This paper discusses the role of Geoinformatics as a new scientific discipline designed for handling of geospatial information.Depending on the scientific background of the people involved in shaping the emerging disc...This paper discusses the role of Geoinformatics as a new scientific discipline designed for handling of geospatial information.Depending on the scientific background of the people involved in shaping the emerging discipline,emphasis may be placed on different aspects of Geoinformatics.Applications and developments may address geoscientific,spatial planning,or computer science related matters.The scientific field of Geoinformatics encompasses the acquisition and storing of geospatial data,the modelling and presentation of spatial information,geoscientific analyses and spatial planning,and the development of algorithms and geospatial database systems.It is the position of the author that these tools from Geoinformatics are necessary to bridge the gap between Digital Earth models and the real world with its real-world problems(‘connecting through location’).It is,however,crucial that Geoinformatics represents a coherent integrated approach to the acquisition,storage,analysis,modeling,presentation,and dissemination of geo-processes and not a patchwork solution of unconnected fields of activity.Geoinformatics is as such not a part of Geography,Surveying,or Computer Science,but a new self-contained scientific discipline.The current paper highlights international and national trends of the discipline and presents a number of Geoinformatics initiatives.The research and teaching activities of the newly formed Institute for Geoinformatics and Remote Sensing(IGF)at the University of Osnabrueck serve as an example for these initiatives.All these developments have lead to the long overdue formation of a scientific‘Society for Geoinformatics’(German:Gesellschaft fu¨r Geoinformatik-GfGI)in Germany.展开更多
Himalayan glaciers are shrinking rapidly,especially after 2000.Glacier shrinkage,however,shows a differential pattern in space and time,emphasizing the need to monitor and assess glacier changes at a larger scale.In t...Himalayan glaciers are shrinking rapidly,especially after 2000.Glacier shrinkage,however,shows a differential pattern in space and time,emphasizing the need to monitor and assess glacier changes at a larger scale.In this study,changes of 48 glaciers situated around the twin peaks of the Nun and Kun mountains in the northwestern Himalaya,hereafter referred to as Nun-Kun Group of Glaciers(NKGG),were investigated using Landsat satellite data during 2000-2020.Changes in glacier area,snout position,Equilibrium Line Altitude(ELA),surface thickness and glacier velocity were assessed using remote sensing data supplemented by field observations.The study revealed that the NKGG glaciers have experienced a recession of 4.5%±3.4%and their snouts have retreated at the rate of 6.4±1.6 m·a^(-1).Additionally,there was a 41%increase observed in the debris cover area during the observation period.Using the geodetic approach,an average glacier elevation change of-1.4±0.4 m·a^(-1)was observed between 2000 and 2012.The observed mass loss of the NKGG has resulted in the deceleration of glacier velocity from 27.0±3.7 m·a^(-1)in 2000 to 21.2±2.2 m·a^(-1)in 2020.The ELA has shifted upwards by 83.0±22 m during the period.Glacier morphological and topographic factors showed a strong influence on glacier recession.Furthermore,a higher recession of 12.9%±3.2%was observed in small glaciers,compared to 2.7%±3.1%in larger glaciers.The debris-covered glaciers showed lower shrinkage(2.8%±1.1%)compared to the clean glaciers(9.3%±5%).The glacier depletion recorded in the NKGG during the last two decades,if continued,would severely diminish glacial volume and capacity to store water,thus jeopardizing the sustainability of water resources in the basin.展开更多
The Alborz Mountains are some of the highest in Iran,and they play an important role in controlling the climate of the country’s northern regions.The land surface temperature(LST)is an important variable that affects...The Alborz Mountains are some of the highest in Iran,and they play an important role in controlling the climate of the country’s northern regions.The land surface temperature(LST)is an important variable that affects the ecosystem of this area.This study investigated the spatiotemporal changes and trends of the nighttime LST in the western region of the Central Alborz Mountains at elevations of 1500-4000 m above sea level.MODIS data were extracted for the period of 2000-2021,and the Mann-Kendall nonparametric test was applied to evaluating the changes in the LST.The results indicated a significant increasing trend for the monthly average LST in May-August along the southern aspect.Both the northern and southern aspects showed decreasing trends for the monthly average LST in October,November,and March and an increasing trend in other months.At all elevations,the average decadal change in the monthly average LST was more severe along the southern aspect(0.60°C)than along the northern aspect(0.37°C).The LST difference between the northern and southern aspects decreased in the cold months but increased in the hot months.At the same elevation,the difference in the lapse rate between the northern and southern aspects was greater in the hot months than in the cold months.With increasing elevation,the lapse rate between the northern and southern aspects disappeared.Climate change was concluded to greatly decrease the difference in LST at different elevations for April-July.展开更多
