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1.
The Code of Conduct for Responsible Fisheries developed in 1995 by the Food and Agriculture Organization (FAO) of the United Nations includes a set of recommendations for reducing the negative impacts of fishing activities on marine ecosystems. The Code is widely believed to be an important tool for fisheries management and, although the Code is voluntary, all stakeholders concerned with the management and development of fisheries, and conservation of fishery resources, are actively encouraged to implement it. Previous analysis at global scale showed widespread low compliance with the Code of Conduct that may be partly due to a lack of empirical support for the overall ecological benefits of adhering to the Code. Here we evaluated these ecological effects by comparing compliance with the Code to changes in five ecological indicators that quantify the ecosystem effects of fishing. We used the loss in production index and the related probability of sustainable fishing index, the mean trophic level of the catch, total catches, and the primary production required to sustain the catch. We also tested if regional differences and development status of countries influenced the results of ecological indicators. Results indicate that countries with higher levels of compliance with the FAO Code of Conduct in 2008 experienced a decrease in the Loss in Production index and an increase in fisheries sustainability from the 1990s to 2000s. We conclude that better implementation of the Code of Conduct may have had overall positive ecological effects with time. A significant decrease in total catch and primary production required with higher compliance was also observed. While a significant increase in ecosystem sustainability was observed after a decade of adoption of the Code at high levels of compliance, further ecosystem degradation had taken place where compliance with the Code was below a given threshold (4, from a ranking of 0–10). Therefore, since compliance with the Code is still low or very low worldwide, these results may encourage individual countries to adopt well-established fishery management measures in order to increase the ecological sustainability of marine resources. 相似文献
2.
采用北京地区13站1960—2008年和20站1978—2008年的气温观测资料,分析其变化的时空特征。1960—2008年北京地区平均气温呈上升趋势。1960—1969年、1969—1983年和1985—1998年北京地区平均气温变化趋势分别为-1.27℃/10a、0.79℃/10a和1.17℃/10a,即经历了快速下降、上升和快速上升3个时段。而1998—2008年出现了长期增暖中的一个减缓期,13站和20站资料揭示的平均气温变化趋势分别为0.02℃/10a和-0.05℃/10a。1998—2008年,城区总体仍然呈增暖趋势,北城的增暖速率是南城的两倍。远郊山区或靠近水体和公园的城镇站呈降温趋势。 相似文献
4.
Boundary-Layer Meteorology - Airborne meteorological in situ measurements as well as stationary measurements at the offshore masts FINO1 and FINO3 in the German Bight are evaluated in order to... 相似文献
5.
We present a theoretically consistent framework for modelling Lagrangian particle deposition in plant canopies. The primary focus is on describing the probability of particles encountering canopy elements (i.e., potential deposition), and provides a consistent means for including the effects of imperfect deposition through any appropriate sub-model for deposition efficiency. Some aspects of the framework draw upon an analogy to radiation propagation through a turbid medium with which to develop model theory. The present method is compared against one of the most commonly used heuristic Lagrangian frameworks, namely that originally developed by Legg and Powell (Agricultural Meteorology, 1979, Vol. 20, 47–67), which is shown to be theoretically inconsistent. A recommendation is made to discontinue the use of this heuristic approach in favour of the theoretically consistent framework developed herein, which is no more difficult to apply under equivalent assumptions. The proposed framework has the additional advantage that it can be applied to arbitrary canopy geometries given readily measurable parameters describing vegetation structure. 相似文献
6.
根据开展气候论证工作经验,结合古今中外的例子,论述了城市规划、重点建设工程、太阳能、风能开发利用必须开展气候可行性论证的必要性,并对今后如何开展气候可行论证工作提出了相应的对策和建议。 相似文献
7.
