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1.
基于植被供水指数的农田干旱遥感监测研究 总被引：21，自引：3，他引：21
应用1995-2000年NOAA卫星资料，结合广西贵港市的数字化土地利用信息，通过时序分析方法找出典型作物代表区，并计算各典型代表区的平均、最大、最小VSWI（Vegetation Supply Water Index；植被供水指数）特征值，归纳分析水田和旱地的干旱指标，继而根据典型代表区的平均VSWI值划分旱情等级，生成农田旱情遥感图像，评估干旱情况。试验表明，该方法可用于湿润、半湿润地区的农田干旱遥感监测。 相似文献
2.
The Ramsar Convention is unquestionably the backbone of modern wetland management theory and practice. In the last four decades, it has mainstreamed wetlands in the environmental discourse and fostered the development of a comprehensive institutional framework for wetland governance. However, many of the wetlands that occur in human-dominated landscapes remain acutely threatened. The problem is most alarming in urban areas, especially in the fast expanding cities of the developing world, where unprecedented wetland destruction is leading to recurring environmental disasters. This triggers the question: are these failures in wetland governance purely induced by factors exogenous to Ramsar-based institutions or are they manifestations of conceptual drawbacks within Ramsar conceptual framework. Here, we investigate the success and failures of the application of the Ramsar framework's policy directives and management guidelines for urban wetlands using two rapidly expanding cities in South Asia as case studies – Colombo (Sri Lanka) and Kolkata (India). We conclude that despite its remarkable achievements over the past four decades, the Ramsar framework has several conceptual drawbacks that weaken its effectiveness in complex urban contexts. An inadequate recognition of the complex dynamics of urban social-ecological systems, an inadequate recognition of the political complexity of the policy processes, and a lack of an environmental justice perspective are the main shortcomings contributing to failures in urban wetlands governance. While we acknowledge that some solutions are contingent upon national and transnational level socio-political processes and reforms, we offer a set of technical and strategic modifications to the Ramsar framework that can significantly improve its effectiveness in urban wetlands governance. 相似文献
3.
气象卫星遥感资料在积雪监测中的应用 总被引：2，自引：2，他引：2
介绍了在地区级气象台站采用气象系统 92 1 0工程下发的FY 1D卫星遥感数据 ,在短红外波段的基础上建立多光谱提取积雪信息的计算方法及监测模型 ,并以2 0 0 2年 1 1月至 2 0 0 3年 5月新疆积雪遥感监测为例 ,介绍了卫星遥感监测积雪深度和积雪覆盖面积的方法 ,分析了积雪覆盖特征和变化规律。 相似文献
4.
极轨气象卫星森林火灾实时监测系统 总被引：1，自引：0，他引：1
介绍了新开发的极轨气象卫星林火实时监测系统的原理、功能及其数据处理流程.其特点是在卫星过境的同时就可处理出森林火灾信息,解决了目前同类气象卫星林火监测系统不能实时监测的问题.极轨气象卫星林火实时监测系统是由3台计算机组成的并行处理系统.该系统将火点判识的时序从模糊到确定分3步进行,并将数据接收、火点判断、火点定位、显示等的运行时序分配在3台计算机中同步运行.该系统于2005年在广州气象卫星地面站投入业务运行.与原有卫星遥感林火监测系统比较,该系统对森林火灾监测的时间可提早约30 min. 相似文献
5.
积雪作为主要的淡水资源,准确地监测积雪覆盖与雪深具有十分重要的意义。随着全球卫星导航系统的不断建设和新技术新应用的不断发展,地基GPS遥感积雪参数技术越来越受国内外学者的重视。本文基于阿勒泰市气象局的GPS地表环境监测站观测数据,采用GPS-MR技术开展了积雪深度反演研究。首先给出了GPS-MR技术用于积雪深度反演的基本原理,其次利用阿勒泰GPS监测站2017年1—3月的数据进行了积雪深度反演分析,最后针对不同GPS卫星高度角区间影响进行精度分析。研究结果表明地基GPS可用于阿勒泰气象站积雪深度反演,与实测雪深较差优于3 cm,且较优卫星高度角区间为5°～20°。地基GPS用于积雪深度反演具有全天候、高精度、高时间分辨率、高自动化、低成本等优点,可充分发挥现有地基GNSS气象监测站在积雪探测领域潜在的应用价值,以期地基GNSS监测站成为积雪遥感探测手段的有效补充。 相似文献
6.
Sensor calibration, including its definition, purpose, traceability options, methodology, complexity, and importance, is examined in this paper in the context of supporting NOAA’s satellite mission. Common understanding of sensor calibration is essential for the effective communication among sensor vendors, calibration scientists, satellite operators, program managers, and remote sensing data users, who must cooperate to ensure that a nation’s strategic investment in a sophisticated operational environmental satellite system serves the nation’s interest and enhances the human lives around the world. Examples of calibration activities at NOAA/NESDIS/ORA are selected to further illustrate these concepts and to demonstrate the lessons learned from the past experience. 相似文献
7.
