Application of Spectral Angle Mapper Classification to Discriminate Hydrothermal Alteration in Southwest Birjand,Iran, Using Advanced Spaceborne Thermal Emission and Reflection Radiometer Image Processing     

Maryam ABDI  Mohammd H. KARIMPOUR 《《地质学报》英文版》2012,86(5):1289-1296

The purpose of this study is to evaluate the Spectral Angle Mapper (SAM) classification method for determining the optimum threshold (maximum spectral angle) to unveil the hydrothermal mineral assemblages related to mineral deposits. The study area indicates good potential for Cu-Au porphyry, epithermal gold deposits and hydrothermal alteration well developed in arid and semiarid climates, which makes this region significant for Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image processing analysis. Given that achieving an acceptable mineral mapping requires knowing the alteration patterns, petrochemistry and petrogenesis of the igneous rocks while considering the effect of weathering, overprinting of supergene alteration, overprinting of hypogene alteration and host rock spectral mixing, SAM classification was implemented for argillic, sericitic, propylitic, alunitization, silicification and iron oxide zones of six previously known mineral deposits: Maherabad, a Cu-Au porphyry system; Sheikhabad, an upper part of Cu-Au porphyry system; Khoonik, an Intrusion related Au system; Barmazid, a low sulfidation epithermal system; Khopik, a Cu-Au porphyry system; and Hanish, an epithermal Au system. Thus, the investigation showed that although the whole alteration zones are affected by mixing, it is also possible to produce a favorable hydrothermal mineral map by such complementary data as petrology, petrochemistry and alteration patterns.  相似文献   

A Modified Becker''s Split-Window Approach for Retrieving Land Surface Temperature from AVHRR and VIRR   总被引：1，自引：0，他引：1       下载免费PDF全文

QUAN Weijun  CHEN Hongbin  HAN Xiuzhen  LIU Yonghong  YE Caihua 《Acta Meteorologica Sinica》2012,26(2):229-240

In order to provide a long time-series, high spatial resolution, and high accuracy dataset of land surface temperature (LST) for climatic change research, a modified Becker and Li's split-window approach is pro- posed in this paper to retrieve LST from the measurements of Advanced Very High Resolution Radiometer (AVHRR) onboard National Oceanic and Atmospheric Administration (NOAA)-7 to -18 and the Visible and InfraRed Radiometer (VIRR) onboard FY-3A. For this purpose, the Moderate Resolution Transmittance Model (MODTRAN) 4.1 was first employed to compute the spectral radiance at the top of atmosphere (TOA) under a variety of surface and atmosphere conditions. Then, a temperature dataset consists of boundary temperature Ts (which is one of the input parameters to MODTRAN), and channels 4 and 5 brightness temperatures (T4 and T5) were constructed. Note that channels 4 and 5 brightness tempera- tures were simulated from the MODTRAN output spectral radiance by convolving them with the spectral response functions (SRFs) of channels 4 and 5 of AVHRRs and VIRR. The coefficients of modified Becker and Li's split-window approach for various AVHRRs and VIRR were subsequently regressed based on this temperature dataset using the least square method. As an example of validation, one AVHRR satellite image over Beijing acquired at 0312 UTC 27 April 2008 by AVHRR onboard NOAA-17 was selected to retrieve the LST image using the modified Becker and Li's approach. The comparison between this LST image and that from the MODIS level-2 LST product provided by the University of Tokyo in Japan indicates that the correlation coefficient is 0.88, the bias is 0.6 K, and the root mean square deviation (RMSD) is 2.1 K. Furthermore, about 70% and 37% pixels in the LST difference image, which is the result of retrieved LST image from AVHRR minus the corresponding MODIS LST image, have the values within ±2 and ±1 K, respectively.  相似文献   

Industrialization and Economic Development in Advanced Placement Human Geography     

《The Journal of geography》2012,111(3-4):142-152

Abstract

This article discusses the contents and significance of the industrialization and economic development section of the Advanced Placement human geography course. It also describes how the course outline breaks into four sections the concern of economic geographers with the analysis of the spatial character of economic activity. In summarizing the content of these sections attention is given to links with other course modules and to the use of effective pedagogies for articulating key concepts.  相似文献   

