基于遥感与GIS的库克苏河流域冰川变化研究

以伊犁河上游库克苏河流域冰川为例,利用1963年地形图、2004年的ASTER数字遥感影像资料及数字高程模型,通过遥感图像处理和分析提取研究区冰川范围,并在地理信息系统技术支持下分析该地区冰川的变化情况.研究表明1963-2004年库克苏河流域冰川整体变化幅度较大,冰川表现为萎缩的趋势,2004年冰川面积、冰储量比19...     

中亚阿拉套地区冰川退缩与气候变化关系研究

以1990-2011年的TM和ETM+遥感资料为信息源,通过遥感图像处理技术和目视解译方法提取冰川界限,应用GIS技术分析了阿拉套地区近22 a冰川面积变化。结果表明:1990-2011年阿拉套地区冰川呈退缩趋势,面积退缩了20.24%,大规模冰川分解使得小规模冰川的总面积和条数均有所增加,较大的变化率是由于研究区面积1 km2的冰川数量占总数的比重较大(近90%)造成的,依据研究区冰川空间结构特征,应用分形理论对未来冰川变化进行初步预测,认为研究区冰川的消融率仍保持比较高的状态。表明阿拉套地区冰川退缩的关键因素是气候变暖,年降水量的增加不能抵消由夏季温度剧烈上升导致的冰川消融。此外,地形条件、冰川规模都是影响冰川波动的重要因素,与西部其他区域相比,阿拉套地区冰川退缩表现出较快的趋势。     

冰川冰储量计算方法及发展趋势

冰川冰储量不仅是冰川的重要属性,而且是核算冰川水资源及预测冰川变化的基础数据,因此准确计算冰川冰储量及其变化具有重要的理论与现实意义。目前冰川储量估算的主要方法有经验公式法、冰厚模型估算法、探地雷达法;冰川储量相对变化计算方法有实地测量法和遥感监测法。通过系统分析和讨论各计算方法的原理、现状及存在的问题,以期为冰川储量估算提供方法参考。研究表明：对于冰川冰储量计算而言,经验公式法适用于区域性或全球性的冰川储量估算;模型估算法适用于个体或小范围冰川储量估算;探地雷达法适用于人类易到达区域冰川储量的估算。对于冰川冰储量相对变化计算,实地测量法适用于对精度要求高且满足实地测量条件的单条或中小型冰川,遥感监测法适用于全球性冰储量变化估算,但需改进算法和提高数据空间分辨率。目前,随着无人机技术的逐步应用,以及冰川流速等理论模型的提出,为冰川冰储量估算方法的发展提供了新契机。     

基于无人机摄影测量的梅里雪山明永冰川末端表面高程动态监测

位于横断山区的梅里雪山地区,受地形与气候的影响,该地区光学遥感及微波遥感应用较为受限。论文基于大疆精灵4RTK无人机搭配中海达UBase,于2018年11月9日和2019年11月12日对梅里雪山地区明永冰川末端开展了2期摄影测量,估算冰川消融区表面高程变化,监测冰川动态变化。研究结果表明:冰川区表面形态在不同位置有显著差别,航测冰川区中下部大量表碛覆盖,有少量沿冰川主流线方向发育的裂隙;航测冰川区中上部表碛覆盖较少,大量横向裂隙发育。2018年11月至2019年11月,明永冰川末端表面高程平均变化-1.67 m。冰川表面高程变化空间分布差异显著,在航测冰川区上部高程差存在正负交替现象,航测冰川区中部以减薄为主,而航测冰川区下部以增厚为主。与高亚洲地区其他山系冰川变化对比,梅里雪山地区是冰川表面高程变化最显著的地区。     

1990—2020年朋曲流域冰川变化及其对气候变化的响应

基于Landsat系列影像、数字高程模型(DEM)等资料,采用遥感图像处理及目视解译方法,提取了朋曲流域1990—2020年冰川边界信息,研究了近30 a来朋曲流域冰川面积的分布、变化及其与气候变化的响应关系.结果表明:(1)1990—2020年研究区冰川面积持续缩小,冰川面积的退缩率为1.52％·a-1,对比不同时段...     

