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Allometric models for estimating aboveground biomass in the tropical woodlands of Ghana, West Africa

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Forest Ecosystems 2020年第3期7卷 539-561页

作者： Raymond Aabeyir Stephen Adu-Bredu Wilson Agyei Agyare Michael J.C.Weir Department of Environment and Resource Studies UDS-Wa CampusWaGhana WASCAL Graduate research Programme on Climate Change and Land Use KNUSTKumasiGhana Biodiversity Conservation and Ecosystem Division CSIR-Forestry Research Institute of GhanaKumasiGhana Department of Agricultural and Biosystems Engineering KNUSTKumasiGhana Department of Natural Resources Faculty of Geoinformation Science and Earth Observation(ITC)University of TwenteEnschedethe Netherlands

Background: Modelling aboveground biomass(AGB) in forest and woodland ecosystems is critical for accurate estimation of carbon stocks. However, scarcity of allometric models for predicting AGB remains an issue that has not been adequately addressed in Africa. In particular, locally developed models for estimating AGB in the tropical woodlands of Ghana have received little attention. In the absence of locally developed allometric models, Ghana will continue to use Tier 1 biomass data through the application of pantropic models. Without local allometric models it is not certain how Ghana would achieve Tier 2 and 3 levels under the United Nations programme for reducing emissions from deforestation and forest degradation. The objective of this study is to develop a mixedspecies allometric model for use in estimating AGB for the tropical woodlands in Ghana. Destructive sampling was carried out on 745 trees(as part of charcoal production) for the development of allometric equations. Diameter at breast height(dbh, i.e. 1.3 m above ground level), total tree height(H) and wood density(ρ) were used as predictors for the models. Seven models were compared and the best model selected based on model efficiency,bias(%) and corrected Akaike Information Criterion. The best model was validated by comparing its results with those of the pantropic model developed by Chave et al.(Glob Chang Biol 20:3177–3190, 2014) using equivalence test and conventional paired ***: The results revealed that the best model for estimating AGB in the tropical woodlands is AGB =0.0580ρ((dbh)2 H)0.999. The equivalence test showed that this model and the pantropic model developed by Chave et al.(Glob Chang Biol 20:3177–3190, 2014) were equivalent within ±10% of their mean predictions(p-values <0.0001 for one-tailed t-tests for both lower and upper bounds at 5% significant level), while the paired t-test revealed that the mean(181.44 ± 18.25 kg) of the model predictions of the best model of this s

关键词： Charcoal Diameter at breast height Tree height Wood density Savannah woodland

Temporal-spatial Distribution of Various Types of Crime in the Special Wards of Tokyo

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Journal of Geodesy and geoinformation Science 2022年第2期5卷 19-28页

作者： Zhuo LIU Hui LIN Qinghua HE Yuling WANG School of Geography and Environment/UNESCO HIST-NB Jiangxi Normal UniversityNanchang 330022China Key laboratory of Poyang Lake Wetland and Watershed research Ministry of Education Nanchang 330022China

Based on the official criminal data released by the Tokyo Metropolitan Police Department in 2019,this paper discusses the temporal-spatial distribution of various types of crimes in the special wards of *** results show that:(1)The times of high and low incidence of different types of crime differ *** vicious crime and violent crime present no obvious monthly distribution,property crime clearly differs between the first and second half of a calendar year.(2)The month before the new year sees a surge in most types of crime.(3)Vicious crime peaks in the hours between night and early *** crime and property crime correlate positively with the frequency of human interaction and peak in the morning and evening commuting hours.(4)The spatial distribution of crime resembles the concentric circles of the three rings of the special wards of Tokyo,with a central high-incidence area,a center-peripheral low-incidence area,and a marginal high-incidence *** addition,the center sees more personal crime than the periphery,whereas property crimes show the opposite trend.(5)A spatial autocorrelation analysis shows that the special wards of Tokyo may be grouped into the“high-high”and“low-low”agglomeration modes of different types of crime,with marked differences between the various types of *** crime can be divided into three types:central agglomeration,double central agglomeration,and decentralized agglomeration.

