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1.
分析了2019年夏季在广州从化人工引雷试验场获取的14次人工触发闪电通道底部电流数据,以有无回击(RS)和初始连续电流(ICC)持续时间长短2个标准对数据进行分类,研究不同触发闪电和不同放电阶段的差异和规律。研究表明:相比无回击的触发闪电,产生回击的触发闪电具有更大的先驱放电脉冲(PCP)及初始先驱放电脉冲(IPCP)的平均峰值电流、更多的IPCP总体转移电荷量、更大的ICC平均电流和总体转移电荷量以及更长的ICC持续时间;初始连续电流持续时间是回击平均峰值电流大小、首次继后回击转移电荷量大小和首次继后回击峰值电流大小的重要影响因素,且长初始连续电流的触发闪电对应的PCP及IPCP平均峰值电流也更大、平均转移电荷量也更多;PCP和IPCP平均峰值电流与ICC持续时间相关性最强,是决定ICC放电持续时间的重要因素,未能产生初始连续电流的PCP脉冲簇其平均转移电荷量小于初始先驱放电脉冲簇,其转化的关键阈值之一是平均转移电荷量大于25.91 μC。 相似文献
2.
Axel Kleidon 《Climatic change》2002,52(4):383-389
The Gaia hypothesis of Lovelock states that life regulates Earth's functioning for its own benefit, maintaining habitable, or even optimum conditions for life. But what is beneficial? What is good for one species, may be bad for another. Problems associated with this important, but ill-defined hypothesis make it difficult to test. In order to address these problems and make the concept of Gaia testable, I give a precise definition of terms. Based on these definitions, I put forward four null hypotheses, describing increasing beneficial effects of life on the conditions of Earth, ranging from an ‘Antigaian’ to an ‘optimising Gaian’ null hypothesis. I list some indications for rejection of all but one hypothesis, and conclude that life has indeed a strong tendency to affect Earth in a way which enhances the overall benefit (that is, carbon uptake). However, this does not imply that the biota regulates Earth's environment for its own benefit. 相似文献
3.
Methodological Development of the Conditional Sampling Method. Part II: Quality Control Criteria of Relaxed Eddy Accumulation Flux Measurements 总被引：1，自引：1，他引：0
Determination of biosphere–atmosphere exchanges requires accurate quantification of the turbulent fluxes of energy and of
a wide variety of trace gases. Relaxed Eddy Accumulation (REA) is a method that has received increasing attention in recent
years, because it does not require any rapid sensor for the scalar measurements as the Eddy Correlation method (EC) does.
As in all micrometeorological studies, REA measurements in the atmospheric surface layer are valid under some restrictive
conditions so as to be representative of a specific ecosystem. These conditions are the homogeneity of the underlying surface,
stationary and horizontally homogeneous turbulence. For most experiments these conditions are not fully satisfied. Data uncertainties
can also be related to not fulfilling the method principles or to the technical characteristics of the REA system itself.
In order to assess REA measurement quality, a methodological approach of data analysis is developed in this study. This methodological
analysis is based on the establishment of criteria for data quality control. A set of them, deduced from the mean and turbulent
flow, are called ‘Dynamic criteria’ and are designated to control the stationarity and homogeneity of the w function and the validation of Taylor’s hypothesis. A second set (‘REA operational criteria’) is designed to check the sampling
process and, more precisely, the homogeneity of the negative and positive selection process throughout the sampling period.
A third set of criteria (‘Chemical scalar criteria’) concerns the scalar measurements. Results of the criteria application
to data measured at two different experimental sites are also presented. Cut-off limits of criteria are defined based on their
statistical distribution and shown to be specific for each site. Strictness of each criterion, defined by the percentage of
flagged samples, is analysed in conjunction with the meteorological conditions and atmospheric stability. It is found that
flagged samples mainly correspond to neutral and stable nocturnal conditions. During daytime, nearly free convection conditions
can also yield poor quality data. 相似文献
4.
5.
