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12篇 您的检索式:作者名="Guonian Lü"
    题名 作者 年代 出处 被引量
1Information geography: A new fulcrum of geographic ternary world显示文摘The development trend of ternary space requires the construction of the information space for information mapping,transmission and transformation of geographic elements and social-human elements. Relevant researches of information geography from the perspective of Geographic Information Science and human geography are reviewed in this paper, then the concept interpretation of information geography from the perspective of ternary space is proposed. It is presented in this paper that information geography can be constructed with a framework using seven geographic elements as the basic expressing dimensions and seven social-human elements as the basic aggregating core. Information geography analyzes spatio-temporal distribution, structural characteristics, evolution process and interactions of various elements in the information space. And it eventually realizes the actual description, multi-scenario simulation, multi-objective decision-making and multi-channel control of the physical world and the social-human world.Guonian LÜ Linwang YUAN Zhaoyuan YU 2022Science China Earth Sciences2022,65,2:4
2On the universal third order Stokes wave solution显示文摘This paper presents a universal third-order Stokes solution with uniform current. This solution is derived on the basis of potential theory by expanding the free surface and potential function in Fourier series and determining the Fourier coefficients by solving a set of nonlinear algebraic equations through the Taylor expansion and perturbation method. The universal solution is expressed upon the still water depth with the still water level as datum and retains a global perturbation parameter. The wave set-up term generated by the self-interaction of oscillatory waves is explicitly included in the free surface function. With the use of different definitions for the wave celerity, different water levels as the datum, different non-dimensional variables as the perturbation parameter, and different treatments for the total head, the universal solution can be reduced to the existing various Stokes solutions, thus explaining the reasons and the physical significance of different non-periodic terms in them, such as the positive or negative constant term in the free surface expression and the time-or space-proportional term in the potential function.SONG ZhiYao ZHAO HongJun LI Ling Lü GuoNian 2013Science China Earth Sciences2013,56,1:2
3Automatic Placement of GIS Vector Map Annotation in Area Feature by Long Diagonal显示文摘This paper discusses the placement of Chinese annotation from point of view of graphics. Area Feature is classified as simple polygon, complex polygon and special polygon. For simple ones, annotations are placed along the longest edge. For complex ones, firstly the polygon are simplified according to close points, then the longest diagonal is gotten by comparing length, lastly, annotations are placed along long diagonal. For special ones, the polygon are partitioned into several parts by a certain rule for getting their sub\|diagonals, then their annotation are placed by means of the second.LAN Xiaoji JIANG Yongfa Lü Guonian DENG Huamei 2005Geo-Spatial Information Science2005,8,4:2
4Extraction of ocean tidal information based on global equal-area grid and satellite altimeter data显示文摘Harmonic analysis of satellite altimetry data based on a global regular grid is affected by the grid spatial tessellation and placement of the grids.With the increase of latitude,the traditional lat/lon grid deforms greatly,resulting in uneven distribution of satellite altimeter data with latitude,which affects the extraction of tidal information.Alternatively,Hexagonal grids have been proved to be advantageous due to their isotropic,uniform neighbourhood,equal-area and more.Considering the merits above,the purpose of this paper is to use the global equal-area hexagonal grid to conduct a harmonic analysis of satellite altimeter data.First,the Icosahedron Snyder Equal Area projection method is used to construct a global equal-area hexagonal grid,Then the time series data of 19.8 years of Jason series satellite altimeter data are obtained.Finally,the harmonic constants of eight constituents(the M2,S2,N2,K2,K1,O1,P1,Q1)are extracted by harmonic analysis.By analysing the results,we conclude that the harmonic constants extracted from the global equal-area hexagonal grid have considerable accuracy and are consistent with the tidal characteristics of the eight components.Meanwhile,the accuracy of harmonic constants extracted from equal-area hexagonal grids is better than that of lat/lon grids.Wenbo Wang Huijun Zhou Senyuan Zheng Guonian Lü Liangchen Zhou 2022International Journal of Digital Earth2022,15,1:0
5Geometric algebra method for multidimensionally-unified GIS computation显示文摘Seamless multidimensional handling and coordinate-free characteristics of geometric algebra (GA) provide means to construct multidimensionally-unified GIS computation models. Using the multivector representation for basic geometric objects within GA, we are able to construct adaptable unified geometric-topological structural models of a multidimensional geographical scene. Multidimensional operators found within the geometry, topology and GIS analysis are developed with basic GA operators. A unified computational framework is proposed, it unifies expressions and operation structures, as well as supports the analysis of multidimensional complex scenes. Finally, we illustrate modelling a three-dimensional residential district, which shows that GAbased multidimensionally-unified computation models can effectively represent and analyze complex and multidimensional geographical scenes. The development of the proposed GIS multidimensionally-unified representation, analysis, and modeling enhances current GIS algorithms and geographical models.YUAN LinWang LüGuoNian LUO Wen YU ZhaoYuan YI Lin SHENG YeHua 2012Chinese Science Bulletin2012,57,7:13
