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1.
利用位于江苏海岸陆地的两座测风塔以及福建海面的一座测风塔气象要素资料,分析了这两种下垫面风速、湍流等要素的日变化规律及廓线特征,探讨了这两种不同下垫面特征导致的风力特征差异。结果表明:海岸陆面日最大风速出现时间较内陆滞后,最小风速出现时间与内陆相差不大,风速日变化位相随高度滞后,日振幅随高度减小,冬季70 m高度风速日变化特征与10 m高度风速日变化特征相反,夜间大于白天,说明冬季的过渡层转换高度低于夏季;海面风速的日变化位相、日振幅等特征随高度变化很小。两种下垫面的风廓线用对数律、指数律拟合的效果相当,海岸陆面的风廓线指数呈现的规律为离岸风组大于向岸风组,冬季大于夏季;海面风廓线指数呈现的规律则是向岸风组大于离岸风组,夏季大于冬季。 相似文献
2.
States have been widely criticized for failing to advance the international climate regime. Many observers now believe that a “new” climate governance is emerging through transnational and/or local forms of action that will eventually plug the resulting governance gaps. Yet states, which remain oddly absent from most discussions of the “new” governance, will remain key players as governance becomes more polycentric. This paper introduces a special issue that explores the ability of states to rise to these interconnected challenges through the analytical prism of policy innovation. It reveals that policy innovation is much more multi-dimensional than is often thought; it encompasses three vital activities: invention (centering on the ‘source’ of new policy elements), diffusion (that produces different ‘patterns’ of policy adoption), and the evaluation of the ‘effects’ that such innovations create in reality. The papers, which range from qualitative case studies to large ‘n’ quantitative studies, offer new insights into the varied roles that states play in relation to all three.They show, for instance that: the policy activity of states has risen dramatically in the past decade; that state innovation is affected to similar degrees by internal and external factors; and that policies that offer flexibility to target groups on how to meet policy goals are most effective but that voluntary reporting requirements are ineffective. This paper draws upon these and many other insights to offer a much more nuanced reflection on the future of climate governance; one that deservedly puts states at the front and center of analysis. 相似文献
3.
乌鲁木齐市降水对大气污染的影响 总被引：4，自引：0，他引：4
根据2002—2003年乌鲁木齐市SO2、NO2、PM10的日平均浓度和日降水量分析了乌鲁木齐市降水对3种大气污染物的湿清除能力。分析表明大雨对SO2和PM10的湿清除能力大于小雨,而小雨大于中雨。中雪对SO2和PM10的湿清除能力大于大雪,而大雪大于小雪。小量以上降水(降雨和降雪)对NO2的湿清除能力基本相当。微雨对3种大气污染物具有湿清除能力,而微雪使3种大气污染物的浓度增加。 相似文献
4.
The Gaia Hypothesis: Fact, Theory, and Wishful Thinking 总被引：4，自引：0，他引：4
James W. Kirchner 《Climatic change》2002,52(4):391-408
Organisms can greatly affect their environments, and the feedback coupling between organisms and their environments can shape the evolution of both. Beyond these generally accepted facts, the Gaia hypothesis advances three central propositions: (1) that biologically mediated feedbacks contribute to environmental homeostasis, (2) that they make the environment more suitable for life, and (3) that such feedbacks should arise by Darwinian natural selection. These three propositions do not fare well under close scrutiny. (1) Biologically mediated feedbacks are not intrinsically homeostatic. Many of the biological mechanisms that affect global climate are destabilizing, and it is likely that the net effect of biological feedbacks will be to amplify, not dampen, global warming. (2) Nor do biologically mediated feedbacks necessarily enhance the environment, although it will often appear as if this were the case, simply because natural selection will favor organisms that do well in their environments – which means doing wellunder the conditions that they and their co-occurring species have created. (3) Finally, Gaian feedbacks can evolve by natural selection, but so can anti-Gaian feedbacks. Daisyworld models evolve Gaian feedback because they assume that any trait that improves the environment will also give a reproductive advantage to its carriers (over other organisms that share the same environment). In the real world, by contrast, natural selection favors any trait that gives its carriers a reproductive advantage over its non-carriers, whether it improves or degrades the environment (and thereby benefits or hinders its carriers and non-carriers alike). Thus Gaian and anti-Gaian feedbacks are both likely to evolve. 相似文献
5.