Growing attention to the impacts of climate change around the world has been accompanied by the profusion of discourses about the lives, livelihoods, and geographies that are “viable” and those that are not in the time of climate change. These discourses of viability often invoke concrete physical limits and tipping points suggesting a transcendent natural order. Conversely, I demonstrate how viability is co-produced through political economic structures that exercise power at multiple scales in shaping the environment and understandings of how it is changing. I describe three dialectics of this co-production: epistemic/material (between ideas about viability and their biophysical and political economic conditions), epistemic/normative (between how the world is understood to be and ideas about how we should live in it), and inter-scalar (between geographic scales, where action at one scale shapes both ecologies and understandings of possible action at another). Each of these dialectics shapes the knowledge regimes that govern the ambiguous social and biophysical process of disappearance and foreclosure of livelihood possibilities in the time of climate change. I examine these discourses of viability through narratives of unviable agrarian livelihoods in coastal Bangladesh, as a lens through which to examine the dialectics of viability more broadly. I situate these discourses concretely in relation to an analysis of interdisciplinary social and natural scientific research on ecological and agrarian viability in coastal Bangladesh now and in the future. Across a broad interdisciplinary spectrum, I find that scientific attention to political economy shapes the politics of possibility. Finally, I demonstrate how discourses of viability limit alternative possible economic and ecological futures. I do this through a concrete examination of the co-production of viable agrarian futures within communities in coastal Bangladesh. These alternative visions indicate that the viability of agriculture is shaped by historical and ongoing decisions in the present about cultivation, water management, and development intervention. 相似文献
6.
A core question still remains after the Paris Agreement: who receives how much of the remaining CO2 budget (resource/burden/effort sharing), so that the increase in the global average temperature is kept to well below 2°C above pre-industrial levels? If converging per capita emissions serve as a possible answer to this question, the discussion focuses primarily on the approach ‘Contraction and Convergence’ (C&C). The Regensburg Model now offers a further option for the mathematical implementation of converging per capita emissions. The authors identify features common to C&C and differences from C&C. They show that, of the convergence models they examined, the Regensburg Model is the most favourable option for industrialized countries.Policy relevanceIn politics, the concept of converging per capita emissions is often accepted at the abstract level. Civil society in particular can then take politicians at their word wherever they take values calculated using the Regensburg Model as points of reference; then prosperous developed countries in particular whose nationally determined contributions do not come up even to these reference values will find it difficult to justify their contributions. 相似文献
7.
R. García-Herrera C. Wilkinson F. B. Koek M. R. Prieto N. Calvo E. Hernández 《Climatic change》2005,73(1-2):13-36
Meteorological observations made on board ships prior to 1854 have until now been overlooked in climatological research largely as a result of the lack of rigorous abstraction and treatment criteria. However, the CLIWOC project has shown that millions of potentially valuable observations have been preserved throughout Europe in the many logbooks that were prepared by officers in the navies of the great powers. Moreover these data can be used and treated in a fashion similar to today's ship-based instrumental observations. The most significant logbook collections are from Spain, the UK, the Netherlands and France. This paper describes the main archives where the logbooks can be found and provides an account of their contents and of the manner in which they were set out. The potential of this source is emphasised by the fact that whilst the CLIWOC project abstracted data for 300,000 days, nearly 90% of the European logbook collections have yet to be examined. This paper concludes with a discussion as to the direction of future studies in this important field. 相似文献
8.
