朱溪流域植被覆盖的时空变化及地形分异特征

分析2003~2011年朱溪流域植被覆盖的时空分布状况及其变化的地形响应特征,为该地区进一步治理水土流失和生态恢复工程提供决策支持。基于RS和GIS技术,采用像元二分法模型计算植被覆盖度,通过植被重心模型、地形响应指数表征其植被覆盖的时空变化规律。(1)朱溪流域植被覆盖度整体呈上升趋势,Ⅳ、Ⅴ类的植被覆盖面积比率已达到区域的62.28%;格局动态上,Ⅰ、Ⅱ类重心向东北方向移动,Ⅲ、Ⅳ、Ⅴ类重心向西南方向移动,表现为流域植被中、西部改善,东部零散退化的空间格局;(2)在海拔0~300m、坡度小于5°和大于35°区域各等级植被覆盖面积变化最显著,治理措施有效到位,而海拔450~500m处I类植被覆盖面积增加,应引起相关注意。8年间该流域植被覆盖有明显改善,各等级植被覆盖变化在不同地形条件下差异明显。     

上海市中心城区地表温度与绿地覆盖率相关性研究

利用卫星遥感提取的外环线以内绿地信息和由热红外波段资料反演的地表温度。对绿地覆盖率和中心城区地表温度进行相关分析。结果表明：在上海市外环线以内的大范围内。在有损估计的条件下。地表温度(T）和绿地覆盖率(S)之间满足线性关系；T=33.2132-4.6915S(r^2=1.000),即对整个外环线范围地区。绿地覆盖率每增加1％。地表平均温度将下降0．047℃；绿地对热岛效应的减缓作用。在斑块水平上体现明显，在绿地斑块水平上，地表温度(T)和绿地覆盖率(S)之间满足非线性关系：T=32.733 0.0121S-0.0011S^2 0.0000074S^2 (r^2=0.985)。用延安中路绿地作为检验表明,绿地建成后,地表平均温度降低了0．87～1．29℃。     

各向异性反射对基于光谱混合分析的植被盖度估算的影响

光谱混合分析法是解决亚像元植被盖度反演估算问题最行之有效的方法,线性光谱混合分析又是其中最常用的研究手段。传统观点认为基于线性光谱混合分析的植被盖度估算精度主要受多重散射和端元光谱可变性的影响,而且各向异性反射这个地物表面所固有的特性也常常被忽略。研究设计了由寸苔草、沙和水3种地物类别组成的棋盘式混合地物反射率光谱测试方案,在探讨分析传统的多重散射与端元光谱可变性的基础上,进一步分析评价了各向异性反射对基于光谱混合分析的植被盖度估算的影响。结果表明,各向异性反射是不可忽视的,在最小化多重散射及端元光谱可变性的影响后,考虑各向异性反射后寸苔草盖度估算精度显著提升,均方根误差RMSE下降了52%。研究不仅证实了各向异性反射在植被盖度估算问题中的重要性,还印证了其是同种端元类型光谱差异性的另一重要来源,拓宽了端元光谱可变性的范畴,为利用光谱混合分析法更准确地进行植被盖度估算提供了新的思路和方法。     

基于MODIS/NDVI与EVI的皖江流域植被覆盖比较分析

利用多时相的TERRA/MODIS影像资料比较了皖江流域NDVI和EVI的时空分布特征,并分析了空间分辨率和大气校正对NDVI和EVI的影响。结果表明：MODIS/NDVI与MODIS/EVI所反映的植被覆盖状况基本一致,但5月份较8月份NDVI和EVI的空间分布差异明显,且在植被生长旺盛时期,EVI比NDVI更能反映植被覆盖状况。在相同的空间分辨率下（250 m、500 m、1 000 m）,EVI比NDVI能更好的反映植被覆盖的空间差异性,随着空间分辨率的降低,这两种指数反映植被覆盖的差异性在减小。大气校正对NDVI和EVI的影响不同,大气校正前NDVI值小于EVI值,大气校正后NDVI值普遍大于EVI值,但大气校正对NDVI的影响不大,对EVI的影响明显     