Detlef P. van Vuuren Jae Edmonds Steven J. Smith Kate V. Calvin Joseph Karas Mikiko Kainuma Nebojsa Nakicenovic Keywan Riahi Bas J. van Ruijven Rob Swart Allison Thomson 《Climatic change》2010,103(3-4):635-642
Long-term scenarios developed by integrated assessment models are used in climate research to provide an indication of plausible long-term emissions of greenhouse gases and other radiatively active substances based on developments in the global energy system, land-use and the emissions associated with these systems. The phenomena that determine these long-term developments (several decades or even centuries) are very different than those that operate on a shorter time-scales (a few years). Nevertheless, in the literature, we still often find direct comparisons between short-term observations and long-term developments that do not take into account the differing dynamics over these time scales. In this letter, we discuss some of the differences between the factors that operate in the short term and those that operate in the long term. We use long-term historical emissions trends to show that short-term observations are very poor indicators of long-term future emissions developments. Based on this, we conclude that the performance of long-term scenarios should be evaluated against the appropriate, corresponding long-term variables and trends. The research community may facilitate this by developing appropriate data sets and protocols that can be used to test the performance of long-term scenarios and the models that produce them. 相似文献
6.
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
7.
The understanding of pupils between the ages of 11 and 16 about the ozone layer — what it is, what will damage it and what will be the likely result of such damage — has been studied. Following the use of a preliminary open-form questionnaire, the ideas of a large cohort of children have been probed by closed-form questionnaire and by interviews with a subset of this group. The authors explain that most pupils seem aware that the ozone layer is a layer of gas around Earth, but less sure what that gas is. They also know that it protects Earth from ultra-violet rays from the sun, and that further depletion will allow more ultra-violet to Earth and cause more skin cancer. Most also know that one cause of depletion is the use of CFCs, but many confuse the depletion of the ozone layer with the greenhouse effect and other forms of atmospheric pollution. The authors provide evidence to suggest that such confusion of ideas is strongly held and that, even with this relatively new and abstract phenomenon, ideas are held in a consistent and similar framework by most pupils. 相似文献
8.
N. Thompson Hobbs Kathleen A. Galvin Chris J. Stokes Jill M. Lackett Andrew J. Ash Randall B. Boone Robin S. Reid Philip K. Thornton 《Global Environmental Change》2008,18(4):776
Fragmentation of the ecosystems of the earth into spatially isolated units has emerged as a primary component of global change. Often, fragmentation results from actions that are intended to enhance human livelihoods and well-being; however, there are often costs to ecosystems and human economies that are not considered. We describe the three general categories of processes causing fragmentation of rangelands worldwide: dissection, decoupling, and compression. We show that access to heterogeneity of landscapes is an important attribute of grazing ecosystems worldwide, and that fragmentation of these systems, even when it proceeds in the absence of habitat loss, can limit options of people and animals, options that are particularly important in temporally heterogeneous environments. We discuss the consequences of fragmentation for people, livestock, wildlife, and landscapes and describe potential adaptations that can mitigate its harmful outcomes. We close by reviewing policy options that promote re-aggregation of landscapes and adaptation to fragmentation. 相似文献
9.
Richard M. Eckman 《Boundary-Layer Meteorology》2008,127(2):345-351
A 2006 article in Boundary-Layer Meteorology by G. Treviño and E.L Andreas presents a derivation that questions the use of time averaging for computing turbulence statistics. Their derivation shows that time averaging over a finite interval always leads to a zero integral time scale. As a result, Treviño and Andreas argue that any turbulence quantities derived from time averaging are tainted and incompatible with the Navier–Stokes equations. While Treviño and Andreas are correct that time averaging does produce integral scales that are quite different from what researchers commonly expect, this comment demonstrates that the theoretical implications are not as dire as they claim. 相似文献
10.