6Performance analysis of global HYCOM flow field using Argo profiles显示文摘Flow field data generated by ocean models are important for simulating ocean currents and circulation patterns,which are essential components in digital Earth construction.To evaluate the accuracy of model-simulatedflow felds,Array for Real-timeGeostrophic Oceanography(Argo)float observations can be considered benchmarks.In this study,a novel method for comparing Argo profiles with 3-dimensional trajectories obtained by simulating Argo floats in Hybrid Coordinate Ocean Model(HYCOM)-provided flow fields was proposed.Surface and subsurface trajectories were calculated,and their spatial matching characteristics were analyzed.The results demonstrated that(1)the HYCOM surface and subsurface flow felds generally conform to the basic characteristics and trends of ocean currents;(2)the HYCOM sea surface current field error pattern exhibits a symmetrical distribution centered on the equator in the Northern and Southern Hemispheres and increases with increasing latitude;and(3)the HYCOM subsurface flow field exhibits regional differences,with the largest differences in the Gulf Stream,North Atlantic Warm Current,and Westerly Wind Drift region.Through analysis of the disparities between HYCOM and Argo data,the effectiveness of using model simulation data can be enhanced,and the accuracy and dependability of ocean models can be improved.Yixuan Zhang Songshan Yue Kai Xu Zhuo Zhang Liangcheng Zhou Yihan Zhang Guonian Lü 2023International Journal of Digital Earth2023,16,1:0
7ENSO signals and their spatial-temporal variation characteristics recorded by the sea-level changes in the northwest Pacific margin during 1965-2005显示文摘Sea-level is closely linked to the Earth's climate and its change is important as a metric for global and regional climate change. Identifying, extracting, and revealing such information through detailed analysis is the prerequisite for understanding the mechanisms of sea-level change. The monthlyaverage tide-change records reported and examined in this paper are from 10 tide gauge stations distributed in the northwest margin of the Pacific Ocean, registered during the period 1965-2005. In particular, we have utilized the Second Order Blind Identification (SOBI) method to identify and the Empirical Mode Decomposition (EMD) method to extract the El Nio-Southern Oscillation (ENSO) signals imprinted in those tide gauge records; and subsequently, we have investigated the spa-tial-temporal characteristics of the extracted ENSO signals using wavelet analysis methods. The following results are obtained: (1) the ENSO events recorded by each tide gauge series are of different types and intensity, which show considerable temporal-spatial variation characteristics, with sea-level responses to ENSO signals remarkably stronger in low latitude areas than in medium-high latitude areas; (2) due to the influences of ocean currents, topographical conditions, and other factors, there exist variations in the type of relationship between the sea-level changes and the recorded ENSO events at different latitudes; (3) sea-level changes can also denote scale-variation characteristics of ENSO events, and particularly, since 1980s, all the tide gauges located south of Kanmen show intense responses to ENSO and the timescale of ENSO events extended gradually from around 4 years to 2-8 years, reflecting variations in the intensity and frequency of ENSO events; and (4) reverse changes of certain scale were noted before and after strong ENSO events recorded by sea-level changes, supporting the research findings about the interaction (mutual coupling and superimposition) between the probability of occurrence of strong ENSO events and their time scale.YUAN LinWang,YU ZhaoYuan,XIE ZhiRen,SONG ZhiYao & Lü GuoNian School of Geographical Science,Nanjing Normal University,Nanjing 210046,China 2009Science China Earth Sciences2009,52,6:14
8A framework on task configuration and execution for distributed geographical simulation显示文摘Geographical simulation is a popular method in geographical and environmental research.Many models developed to address geographic and environmental issues are distributed worldwide.However,due to the lack of portals,these models are still difficult to invoke for geographical simulations in open web environments.This study designs and develops a framework to assemble service-oriented models from volunteers distributed worldwide for geographical simulations on the web.The framework consists of three layers(task layer,data exchange layer,and model execution layer)that establish a network of serviceoriented locally shared models and simulation tasks for user configurations.With the help of such a framework,users can configure simulation tasks and invoke suitable models shared worldwide for geographical simulations.This article provides an application of the distributed simulation of gross primary production(GPP)by the Biome-BioGeochemical Cycles(BGC)model in China.This application shows that the framework can be beneficial for model assembly from volunteers’computers and distributed simulation tasks that are run for geographical and environmental issues,which can be applied to Digital Earth initiatives.Fengyuan Zhang Min Chen Ming Wang Zihuan Wang Shuo Zhang Songshan Yue Yongning Wen Guonian Lü 2021International Journal of Digital Earth2021,14,9:1