Globally,groundwater contamination by nitrate is one of the most widespread environmental problems,particularly in arid and semiarid areas,which are characterized by low amounts of rainfall and groundwater recharge.Th...Globally,groundwater contamination by nitrate is one of the most widespread environmental problems,particularly in arid and semiarid areas,which are characterized by low amounts of rainfall and groundwater recharge.The stable isotope composition of groundwater(δ2H-H2O andδ18O-H2O)and dissolved nitrate(δ15N-NO3–andδ18O-NO3–)and factor analysis(FA)were applied to explore groundwater provenance,pollution,and chemistry evolution in the northwestern part of the Amman-Al Zarqa Basin,Jordan.In this study,we collected 23 samples from the Lower Ajloun aquifer in 2021,including 1 sample from a groundwater well and 22 samples from springs.These samples were tested for electrical conductivity,total dissolved solids,pH,temperature,dissolved oxygen,the concentration of major ions(Ca2+,Mg2+,Na+,K+,HCO3–,Cl–,SO42–,and NO3–),and the stable isotope composition of groundwater and dissolved nitrate.The results revealed that groundwater in the study area is mainly Ca–Mg–HCO3 type and can be classified as fresh water,hard water,and very hard water.The range and average concentration of NO3–were 3.5–230.8 and 50.9 mg/L,respectively.Approximately 33%of the sampling points showed NO3–levels above the maximum allowable concentration of 50.0 mg/L set by the World Health Organization(WHO)guidelines for drinking water quality.The values ofδ18O-H2O andδ2H-H2O showed that groundwater in the study area is part of the current water cycle,originating in the Mediterranean Sea,with significant evaporation,orographic,and amount effects.The values of the stable isotope composition of NO3–corresponded toδ15N-NO3–andδ18O-NO3–values produced by the nitrification process of manure or septic waste and soil NH4+.The FA performed on the hydrochemical parameters and isotope data resulted in three main factors,with Factor 1,Factor 2,and Factor 3,accounting for 50%,21%,and 11%of the total variance,respectively.Factor 1 was considered human-induced factor,named"pollution factor",whereas Factor 2,named"conservative fingerprint factor",and Factor 3,named"hardness factor",were considered natural factors.This study will help local researchers manage groundwater sustainably in the study area and other similar arid and semiarid areas in the world.展开更多
The present study deals with the determination of Mount Olympus summit(Mytikas),exploiting modern observations such as Global Navigation Satellite Systems(GNSS)and existing geodetic information.The last official Olymp...The present study deals with the determination of Mount Olympus summit(Mytikas),exploiting modern observations such as Global Navigation Satellite Systems(GNSS)and existing geodetic information.The last official Olympus height determination goes back 102 years by the Swiss surveyor M.Kurz.Since then,only unofficial measurement campaigns have taken place.There is a variety of released heights,which range from 2917 to 2919 meters.In September and October of 2022,we conducted a GNSS campaign,focusing on the area of highest Olympus peaks.Employing precise GNSS measurements(accuracy of 1-3 cm),in conjunction with height information from Greece’s National Triangulation Network(5-10 cm accuracy)and an appropriate,recent geoid model(5-6 cm accuracy),we estimate through the so-called GNSS-levelling,the height of Olympus to 2917.727 m with respect to Greece’s officially accepted mean sea level and 2918.390 m with respect to the global vertical datum.Our estimation of Olympus highest peak shows remarkable consistency at the level of 12.8 cm to that of M.Kurz in 1921.展开更多
Despite the exceptional species richness and endemism,the environmental drivers of plant diversity along old tropical mountains remain underexplored.The respective importance of vegetation types,elevation,slope,and so...Despite the exceptional species richness and endemism,the environmental drivers of plant diversity along old tropical mountains remain underexplored.The respective importance of vegetation types,elevation,slope,and soil to drive diversity across life-forms is poorly addressed.Here,we tested whether environmental variables drove local and regional plant diversity along an old tropical mountain according to the three main life-forms:graminoids,herbaceous and woody species.We sampled all Angiosperm species on 180 plots across five elevations,at the tropical old-mountain region of Serra do Cipó,South-eastern Brazil.We assessed soil,slope,and vegetation types,and calculated richness and beta-diversity,applying generalized least square models,linear mixed-models and partial Mantel tests to test for relationships.Richness of graminoids and herbaceous species increased with greater elevation and more nutrient-impoverished soils,while woody richness showed the inverse pattern.Beta-diversity was primarily driven by species turnover,correlated with elevation and soil and higher in less dominant vegetation types,with unique species.Despite the limited elevational range in these old mountains,it still played an important role in filtering woody species,while fostering graminoid and herbaceous species.Conservation and restoration actions need to foster the high regional diversity supported by the old mountain heterogeneous landscape and the diversity of life-forms,especially the dominant and highly diverse grassy component.展开更多
Needs for real-time interactive visualization of 3D Tiles for massive 3D content on the web-based virtual globe is rapidly increasing, and to achieve this goal, 3D Tiles needs to be correctly geo-referenced to other g...Needs for real-time interactive visualization of 3D Tiles for massive 3D content on the web-based virtual globe is rapidly increasing, and to achieve this goal, 3D Tiles needs to be correctly geo-referenced to other geospatial data on a web-based virtual globe. It is possible to generate 3D Tiles from different kinds of spatial data through various software tools. However, due to various factors the 3D Tile datasets are often poorly or not at all geo-referenced. To tackle this issue, we propose a new 3D WebGIS framework that facilitates dynamic geo-referencing 3D Tiles on the CesiumJS virtual globe.展开更多
Essentially, CesiumJS—which can be accessed through the link, http://cesiumjs.org, is an open-source JavaScript library for creating virtual globe environment in performance effective, high quality of rendering, prec...Essentially, CesiumJS—which can be accessed through the link, http://cesiumjs.org, is an open-source JavaScript library for creating virtual globe environment in performance effective, high quality of rendering, precision, and user friendly. It is a wonderful tool for 3D-themed visualizations of earth. CesiumJS has a number of data sources, but none of them supports vector tile format. This article explains how to visualize Mapbox vector tiles in a CesiumJS virtual globe environment. CartoDB/BigQuery hosts vector tiles, and a process for producing vector tiles from massive vector data using the BigQuery tiler of CartoDB has been provided.展开更多