Axel Kleidon 《Climatic change》2007,85(3-4):259-266
In his critique of Kleidon (Clim Change 66:271–319, 2004), Volk (Clim Change 85:3–4, 2007) concludes that maximum entropy production (MEP) has no great relevance for biological evolution and the time history of
life on Earth. I think that most of his points are not justified but rather reflect (a) a lack of appreciation of the central
importance of entropy production as the “universal currency” that measures what keeps systems working, including the biosphere,
(b) a misunderstanding of how biotic activity is embedded in the global entropy budget, and (c) a lack of distinction between
optimal environmental conditions that maximize productivity and result from environmental tradeoffs versus optimal function
of organisms to some internal tradeoffs. The examples that he uses to support his conclusions show flaws in that these mostly
discuss single environmental effects and immediate system responses. Optimal environmental conditions, however, requires at
least two effects that result in a trade-off, so it is not surprising that his examples seem to contradict optimality and
MEP. And the immediate response of a system to change can be very different than the response in steady state, for which MEP
applies. This is specifically important to be considered in the context of the “cheater” problem. In summary, I do not think
that Volk makes convincing arguments that contradict MEP, although I certainly agree that there is a lot more work to be done
to fully recognize the great importance that thermodynamics and MEP play in shaping the Earth’s biosphere and its evolutionary
history. 相似文献
9.
The dominant discourse on the security implications of climate change has asserted that acute environmental scarcity—such as that caused by drought—causes political violence. In contrast, we argue that there are good reasons why water scarcity might have a pacifying effect on armed conflict, and that political violence should be more prevalent during periods of comparatively better agro-climatic conditions. Political violence is more prevalent when basic needs are met and when the tactical environment is more conducive to attacks—conditions that hold when water is comparatively abundant. Empirically, this paper explores the relationship between environmental scarcity and political violence in a global sample of countries, 1970–2006. We find that water abundance is positively correlated with political violence, and that this relationship is stronger in less developed, more agriculturally dependent societies. These findings are robust to several different operationalizations of our variables. We conclude with a brief discussion of the policy implications of our findings. 相似文献
10.
《Climate Policy》2013,13(3):316-329
Germany's National Allocation Plans (NAP I and NAP II) for implementing the EU Emissions Trading Scheme (EU ETS) are critically analysed. Emissions trading has created a new scarcity, and grandfathering constitutes a subsidy that is used to reach additional policy goals related to energy and distribution policy. With respect to energy policy, the objective was to protect the German coal industry; but in terms of distribution policy the hidden agenda was to allocate as many emissions allowances as possible to the industries involved. The whole discussion is based on the false premise that a generous, or at least ‘needs-based’, allocation of costless emissions allowances increases an industry's competitiveness. As a consequence, NAP I is overburdened with several complex special rules and exemptions which distort the incentive effect of emissions trading, thus making climate change mitigation in Germany more costly than necessary. The attempted continuation of this policy, in particular with regard to new installations and an over-generous cap, has led to the European Commission's rejection of these rules in the German NAP II in November 2006. Despite significant improvements since then, some important shortfalls remain. Unfortunately, the economic literature available on this topic refers to highly stylized models of allocation rules and neglects the concrete details of the German NAP II. This article tries to close this gap in the literature by analysing the most distorting rules as well as the most important and arguments of the misguided debate on competitiveness. 相似文献
11.
Noah Kaufman 《Climatic change》2012,110(3-4):575-595
Climate scientists currently predict there is a small but real possibility that climate change will lead to civilization threatening catastrophic events. Martin Weitzman has used this evidence along with his controversial “Dismal Theorem” to argue that integrated assessment models of climate change cannot be used to determine an optimal price for carbon dioxide. In this paper, I provide additional support for Weitzman’s conclusions by running numerical simulations to estimate risk premiums toward climate catastrophes. Compared to the assumptions found in most integrated assessment models, I incorporate into the model a more realistic range of uncertainty for both climate catastrophes and societal risk aversion. The resulting range of risk premiums indicates that the conclusions drawn from integrated assessment models that do not incorporate the potential for climate catastrophes are too imprecise to support any particular policy recommendation. The analysis of this paper is more straightforward and less technical than Weitzman’s, and therefore the conclusions should be accessible to a wider audience. 相似文献
12.
The limited area 5-level primitive equation model,as the first operational precipitation forecast model inChina,has been run at Beijing (National) Meteorological Center (BMC) for more than four years.The opera-tional results show that this model gives continuous services,and the forecast skill is satisfied for the forecastof some weather situations,such as extratropical cyclone,front and the precipitation associated with them.The forecast guides are widely used at the local weather services now. 相似文献
13.