Need for a wind of change? Use of offshore wind messages by stakeholders and the media in Germany and their effects on public acceptance

This study investigates German news media coverage and PR material of offshore wind stakeholders from industry, politics, science and civil society thoroughly to provide insights about offshore wind benefits and risks communicated frequently and rarely to the public. By comparative analyses, differences between stakeholder and media messages are revealed: while stakeholders strongly focused on the supportive argument relevance of offshore wind for the energy turnaround, the media often discussed the negative impacts higher costs and delays in grid connection. Furthermore, the influence of offshore wind arguments on acceptance is measured within a survey representative of the German population. With these results, it can be assessed how far influential arguments were presented and which messages have been used frequently despite their low impact. Disruptions to viewscapes, limitation of commercial fishing areas, and hazards to shipping proved to be effective arguments to influence offshore wind acceptance – however, they were seldom used.     

Functional decomposition—A contribution to overcome the parameter space explosion during validation of highly automated driving

Abstract

Objective: Particular testing by functional decomposition of the automated driving function can potentially contribute to reducing the effort of validating highly automated driving functions. In this study, the required size of test suites for scenario-based testing and the potential to reduce it by functional decomposition are quantified for the first time.

Methods: The required size of test suites for scenario-based approval of a so-called Autobahn-Chauffeur (SAE Level 3) is analyzed for an exemplary set of scenarios. Based on studies of data from failure analyses in other domains, the possible range for the required test coverage is narrowed down and suitable discretization steps, as well as ranges for the influence parameters, are assumed. Based on those assumptions, the size of the test suites for testing the complete system is quantified. The effects that lead to a reduction in the parameter space for particular testing of the decomposed driving function are analyzed and the potential to reduce the validation effort is estimated by comparing the resulting test suite sizes for both methods.

Results: The combination of all effects leads to a reduction in the test suites’ size by a factor between 20 and 130, depending on the required test coverage. This means that the size of the required test suite can be reduced by 95–99% by particular testing compared to scenario-based testing of the complete system.

Conclusions: The reduction potential is a valuable contribution to overcome the parameter space explosion during the validation of highly automated driving. However, this study is based on assumptions and only a small set of exemplary scenarios. Thus, the findings have to be validated in further studies.     

康平县生态环境建设中的气候效应分析

利用康平县1959—2008年气象观测资料,分析了康平县近50a气候变化规律特征,论述了增大森林覆盖率对未来气候可能产生的调节作用。结果表明:在全球变暖的大背景下,康平县的气温增高、蒸发量增大、风力减弱、降水量呈下降趋势且干旱少雨期增长;植树造林增加植被覆盖率对防风固沙、改善康平县生态环境有着积极的促进作用,但对降水量的增加作用有限。     

以最大化人口覆盖为目标的城市空气质量监测点空间布局评估与优化研究

城市空气质量监测点布局对于客观、准确、全面评估城市空气质量至关重要,现有技术规范仅明确城市监测点的数量要求,尚无监测点空间布局的具体标准和规范.本研究提出最大化人口覆盖目标下优化城市空气质量监测点空间布局的方法框架,并以北京市为例评估现有监测网络和测算目标优化效果.研究表明,北京市空气质量监测网络存在监测点间距小、人口覆盖率低、监测点间替代性强等问题.以最大人口覆盖为目标对现有监测网络进行优化,在新增监测点情景下,需要新增5个监测点实现人口覆盖率从目前的39.8%提升至51.4%.在调整已有监测点情景下,通过调整9个重合度较高的监测点,可以实现53.1%的人口覆盖率.两种情景下,优化后监测点位一致性较好,均覆盖人口新增较快区域.建议未来优化和评估城市监测网络点位布局时,可采用本文提出的监测点空间距离、监测区域重合度、覆盖人口数、污染物浓度相关性作为评估指标,将最大化人口覆盖作为优化监测点位空间布局的技术标准.