1978-2015年喀喇昆仑山克勒青河流域冰川变化的遥感监测

本文采用1978、1991、2001和2015年的Landsat MSS、TM、ETM+和OLI遥感影像,通过遥感图像计算机辅助分类和目视解译等方法提取冰川边界,分析喀喇昆仑山克勒青河流域冰川在1978-2015年间的进退变化。结果表明：1978-2015年间研究区冰川面积由1821.70 km2减少至1675.92 km2,减少145.78 km2,占1978年冰川总面积的8.00%;冰川消融率较低,在气候变暖的背景下反而呈现出退缩速率由快变慢的趋势。研究区东南向冰川退缩率明显高于西北向,冰川退缩率随冰川规模的增大而减小。研究区内有27处冰川在1978-2015年间发生过特殊的前进现象,面积与长度显著增加。其中,木斯塔冰川西侧冰川末端在1996-1998年间前进速度为904 m/a,乔戈里冰川东侧冰川末端在2007-2009年间前进速度为446 m/a,5Y654D0097冰川末端在1978-1990年间前进速度为238 m/a,初步判定这三条冰川为跃动冰川。以10 a为滞后期分析研究区周边气象站点资料发现：研究区气温持续升高,降水量以1981年为分界点呈现“先减后增”趋势是冰川退缩速率减慢的原因之一;此外,亚大陆型冰川性质、巨大山势条件和高山冷储作用,也可能是冰川退缩幅度较小的原因。     

近30年珠穆朗玛峰国家自然保护区冰川变化的遥感监测

利用1976、1988和2006年的3期陆地卫星遥感数据,采用面向对象的解译方法并结合专家知识分类规则自动提取珠穆朗玛峰国家自然保护区(以下简称珠峰保护区)3个时期的冰川信息,并利用遥感、地理信息系统和图谱的方法对冰川时空分布特征和变化及其原因与不确定性进行了分析。结果如下:(1)2006年珠峰保护区内冰川面积为2710.17±0.011km²,为研究区总面积的7.41%,主要分布在研究区南部海拔4700～6800m的高山区;(2)1976-2006年,珠峰保护区冰川持续退缩明显,总面积减少501.91±0.035km²,冰湖扩张迅速(净增加36.88±0.035km²);研究区南坡子流域冰川退缩率(16.79%)高于北坡子流域(14.40%);珠峰保护区冰川以退缩为主,退缩冰川主要分布于海拔4700～6400m,退缩区上限海拔为6600～6700m;(3)1976年以来,气温显著上升和降水减少是冰川退缩的关键因素。     

1980～2007年喜马拉雅东段洛扎地区冰川变化遥感监测

利用1980年地形图和多年遥感资料,采用目视解译方法手工提取了喜马拉雅东段洛扎地区4个时期的冰川信息,对冰川时空分布特征和变化与不确定性进行了分析,并结合近28年(1980～2007年)的气温、降水量资料对研究区的冰川变化原因进行了研究.结果表明:(1)1980～2007年,洛扎地区冰川面积从491.64 km<'2>...     

1959-2008年新疆阿尔泰山友谊峰地区冰川变化特征

 利用1959年地形图、2008年ASTER数字遥感影像及数字高程模型,在地理信息系统技术支持下分析了新疆阿尔泰山友谊峰地区冰川的变化特征。研究表明：1959-2008年该区冰川整体呈萎缩趋势,且变化幅度相对较大。相对于1959年,2008年冰川面积和数量分别变化-32.5%和-27.9%。其中,小于1 km2的冰川面积平均变化率为-66.7%,面积小于0.5 km2的冰川面积变化率大于-70%,面积大于1 km2以上的冰川面积变化率为-35.0%,1~5 km2的冰川面积变化率为-27.9%。冰川末端平均后退253 m,末端退缩比例为-18.3%,且南坡冰川末端变化率大于北坡。分析发现,研究区冰川面积亏损较大主要缘于该区小冰川分布数量较多（面积小于1 km2的冰川数量达75%),对气候变化的响应较为敏感。     

极地记录冰川和达尔克冰川流速的遥感监测研究

测定南极冰川的流速 ,对于研究南极冰雪物质平衡、南极环境变化及其对全球环境的影响有重大意义。本文论述了利用多时相卫星遥感影像监测冰川变化的原理和方法 ,通过对英格里特 .克里斯泰森海岸不同时期的遥感影像进行几何纠正和配准及叠加处理 ,测量和计算出极地记录冰川和达尔克冰川的平均流速 ,并对它们的变化特点进行了初步的分析和评价。     