Fuzzy logic is a contemporary theory that has found numerous applications in Geographic Information Systems (GIS). Fuzzy logic allows for the representation of uncertainty and imprecision in spatial data, making it a ...Fuzzy logic is a contemporary theory that has found numerous applications in Geographic Information Systems (GIS). Fuzzy logic allows for the representation of uncertainty and imprecision in spatial data, making it a valuable tool for dealing with the inherent ambiguity present in many geographic datasets. To solve a problem using a knowledge-based fuzzy system, the description and processing of the influencing factors or variables in fuzzy terms is required. The key components of a knowledge-based fuzzy system within the context of GIS are: Fuzzification, definition of the knowledge base, processing of the rules and finally defuzzification. Defuzzification is an important aspect of fuzzy logic and fuzzy set theory, as it helps convert fuzzy linguistic terms or fuzzy sets into crisp values that can be used in decision-making or analysis. Moreover, this might seem contradictory to the primary objective of fuzzy set theory, which is to model and work with uncertainty and imprecision. The aim of this paper is, first, to review defuzzification operators that are suitable for handling geographic data of ratio scale and second to compare these defuzzification operators by applying them to actual geographic data sets. For this reason, a case study based on pollution data of the municipality of Athens, Greece, was carried out to estimate pollution produced by SO<sub>2</sub>. The results of the application of defuzzification operators for the above geographic data set are compared and final conclusions are presented.展开更多
Sand excavations in river beds have compromised the safety of several bridges in recent years. Large scale sand mining from river beds is now common in the Niger Delta, due to the necessity of reclaiming land for deve...Sand excavations in river beds have compromised the safety of several bridges in recent years. Large scale sand mining from river beds is now common in the Niger Delta, due to the necessity of reclaiming land for development purposes and to meet construction needs in the region. There is currently no regulation as to where sand can be mined in river channels because of the lack of adequate understanding of the risks to coastal infrastructure involved with its abstraction. The phenomenon of bridge Abutment and bank failure induced by excessive dredging of sand river bed is considered. Two types of instability were distinguished, one relating to the equilibrium slope of the riverbed and the other riverbank instability. An empirical relationship in the form X<sub>s</sub> = 3Htan(90 - α) has been developed through analysis, supported by examples that a minimum distance of 94 m (for sand river beds) from a bridge should be observed for sand abstraction in order to guaranty the safety of bridge foundation. For clay riverbeds, slightly shorter minimum distances can be considered safe. The study further shows that the capacity of sand borrowing in river channels to generate bank instability is dependent on the composition and stratigraphy beneath the river bed.展开更多
Soil conductivity is responsible for its aggressive behavior to metallic objects either in contact or buried in the ground. Rapid deterioration and eventual rupture of pipelines leading ultimately to crude oil spillag...Soil conductivity is responsible for its aggressive behavior to metallic objects either in contact or buried in the ground. Rapid deterioration and eventual rupture of pipelines leading ultimately to crude oil spillages have been of economic as well as environmental concern. Although many factors contribute to soil resistivity, these relationships have hardly been quantitatively expressed. This paper explores the factors affecting soil resistivity firstly by matching the spatial regional distribution with each of the identified factors of influence, including ground elevation soil type, depth to water table and undrained strength. 183 Vertical Electrical Sounding VES with the ABEM SAS 1000, using Schlumberger electrode configuration were carried out along a pipeline route to generate resistivity distribution across a linear alignment that traverses three geomorphic sub-environments in the Niger Delta Region. The apparent resistivity values averaged over depths of 3 m and 10 m were plotted against the co-ordinates using Surfer-16 and overlaid on Google earth Pro to produce a spatial distribution with enhanced location visibility. The results show that apparent resistivity is influenced by depth to water table with lower values in areas of shallow water table occurrence. Furthermore, it is shown that changes in resistivity below the water table are more due to variation in soil type. Within a soil type above the water table, soil resistivity increases monotonically with depth until the depth of probe extends to a different soil horizon. Results of this study provide guidance as to what ground resistivity to expect in different part of the delta as well as provide valuable information to assess the risks to assets either as a means of prioritizing maintenance or of improving design for new installations in the Niger Delta Region.展开更多
A new real-time map matching algorithm based on fuzzy logic is proposed. 3 main factors affecting the reliability of map matching, including the distance between the vehicle location and the matching road segment, the...A new real-time map matching algorithm based on fuzzy logic is proposed. 3 main factors affecting the reliability of map matching, including the distance between the vehicle location and the matching road segment, the angle between the vehicle direction and the road segment direction and the road connectivity are discussed. Fuzzy rules for the distance, angle and connectivity are presented to calculate the matching reliability. 2 indicators for estimating the matching reliability are then derived, one is the lower limit of the reliability, and the other is the limit error of the difference between the maximal value and the second-maximal value of the reliability. A real-time map-matching system based on fuzzy logic is therefore developed. Using the real data of global positioning system(GIS) based navigation and geographic information system(GPS) based road map, the method is verified and the (results) prove the effectiveness of the proposed method.展开更多
