in 2010 and 7.90%in 2020 than the model excluding drought intensity *** suggested that the urban growth of Urumqi City was affected by drought,and therefore taking drought intensity factor into account would contribute to simulation *** BA-POO-CA model including drought intensity factor was used to project two possible scenarios(i.e.,business-as-usual(BAU)scenario and ecological scenario)in *** the BAU scenario,the urban growth dominated mainly in urban fringe areas,especially in the northern part of Toutunhe District,Xinshi District,and Midong *** exceptional and extreme drought areas as a spatial constraint,the urban growth was mainly concentrated in the"main urban areas-Changji-Hutubi"corridor urban pattern in the ecological *** results of this research can help to adjust urban planning and development *** mode

关键词： bat algorithm cellular automata(CA) probability-of-occurrence drought intensity algorithm-probability-of-occurrence-cellular automata(BA-POO-CA)model arid areas

Generation of simultaneous H^(+)and He^(+)band EMIC waves in the nightside radiation belt

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Science China(Technological Sciences) 2020年第11期63卷 2369-2374页

作者： GUAN ChunYi SHANG XiongJun XIE YanQiong YANG Chang ZHANG Sai LIU Si XIAO FuLiang School of Physics and Electronic Sciences Changsha University of Science and TechnologyChangsha 410114China college of Meteorology and oceanography National University of Defense TechnologyNanjing 211101China State Key Laboratory of space Weather Chinese Academy of SciencesBeijing 100190China

Previous studies have shown that EMIC waves occur preferentially in the afternoon sector of the *** we report obliquely propagating H^(+)and He^(+)band EMIC waves detected by Van Allen Probe B in the region of MLT=22.7–23.5 during the June 20,2013 *** the correlated energetic proton data,we present continuous calculations on EMIC wave growth rates along the inward orbit in the region L=5.5–*** modeled growth rate shows remarkable agreement with the observed double band EMIC waves in both temporal and spatial *** current results demonstrate that H^(+)and He^(+)band EMIC waves can be simultaneously excited in the midnight sector under appropriate conditions.

关键词： EMIC waves instability nightside radiation belt Van Allen Probes coordinated observations

Effect of stratification on current hydrodynamics over Louisiana shelf during Hurricane Katrina

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Water Science and Engineering 2017年第2期10卷 154-165页

作者： Mohammad Nabi Allahdadi Chunyan Li Department of oceanography and Coastal Sciences College of the Coast and Environment Louisiana State University Baton Rouge 70803 USA

Numerical experiments were conducted using the finite volume community ocean model(FVCOM) to study the impact of the initial density stratification on simulated currents over the Louisiana shelf during Hurricane Katrina. Model results for two simulation scenarios, including an initially stratified shelf and an initially non-stratified shelf, were examined. Comparison of two simulations for two-dimensional(2D) currents,the time series of current speed, and variations of cross-shore currents across different sections showed that the smallest differences between simulated currents for these two scenarios occurred over highly mixed regions within 1 radius of maximum wind(RMW) under the *** areas farther from the mixed zone, differences increased, reaching the maximum values off Terrebonne Bay. These large discrepancies correspond to significant differences between calculated vertical eddy viscosities for the two scenarios. The differences were addressed based on the contradictory behavior of turbulence in a stratified fluid, as compared to a non-stratified fluid. Incorporation of this behavior in the MellorYamada turbulent closure model established a Richardson number-based stability function that was used for estimation of the vertical eddy viscosity from the turbulent energy and macroscale. The results of this study demonstrate the necessity for inclusion of shelf stratification when circulation modeling is conducted using three-dimensional(3D) baroclinic models. To achieve high-accuracy currents, the parameters associated with the turbulence closures should be calibrated with field measurements of currents at different depths.

关键词： Hurricane Katrina Louisiana shelf Hydrodynamics Baroclinic and barotropic models Stratification