Policy Change and Venue Choices: Field Burning in Idaho and Washington

Grass seed farmers have burned their fields in Idaho and Washington State for decades. Field burning, however, creates small particulate matter air pollution, thus engendering a growing public backlash by the 1990s that manifested itself in new clean air advocacy groups. The new groups’ push for policy change eventually met with significant success in both cases. How did each set of advocates approach the challenge of policy change? More specifically, what kinds of policy venues did each group choose and why? This research uses the cases to explore and explain each clean air group's choices vis-à-vis hypotheses of venue choice. Three hypotheses are tested—Schattschneider's (1960 Schattschneider , E. E. 1960 . The semisovereign people . New York , NY : Holt, Rinehart, and Winston . [Google Scholar]) “expanded scope of conflict” thesis, ACF's (Sabatier and Jenkins-Smith 1999 Sabatier , P. , and H. Jenkins-Smith . 1999 . The advocacy coalition framework: An assessment . In Theories of the policy process , ed. P. A. Sabatier , 117 – 166 . Boulder , CO : Westview Press . [Google Scholar]) contention that groups strategically apply their resources in order to increase the likelihood of achieving their primary goal(s), and Pralle's (2003 Pralle , S. B. 2003 . Venue shopping, political strategy, and policy change . J. Public Policy 23 : 233 – 260 .[Crossref] , [Google Scholar], 2010 Pralle , S. B. 2010 . Shopping around: Environmental organizations and the search for policy venues . In Advocacy organizations and collective action , ed. A. Prakash and M. K. Gugerty , 177 – 203 . Cambridge , MA : Cambridge University Press .[Crossref] , [Google Scholar]) thesis that internal group constraints deter groups from moving into new venues.     

Numerical experiments with cooperating multiple quadratic snakes for road extraction

Higher-order active contours or snakes show much promise for the extraction of complex objects from noisy imagery. These models provide an elegant mathematical framework for specifying the desired properties of target objects through energy functionals that can be minimized with standard optimization techniques. However, techniques to allow quadratic snakes to change topology during segmentation have not been fully exploited. Additionally, external forces for improving convergence of quadratic snakes have similarly yet to be explored. In this article, we propose a model that allows multiple quadratic snakes to split, merge, and disappear. Although the separate components of our approach have been introduced elsewhere by Cohen (1991 Cohen, L.D. 1991. On active contour models and balloons. CVGIP: Image Understanding, 53(2): 211–218.  [Google Scholar]), Xu and Prince (1997 Xu, C. and Prince, J.L. Gradient vector flow: a new external force for snakes. IEEE Conference on Computer Vision and Pattern Recognition (CVPR). June, San Juan. pp.66–71.  [Google Scholar]), and Rochery et al. (2006 Rochery, M., Jermyn, I.H. and Zerubia, J. 2006. Higher order active contours. International Journal of Computer Vision, 69(1): 27–42.  [Google Scholar]), this article is the first comprehensive empirical study of their performance on real-world complex network extraction tasks. We analyze the applicability of the model to road extraction from satellite images that vary in complexity from simple networks to large networks with multiple loops. We also analyze the effects of external forces enhanced by oriented filtering, gradient vector flow fields, and Canny edge detection. In a series of experiments, we found that the multiple cooperating quadratic snake model performs well on complex, noisy images. Our experiments also establish a performance improvement when the proposed quadratic model is coupled with the Canny-based gradient vector flow technique.     

Response to ‘Comments on “Combining spatial transition probabilities for stochastic simulation of categorical fields” with communications on some issues related to Markov chain geostatistics’