Does public policy support or undermine climate change adaptation? Exploring policy interplay across different scales of governance 总被引：4，自引：0，他引：4
Policy makers have now recognised the need to integrate thinking about climate change into all areas of public policy making. However, the discussion of ‘climate policy integration’ has tended to focus on mitigation decisions mostly taken at international and national levels. Clearly, there is also a more locally focused adaptation dimension to climate policy integration, which has not been adequately explored by academics or policy makers. Drawing on a case study of the UK, this paper adopts both a top-down and a bottom-up perspective to explore how far different sub-elements of policies within the agriculture, nature conservation and water sectors support or undermine potential adaptive responses. The top-down approach, which assumes that policies set explicit aims and objectives that are directly translated into action on the ground, combines a content analysis of policy documents with interviews with policy makers. The bottom-up approach recognises the importance of other actors in shaping policy implementation and involves interviews with actors in organisations within the three sectors. This paper reveals that neither approach offers a complete picture of the potentially enabling or constraining effects of different policies on future adaptive planning, but together they offer new perspectives on climate policy integration. These findings inform a discussion on how to implement climate policy integration, including auditing existing policies and ‘climate proofing’ new ones so they support rather than hinder adaptive planning. 相似文献
14.
2006年广西气象培训班学员满意度调查与分析 总被引：1，自引：0，他引：1
根据2006年广西气象培训中心承办的14期气象培训班的学员满意度问卷调查数据,详细统计分析了学员对培训效果等11项调查内容的评价情况。结果表明,各培训班学员对培训效果表示满意或基本满意的比率在96%以上,远远高于目标考核要求的70%,培训效果比较好。学员对住宿及用餐等后勤保障工作的满意或基本满意率也高于70%,但有一定比例的学员对后勤保障工作不满意,并就如何改进气象培训工作提出了多项设想与建议。 相似文献
15.
根据2006年广西气象培训中心承办的14期气象培训班的学员满意度问卷调查数据,详细统计分析了学员对培训效果等11项调查内容的评价情况。结果表明,各培训班学员对培训效果表示满意或基本满意的比率在96%以上,远远高于目标考核要求的70%,培训效果比较好。学员对住宿及用餐等后勤保障工作的满意或基本满意率也高于70%,但有一定比例的学员对后勤保障工作不满意,并就如何改进气象培训工作提出了多项设想与建议。 相似文献
16.
Climate Change in China from 1880 to 1998 and its Impact on the Environmental Condition 总被引：27，自引：0，他引：27
The global mean surface air temperature (SAT) or the Northern Hemisphere mean SAT has increased since the late nineteenth century, but the mean precipitation around the world has not formed a definite tendency to increase. A lot of studies showed that different climate and environmental changes during the past 100 years over various regions in the world were experienced. The climate change in China over the past 100 years and its impact on China's environmental conditions needs to be investigated in more detail.Data sets of surface air temperature and atmospheric precipitation over China since 1880 up to the present are now available. In this paper, a drought index has been formulated corresponding to both the temperature and precipitation. Based on three series of temperature, precipitation, and drought index, interdecadal changes in all 7 regions of China and temperature differences among individual regions are analyzed. Some interesting facts are revealed using the wavelet transform method. In Northeast China, the aridification trend has become more serious since 1970s. Drought index in North China has also reached a high value during 1990s, which seems similar to that period 1920s–1940s. In NorthwestChina, the highest temperature appeared over the period 1930s–1940s. Along the Yangtze River valley in central eastern China and Southwest China, interdecadal high temperature occurred from 1920s to 1940s and in 1990s, but the drought climate mainly appeared from 1920s to early 1940s. In South China, temperature remained at a high value over the period 1910s–1940s,but the smaller-scale variation of drought index was remarkable from 1880 to 1998. Consequently, the quasi-20-year oscillation (smaller-scale variation) and the quasi-70-year oscillation (secular variation) obviously exist in temperature and precipitation series in different regions over China.Climate change and intensified human activity in China have induced certain environmental evolutions, such as the frequency change of dust-storm event in northern China, no-flow in the lower reaches of the Yellow River and the runoff variation in Northwest China. On the other hand, frequent floods along the Yangtze River and high frequency of drought disaster have resulted in tremendous economic losses in the last decade in China. The primary reason for these happenings may be attributed to the evolution of the monsoon system in East Asian. 相似文献
17.