9Aesthetic style transferring method based on deep neural network between Chinese landscape painting and classical private garden's virtual scenario显示文摘Most of the existing virtual scenarios built for the digital protection of Chinese classical private gardens are too modern in expression style to show the aesthetic significance of their historical period.Considering the aesthetic commonality between traditional Chinese landscape paintings and classical private gardens and referring to image style transfer,here,a deep neural network was proposed to transfer the aesthetic style from landscape paintings to the virtual scenario of classical private gardens.The network consisted of two parts:style prediction and style transfer.The style prediction network was used to obtain style representation from style paintings,and the style transfer network was used to transfer style representation to the content scenario.The pre-trained network was then embedded into the scenario rendering pipeline and combined with the screen post-processing method to realise the stylised expression of the virtual scenario.To verify the feasibility of this methodology,a virtual scenario of the Humble Administrator’s Garden was used as the content scenario andfive garden landscape paintings from different time periods and painting styles were selected for the case study.The results demonstrated that this methodology could effectively achieve the aesthetic style transfer of a virtual scenario.Shuai Hong Jie Shen Guonian Lü Xiaoyan Liu Yirui Mao Nina Sun Long Tang 2023International Journal of Digital Earth2023,16,1:0
10Impacts of major volcanic eruptions over the past two millennia on both global and Chinese climates:A review显示文摘Major volcanic eruptions(MVEs)have attracted increasing attention from the scientific community.Previous studies have explored the climatic impact of MVEs over the past two millennia.However,proxy-based reconstructions and climate model simulations indicate divergent responses of global and China’s regional climates to MVEs.Here,we used multiple data from observations,reconstructions,simulations,and assimilations to summarize the historical facts of MVEs,the characteristics and mechanisms of their climatic impact,and directions for future research.We reviewed volcanic datasets and determined intensive MVE periods;these periods corresponded to the years 530–700,1200‒1460,and 1600‒1840 CE.After tropical MVEs,a substantial cooling effect is observed throughout the globe and China on the interannual-interdecadal time scales but an inconsistent cooling magnitude is detected between reconstructions and simulations.In the first summer after tropical MVEs,a decrease in global and monsoonal precipitation is observed.In reconstructions and simulations,an increased precipitation is seen for the Yangtze River Basin,while large uncertainties in precipitation changes are present for other regions of China.Decadal drought can be induced by frequent eruptions and volcanism superimposed on low solar irradiation and internal variability.MVEs affect climate directly through the radiative effect and indirectly by modulating internal variability,such as the El Niño‒Southern Oscillation(ENSO)and Atlantic Multidecadal Oscillation(AMO).However,changes in the phase,amplitude,and periodicity of ENSO and AMO after MVEs and the associated mechanisms remain controversial,which could account for model-reconstruction disagreements.Moreover,other internal variability,uncertainties in reconstruction methods and aerosol‒climate models,and climate background may also induce model-reconstruction disagreements.Knowledge gaps and directions for future research are also discussed.Weiyi SUN Deliang CHEN Guonian LÜ Liang NING Chaochao GAO Renhe ZHANG Bin WANG Jian LIU 2024Science China Earth Sciences2024,67,1:0
11Geographic scenario:a possible foundation for further development of virtual geographic environments显示文摘It has been two decades since virtual geographic environments(VGEs)were initially proposed.While relevant theories and technologies are evolving,data organization models have always been the foundation of VGE development,and they require further exploration.Based on the comprehensive consideration of the characteristics of VGEs,geographic scene is proposed to organize geographic information and data.We empirically find that geographic scene provides a suitable organization schema to support geo-visualization,geo-simulation,and geo-collaboration.To systematically investigate the concept and method of geographic scene,Geographic Scenario is proposed as the theory on developing geographic scene,and corresponding key issues of the Geographic Scenario are illustrated in this article.Prospects of the proposed method are discussed with the hope of informing future studies of VGEs.Guonian Lü Min Chen Linwang Yuan Liangchen Zhou Yongning Wen Mingguan Wu Bin Hu Zhaoyuan Yu Songshan Yue Yehua Sheng 2018International Journal of Digital Earth2018,11,4:4
12A new academic impact metric for evaluating geographic simulation models显示文摘Geographic simulation models can be used to explore and better understand the geographical environment. Recent advances in geographic and socio-environmental research have led to a dramatic increase in the number of models used for this purpose. Some model repositories provide opportunities for users to explore and apply models,but few provide a general evaluation method for assessing the applicability and recognition of models. In this study,an academic impact evaluation method for models is proposed. Five indices are designed based on their pertinence. The analytical hierarchy process is used to calculate the index weights,and the academic impacts of models are quantified with the weighted sum method. The time range is controlled to evaluate the life-term and annual academic impacts of the models. Some models that met the evaluation criteria from different domains are then evaluated. The results show that the academic impact of a model can be quantified with the proposed method,and the major research areas that models impact are identified.Kai Xu Min Chen Albert J.Kettner C.Michael Barton Barry F.W.Croke Anthony J.Jakeman Daniel P.Ames Hsiao-Hsuan Wang Susan M.Cuddy Songshan Yue Yongning Wen Fengyuan Zhang Yixuan Zhang Guonian Lü 2022International Journal of Digital Earth2022,15,1:0
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