关键词： crime geography temporal-spatial distribution spatial analysis special wards of Tokyo

A hierarchical indexing strategy for optimizing Apache Spark with HDFS to efficiently query big geospatial raster data

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International Journal of Digital Earth 2020年第3期13卷 410-428页

作者： Fei Hu Chaowei Yang Yongyao Jiang Yun Li Weiwei Song Daniel Q.Duffy John L.Schnase Tsengdar Lee NSF Spatiotemporal Innovation Center and Dept.of Geography and geoinformation Sciences George Mason UniversityFairfaxVAUSA Center for Open-Source data and AI Technologies IBMSan FranciscoCAUSA Office of Computational and Information Sciences and Technology NASA Goddard Space Flight CenterGreenbeltMDUSA NASA Center for Climate Simulation Goddard Space Flight CenterGreenbeltMDUSA Earth Science Division NASA HeadquartersWashingtonDCUSA

Earth observations and model simulations are generating big multidimensional array-based raster ***,it is difficult to efficiently query these big raster data due to the inconsistency among the geospatial raster data model,distributed physical data storage model,and the data pipeline in distributed computing *** efficiently process big geospatial data,this paper proposes a three-layer hierarchical indexing strategy to optimize Apache Spark with Hadoop Distributed File System(HDFS)from the following aspects:(1)improve I/O efficiency by adopting the chunking data structure;(2)keep the workload balance and high data locality by building the global index(k-d tree);(3)enable Spark and HDFS to natively support geospatial raster data formats(e.g.,HDF4,NetCDF4,GeoTiff)by building the local index(hash table);(4)index the in-memory data to further improve geospatial data queries;(5)develop a data repartition strategy to tune the query parallelism while keeping high data *** above strategies are implemented by developing the customized RDDs,and evaluated by comparing the performance with that of Spark SQL and *** proposed indexing strategy can be applied to other distributed frameworks or cloud-based computing systems to natively support big geospatial data query with high efficiency.

关键词： big data hierarchical indexing multi-dimensional Apache Spark HDFS distributed computing GIS

Evaluation of diverse classification approaches for land use/cover mapping in a Mediterranean region utilizing Hyperion data

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International Journal of Digital Earth 2014年第3期7卷 194-216页

作者： Alata Elatawneh Chariton Kalaitzidis George P.Petropoulosc Thomas Schneider Institute of Forest Management Technische Universität Muünchen(TUM)85354 FreisingGermany Department of geoinformation in Environmental Management Mediterranean Agronomic Institute of Chania(MAICh)Chania 73100Greece INFOCOSMOS 13341 AthensGreece

Information on Earth’s land surface cover is commonly obtained through digital image analysis of data acquired from remote sensing *** this study,we evaluated the use of diverse classification techniques in discriminating land use/cover types in a typical Mediterranean setting using Hyperion *** this purpose,the spectral angle mapper(SAM),the object-based and the non-linear spectral unmixing based on artificial neural networks(ANNs)techniques were applied.A further objective had been to investigate the effect of two approaches for training sites selection in the SAM classification,namely of the pixel purity index(PPI)and of the direct selection of training points from the Hyperion imagery assisted by a QuickBird imagery and field-based training *** classification outperformed the other techniques with an overall accuracy of 83%.Sub-pixel classification based on the ANN showed an overall accuracy of 52%,very close to that of SAM(48%).SAM applied using the training sites selected directly from the Hyperion imagery supported by the QuickBird image and the field visits returned an increase accuracy by 16%.Yet,all techniques appeared to suffer from the relatively low spatial resolution of the Hyperion imagery,which affected the spectral separation among the land use/cover classes.

关键词： Hyperion Earth’s land use/cover mapping digital image analysis spectral angle mapper sub-pixel classification artificial neural networks Greece

基于MODIS数据的南极半岛北部冰架表面流速估算（英文）

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地理学报：英文版 2016年第2期26卷 243-256页

作者：陈军柯长青周小兵邵珠德李澜宇 Jiangsu Provincial Key laboratory of Geographic Information Science and Technology Nanjing University Key laboratory for Satellite Mapping Technology and Applications of State Administration of Surveying Mapping and Geoinformation of ChinaNanjing University Department of Geophysical Engineering Montana Tech of the University of Montana

The ice shelves in the northern Antarctic Peninsula are highly sensitive to variations of temperature and have therefore served as indicators of global warming. In this study,we estimate the velocities of the ice shelves in the northern Antarctic Peninsula using co-registration of optically sensed images and correlation module(COSI-Corr) in the Environment for Visualizing Images(ENVI) based on Moderate Resolution Imaging Spectroradiometer(MODIS) images during 2000–2012,from which we conclude that the ice flow directions generally match the peninsulas pattern and the crevasse,ice flows mainly eastward into the Weddell Sea. The spatial pattern of velocity field exhibits an increasing trend from the western grounding line to the maximum at the middle part of the ice shelf front on Larsen C with a velocity of approximately 700 ma–1,and the velocity field shows relatively higher values in its southerly neighboring ice shelf(e.g. Smith Inlet). Additionally,ice flows are relatively quicker in the outer part of the ice shelf than in the inner parts. Temporal changes in surface velocities show a continuous increase from 2000 to 2012. It is worth noting that,the acceleration rate during 2000–2009 is relatively higher than that during 2009–2012,while the ice movement on the southern Larsen C and Smith Inlet shows a deceleration from 2009 to 2012.