D. W. Sanders 《Climatic change》1986,9(1-2):187-194
Under natural conditions, balanced ecological systems develop in which the soil is protected by a cover of different plants. When man modifies the environment, in his attempts to produce more food, fiber and fuel, the ecological system is changed.This often results in the soil being exposed to the processes of accelerated water erosion. In this way, millions of hectares of land, particularly in the semi arid areas are now eroding.This paper stresses that the most important principle in controlling water erosion is to develop a new balanced system which is not only productive but which is also stable.Water erosion control schemes should therefore be based on the selection and introduction of correct land use.Examples are given of the types of measures that may be needed for cultivated, grazing and forestry lands.In some cases, a change in land use may also have to be supported by the construction of physical conservation measures. Some common examples of such measures are briefly described. 相似文献
18.
Evolution of large scale disturbances and their interaction with mean flow in a rotating barotropic atmosphere—Part II 总被引：1，自引：0，他引：1
In part I of this paper, we have discussed two problems: the general properties of two-dimensional baro-tropic motion and the evolution and structure of both Rossby wave packet and inertio-gravity wave packet. In this part, we shall continue our discussion. Third, normal modes and continuous spectra of both quasi-geostrophic and non-geostrophic models, their different behaviour, and the comparison of normal mode approach to the wave packet approach. Fourth, weakly nonlinear theory of interaction based on the analysis of eddy transports. A nonzonal basic flow as well as non-geostroptaic model is also included in the consideration. The last, the fully nonlinear theory, making emphasis on the conditions for the maintenance of nonzonal disturbances and the conditions for their continuous and complete absorption by the zonal flow. A comparison of Rossby wave absorption to energy cascade in the two-dimensional turbulence is also given. 相似文献
19.
Srkzi Szilrd 《Atmospheric Research》2007,83(2-4):263-271
Due to the significant amount of severe storm damage from the mid 1990s, a practical need has arisen for updating risk assessment. For reliable and systematic sampling of events, data acquisition has been arranged through the disaster management official body using a pyramidal national coverage. Post-analysis, including its meteorological part, proceeds in a GIS environment. This paper focuses specifically on damaging tornadoes, since those are the most violent and best-documented phenomena. Different statistics are calculated and explained, such as seasonal, diurnal and magnitude distributions. Spatial occurrence and features are mapped. A complete synoptic climatology is given by typifying the generating conditions and categorizing events into certain classes, while discussing the role of the Carpathian Basin. In the end a conceptual issue in connection with self-similarity is raised for further discussion. 相似文献
20.
高分辨率WRF三维变分同化在北京地区降水预报中的应用 总被引：14，自引：4，他引：10
为迎接2008年北京奥运会,改进北京地区的天气预报,建立了一个基于三重嵌套区域(27/9/3 km)的WRF三维变分同化(WRFVar)和WRF模式的高分辨率快速更新循环同化预报(Rapid-Up-date Cycle)系统,并针对2006年8月1日发生在北京地区的强对流天气进行了一系列数值试验,结果表明:高分辨率的快速更新循环系统很好地预报出了此次强降水过程;在WRF三维变分同化里调节背景场误差和观测误差,提高了降水预报的效果;插值得出的3 km背景场误差可以作为一个合理的近似在3 km分辨率的WRFVar中使用,用户可以不必积累高分辨率的预报场去计算背景场误差,从而节省大量计算资源。3 h频次的RUC已经能满足预报要求,更高频次(1 h)的RUC并没有导致预报的进一步提高。 相似文献