AIM To perform a comprehensive review and provide an up-to-date synopsis of the incidence and trends of inflammatory bowel disease(IBD). METHODS We systematically searched the MEDLINE(source Pub Med), EMBASE and Cochr...AIM To perform a comprehensive review and provide an up-to-date synopsis of the incidence and trends of inflammatory bowel disease(IBD). METHODS We systematically searched the MEDLINE(source Pub Med), EMBASE and Cochrane Library databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines(period: 1985-2018) to identify studies reporting population-based data on the incidence of pediatriconset(< 19 years at diagnosis) IBD in full manuscripts. Two authors carried out screening and data extraction. Choropleth interactive maps and temporal trends were used to illustrate the international differences and incidences of and changes in IBD and subtypes.RESULTS In total, one hundred forty studies reporting data from 38 countries were considered in this review. The highest annual pediatric incidences of IBD were 23/100000 person-years in Europe, 15.2/100000 in North America, and 11.4/100000 in Asia/the Middle East and Oceania. The highest annual incidences of Crohn's disease(CD) were 13.9/100000 in North America and 12.3/100000 in Europe. The highest annual incidences of ulcerative colitis(UC) were 15.0/100000 in Europe and 10.6/100000 in North America. The highest annual incidences of IBD-unclassified(IBD-U) were 3.6/100000 in Europe and 2.1/100000 in North America. In the time-trend analyses, 67% of CD, 46% of UC and 11% of IBD-U studies reported an increasing incidence(P < 0.05). The risk of IBD is increasing among firstgeneration of migrant populations.CONCLUSION Globally, the incidence of IBD varies greatly by geographical areas. The steadily increasing incidence of pediatric IBD over time indicates its emergence as a global disease, suggesting that studies should investigate the environmental risk factors among pediatric cohorts.展开更多
Tropospheric delay is a primary error source in earth observations and a variety of radio navigation technologies. In this paper, the relationship between zenith tropospheric delays and the elevation and longitude of ...Tropospheric delay is a primary error source in earth observations and a variety of radio navigation technologies. In this paper, the relationship between zenith tropospheric delays and the elevation and longitude of stations is analyzed using the zenith tropospheric delay final products of International GNSS Service (IGS) stations from 2011. Two new models are proposed for estimating zenith tropospheric delays from regional CORS data without meteorological data. The proposed models are compared with the direct interpolation method and the remove-restore method using data from Guangxi CORS. The results show that the new models significantly improve the calculated precision. Finally, the root mean square (RMS) errors of the new models were used to estimate the surface precipitable water vapor (PWV) value at CORS station, which was determined to be less than 2 mm.展开更多
The oleanane parameter, i.e., OP (oleananes/(oleananes+C30hopanes)) in the two sedimentary columns of the Beibuwan Basin, South China Sea, can be used to delimit the top of oil generation window, with Ro (/%) o...The oleanane parameter, i.e., OP (oleananes/(oleananes+C30hopanes)) in the two sedimentary columns of the Beibuwan Basin, South China Sea, can be used to delimit the top of oil generation window, with Ro (/%) of 0.53 in Well M1 and 0.55 in Wells H1/Hd1/Hd2, respectively. Comparing with vitrinite reflectance (Ro/%), the OP features a dynamic range and can indicate the oil generation window more precisely. By using OP and other geochemical indices, the oil-source correlation is also conducted. It suggests that the oils in wells M1 and M2 are derived from the source rocks in situ. The mudstone in Huachang uplift is not the main source rocks for oils in this area, The OP is also a useful oil-source correlation parameter in some Tertiary lacustrine basins.展开更多
Landslides are the most common natural disaster in hilly terrain which causes changes in landscape and damage to life and property. The main objective of the present study was to carry out landslide hazard zonation ma...Landslides are the most common natural disaster in hilly terrain which causes changes in landscape and damage to life and property. The main objective of the present study was to carry out landslide hazard zonation mapping on 1:50,000 scale along ghat road section of Kolli hills using a Landslide Hazard Evaluation Factor(LHEF) rating scheme. The landslide hazard zonation map has been prepared by overlaying the terrain evaluation maps with facet map of the study area. The terrain evaluation maps include lithology, structure, slope morphometry, relative relief, land use and land cover and hydrogeological condition. The LHEF rating scheme and the Total Estimated Hazard(TEHD) were calculated as per the Bureau of Indian Standard(BIS) guidelines(IS: 14496(Part-2) 1998) for the purpose of preparation of Landslide Hazard Zonation(LHZ) map in mountainous terrains. The correction due to triggering factors such as seismicity, rainfall and anthropogenic activities were also incorporated with Total Estimated Hazard to get final corrected TEHD. The landslide hazard zonation map was classified as the high, moderate and low hazard zones along the ghat road section based on corrected TEHD.展开更多
The contents of nitrogen and organic carbon in an agricultural soil were analyzed using reflectance measurements (n=52)performed with an ASD FieldSpec-Ⅱspectroradiometer.For parameter prediction,empirical models base...The contents of nitrogen and organic carbon in an agricultural soil were analyzed using reflectance measurements (n=52)performed with an ASD FieldSpec-Ⅱspectroradiometer.For parameter prediction,empirical models based on partial least squares(PLS)regression were defined from the measured reflectance spectra(0.4 to 2.4μm).Here,reliable estimates were obtained for nitrogen content,but prediction accuracy was only moderate for organic carbon.For nitrogen, the real spatial pattern of within-field variability was reproduced with high accuracy.The results indicate the potential of this method as a quick screening tool for the spatial assessment of nitrogen and organic carbon,and therefore an appropriate alternative to time-and cost-intensive chemical analysis in the laboratory.展开更多
