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An Edge-assisted, Object-oriented Random Forest Approach for Refined Extraction of Tea Plantations Using Multi-temporal Sentinel-2 and High-resolution Gaofen-2 Imagery

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Journal of Geodesy and Geoinformation Science 2023年第1期6卷 31-46页

作者： Juanjuan YU Xiufeng HE Jia XU Zhuang GAO Peng YANG Yuanyuan CHEN Jiacheng XIONG School of Earth Sciences and Engineering Hohai UniversityNanjing 211100China College of Givil Engineering Nanjing Forestry UniversityNanjing 210037China gfz german research Gentre for geosciences Potsdam 14473Germany

As a consumed and influential natural plant beverage,tea is widely planted in subtropical and tropical areas all over the world.Affected by(sub)tropical climate characteristics,the underlying surface of the tea distribution area is extremely complex,with a variety of vegetation types.In addition,tea distribution is scattered and fragmentized in most of China.Therefore,it is difficult to obtain accurate tea information based on coarse resolution remote sensing data and existing feature extraction methods.This study proposed a boundary-enhanced,object-oriented random forest method on the basis of high-resolution GF-2 and multi-temporal Sentinel-2 data.This method uses multispectral indexes,textures,vegetable indices,and variation characteristics of time-series NDVI from the multi-temporal Sentinel-2 imageries to obtain abundant features related to the growth of tea plantations.To reduce feature redundancy and computation time,the feature elimination algorithm based on Mean Decrease Accuracy(MDA)was used to generate the optimal feature set.Considering the serious boundary inconsistency problem caused by the complex and fragmented land cover types,high resolution GF-2 image was segmented based on the MultiResolution Segmentation(MRS)algorithm to assist the segmentation of Sentinel-2,which contributes to delineating meaningful objects and enhancing the reliability of the boundary for tea plantations.Finally,the object-oriented random forest method was utilized to extract the tea information based on the optimal feature combination in the Jingmai Mountain,Yunnan Province.The resulting tea plantation map had high accuracy,with a 95.38%overall accuracy and 0.91 kappa coefficient.We conclude that the proposed method is effective for mapping tea plantations in high heterogeneity mountainous areas and has the potential for mapping tea plantations in large areas.

关键词： tea plantation mapping multi-temporal edge-assisted object-oriented random forest Sentinel-2 Gaofen-2

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Addressing administrative units in international tsunami early warning systems: shortcomings in international geocode standards

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International Journal of Digital Earth 2012年第4期5卷 356-371页

作者： Matthias Lendholt Martin Hammitzsch german research centre for geosciences Centre for GeoInformation TechnologyPotsdamGermany

Administrative units reflect the territorial hierarchies established within all countries of the world.The units are addressable with geocodes that provide a bijective mapping between territories and unique identification codes.Early warning systems for natural or man-made hazards often map affected or threatened areas to administrative units to establish a spatial reference that is comprehensible to all parts of the population.Addressing these territories in an international context has several requirements,such as worldwide coverage,completeness and topicality,which must be met by geocode standards.In this paper,the practicability and suitability of international geocode standards are examined in the context of the requirements of large-scale early warning systems.This paper exposes the insufficiencies and limitations of existing geocode standards International Organization for Standardization(ISO)-3166,Second Administrative Level Boundaries data set project(SALB)and Nomenclature of the Territorial Units for Statistics(NUTS)and emphasises the suitability of the non-official hierarchical administrative subdivision codes(HASC).The analysis is framed in the context of addressing affected areas for an Indian Ocean tsunami early warning system.This system was developed within the Distant Early Warning Systems project according to the requirements of the United Nations Educational,Scientific and Cultural Organization(UNESCO)Intergovernmental Oceanic Commission for Regional Tsunami Watch Providers(RTWPs).

关键词： digital earth early warning system spatial reference geocode SALB HASC ISO-3166

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Revisiting the dissolution of biogenic Si in marine sediments： a key term in the ocean Si budget

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Acta Geochimica 2017年第3期36卷 429-432页

作者： Patrick Frings Department of Geoscience Swedish Museum of Natural History 10405 Stockholm Sweden Earth Surface Geochemistry GFZ German Research Centre for Geosciences 14473 Telegrafenberg Potsdam Germany

Of the　~240*10^(12)mol year^(-1)of biogenic silica(bSi)produced by diatoms and other silicifying organisms,only roughly 3%–4%escapes dissolution to be permanently buried.At the global scale,how,where and why b Si is preserved in sediment is not well understood.To help address this,I compile 6245 porewater dissolved Si concentrations from 453 sediment cores,to derive the concentration gradient at the sediment–water interface and thus diffusive fluxes out of the sediment.These range from\0.002 to 3.4 mol m^(-2)year^(-1),and are independent of temperature,depth and latitude.When classified by sediment lithology,predominantly siliceous sediments unsurprisingly have higher mean diffusive fluxes than predominantly calcareous or clay-rich sediment.Combined with the areal extent of these lithologies,the‘best-guess’global sedimentary b Si recycling flux is69 9 10^(12)mol year^(-1).