用FY-1C/CAVHRR数据估算巢湖蓝藻叶绿素的含量 总被引：6，自引：0，他引：6
以巢湖为实验区，以气象卫星FY－1C／CAVHRR数据为信息源，通过遥感监测值与（淮）同步湖区实地采样叶绿素α(chl-α)含量的对比分析，建立基于FY－1C／CAVHRR数据的叶绿素α含量遥感估算模型。研究表明，FY－1C气象卫星可用于内陆大面积湖泊湖面叶绿素含量的遥感监测，在动态监测方面有明显优势，可作为现有湖泊水质采样观测的补充手段。 相似文献
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J. Ricardo A. De França J. -M. Brustet J. Fontan 《Journal of Atmospheric Chemistry》1995,22(1-2):81-110
Remote sensing measurements provide a vauable means of determining the extent of burning areas and of estimating the overall distribution of pollutant sources (identified from experimental studies) in time and space. This distribution has to be taken into account in the boundary conditions of chemistry atmospheric models.Recent methods developed for the remote sensing of active fires in tropical or temperated forest zones, have been found to be completely inadequate for fire detection on West African savannas. In order to accurately estimate the active fire distribution in the function of different sorts of West African savannas (Sahelian, Sudanian and Guinean) and forests, a multispectral methodology has been developed based on NOAA/11-AVHRR satellite data, with the purpose of eliminating as much as possible the problems related to large surface heterogeneity, confusion and bias, produced by clouds, smoke, haze, background emissivities, etc.Unlike other methods, the results show that the multispectral method, in spite of its selectivity, provides realistic results, and does not under- or over-estimate the number of fires that can be sensed by the satellite. Consequently, this methodology is more appropriate than the simplest ones for a systematic sensing of this phenomenon. 相似文献
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11.
Existing studies of mangroves in Senegal and The Gambia have found net increases in mangrove tree cover at the national scale, but these do not accord with local accounts and explanations of loss. This paper utilizes remote sensing analysis and political ecology frameworks to assess local accounts of mangrove wood trafficking across the border between The Gambia and southern Senegal, which were encountered in conducting qualitative field research. The remote sensing results demonstrate overall increases in mangrove cover in The Gambia and in the Sine Saloum and Low Casamance estuaries in Senegal between 1988 and 2018, but also highlight greater declines in mangrove cover in Low Casamance in the 1990s—a period of heightened regional political conflict—and in particular areas of the estuary near the Gambian and Guinea-Bissauan borders. Focusing on political ecology’s attention to multiple scales of analysis, this paper addresses divergent interpretations of mangrove changes in the region, and how local accounts of destruction may not be fully captured by the scale of observation and analysis in remote sensing. The paper argues for greater attention to spatial and temporal variation in studies of mangrove dynamics, and greater consideration for how these patterns may result from confluences of political, social, and natural factors. 相似文献
12.
Sensor calibration, including its definition, purpose, traceability options, methodology, complexity, and importance, is examined in this paper in the context of supporting NOAA's satellite mission. Common understanding of sensor calibration is essential for the effective communication among sensor vendors, calibration scientists, satellite operators, program managers, and remote sensing data users, who must cooperate to ensure that a nation's strategic investment in a sophisticated operational environmental satellite system serves the nation's interest and enhances the human lives around the world. Examples of calibration activities at NOAA/NESDIS/ORA are selected to further illustrate these concepts and to demonstrate the lessons learned from the past experience. 相似文献
13.
通过对浒苔的光谱特性分析,建立基于极轨气象卫星和环境卫星资料监测浒苔的模型技术方法,利用该模型实现浒苔信息提取,生成浒苔监测产品,并在地理信息技术支持下,分析浒苔影响范围及移动路径。利用2006—2008年卫星资料分析表明:2006年和2007年夏季,黄海未出现明显的浒苔信息;2008年5月中旬,浒苔始发于黄海中南部;6月中下旬,浒苔影响范围最大时达到800 km2;7月中下旬,黄海海域浒苔范围明显减小。对浒苔移动路径和黄海海域风场等资料的综合分析结果表明,浒苔位置移动主要受风力和洋流作用的影响。 相似文献
14.