Reflected signals from global navigation satellite systems(GNSSs) have been widely acknowledged as an important remote sensing tool for retrieving sea surface wind speeds.The power of GNSS reflectometry(GNSS-R)sig...Reflected signals from global navigation satellite systems(GNSSs) have been widely acknowledged as an important remote sensing tool for retrieving sea surface wind speeds.The power of GNSS reflectometry(GNSS-R)signals can be mapped in delay chips and Doppler frequency space to generate delay Doppler power maps(DDMs),whose characteristics are related to sea surface roughness and can be used to retrieve wind speeds.However,the bistatic radar cross section(BRCS),which is strongly related to the sea surface roughness,is extensively used in radar.Therefore,a bistatic radar cross section(BRCS) map with a modified BRCS equation in a GNSS-R application is introduced.On the BRCS map,three observables are proposed to represent the sea surface roughness to establish a relationship with the sea surface wind speed.Airborne Hurricane Dennis(2005) GNSS-R data are then used.More than 16 000 BRCS maps are generated to establish GMFs of the three observables.Finally,the proposed model and classic one-dimensional delay waveform(DW) matching methods are compared,and the proposed model demonstrates a better performance for the high wind speed retrievals.展开更多
文摘This paper discusses the role of Geoinformatics as a new scientific discipline designed for handling of geospatial information.Depending on the scientific background of the people involved in shaping the emerging discipline,emphasis may be placed on different aspects of Geoinformatics.Applications and developments may address geoscientific,spatial planning,or computer science related matters.The scientific field of Geoinformatics encompasses the acquisition and storing of geospatial data,the modelling and presentation of spatial information,geoscientific analyses and spatial planning,and the development of algorithms and geospatial database systems.It is the position of the author that these tools from Geoinformatics are necessary to bridge the gap between Digital Earth models and the real world with its real-world problems(‘connecting through location’).It is,however,crucial that Geoinformatics represents a coherent integrated approach to the acquisition,storage,analysis,modeling,presentation,and dissemination of geo-processes and not a patchwork solution of unconnected fields of activity.Geoinformatics is as such not a part of Geography,Surveying,or Computer Science,but a new self-contained scientific discipline.The current paper highlights international and national trends of the discipline and presents a number of Geoinformatics initiatives.The research and teaching activities of the newly formed Institute for Geoinformatics and Remote Sensing(IGF)at the University of Osnabrueck serve as an example for these initiatives.All these developments have lead to the long overdue formation of a scientific‘Society for Geoinformatics’(German:Gesellschaft fu¨r Geoinformatik-GfGI)in Germany.
基金as part of the Department of Science and Technology (DST), Government of India sponsored research projects titled “Centre of Excellence for Glaciological Research in Western Himalaya”the financial assistance received from the Department under the projects to conduct the research。
文摘Himalayan glaciers are shrinking rapidly,especially after 2000.Glacier shrinkage,however,shows a differential pattern in space and time,emphasizing the need to monitor and assess glacier changes at a larger scale.In this study,changes of 48 glaciers situated around the twin peaks of the Nun and Kun mountains in the northwestern Himalaya,hereafter referred to as Nun-Kun Group of Glaciers(NKGG),were investigated using Landsat satellite data during 2000-2020.Changes in glacier area,snout position,Equilibrium Line Altitude(ELA),surface thickness and glacier velocity were assessed using remote sensing data supplemented by field observations.The study revealed that the NKGG glaciers have experienced a recession of 4.5%±3.4%and their snouts have retreated at the rate of 6.4±1.6 m·a^(-1).Additionally,there was a 41%increase observed in the debris cover area during the observation period.Using the geodetic approach,an average glacier elevation change of-1.4±0.4 m·a^(-1)was observed between 2000 and 2012.The observed mass loss of the NKGG has resulted in the deceleration of glacier velocity from 27.0±3.7 m·a^(-1)in 2000 to 21.2±2.2 m·a^(-1)in 2020.The ELA has shifted upwards by 83.0±22 m during the period.Glacier morphological and topographic factors showed a strong influence on glacier recession.Furthermore,a higher recession of 12.9%±3.2%was observed in small glaciers,compared to 2.7%±3.1%in larger glaciers.The debris-covered glaciers showed lower shrinkage(2.8%±1.1%)compared to the clean glaciers(9.3%±5%).The glacier depletion recorded in the NKGG during the last two decades,if continued,would severely diminish glacial volume and capacity to store water,thus jeopardizing the sustainability of water resources in the basin.
文摘The Alborz Mountains are some of the highest in Iran,and they play an important role in controlling the climate of the country’s northern regions.The land surface temperature(LST)is an important variable that affects the ecosystem of this area.This study investigated the spatiotemporal changes and trends of the nighttime LST in the western region of the Central Alborz Mountains at elevations of 1500-4000 m above sea level.MODIS data were extracted for the period of 2000-2021,and the Mann-Kendall nonparametric test was applied to evaluating the changes in the LST.The results indicated a significant increasing trend for the monthly average LST in May-August along the southern aspect.Both the northern and southern aspects showed decreasing trends for the monthly average LST in October,November,and March and an increasing trend in other months.At all elevations,the average decadal change in the monthly average LST was more severe along the southern aspect(0.60°C)than along the northern aspect(0.37°C).The LST difference between the northern and southern aspects decreased in the cold months but increased in the hot months.At the same elevation,the difference in the lapse rate between the northern and southern aspects was greater in the hot months than in the cold months.With increasing elevation,the lapse rate between the northern and southern aspects disappeared.Climate change was concluded to greatly decrease the difference in LST at different elevations for April-July.
基金funded by the Deanship of Scientific Research,Jordan University of Science and Technology(20210159).