Li and Zhang (2012b Li, W. and Zhang, C. 2012b. Comments on ‘Combining spatial transition probabilities for stochastic simulation of categorical fields’ with communications on some issues related to Markov chain geostatistics. International Journal of Geographical Information Science, 26(10): 1725–1739. [Taylor & Francis Online] , [Google Scholar], Comments on ‘Combining spatial transition probabilities for stochastic simulation of categorical fields’ with communications on some issues related to Markov chain geostatics) raised a series of comments on our recent paper (Cao, G., Kyriakidis, P.C., and Goodchild, M.F., 2011 Cao, G., Kyriakidis, P.C. and Goodchild, M.F. 2011. Combining spatial transition probabilities for stochastic simulation of categorical fields. International Journal of Geographical Information Science, 25(11): 1773–1791. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]. Combining spatial transition probabilities for stochastic simulation of categorical fields. International Journal of Geographical Information Science, 25 (11), 1773–1791), which include a notation error in the model equation provided for the Markov chain random field (MCRF) or spatial Markov chain model (SMC), originally proposed by Li (2007b Li, W. 2007b. Markov chain random fields for estimation of categorical variables. Mathematical Geology, 39(3): 321–335. [Crossref] , [Google Scholar], Markov chain random fields for estimation of categorical variables. Mathematical Geology, 39 (3), 321–335), and followed by Allard et al. (2011 Allard, D., D'Or, D. and Froideveaux, R. 2011. An efficient maximum entropy approach for categorical variable prediction. European Journal of Soil Science, 62: 381–393. [Crossref], [Web of Science ®] , [Google Scholar], An efficient maximum entropy approach for categorical variable prediction. European Journal of Soil Science, 62, 381–393) about the misinterpretation of MCRF (or SMC) as a simplified form of the Bayesian maximum entropy (BME)-based approach, the so-called Markovian-type categorical prediction (MCP) (Allard, D., D'Or, D., and Froideveaux, R., 2009 Allard, D., D'Or, D. and Froidevaux, R. 2009. Estimating and simulating spatial categorical data using an efficient maximum entropy approach, Avignon: Unité Biostatistique et Processus Spatiaux Institut National de la Recherche Agronomique. Technical Report No. 37 [Google Scholar]. Estimating and simulating spatial categorical data using an efficient maximum entropy approach. Avignon: Unite Biostatisque et Processus Spatiaux Institute National de la Recherche Agronomique. Technical Report No. 37; Allard, D., D'Or, D., and Froideveaux, R., 2011 Allard, D., D'Or, D. and Froideveaux, R. 2011. An efficient maximum entropy approach for categorical variable prediction. European Journal of Soil Science, 62: 381–393. [Crossref], [Web of Science ®] , [Google Scholar]. An efficient maximum entropy approach for categorical variable prediction. European Journal of Soil Science, 62, 381–393). Li and Zhang (2012b Li, W. and Zhang, C. 2012b. Comments on ‘Combining spatial transition probabilities for stochastic simulation of categorical fields’ with communications on some issues related to Markov chain geostatistics. International Journal of Geographical Information Science, 26(10): 1725–1739. [Taylor & Francis Online] , [Google Scholar], Comments on ‘Combining spatial transition probabilities for stochastic simulation of categorial fields’ with communication on some issues related to Markov chain geostatistics. International Journal of Geographical Information Science) also raised concerns regarding several statements Cao et al. (2011 Cao, G., Kyriakidis, P.C. and Goodchild, M.F. 2011. Combining spatial transition probabilities for stochastic simulation of categorical fields. International Journal of Geographical Information Science, 25(11): 1773–1791. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar], Combining spatial transition probabilities for stochastic simulation of categorical fields. International Journal of Geographical Information Science, 25 (11), 1773–1791) had made, which mainly include connections between permanence of ratios and conditional independence, connections between MCRF and Bayesian networks and transiograms as spatial continuity measures. In this response, all of the comments and concerns will be addressed, while also communicating with Li and other colleagues on general topics in Markov chain geostatistics.     

Effective Community Engagement for Sustainability: Wombat Community Forest Management Case Study

The first significant government sponsored community‐based forest management project in Australia was initiated in Central Victoria in 2002. This paper analyses the initial stage of the Wombat Community Forest Management Pilot Project. The paper develops a functional concept of ‘effective community’ for structuring community engagement in these kinds of natural resource management projects. The effective community has characteristics in common with a community of interest, adopts a bioregional perspective, embodies the values of environmental stewardship and interacts in a fully informed way as a ‘discursive community’ (Meppam 2000 Meppam, T. 2000. ‘The discursive community: evolving institutional structures for planning sustainability’, Ecological Economics, 34: 47–61.  [Google Scholar]). The paper offers general advice for organising effective community engagement in such projects and 12 recommendations for governments developing similar initiatives elsewhere.     