统计分析了大量的暴雨资料发现；河南省夜间多暴雨，主要表现在暴雨次数和雨量夜间比白天均多２１．６％，暴雨地理分布夜间比白范围大８６．６％。由于暴雨等级不同，其降水集中时段出现时间也不一样：一般暴雨多出现在下半夜（最高峰点出现在４－５时），大暴雨和物质特大暴雨多出现在上半夜（最高峰点分别出现在０２时和２１－２２时）。物理成因分析表明：热力、动力和地形因子可能是河南省夜间多暴雨的直接成因。 相似文献
11.
作者从流域地形，气候变化以及水库影响３个方面来探讨四川省升钟水库运行初期水量不足的原因，分析结果表明，建库前后库区及库周地区年降水量时空分布趋势一致，所不同的是建库后较之建库前各地年降水量普遍偏少２００ｍｍ左右，在库周各地建库前后地形不变，且水库蓄水后对为中周站年降水量最大影响为减少近４０ｍｍ，且建库后３年连年姓严重干旱说明气候对降水的影响比水库的影响要大得多，气候变化是影响水库运动初期水量不足的 相似文献
12.
锡林郭勒盟沙尘暴分布与气象因子和下垫面性质有关,沙尘暴西多东少的分布特征,与大风西多东少、降水西北少东南多、温度西南高东北低的分布特征基本相似;大风是沙尘暴的主要动力因子,温度是产生沙尘暴的热力因素,降水和下垫面性质决定了沙尘暴产生的环境条件。沙尘暴日数随着大风日数与温度增加(升高)而增多;随降水增加而减少;下垫面要素中的地形、地貌为沙尘暴的发生提供沙源、起沙条件;土壤成分自西北向东南为棕钙土带、栗钙土带、黑钙土带、灰色森林土带,植被覆盖度依次增加,沙尘暴分布也依次减少。 相似文献
13.
Akula Venkatram 《Boundary-Layer Meteorology》1986,36(1-2):149-156
This paper examines the assumptions and derivations that govern commonly used methods of estimating the height of the thermal internal boundary layer (TIBL) that occurs near shorelines. We show that nearly all these methods require inputs that can be defined only in the very limited context of the data set used to derive the empirical equations for the boundary-layer height. This analysis suggests that the current formulations have little general applicability, and it points to the need for more reliable methods for estimating the TIBL height. 相似文献
14.
The definition of the sensible heat flux is examined in the light of a paper published by Brook (1978). We show that the convergence of the flux defined in this paper and that of the standard definition are related to different quantities and that care must be taken to ensure that compatible definitions are used. 相似文献
15.
Siambabala Bernard Manyena Emmanuel Mavhura Chipo Muzenda Elias Mabaso 《Global Environmental Change》2013,23(6):1786-1794
Disaster research and scholarship is now advocating a shift from focusing on the hazard event to processes that generate vulnerability and loss of resilience to disasters. Disaster legislations are among prominent instruments that can highlight the tensions as well as challenges that are being encountered towards this change in focus. Using textual analysis, this paper presents a study that investigated whether five post-2002 disaster legislations have shifted emphasis from the hazard to the vulnerability and resilience paradigms. The five examples illustrate that while there is a slight change, at least in rhetoric, from response to a prevention focus, disaster legislations largely promote a centralised institutional framework, with inadequate resource commitments and limited participation from vulnerable communities. Consequently, while generalisations simply cannot be made without a wider analysis of many more examples from different countries, the five disaster legislations appear to re-emphasise the response focus with less attention on the processes that reduce vulnerability and enhance resilience. The conclusion is that while the rhetoric has changed, the disaster legislations have not significantly moved from the hazard to vulnerability and resilience focus suggesting that reduction of losses and damages to disasters remains a big challenge 相似文献
16.