文摘Globally,groundwater contamination by nitrate is one of the most widespread environmental problems,particularly in arid and semiarid areas,which are characterized by low amounts of rainfall and groundwater recharge.The stable isotope composition of groundwater(δ2H-H2O andδ18O-H2O)and dissolved nitrate(δ15N-NO3–andδ18O-NO3–)and factor analysis(FA)were applied to explore groundwater provenance,pollution,and chemistry evolution in the northwestern part of the Amman-Al Zarqa Basin,Jordan.In this study,we collected 23 samples from the Lower Ajloun aquifer in 2021,including 1 sample from a groundwater well and 22 samples from springs.These samples were tested for electrical conductivity,total dissolved solids,pH,temperature,dissolved oxygen,the concentration of major ions(Ca2+,Mg2+,Na+,K+,HCO3–,Cl–,SO42–,and NO3–),and the stable isotope composition of groundwater and dissolved nitrate.The results revealed that groundwater in the study area is mainly Ca–Mg–HCO3 type and can be classified as fresh water,hard water,and very hard water.The range and average concentration of NO3–were 3.5–230.8 and 50.9 mg/L,respectively.Approximately 33%of the sampling points showed NO3–levels above the maximum allowable concentration of 50.0 mg/L set by the World Health Organization(WHO)guidelines for drinking water quality.The values ofδ18O-H2O andδ2H-H2O showed that groundwater in the study area is part of the current water cycle,originating in the Mediterranean Sea,with significant evaporation,orographic,and amount effects.The values of the stable isotope composition of NO3–corresponded toδ15N-NO3–andδ18O-NO3–values produced by the nitrification process of manure or septic waste and soil NH4+.The FA performed on the hydrochemical parameters and isotope data resulted in three main factors,with Factor 1,Factor 2,and Factor 3,accounting for 50%,21%,and 11%of the total variance,respectively.Factor 1 was considered human-induced factor,named"pollution factor",whereas Factor 2,named"conservative fingerprint factor",and Factor 3,named"hardness factor",were considered natural factors.This study will help local researchers manage groundwater sustainably in the study area and other similar arid and semiarid areas in the world.
文摘The present study deals with the determination of Mount Olympus summit(Mytikas),exploiting modern observations such as Global Navigation Satellite Systems(GNSS)and existing geodetic information.The last official Olympus height determination goes back 102 years by the Swiss surveyor M.Kurz.Since then,only unofficial measurement campaigns have taken place.There is a variety of released heights,which range from 2917 to 2919 meters.In September and October of 2022,we conducted a GNSS campaign,focusing on the area of highest Olympus peaks.Employing precise GNSS measurements(accuracy of 1-3 cm),in conjunction with height information from Greece’s National Triangulation Network(5-10 cm accuracy)and an appropriate,recent geoid model(5-6 cm accuracy),we estimate through the so-called GNSS-levelling,the height of Olympus to 2917.727 m with respect to Greece’s officially accepted mean sea level and 2918.390 m with respect to the global vertical datum.Our estimation of Olympus highest peak shows remarkable consistency at the level of 12.8 cm to that of M.Kurz in 1921.
基金Sao Paulo Research Foundation(FAPESP)for financial support through the grants:#2009/54208-6Fapesp-Microsoft Research Institute#2013/50155-0+6 种基金Fapesp-Vale#2010/51307-0,#2021/10639-5 to LPCMthrough fellowships FAPESP#2015/10754-8 to MGGC and#2019/09248-1 to ASSCoordena??o de Aperfei?oamento de Pessoal de Nível Superior–(CAPES)for scholarships granted to MGGC(Process#88887.583309/2020-00)PPL(#88887.583146/2020-00)JSS(CAPES Finance Code 001)National Council for Scientific and Technological Development(CNPq)for the grants:CNPq-PVE#400717/2013-1 and PDJ#150404/2016-6 to SLSfor the productivity fellowship and grant#311820/2018-2,#306563/2022-3 to LPCM。
文摘Despite the exceptional species richness and endemism,the environmental drivers of plant diversity along old tropical mountains remain underexplored.The respective importance of vegetation types,elevation,slope,and soil to drive diversity across life-forms is poorly addressed.Here,we tested whether environmental variables drove local and regional plant diversity along an old tropical mountain according to the three main life-forms:graminoids,herbaceous and woody species.We sampled all Angiosperm species on 180 plots across five elevations,at the tropical old-mountain region of Serra do Cipó,South-eastern Brazil.We assessed soil,slope,and vegetation types,and calculated richness and beta-diversity,applying generalized least square models,linear mixed-models and partial Mantel tests to test for relationships.Richness of graminoids and herbaceous species increased with greater elevation and more nutrient-impoverished soils,while woody richness showed the inverse pattern.Beta-diversity was primarily driven by species turnover,correlated with elevation and soil and higher in less dominant vegetation types,with unique species.Despite the limited elevational range in these old mountains,it still played an important role in filtering woody species,while fostering graminoid and herbaceous species.Conservation and restoration actions need to foster the high regional diversity supported by the old mountain heterogeneous landscape and the diversity of life-forms,especially the dominant and highly diverse grassy component.
文摘Needs for real-time interactive visualization of 3D Tiles for massive 3D content on the web-based virtual globe is rapidly increasing, and to achieve this goal, 3D Tiles needs to be correctly geo-referenced to other geospatial data on a web-based virtual globe. It is possible to generate 3D Tiles from different kinds of spatial data through various software tools. However, due to various factors the 3D Tile datasets are often poorly or not at all geo-referenced. To tackle this issue, we propose a new 3D WebGIS framework that facilitates dynamic geo-referencing 3D Tiles on the CesiumJS virtual globe.
文摘Essentially, CesiumJS—which can be accessed through the link, http://cesiumjs.org, is an open-source JavaScript library for creating virtual globe environment in performance effective, high quality of rendering, precision, and user friendly. It is a wonderful tool for 3D-themed visualizations of earth. CesiumJS has a number of data sources, but none of them supports vector tile format. This article explains how to visualize Mapbox vector tiles in a CesiumJS virtual globe environment. CartoDB/BigQuery hosts vector tiles, and a process for producing vector tiles from massive vector data using the BigQuery tiler of CartoDB has been provided.
