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81.
The key problem in nonparametric frequency analysis of flood and droughts is the estimation of the bandwidth parameter which defines the degree of smoothing. Most of the proposed bandwidth estimators have been based on the density function rather than the cumulative distribution function or the quantile that are the primary interest in frequency analysis. We propose a new bandwidth estimator derived from properties of quantile estimators. The estimator builds on work by Altman and Léger (1995). The estimator is compared to the well-known method of least squares cross-validation (LSCV) using synthetic data generated from various parametric distributions used in hydrologic frequency analysis. Simulations suggest that our estimator performs at least as well as, and in many cases better than, the method of LSCV. In particular, the use of the proposed plug-in estimator reduces bias in the estimation as compared to LSCV. When applied to data sets containing observations with identical values, typically the result of rounding or truncation, the LSCV and most other techniques generally underestimates the bandwidth. The proposed technique performs very well in such situations.  相似文献   
82.
We estimate current vertical movements along the Apennines (Italy) through repeatedly measured high precision levelling routes. In order to highlight regional crustal deformation the analysis of a geodetic database, with a minimum benchmark density of 0.7 bm/km (1943–2003 time period), is carried out. We evaluate systematic and random error and their propagation along the levelling routes. Tests on original raw height data have been carried out to define error propagation. The computed relative vertical rates stand significantly above error propagation. A series of traverses along and across the Apennines and a map of relative vertical velocities reveal a geodetic signal characterised by values up to 2.5–3.0 mm/a and by wavelengths up to 100 km.  相似文献   
83.
地球物理场观测中的大气效应问题研究   总被引:2,自引:2,他引:2  
作用在地表的大气质量不仅产生引力位的扰动,而且会引起各种地球物理场的附加效应,本文综述了近年来国内外同行在研究地表位移、重力、倾斜和应变固体潮观测中实施的大气效应改正问题,包括利用台站气压资料建立的实测模型,建立大气重力格林函数,利用全球和区域气象数据计算大气效应,建立大气改正的误差模型等,最后文章讨论了今后研究展望。  相似文献   
84.
通过处理1990年1月1日~2005年12月31日云南省地震遥测台网记录的速报地震目录,分析滇西地震预报实验场(以下简称实验场)及邻区6级以上强震半年前到3个月3.0~3.9级调制小震活动图像,利用3.0~3.9级调制小震活动图像,提供6级以上强震的潜在危险区。  相似文献   
85.
浅谈地面气象观测"新规范"学习要点   总被引:1,自引:0,他引:1  
阐述了“地面气象观测规范”2003版中总则、气象要素观测、记录处理和报表编制的学习要点,并认为新旧规范具有一定的连续性,在学习中应从其编制原则出发,从新旧规范的差异和修改理由入手,重点放在新增加及有变更的内容上。  相似文献   
86.
Climate change poses a significant risk for communities, and local governments around the world have begun responding by developing climate adaptation policies. Scholarship on local adaptation policy has proliferated in recent years, but insufficient attention has been paid to operationalization of the unit of analysis, and methods employed are typically inadequate to draw inferences about variation across cases. This article seeks to contribute to the conceptual and methodological foundations of a research agenda for comparative analysis of local adaptation policies and policy-making. Synthesizing insights from policy studies literature and existing adaptation research, the article identifies and operationalizes two aspects of public policy—policy content and policy process—which are salient objects of comparative analysis that typically vary from one community to another. The article also addresses research design, outlining a comparative case study methodology that incorporates various qualitative analytical techniques as the vehicle to examine these policy elements in empirical settings.  相似文献   
87.
通过雅鲁藏布江和北祁连山南北两个典型蛇绿岩带的研究实践,作者提出并讨论了构造背景与岩石地层相结合、结构构造特征与矿物岩石分析相结合、物理化学成因与区域地质工作相结合、岩石类型年代学与地层年代学研究相结合的蛇绿岩研究思想,以及综合恢复重建古洋壳的古地磁资料分析、扩张速度分析、俯冲速率分析和古生物地理环境分析4种方法,并提供了青藏高原主要古大洋区的有关特征数据。  相似文献   
88.