关键词：海洋沉积物生物硅溶解硅术语预算浓度梯度扩散通量岩性分类

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The role of temperature‐enhanced fault closure in promoting postinjection pressure diffusion and seismicity in enhanced geothermal systems

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Deep Underground Science and Engineering 2023年第4期2卷 394-405页

作者： Yinlin Ji Yuedu Chen Hannes Hofmann Yuan Zhang Arno Zang Günter Zimmermann Helmholtz centre Potsdam gfz german research centre for geosciences PotsdamGermany Key Laboratory of In‐situ Property‐improving Mining of Ministry of Education Taiyuan University of TechnologyTaiyuanChina Institute of Applied geosciences Technische Universität BerlinBerlinGermany Key Laboratory of Deep Coal Resource Mining(CUMT) Ministry of EducationSchool of MinesChina University of Mining and TechnologyXuzhouChina

Post shut‐in seismic events in enhanced geothermal systems(EGSs)occur predominantly at the outer rim of the co‐injection seismic cloud.The concept of postinjection fracture and fault closure near the injection well has been proposed and validated as a mechanism for enhancing post shut‐in pressure diffusion that promotes seismic hazard.This phenomenon is primarily attributed to the poro‐elastic closure of fractures resulting from the reduction of wellbore pressure after injection termination.However,the thermal effects in EGSs,mainly including heat transfer and thermal stress,may not be trivial and their role in postinjection fault closure and pressure evolution needs to be explored.In this study,we performed numerical simulations to analyze the relative importance of poro‐elasticity,heat transfer,and thermo‐elasticity in promoting postinjection fault closure and pressure diffusion.The numerical model wasﬁrst validated against analytical solutions in terms ofﬂuid pressure diffusion and against heatedﬂow‐through experiments in terms of thermal processes.We then quantiﬁed and distinguished the contribution of each individual mechanism by comparing four different shut‐in scenarios simulated under different coupled conditions.Our results highlight the importance of poro‐elastic fault closure in promoting postinjection pressure buildup and seismicity,and suggest that heat transfer can further augment the fault closure‐induced pressure increase and thus potentially intensify the postinjection seismic hazard,with minimal contribution from thermo‐elasticity.

关键词： enhanced geothermal system(EGS) fault closure hydraulic stimulation postinjection seismicity thermal effects thermo‐poro‐elasticity

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Quantification and depth distribution analysis of carbon to nitrogen ratio in forest soils using reflectance spectroscopy

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International Soil and Water Conservation research 2023年第1期11卷 112-124页

作者： Asa Gholizadeh Mohammadmehdi Saberioon Nastaran Pouladi Eyal Ben-Dor Department of Soil Science and Soil Protection Faculty of AgrobiologyFood and Natural ResourcesCzech University of Life Sciences Prague16500PragueCzech Republic Section 1.4 Remote Sensing and Geoinformatics Helmholtz Centre Potsdam GFZ German Research Centre for GeosciencesTelegrafenberg14473Potsdam Germany knoell germany GmbH Konrad-Zuse-Ring68163MannheimGermany Remote Sensing Laboratoryeparmentof Ggraphy and HumanEnvionmnt Porter Schoolf Evionmntand Earth ScienceTelAvivUniverty 69978TelAvivIsrael