Beam超前地质预报技术在铜锣山隧道中的应用   总被引：8，自引：0，他引：8  

朱劲  李天斌  李永林  周大川  兰富安  姜洪涛  钱琳 《工程地质学报》2007,15(2):258-262

Beam是一种新型的电法超前预报技术,目前在国内应用很少。文章首先介绍了Beam超前地质预报方法的工作原理,然后结合Beam在国内垫邻高速公路铜锣山隧道施工中的首次应用,对该方法的具体工作过程和预报结果进行了介绍。与地质雷达、TSP预报结果以及实际开挖情况进行对比表明,Beam对掌子面前方水体具有良好的探测效果。最后对Beam在国内的推广应用提出了建议。  相似文献   

Photochemical Degradation of Hydrophilic Xenobiotics in the UV/H2O2-process. Influence of Humic Matter on the Degradation Rate of 2-Amino-1-naphthalenesulfonate and Ethylenediaminetetraacetate     

M. Srensen  U. Tanner  G. Sagawe  F. H. Frimmel 《洁净——土壤、空气、水》1996,24(3):132-136

Photochemical oxidation methods are able to eliminate hydrophilic xenobiotics with a high efficiency. In waters with high DOC values caused by humic substances (HS) which are able to absorb UV light, problems can result. The degradation rates of the micropollutants using irradiation wavelengths in the range between λ = 200 nm to λ = 260 nm are significantly influenced by HS. This is mainly caused by the high absorption of the HS at shorter wavelength. In the presence of HS, the photolytic degradation of EDTA and FeEDTA was slowed down by an inner filter effect. A similar tendency could be seen for the photolytic degradation of 2-amino-1-naphthalenesulfonate where additional effects to the inner filter effect were also operating. In the UV/H₂O₂-process, the decrease of the degradation rate could be assigned to the ability of the HS to scavenge HO radicals.  相似文献   

地下坑道开挖前方结构面超前探测   总被引：4，自引：0，他引：4  

张国  赵文 《工程地质学报》1997,5(2):169-173

本文在分析总结现有地球物理勘探方法的基础上, 提出了一种适合地下工程开挖前方结构面探测的新的方法--TVSP法, 同时对该方法进行了必要的分析。  相似文献   

ASTER数据在浅覆盖区蚀变遥感异常信息提取中的应用——以新疆西准噶尔包古图斑岩铜矿岩体为例   总被引：8，自引：0，他引：8  

耿新霞  杨建民  张玉君  姚佛军 《地质论评》2008,54(2):184-191

遥感卫星的多光谱数据应用于找矿已取得显著成效,2004年7月中国卫星地面站开始提供ASTER（Advanced Spaceborne Thermal Emission and Reflection Radiometer,高级星载热发射反照辐射计）数据,因涵盖波长范围宽［VNIR（Visible and Near Infrared）、SWIR（Short wavelength Infrared）、TIR（Thermal Infrared）］、波段多（14个波段）、性价比合理等因素,ASTER数据的研究迅速发展。长久以来,对覆盖区进行蚀变遥感异常信息提取一直是遥感找矿的关注点之一。笔者等利用ASTER数据对浅覆盖区——包古图斑岩铜矿的Ⅱ号、Ⅴ号斑岩体进行蚀变遥感异常提取,提取的蚀变异常与野外地质情况吻合性好。分别提取了光谱特征谱带差异明显的2组蚀变矿物的异常信息：第一组是蒙脱石、埃洛石、伊利石与绢云母;第二组是方解石、黑云母与绿泥石。提出了需要进一步工作的异常靶区。  相似文献   

Advanced Marginality as a comparative research strategy in praxis: the Danish “Grey Belt” in conversation with the French “Red Belt”     

Troels Schultz Larsen 《Urban geography》2018,39(8):1131-1151

Urban Outcast and advanced marginality belongs to a theory culture rarely engaged in comparative urban studies. Here the potential of advanced marginality as a comparative research strategy is explored paying special attention to the concepts of epistemic reflexivity, analogical reasoning and homology. These concepts are applied as the foundation of a comparative research design comprising three necessary and interconnected analytical moments linking reflexivity, theory and empirical analysis. Empirically this strategy and design is confronted in the case of four Danish “Grey belt” housing estates. The empirical confrontation demonstrates that both strategy and design are relevant and productive. Nevertheless, there is a need to question, adapt and extent the six original properties of advanced marginality. Secondly the empirical confrontation demonstrates that both strategy and design can contribute to the current conversations on the comparative in urban studies empirically and conceptually, underscoring the curiosity of its eclipse in these conversations.  相似文献   

The 1997 eruption of Okmok Volcano, Alaska: a synthesis of remotely sensed imagery     