关键词： MODIS数据表面速度南极半岛冰架中分辨率成像光谱辐射计估计图像配准 Smith

Temporal Three-Dimensional Ontology for Geographical Information Science (GIS)—A Review

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Journal of Geographic Information System 2013年第3期5卷 314-323页

作者： Uznir Ujang Alias Abdul Rahman 3D GIS research Lab Faculty of Geoinformation and Real Estate Universiti Teknologi Malaysia Johor Bahru Malaysia

While the use of three-dimensional (3D) geographical information system (GIS) is becoming in rapid development and being used in various fields such as urban and regional planning, disaster management and planning, mobile navigation and etc., commercial and open source GIS software packages tend to offer 3D-GIS functionalities for their products. On the basis, GIS analysis functions are to provide information with respect to geographical location and by having 3D spatial data as an input, it will give advantages in providing horizontal position information. However, to analyze moving objects (temporal) in 3D seems not an easy task and not fully supported by current GIS platform packages. Previously in two-dimensional (2D) GIS practice, main issue addressed by researchers in managing temporal spatial objects is GIS packages were designed based on hardware and software constraints whereby it should be based on the temporal spatial objects ontology. Nowadays, the trend of managing temporal 3D data is via 3D spatial simulation or animation. This approach will not in assistance for GIS users in conducting spatial queries. Without having a suitable ontology and valid topological data structure for temporal 3D data, it will cause repetitive of temporal data (redundancy) and complications in executing spatial analysis in 3D environment. Therefore this paper focuses on the ontology for managing moving 3D spatial objects (i.e. air pollution, flood). The characteristics of moving objects were reviewed thoroughly by categorizing it based on its different appearances. Moreover, existing methods in managing temporal database were addressed and discussed for its practicalities. Another important aspect in managing temporal 3D objects is the implementation of topological data structures for 3D spatial objects were reviewed. In the last section of this paper it summarized the issues and further ideas towards implementing and managing temporal 3D spatial objects in GIS based on the G

关键词： Multidimensional GIS Temporal GIS geoinformation Ontology 3D GIS 3D City Modeling

Regression model to estimate flood impact on corn yield using MODIS NDVI and USDA cropland data layer

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Journal of Integrative Agriculture 2017年第2期16卷 398-407页

作者： Ran jay Shrestha Liping Di Eugene G. Yu Lingjun Kang SHAO Yuan-zhen BAI Yu-qi Center for Spatial Information Science and Systems (CSISS) George Mason University VA 22030 USA Department of Geography and geoinformation Science George Mason University VA 22030 USA State Key laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan University Wuhan 430079 P. R. China Key laboratory for Earth System Modelling Ministry of Education/Department of Earth System Science (DESS) Tsinghua University Beijing 100084 P.R.China

Flood events and their impact on crops are extremely significant scientific research issues; however, flood monitoring is an exceedingly complicated process. Flood damages on crops are directly related to yield change, which requires accurate assessment to quantify the damages. Various remote sensing products and indices have been used in the past for this purpose. This paper utilizes the moderate resolution imaging spectroradiometer （MODIS） weekly normalized difference vegetation index （NDVI） product to detect and further quantify flood damages on corn within the major corn producing states in the Midwest region of the US. County-level analyses were performed by taking weighted average of all pure corn pixels （〉90%） masked by the United States Department of Agriculture （USDA） Cropland data Layer （CDL）. The NDVI-based time-series difference between flood years and normal year （median of years 2000-2014） was used to detect flood occur- rences. To further measure the impact of the flood on corn yield, regression analysis between change in NDVI and change in corn yield as independent and dependent variables respectively was performed for 30 different flooding events within growing seasons of the corn. With the R2 value of 0.85, the model indicates statistically significant linear relation between the NDVI and corn yield. Testing the predictability of the model with 10 new cases, the average relative error of the model was only 4.47%. Furthermore, small error （4.8%） of leave-one-out cross validation （LOOCV） along with smaller statistical error indicators （root mean square error （RMSE）, mean absolute error （MAE）, and mean bias error （MBE））, further validated the accuracy of the model. Utilizing the linear regression approach, change in NDVI during the growing season of corn appeared to be a good indicator to quantify the yield loss due to flood. Additionally, with the 250 m MODIS-based NDVI, these yield losses can be estimated up to field level.