文摘Fuzzy logic is a contemporary theory that has found numerous applications in Geographic Information Systems (GIS). Fuzzy logic allows for the representation of uncertainty and imprecision in spatial data, making it a valuable tool for dealing with the inherent ambiguity present in many geographic datasets. To solve a problem using a knowledge-based fuzzy system, the description and processing of the influencing factors or variables in fuzzy terms is required. The key components of a knowledge-based fuzzy system within the context of GIS are: Fuzzification, definition of the knowledge base, processing of the rules and finally defuzzification. Defuzzification is an important aspect of fuzzy logic and fuzzy set theory, as it helps convert fuzzy linguistic terms or fuzzy sets into crisp values that can be used in decision-making or analysis. Moreover, this might seem contradictory to the primary objective of fuzzy set theory, which is to model and work with uncertainty and imprecision. The aim of this paper is, first, to review defuzzification operators that are suitable for handling geographic data of ratio scale and second to compare these defuzzification operators by applying them to actual geographic data sets. For this reason, a case study based on pollution data of the municipality of Athens, Greece, was carried out to estimate pollution produced by SO<sub>2</sub>. The results of the application of defuzzification operators for the above geographic data set are compared and final conclusions are presented.
文摘Sand excavations in river beds have compromised the safety of several bridges in recent years. Large scale sand mining from river beds is now common in the Niger Delta, due to the necessity of reclaiming land for development purposes and to meet construction needs in the region. There is currently no regulation as to where sand can be mined in river channels because of the lack of adequate understanding of the risks to coastal infrastructure involved with its abstraction. The phenomenon of bridge Abutment and bank failure induced by excessive dredging of sand river bed is considered. Two types of instability were distinguished, one relating to the equilibrium slope of the riverbed and the other riverbank instability. An empirical relationship in the form X<sub>s</sub> = 3Htan(90 - α) has been developed through analysis, supported by examples that a minimum distance of 94 m (for sand river beds) from a bridge should be observed for sand abstraction in order to guaranty the safety of bridge foundation. For clay riverbeds, slightly shorter minimum distances can be considered safe. The study further shows that the capacity of sand borrowing in river channels to generate bank instability is dependent on the composition and stratigraphy beneath the river bed.
文摘Soil conductivity is responsible for its aggressive behavior to metallic objects either in contact or buried in the ground. Rapid deterioration and eventual rupture of pipelines leading ultimately to crude oil spillages have been of economic as well as environmental concern. Although many factors contribute to soil resistivity, these relationships have hardly been quantitatively expressed. This paper explores the factors affecting soil resistivity firstly by matching the spatial regional distribution with each of the identified factors of influence, including ground elevation soil type, depth to water table and undrained strength. 183 Vertical Electrical Sounding VES with the ABEM SAS 1000, using Schlumberger electrode configuration were carried out along a pipeline route to generate resistivity distribution across a linear alignment that traverses three geomorphic sub-environments in the Niger Delta Region. The apparent resistivity values averaged over depths of 3 m and 10 m were plotted against the co-ordinates using Surfer-16 and overlaid on Google earth Pro to produce a spatial distribution with enhanced location visibility. The results show that apparent resistivity is influenced by depth to water table with lower values in areas of shallow water table occurrence. Furthermore, it is shown that changes in resistivity below the water table are more due to variation in soil type. Within a soil type above the water table, soil resistivity increases monotonically with depth until the depth of probe extends to a different soil horizon. Results of this study provide guidance as to what ground resistivity to expect in different part of the delta as well as provide valuable information to assess the risks to assets either as a means of prioritizing maintenance or of improving design for new installations in the Niger Delta Region.
基金Projects(40301043 and 40171078) supported by the National Natural Science Foundation of China
文摘A new real-time map matching algorithm based on fuzzy logic is proposed. 3 main factors affecting the reliability of map matching, including the distance between the vehicle location and the matching road segment, the angle between the vehicle direction and the road segment direction and the road connectivity are discussed. Fuzzy rules for the distance, angle and connectivity are presented to calculate the matching reliability. 2 indicators for estimating the matching reliability are then derived, one is the lower limit of the reliability, and the other is the limit error of the difference between the maximal value and the second-maximal value of the reliability. A real-time map-matching system based on fuzzy logic is therefore developed. Using the real data of global positioning system(GIS) based navigation and geographic information system(GPS) based road map, the method is verified and the (results) prove the effectiveness of the proposed method.
基金Supported by the“On Our Own Feet Movement-P?áteléstonozky”-Endowment Programand Research Project Progress Q-39
文摘AIM To perform a comprehensive review and provide an up-to-date synopsis of the incidence and trends of inflammatory bowel disease(IBD). METHODS We systematically searched the MEDLINE(source Pub Med), EMBASE and Cochrane Library databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines(period: 1985-2018) to identify studies reporting population-based data on the incidence of pediatriconset(< 19 years at diagnosis) IBD in full manuscripts. Two authors carried out screening and data extraction. Choropleth interactive maps and temporal trends were used to illustrate the international differences and incidences of and changes in IBD and subtypes.RESULTS In total, one hundred forty studies reporting data from 38 countries were considered in this review. The highest annual pediatric incidences of IBD were 23/100000 person-years in Europe, 15.2/100000 in North America, and 11.4/100000 in Asia/the Middle East and Oceania. The highest annual incidences of Crohn's disease(CD) were 13.9/100000 in North America and 12.3/100000 in Europe. The highest annual incidences of ulcerative colitis(UC) were 15.0/100000 in Europe and 10.6/100000 in North America. The highest annual incidences of IBD-unclassified(IBD-U) were 3.6/100000 in Europe and 2.1/100000 in North America. In the time-trend analyses, 67% of CD, 46% of UC and 11% of IBD-U studies reported an increasing incidence(P < 0.05). The risk of IBD is increasing among firstgeneration of migrant populations.CONCLUSION Globally, the incidence of IBD varies greatly by geographical areas. The steadily increasing incidence of pediatric IBD over time indicates its emergence as a global disease, suggesting that studies should investigate the environmental risk factors among pediatric cohorts.