This study demonstrates that IPCC Third Assessment Report is strongly dominated by Natural sciences, especially the Earth sciences. The Social sciences are dominated by Economics. The IPCC assessment also results in the separation of the Earth, Biological and Social sciences. The integration that occurs is mainly between closely related scientific fields. The research community consequently imposes a physical and economic bias and a separation of scientific fields that the IPCC reproduces in the policy sphere. It is argued that this physical and economic bias distorts a comprehensive understanding of climate change and that the weak integration of scientific fields hinders climate change from being fully addressed as an integral environmental and social problem. If climate change is to be understood, evaluated and responded to in its fullness, the IPCC must broaden its knowledge base and challenge the anthropocentric worldview that places humans outside of nature. 相似文献
17.
The notion that pathways can be identified and followed towards more sustainable futures has become an increasingly prevalent idea across the science and policy of global environmental change. Focusing on the debate within literatures on socio-technical systems, we find that pathways are often tied to the concept of scaling up such that they are dependent on trajectories which extend from the geographically small to large scale or from singular incidences to widespread adoption. Building on relational approaches to scaling, in this paper we argue that sustainability pathways need to be conceived as emerging from the catalytic interaction of multiple and overlapping efforts to change the status quo. We suggest that pathways can be conceptualized as being composed of ‘stepping stones’: bundles of related interventions that seize or create opportunities to build momentum for the implementation of innovations, the form of which is not predetermined. Drawing on 243 interviews, participant observation, and document analysis examining urban nature-based solutions across six European countries and the EU, we identify 20 stepping stones that can be used to accelerate the uptake of urban NBS in European cities. In the case of urban NBS in Europe, we find that the capacity of stepping stones to generate catalytic change strongly depends on how they interact with one another. We illustrate that pathways are not given but rather assembled through key interventions that collectively generate the capacities and momentum needed to overcome inertia and generate new socio-material orders in which such interventions are normalized as mainstream responses to sustainability challenges. 相似文献
18.
对上海市郊林带附近与非林带冬、夏季典型天气下温、湿度、蒸发、辐射量的同步观测资料分析研究显示:林带附近气温日较差比非林带大,林带背风侧气温日较差比林带迎风侧大。林带附近日蒸发量比非林带小,日平均相对湿度比非林带大。林带附近散射辐射比非林带小,反射辐射比非林带大,总辐射差异与季节及林带树叶的茂密程度有关,白天净辐射差异主要取决于总辐射和反射辐射差异,夜间净辐射差异与林带及两地地温差有关。 相似文献
19.
George Chimonas 《Dynamics of Atmospheres and Oceans》1998,27(1-4)
Geophysical flows include small-scale substructures that support shear instabilities where the smoothed mean profiles indicate only stability. The substructures must draw their energy from the mean flow, probably through wave interactions, and it is shown that the substructures themselves give rise to a type of mode that is well suited for nonlinear interactions with the flow in and around them. The study indicates that substructures and their associated modes form a dynamically interacting system that may contribute to the chaotic nature of a stably stratified region. 相似文献
20.
Our aim is to theorize the shifting relationship between cities and the biosphere in ways that can incorporate vanguard scientific, technical and social innovations. We specify that the city (a) generates third natures - specific new environments - such as heat islands, that today are destructive of the biosphere, and (b) that the city has systemic properties that correspond to those of the biosphere, but today are mostly flattened out of action through the ruptures that dominate today's articulation between cities and biosphere. That is to say, our specific project agrees with the problematizing of the category “nature,” which pertains to our presence in the biosphere. But we do not take Harvey's more absolute statement that the city itself is nature nor do we confine our analysis only to Latourian natures-cultures. Our analysis is less centered in the work of correcting a false binary, as is the case with both Latour and Harvey, notwithstanding their different objects of study. We focus on the complex in-between space that is the site of both the transactions between city and biosphere, as well as the site of the ruptures that characterize these transactions. 相似文献