The purpose of this article is to analyze the advances of, and obstacles to, progressive attempts at modifying the balance of power over water through the use of the law as a tool for social transformation and to characterize the alternatives based on the ways in which they challenge neoliberal principles. The study of such dynamics using a broad perspective on the law which includes not only written laws, but also historical moments in which water laws were created and used, provides a platform to discern alternatives that in many cases might otherwise remain invisible.We critically analyze the major legal contradictions and tensions in Bolivia, Colombia and Peru that suggest post- and counter-neoliberal alternatives. First, certain alternatives indicate a break from neoliberal principles based on relational ontologies (that avoid divisions between nature and culture as well as between individuals and communities). Such breaks include the statement that water is a common good or a common resource for the benefit of all, the goal to re-establish the human connection with nature, and support for a water provision system based on reciprocity, community and cooperative principles. Second, additional proposals that can be characterized as counter-neoliberal oppose neoliberal means or outcomes, such as proposals for more equitable water allocation or inclusive participation mechanisms for decision making. Both counter- and post-neoliberal alternatives also find much resistance in water laws; however, they do represent progressive alternatives that reach state laws and challenge neoliberal conceptions of nature.  相似文献   
89.
Strategic issue framing is widely regarded as an effective communication strategy to alter public opinion and citizens’ policy support. However, it is unclear to what extent strategic framing can increase support for ambitious demand-side actions and policies that make the cost of mitigation perceptible in citizens’ everyday lives. Taking an exploratory approach, we conducted qualitative interviews and a comparative framing experiment with 9,750 survey respondents from China, Germany, and the United States. We analyzed strategic issue framing effects in two areas known to be key for increasing the sustainability of consumption: meat/fish consumption, and fossil-fuel car usage. Employing both classical linear regressions and advanced Bayesian sparse estimations, we show that in all three countries widespread arguments in favor of reduced meat/fish consumption and car use are unlikely to substantially alter citizens’ concern, willingness to pay, behavioral intentions and policy support for demand-side action. Our findings suggest that in the absence of a broader behavioral change campaign, strategic issue framing alone is unlikely to be effective in changing entrenched attitudes and behaviors. On its own, it is also unlikely to substantially increase public support for demand-side policies to reduce consumption. More careful research is needed to help policymakers understand the role and limits of different strategic framing techniques.  相似文献   
90.
Hydroxyl nightglow is intensively studied in the Earth atmosphere, due to its coupling to the ozone cycle. Recently, it was detected for the first time also in the Venus atmosphere, thanks to the VIRTIS-Venus Express observations. The main Δν=1, 2 emissions in the infrared spectral range, centred, respectively, at 2.81 and 1.46 μm (which correspond to the (1-0) and (2-0) transitions, respectively), were observed in limb geometry (Piccioni et al., 2008) with a mean emission rate of 880±90 and 100±40 kR (1R=106 photon cm−2 s−1 (4πster)−1), respectively, integrated along the line of sight. In this investigation, the Bates-Nicolet chemical reaction is reported to be the most probable mechanism for OH production on Venus, as in the case of Earth, but HO2 and O may still be not negligible as mechanism of production for OH, differently than Earth. The nightglow emission from OH provides a method to quantify O3, HO2, H and O, and to infer the mechanism of transport of the key species involved in the production. Very recently, an ozone layer was detected in the upper atmosphere of Venus by the SPICAV (Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus) instrument onboard Venus Express (Montmessin et al., 2009); this discovery enhances the importance of ozone to the OH production in the upper atmosphere of Venus through the Bates-Nicolet mechanism. On Venus, OH airglow is observed only in the night side and no evidence has been found whether a similar emission exists also in the day side. On Mars it is expected to exist both on the day and night sides of the planet, because of the presence of ozone, though OH airglow has not yet been detected.In this paper, we review and compare the OH nightglow on Venus and Earth. The case of Mars is also briefly discussed for the sake of completeness. Similarities from a chemical and a dynamical point of view are listed, though visible OH emissions on Earth and IR OH emissions on Venus are compared.  相似文献   
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