Micronutrient deficiencies constitute a pressing public health concern, especially in developing countries. As a dense source of bioavailable nutrients, aquatic foods can help alleviate such deficiencies. Developing aquaculture that provides critical micronutrients without sacrificing the underlying environmental resources that support these food production systems is therefore essential. Here, we address these dual challenges by optimizing nutrient supply while constraining the environmental impacts from aquaculture. Using life cycle assessment and nutritional data from Indonesia, a top aquaculture producer, we sought to identify aquaculture systems that increase micronutrient supplies and reduce environmental impacts (e.g., habitat destruction, freshwater pollution, and greenhouse gas emissions). Aquaculture systems in Indonesia vary more by environmental impacts (e.g. three order of magnitude for fresh water usage) than by nutritional differences (approximately ± 50% differences from mean relative nutritional score). Nutritional-environmental tradeoffs exist, with no single system offering a complete nutrition-environment win–win. We also find that previously proposed future aquaculture paths suboptimally balance nutritional and environmental impacts. Instead, we identify optimized aquaculture production scenarios for 2030 with nutrient per gram densities 105–320% that of business-as-usual production and with environmental impacts as low as 25% of those of business-as-usual. In these scenarios Pangasius fish (Pangasius hypophthalmus) ponds prove desirable due to their low environmental impacts, but average relative nutrient score. While the environmental impacts of the three analyzed brackish water systems range from average to high compared to other aquaculture systems, their nutritional attributes render them necessary when maximizing all nutrients except vitamin A. Common carp (Cyprinus carpio) ponds also proved essential in maximizing zinc and omega n-3, while Tilapia (Oreochromis niloticus) cages were necessary in optimizing the production of calcium and vitamin A. These optimal aquaculture strategies also reduce business-as-usual demand for wild fish-based feed by 0–30% and mangrove expansion by 0–75% with no additional expansion into inland open waters and freshwater ponds. As aquaculture production expands globally, optimization presents a powerful opportunity to reduce malnutrition rates at reduced environmental impacts. The proposed reorientation promotes UN sustainable development goals 2 (zero hunger), 3 (health), 13 (climate action) and 14 (life under water) and requires concerted and targeted policy changes. 相似文献
15.
Long-term observations for monitoring of the cryosphere 总被引：1，自引：0，他引：1
John E. Walsh 《Climatic change》1995,31(2-4):369-394
Variations of the cryosphere over decadal-to-century timescales are assessed by a survey of data on sea ice, snow cover, glaciers and ice sheets, permafrost and lake ice. The recent variations are generally consistent across the different cryospheric variables, especially when placed into the context of variations of temperature and precipitation. The recent warming over northern land areas has been accompanied by a decrease of snow cover, particularly during spring; the retreat of mountain glaciers is, in an aggregate sense, compatible with the observed warming; permafrost extent and lake ice duration show similar variations in areas for which data are available. Corresponding trends are not apparent, however, in data for some regions such as eastern Canada, nor in hemispheric sea ice data, especially for winter. The data also suggest an increase of snowfall over high latitudes, including the Antarctic ice sheet.Estimates of both the climatic and the statistical significance of the recent variations are hampered by data inhomogeneities, the shortness of the records of many variables and the absence of central archives for data on several variables. The potential of monitoring by satellite remote sensing has been realized with several variables (extent of sea ice, snow cover). Other cryospheric variables (snow depth, ice sheet elevation, lake ice, mountain glaciers) may be amenable to routine monitoring by satellites pending advances in instrumentation, modifications of satellite orbit, and further developments in signal detection algorithms. The survey of recent variations leads to recommendations concerning the use of historical data,in situ measurements, and remote sensing applications in the monitoring of the cryosphere. 相似文献
16.
以FY-3可见光与红外辐射计（VIRR）为主要数据,利用FY3\VIRR 1、6、10通道数据,以指数法和光谱阈值相结合的多光谱积雪监测算法对2013年阿勒泰地区卫星数据进行积雪监测处理。处理结果与MODIS积雪监测业务产品对比分析得出：利用FY3\VIRR可以实现对研究区的积雪遥感监测,监测结果与现有MODIS积雪监测业务产品较一致,具有可比性。 相似文献
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Agricultural systems, with their links to human wellbeing, have been at the heart of sustainability debates for decades. But there is only limited agreement among scientists and stakeholders about the indicators needed to measure the sustainability of agricultural commodity production. We analyze the metrics and indicators of sustainability used in contemporary research on commodity agriculture to demonstrate that new sustainability indicators continue to be developed rapidly by researchers interested in the three principal pillars of sustainability (environmental, economic, and sociocultural). Data from interviews with main agencies and organizations investing in sustainable commodity agriculture reveals that the most commonly used indicators in the academic literature do not overlap with the central aspects of agricultural commodity production that practitioners seek to monitor. Increased dialogue between researchers and practitioners is necessary for better design and use of metrics and indicators that are cost-effective and can be used to compare sustainability outcomes across countries and commodities. We argue that finding common ground among researchers and practitioners requires coordinating ongoing data collection efforts, a greater focus on linking data collection to relevant indicators for sustainable agricultural production, and more attention to the analysis of combined datasets, rather than on the collection of new data on new indicators. By outlining twelve key aspects of agricultural commodity production that the interviewed practitioners from major agencies and organizations deem important to track, our analysis provides a strong framework that can help bridge research-practitioner divisions related to agricultural commodity production and the use of indicators to monitor and assess its sustainability. Our findings are relevant to the search for a parsimonious set of sustainability indicators at a critical time within the context of a new emerging global sustainability agenda. 相似文献
19.
沿袭了遥感地物分类中K-L变换思想, 以归一化处理后的遥感数据, 结合地面土壤湿度观测数据, 应用主成分分析方法, 采用MODIS不同红外波段数据, 通过相关关系计算, 在监测结果中融合MODIS具有250 m分辨率的第2波段数据, 建立了青海省多维特征空间土壤湿度监测模型。模型的建立克服了热惯量法监测干旱需多时相遥感数据的缺陷, 经初步检验, 此模型可以在一定精度范围之内监测表层土壤湿度, 具有业务应用潜力。 相似文献