M. R. Patrick  J. Dehn  K. R. Papp  Z. Lu  K. Dean  L. Moxey  P. Izbekov  R. Guritz 《Journal of Volcanology and Geothermal Research》2003,127(1-2):87-105

Okmok Volcano, in the eastern Aleutian Islands, erupted in February and March of 1997 producing a 6-km-long lava flow and low-level ash plumes. This caldera is one of the most active in the Aleutian Arc, and is now the focus of international multidisciplinary studies. A synthesis of remotely sensed data (AirSAR, derived DEMs, Landsat MSS and ETM+ data, AVHRR, ERS, JERS, Radarsat) has given a sequence of events for the virtually unobserved 1997 eruption. Elevation data from the AirSAR sensor acquired in October 2000 over Okmok were used to create a 5-m resolution DEM mosaic of Okmok Volcano. AVHRR nighttime imagery has been analyzed between February 13 and April 11, 1997. Landsat imagery and SAR data recorded prior to and after the eruption allowed us to accurately determine the extent of the new flow. The flow was first observed on February 13 without precursory thermal anomalies. At this time, the flow was a large single lobe flowing north. According to AVHRR Band 3 and 4 radiance data and ground observations, the first lobe continued growing until mid to late March, while a second, smaller lobe began to form sometime between March 11 and 12. This is based on a jump in the thermal and volumetric flux determined from the imagery, and the physical size of the thermal anomalies. Total radiance values waned after March 26, indicating lava effusion had ended and a cooling crust was growing. The total area (8.9 km²), thickness (up to 50 m) and volume (1.54×10⁸ m³) of the new lava flow were determined by combining observations from SAR, Landsat ETM+, and AirSAR DEM data. While the first lobe of the flow ponded in a pre-eruption depression, our data suggest the second lobe was volume-limited. Remote sensing has become an integral part of the Alaska Volcano Observatory’s monitoring and hazard mitigation efforts. Studies like this allow access to remote volcanoes, and provide methods to monitor potentially dangerous ones.  相似文献   

Modelling of piping collapses and gully headcut landforms:Evaluating topographic variables from different types of DEM   总被引：1，自引：0，他引：1  

Alireza Arabameri  Fatemeh Rezaie  Subodh Chandra Pal  Artemi Cerda  Asish Saha  Rabin Chakrabortty  Saro Lee 《地学前缘(英文版)》2021,12(6):129-146

The geomorphic studies are extremely dependent on the quality and spatial resolution of digital elevation model(DEM)data.The unique terrain characteristics of a particular landscape are derived from DEM,which are responsible for initiation and development of ephemeral gullies.As the topographic features of an area significantly influences on the erosive power of the water flow,it is an important task the extraction of terrain features from DEM to properly research gully erosion.Alongside,topography is highly correlated with other geo-environmental factors i.e.geology,climate,soil types,vegetation density and floristic composition,runoff generation,which ultimately influences on gully occurrences.Therefore,terrain morphometric attributes derived from DEM data are used in spatial prediction of gully erosion susceptibility(GES)mapping.In this study,remote sensing-Geographic information system(GIS)tech-niques coupled with machine learning(ML)methods has been used for GES mapping in the parts of Semnan province,Iran.Current research focuses on the comparison of predicted GES result by using three types of DEM i.e.Advanced Land Observation satellite(ALOS),ALOS World 3D-30 m(AW3D30)and Advanced Space borne Thermal Emission and Reflection Radiometer(ASTER)in different resolutions.For further progress of our research work,here we have used thirteen suitable geo-environmental gully erosion conditioning factors(GECFs)based on the multi-collinearity analysis.ML methods of conditional inference forests(Cforest),Cubist model and Elastic net model have been chosen for modelling GES accordingly.Variable's importance of GECFs was measured through sensitivity analysis and result show that elevation is the most important factor for occurrences of gullies in the three aforementioned ML methods(Cforest=21.4,Cubist=19.65 and Elastic net=17.08),followed by lithology and slope.Validation of the model's result was performed through area under curve(AUC)and other statistical indices.The validation result of AUC has shown that Cforest is the most appropriate model for predicting the GES assessment in three different DEMs(AUC value of Cforest in ALOS DEM is 0.994,AW3D30 DEM is 0.989 and ASTER DEM is 0.982)used in this study,followed by elastic net and cubist model.The output result of GES maps will be used by decision-makers for sustainable development of degraded land in this study area.  相似文献