Forest soils have large contents of carbon(C)and total nitrogen(TN),which have significant spatial variability laterally across landscapes and vertically with depth due to decomposition,erosion and leaching.Therefore,the ratio of C to TN contents(C∶N),a crucial indicator of soil quality and health,is also different depending on soil horizon.These attributes can cost-effectively and rapidly be estimated using visible-near infrared-shortwave infrared(VNIR-SWIR)spectroscopy.Nevertheless,the effect of different soil layers,particularly over large scales of highly heterogeneous forest soils,on the perfor-mance of the technique has rarely been attempted.This study evaluated the potential of VNIR-SWIR spectroscopy in quantification and variability analysis of C∶N in soils from different organic and min-eral layers of forested sites of the Czech Republic.At each site,we collected samples from the litter(L),fragmented(F)and humus(H)organic layers,and from the A_(1)(depth of 2-10 cm)and A_(2)(depth of 10-40 cm)mineral layers providing a total of 2505 samples.Support vector machine regression(SVMR)was used to train the prediction models of the selected attributes at each individual soil layer and the merged layer(profile).We further produced the spatial distribution maps of C∶N as the target attribute at each soil layer.Results showed that the prediction accuracy based on the profile spectral data was adequate for all attributes.Moreover,F was the most accurately predicted layer,regardless of the soil attribute.C∶N models and maps in the organic layers performed well although in mineral layers,models were poor and maps were reliable only in areas with low and moderate C∶N.On the other hand,the study indicated that reflectance spectra could efficiently predict and map organic layers of the forested sites.Although,in mineral layers,high values of C∶N(≥50)were not detectable in the map created based on the reflectance spectra.In general,the study suggests that VNIR-SWIR spectroscopy has the feasibility of modelling and mapping

关键词： Forest soil Soilorganiccarbon C:N Soilhorizons VNIR-SWIRspectroscopy

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An improved adaptive Sage filter with applications in GEO orbit determination and GPS kinematic positioning

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Science China(Physics,Mechanics & Astronomy) 2012年第5期55卷 892-898页

作者： XU TianHe JIANG Nan SUN ZhangZhen Xi'an research Institute of Surveying and Mapping Xi'an 710054China gfz german research centre for geosciences Potsdam 14473Germany College of Geology Engineering and Geomatic Chang'an UniversityXi'an 710054China

The shortcomings of an adaptive Sage filter are analyzed in this paper.An improved adaptive Sage filter is developed by using a weighted average quadratic form of the historical residuals of observations and predicted states to evaluate the covariance matrices of observations and dynamic model errors at the present epoch.The weight function is constructed based on the variances of observational residuals or predicted state residuals and the space distance between the previous and the present epoch.In order to balance the contributions of the measurements and the dynamic model information,an adaptive factor is applied by using a two-segment function and predicted state discrepancy statistics.Two applications,orbit determination of a maneuvered GEO satellite and GPS kinematic positioning,are conducted to verify the performance of the proposed method.

关键词：导航定位功能应用自适应地球静止轨道过滤器 GPS 协方差矩阵 GEO卫星

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Paleoarchean bedrock lithologies across the Makhonjwa Mountains of South Africa and Swaziland linked to geochemical,magnetic and tectonic data reveal early plate tectonic genes flanking subduction margins

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Geoscience Frontiers 2018年第3期9卷 603-665页

作者： Maarten de Wit Harald Furnes Scott MacLennan Moctar Doucouré Blair Schoene Ute Weckmann Uma Martinez Sam Bowring AEON-ESSRI (Africa Earth Observatory Network-Earth Stewardship Science research Institute) Nelson Mandela University Department of Earth Science & centre for Geobiology University of Bergen Department of geosciences Princeton University Department of geosciences Nelson Mandela University Department Geophysics GFZ-German Research Centre for GeosciencesHelmholtz Centre GISCAPETOWN Earth Atmosphere and Planetary SciencesMassachusetts Institute of Technology

The Makhonjwa Mountains, traditionally referred to as the Barberton Greenstone Belt, retain an iconic Paleoarchean archive against which numerical models of early earth geodynamics can be tested. We present new geologic and structural maps, geochemical plots, geo- and thermo-chronology, and geophysical data from seven silicic, mafic to ultramafic complexes separated by major shear systems across the southern Makhonjwa Mountains. All reveal signs of modern oceanic back-arc crust and subductionrelated processes. We compare the rates of processes determined from this data and balance these against plate tectonic and plume related models. Robust rates of both horizontal and vertical tectonic processes derived from the Makhonjwa Mountain complexes are similar, well within an order of magnitude, to those encountered across modern oceanic and orogenic terrains flanking Western Pacific-like subduction zones. We conclude that plate tectonics and linked plate-boundary processes were well established by 3.2-3.6 Ga. Our work provides new constraints for modellers with rates of a 'basket' of processes against which to test Paleoarchean geodynamic models over a time period close to the length of the Phanerozoic.