关键词： NDVI MODIS agriculture corn yield remote sensing regression

Regional features of topographic relief over the Loess Plateau,China:evidence from ensemble empirical mode decomposition

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Frontiers of Earth Science 2020年第4期14卷 695-710页

作者： Yongjuan Liu Jianjun Cao Liping Wang Xuan Fang Wolfgang Wagner School of Environment Science and Spatial Informatics China University of Mining and TechnologyXuzhou221116China School of Geography Science/Key laboratory of Virtual Geographic Environment of Ministry of Education Nanjing Normal UniversityNanjing210023China School of Environmental Science Nanjing Xiaozhuang UniversityNanjing211171China Department of Geodesy and geoinformation Vienna University of TechnologyVienna1040Austria

Landforms with similar surface matter compositions,endogenic and exogenic forces,and development histories tend to exhibit significant degrees of self-similarity in morphology and spatial *** loess hill-gully areas,ridges and hills have similar topographic relief characteristics and present nearly periodic variations of similar repeating structures at certain spatial scales,which is termed the topographic relief period(TRP).This is a relatively new concept,which is different from the degree of relief,and describes the fluctuations of the terrain from both horizontal and vertical(cross-section)perspectives,which can be used for in-depth analysis of 2-D topographic relief *** technique provides a new perspective for understanding the macro characteristics and differentiation patterns of loess *** investigate TRP variation features of different landforms on the Loess Plateau,China,by extracting catchment boundary profiles(CBPs)from 5 m resolution digital elevation model(DEM)*** profiles were subjected to temporal-frequency analysis using the ensemble empirical mode decomposition(EEMD)*** results showed that loess landforms are characterized by significant regional topographic relief;the CBP of 14 sample areas exhibited an overall pattern of decreasing TRPs and increasing topographic relief spatial frequencies from south to *** to the TRPs and topographic relief characteristics,the topographic relief of the Loess Plateau was divided into four types that have obvious regional *** findings of this study enrich the theories and methods for digital terrain data analysis of the Loess *** study should undertake a more in-depth investigation regarding the complexity of the region and to address the limitations of the EEMD method.

关键词： catchment boundary profile topographic relief period ensemble empirical mode decomposition Loess Plateau

Winter sea ice albedo variations in the Bohai Sea of China

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Acta Oceanologica Sinica 2017年第1期36卷 56-63页

作者： ZHENG Jiajia KE Changqing SHAO Zhude Jiangsu Provincial Key laboratory of Geographic Information Science and Technology Nanjing UniversityNanjing 210023China Key laboratory for Satellite Mapping Technology and Applications of State Administration of Surveying Mapping and Geoinformation of ChinaNanjing UniversityNanjing 210023China Collaborative Innovation Center of Novel Software Technology and Industrialization Nanjing 210023China Collaborative Innovation Center of South China Sea Studies Nanjing 210023China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China

Sea ice conditions in the Bohai Sea of China are sensitive to large-scale climatic variations. On the basis of CLARA-A1-SAL data, the albedo variations are examined in space and time in the winter（December, January and February） from 1992 to 2008 in the Bohai Sea sea ice region. Time series data of the sea ice concentration（SIC）, the sea ice extent（SIE） and the sea surface temperature（SST） are used to analyze their relationship with the albedo. The sea ice albedo changed in volatility appears along with time, the trend is not obvious and increases very slightly during the study period at a rate of 0.388% per decade over the Bohai Sea sea ice *** interannual variation is between 9.93% and 14.50%, and the average albedo is 11.79%. The sea ice albedo in years with heavy sea ice coverage, 1999, 2000 and 2005, is significantly higher than that in other years; in years with light sea ice coverage, 1994, 1998, 2001 and 2006, has low values. For the monthly albedo, the increasing trend（at a rate of 0.988% per decade） in December is distinctly higher than that in January and February. The mean albedo in January（12.90%） is also distinctly higher than that in the other two months. The albedo is significantly positively correlated with the SIC and is significantly negatively correlated with the SST（significance level 90%）.

关键词： Bohai Sea sea ice region albedo variations in space and time trend sea ice concentration sea ice extent sea surface temperature