A Critical Evaluation of Structural Reform Considerations in ‘Rates and Taxes: A Fair Share for Responsible Local Government’

In its landmark report entitled Rates and Taxes: A Fair Share for Responsible Local Government, the Commonwealth House of Representatives Standing Committee on Economics, Finance and Public Administration (2003 Commonwealth House of Representatives Standing Committee On Economics, Finance and Public Administration [‘Hawker Report’] ( 2003 ) Rates and taxes: a fair share for responsible local government , Commonwealth of Australia, Canberra . [Google Scholar]) considered the plight of Australian local government given its very wide terms of reference involving local government's roles and responsibilities, current funding arrangements, municipal capacity, council expenditure, scope for rationalisation, and the findings of the Commonwealth Grants Commission Review (2001 Commonwealth Grants Commission (CGC) ( 2001 ) Review of the Operation of Local Government (Financial Assistance) Act 1995 , Canberra . [Google Scholar]) of the Local Government (Financial Assistance) Act 1995. The authors of the ‘Hawker Report’ brought down 18 recommendations, two of which dealt directly with the thorny question of structural reform. This paper seeks to provide a critical assessment of those aspects of the Report that concern structural reform in Australian local government.     

An analytic solution to the alibi query in the space–time prisms model for moving object data

Moving objects produce trajectories, which are stored in databases by means of finite samples of time-stamped locations. When speed limitations in these sample points are also known, space–time prisms (also called beads) (Pfoser and Jensen 1999 Pfoser, D. and Jensen, C.S. 1999. “Capturing the uncertainty of moving-object representations”. In Advances in spatial databases (SSD’99), Hong Kong, China, July 20–23, 1999, Vol. 1651, 111–132. Lecture notes in Computer Science.  [Google Scholar], Egenhofer 2003 Egenhofer, M. 2003. “Approximation of geopatial lifelines”. In SpadaGIS, workshop on spatial data and geographic information systsems, 4SpaDaGIS–Workshop on Spatial Data and Geographic Information Systems, Milano, Italy, March 2003. University of Genova.  [Google Scholar], Miller 2005 Miller, H. 2005. A measurement theory for time geography. Geographical Analysis, 37(1): 17–45. [Crossref], [Web of Science ®] , [Google Scholar]) can be used to model the uncertainty about an object's location in between sample points. In this setting, a query of particular interest that has been studied in the literature of geographic information systems (GIS) is the alibi query. This boolean query asks whether two moving objects could have physically met. This adds up to deciding whether the chains of space–time prisms (also called necklaces of beads) of these objects intersect. This problem can be reduced to deciding whether two space–time prisms intersect.

The alibi query can be seen as a constraint database query. In the constraint database model, spatial and spatiotemporal data are stored by boolean combinations of polynomial equalities and inequalities over the real numbers. The relational calculus augmented with polynomial constraints is the standard first-order query language for constraint databases and the alibi query can be expressed in it. The evaluation of the alibi query in the constraint database model relies on the elimination of a block of three exªistential quantifiers. Implementations of general purpose elimination algorithms, such as those provided by QEPCAD, Redlog, and Mathematica, are, for practical purposes, too slow in answering the alibi query for two specific space–time prisms. These software packages completely fail to answer the alibi query in the parametric case (i.e., when it is formulated in terms of parameters representing the sample points and speed constraints).

The main contribution of this article is an analytical solution to the parametric alibi query, which can be used to answer the alibi query on two specific space–time prisms in constant time (a matter of milliseconds in our implementation). It solves the alibi query for chains of space–time prisms in time proportional to the sum of the lengths of the chains. To back this claim up, we implemented our method in Mathematica alongside the traditional quantifier elimination method. The solutions we propose are based on the geometric argumentation and they illustrate the fact that some practical problems require creative solutions, where at least in theory, existing systems could provide a solution.     

Comment on Rust et al.: Human–Carnivore Conflict in Namibia Is Not Simply About Black and White

Carnivore conservationists agree that addressing the socioeconomic needs of people is critical to human-carnivore conflict mitigation. We therefore welcome studies that encompass complex social and cultural factors that affect the severity of human-carnivore conflict on Namibian farmlands. However, we contend that the recent study by Rust et al. (2016 Rust, N. A., J. Tzanopoulos, T. Humle, and D. C. MacMillan. 2016. Why has human–carnivore conflict not been resolved in Namibia? Society &; Natural Resources 29 (9):1079–94. doi:10.1080/08941920.2016.1150544[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) was poorly designed, used inappropriate sampling methods, lacked quantitative information on their qualitative results, and ultimately produced unsupported conclusions about the role of historic apartheid and current racism in exacerbating human-carnivore conflict in Namibia. We outline our concerns regarding the methods used, and demonstrate that the conclusions drawn by Rust et al. were not supported by their data.