关键词： Paleoarchean Barberton Greenstone Belt Onverwacht Suite Geologic bedrock and structural maps Geochemistry and geophysics Plate tectonics

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两种硅酸盐碎屑组分^(234)U/^(238)U测试前处理方法的比较及启示

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矿物岩石地球化学通报 2022年第1期41卷 127-134页

作者：马松阳李超王晨羽郭玉龙段知非杨守业海洋地质国家重点实验室(同济大学) 上海200092 gfz german research centre for geosciences Earth Surface GeochemistryTelegrafenbergPotsdam14473Germany

沉积物不同组分(化学相态)的精确提取是还原其所经历地质过程或环境要素的关键。本文比较了两种针对铀系同位素(^(234)U/^(238)U)测试开发的沉积物碎屑组分提取方法,结果表明Francke提出的方法对岩石样品淋洗效果更好。对长江、黄河和... 详细信息

沉积物不同组分(化学相态)的精确提取是还原其所经历地质过程或环境要素的关键。本文比较了两种针对铀系同位素(^(234)U/^(238)U)测试开发的沉积物碎屑组分提取方法,结果表明Francke提出的方法对岩石样品淋洗效果更好。对长江、黄河和台湾浊水溪沉积物样品,Dosseto和Francke建议的方法各有优势。此外,本文还发现台湾浊水溪流域岩石露头样品的(^(234)U/^(238)U)并没有如预期处于久期平衡状态,可能是因为岩石样品混入了部分次生物质,也可能与该岩石露头样品多为砂岩、孔隙较发育而产生了明显的优先淋滤有关。本研究对于表生环境下沉积物硅酸盐碎屑组分(^(234)U/^(238)U)的精确测定具有一定的参考价值,同时对于岩石铀系不平衡研究也有一定启示意义。

关键词：碎屑组分提取顺序淋滤 (^(234)U/^(238)U) 岩石沉积物

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Rapid afterslip and short-term viscoelastic relaxation following the 2008 M_W7.9 Wenchuan earthquake

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Earthquake Science 2011年第2期24卷 163-175页

作者： Zhigang Shao Rongjiang Wang Yanqiang Wu Langping Zhang Institute of Earthquake Science China Earthquake Administration Beijing 100036 China gfz german research Center for geosciences D-14473 Potsdam Germany

Significant postseismic deformation of the 2008 M W 7.9 Wenchuan earthquake has been observed from GPS data of the first 14 days after the earthquake. The possible mechanisms for the rapid postseismic deformation are assumed to be afterslip on the earthquake rupture plane and viscoelastic relaxation of coseismiclly stress change in the lower crust or upper mantle. We firstly use the constrained least squares method to find an afterslip model which can fit the GPS data best. The afterslip model can explain near-field data very well but shows considerable discrepancies in fitting far-field data. To estimate the effect due to the viscoelastic relaxation in the lower crust, we then ignore the contribution from the afterslip and attempt to invert the viscosity structure beneath the Longmenshan fault where the Wenchuan earthquake occurred from the postseismic deformation data. For this purpose, we use a viscoelastic model with a 2D geometry based on the geological and seismological observations and the coseismic slip distribution derived from the coseismic GPS and InSAR data. By means of a grid search we find that the optimum viscosity is 9×10 18 Pa·s for the middle-lower crust in the Chengdu Basin, 4×10 17 Pa·s for the middle-lower crust in the Chuanxi Plateau and 7×10 17 Pa·s for the low velocity zone in the Chuanxi plateau. The viscoelastic model explains the postseismic deformation observed in the far-field satisfactorily, but it is considerably worse than the afterslip model in fitting the near-fault data. It suggests therefore a hybrid model including both afterslip and relaxation effects. Since the viscoelastic model produces mainly the far-field surface deformation and has fewer degree of freedoms （three viscosity parameters） than the afterslip model with a huge number of source parameters, we fix the viscositiy structure as obtained before but redetermine the afterslip distribution using the residual data from the viscoelastic modeling. The redetermined afterslip distribution becomes physically more reasonable

关键词： Wenchuan earthquake short-term postseismic deformation aseismic slip viscoelastic relaxation

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松辽盆地大陆科学钻探发现深部地下连续高含量氢气:清洁能源勘探新启示

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Science Bulletin 2022年第10期67卷 1003-1006页

作者：韩双彪唐致远王成善 Brian Horsfield 王天天 Nicolaj Mahlstedt College of Geoscience and Surveying Engineering China University of Mining and TechnologyBeijing 100083China State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesBeijing 100083China german research centre for geosciences Potsdam 14473Germany

Supplying an ever-growing world population with industrial raw materials,energy and clean water,and at the same time addressing the threats posed by global change,these are the two fundamental challenges facing mankin... 详细信息

关键词：能源勘探 threat today

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