基金supported by the National Natural Foundation of China(4106400141071294)+1 种基金the Natural Science Foundation of Guangxi(2012GXNSFAA053183)Guangxi Key Laboratory of Spatial Information and Geomatics(1103108-06)
文摘Tropospheric delay is a primary error source in earth observations and a variety of radio navigation technologies. In this paper, the relationship between zenith tropospheric delays and the elevation and longitude of stations is analyzed using the zenith tropospheric delay final products of International GNSS Service (IGS) stations from 2011. Two new models are proposed for estimating zenith tropospheric delays from regional CORS data without meteorological data. The proposed models are compared with the direct interpolation method and the remove-restore method using data from Guangxi CORS. The results show that the new models significantly improve the calculated precision. Finally, the root mean square (RMS) errors of the new models were used to estimate the surface precipitable water vapor (PWV) value at CORS station, which was determined to be less than 2 mm.
基金supported by the Natural Science Foundation of China(Grant No.40672093)CNPC Innovation Fund(07El001)the ESS-China Hydrocarbon Geosciences Collaboration Project under Natural Resources Canada's International Opportunities Program.
文摘The oleanane parameter, i.e., OP (oleananes/(oleananes+C30hopanes)) in the two sedimentary columns of the Beibuwan Basin, South China Sea, can be used to delimit the top of oil generation window, with Ro (/%) of 0.53 in Well M1 and 0.55 in Wells H1/Hd1/Hd2, respectively. Comparing with vitrinite reflectance (Ro/%), the OP features a dynamic range and can indicate the oil generation window more precisely. By using OP and other geochemical indices, the oil-source correlation is also conducted. It suggests that the oils in wells M1 and M2 are derived from the source rocks in situ. The mudstone in Huachang uplift is not the main source rocks for oils in this area, The OP is also a useful oil-source correlation parameter in some Tertiary lacustrine basins.
基金the Natural Resources Data Management System (NRDMS),Department of Science and Technology, New Delhi, to sponsor the project
文摘Landslides are the most common natural disaster in hilly terrain which causes changes in landscape and damage to life and property. The main objective of the present study was to carry out landslide hazard zonation mapping on 1:50,000 scale along ghat road section of Kolli hills using a Landslide Hazard Evaluation Factor(LHEF) rating scheme. The landslide hazard zonation map has been prepared by overlaying the terrain evaluation maps with facet map of the study area. The terrain evaluation maps include lithology, structure, slope morphometry, relative relief, land use and land cover and hydrogeological condition. The LHEF rating scheme and the Total Estimated Hazard(TEHD) were calculated as per the Bureau of Indian Standard(BIS) guidelines(IS: 14496(Part-2) 1998) for the purpose of preparation of Landslide Hazard Zonation(LHZ) map in mountainous terrains. The correction due to triggering factors such as seismicity, rainfall and anthropogenic activities were also incorporated with Total Estimated Hazard to get final corrected TEHD. The landslide hazard zonation map was classified as the high, moderate and low hazard zones along the ghat road section based on corrected TEHD.
文摘The contents of nitrogen and organic carbon in an agricultural soil were analyzed using reflectance measurements (n=52)performed with an ASD FieldSpec-Ⅱspectroradiometer.For parameter prediction,empirical models based on partial least squares(PLS)regression were defined from the measured reflectance spectra(0.4 to 2.4μm).Here,reliable estimates were obtained for nitrogen content,but prediction accuracy was only moderate for organic carbon.For nitrogen, the real spatial pattern of within-field variability was reproduced with high accuracy.The results indicate the potential of this method as a quick screening tool for the spatial assessment of nitrogen and organic carbon,and therefore an appropriate alternative to time-and cost-intensive chemical analysis in the laboratory.
基金The National Natural Science Foundation of China under contract No.41371355the Director Fund Project of Institute of Remote Sensing and Digital Earth of CAS under contract No.Y6SJ0600CX
文摘Reflected signals from global navigation satellite systems(GNSSs) have been widely acknowledged as an important remote sensing tool for retrieving sea surface wind speeds.The power of GNSS reflectometry(GNSS-R)signals can be mapped in delay chips and Doppler frequency space to generate delay Doppler power maps(DDMs),whose characteristics are related to sea surface roughness and can be used to retrieve wind speeds.However,the bistatic radar cross section(BRCS),which is strongly related to the sea surface roughness,is extensively used in radar.Therefore,a bistatic radar cross section(BRCS) map with a modified BRCS equation in a GNSS-R application is introduced.On the BRCS map,three observables are proposed to represent the sea surface roughness to establish a relationship with the sea surface wind speed.Airborne Hurricane Dennis(2005) GNSS-R data are then used.More than 16 000 BRCS maps are generated to establish GMFs of the three observables.Finally,the proposed model and classic one-dimensional delay waveform(DW) matching methods are compared,and the proposed model demonstrates a better performance for the high wind speed retrievals.