1 外场试验情况 由中国气象科学研究院人工影响天气研究中心与青海省气象局共同主持研究的“人工增雨成套技术预研究”在总参大气环境研究所的通力合作及空军某部机组、民航有关飞行保障单位的密切配合下,于今年5月开展实施两架飞机(运-8,安-26)组成的飞机人工增雨综合监测和催化作业试验,对黄河上游不同降水天气系统进行了综合监测和催化作业。 相似文献
9.
利用宁夏24个测站1971~2000年常规地面观测中总云量、低云量、云状、降水量等资料,结合NCEP/NCAR(1971~2000年)逐日全球再分析资料,对宁夏30年层状云、对流云及混合云降水的时空分布及环流特征进行综合分析。结果表明:30年中,宁夏层状云降水次数明显多于对流云和混合云降水次数,是宁夏降水的主要类型;而大雨以上降水主要为混合云降水;宁夏南部地区以层状云降水为主,北部地区对流云和混合云降水次数相对较多。 相似文献
10.
This article presents results from a model study of interannual and decadal variability in the Nordic Seas. Fifty years of simulations were conducted in an initial condition ensemble mode forced with the National Centers for Environmental Prediction (NCEP) reanalysis. We studied two major events in the interannual and interdecadal variability of the Nordic Seas during the past fifty years: the Great Salinity Anomaly in the 1960s and early 1970s and the warming of the Arctic and subarctic oceans in the late 1990s. Previous studies demonstrated that the Great Salinity Anomaly observed in the subarctic ocean in 1960 was originally generated by intensified sea-ice and freshwater inflow from the Arctic Ocean. Our model results demonstrate that the increase in the transport of fresh and cold waters through Fram Strait in the 1960s was concurrent with a reduction in the meridional water exchange over the Greenland–Scotland Ridge. The resulting imbalance in salinity and heat fluxes through the strait and over the ridge also contributed to the freshening of the water masses of the Nordic Seas and intensified the Great Salinity Anomaly in the Nordic Seas. The warming of the Atlantic Waters in the Nordic Seas and Arctic Ocean during the past two decades had an important impact on the variability of these two ocean basins. Some previous observational and model studies demonstrated that the warming of the subpolar Atlantic Ocean in the late 1990s and the meridional transport of the Atlantic Water mass (AW) into the Nordic Seas and Arctic Ocean contributed to this process. At the same time, observations show that the warming of the AW in the Nordic Seas started in the 1980s (i.e., earlier than the warming of the subpolar North Atlantic Ocean). Our model results suggest that this process was triggered by an imbalance in the lateral heat fluxes through Fram Strait and over the Greenland–Scotland Ridge. In the late 1980s the AW transport over the Greenland–Scotland Ridge was stronger than normal while the exchange through Fram Strait was close to normal. The related imbalance in the lateral heat fluxes through the strait and over the ridge warmed the Nordic Seas and caused an increase in the temperature of the AW inflow to the Arctic Ocean in the late 1980s (i.e., about a decade earlier than the warming of the source of the AW in the subpolar North Atlantic Ocean). Thus the model results suggest that the imbalance in lateral heat and salinity fluxes through the strait and over the ridge connecting the Nordic Seas to the North Atlantic and Arctic oceans could amplify the interannual variability in the subarctic ocean. [Traduit par la rédaction] Cet article présente les résultats d'une étude par modèle de la variabilité interannuelle et décennale dans les mers nordiques. Nous avons effectué des simulations sur une période de cinquante ans en mode d'ensemble de conditions initiales forcé avec les réanalyses des NCEP (National Centers for Environmental Prediction). Nous avons étudié deux événements majeurs survenus dans la variabilité interannuelle et décennale des mers nordiques au cours des cinquante dernières années : la grande anomalie de salinité des années 1960 et du début des années 1970 et le réchauffement des océans Arctique et subarctique vers la fin des années 1990. Des études précédentes ont démontrées que la grande anomalie de salinité observée dans l'océan subarctique en 1960 a été causée par une intensification de l'apport de glace de mer et d'eau douce depuis l'océan Arctique. Les résultats que nous avons obtenus du modèle montrent que l'accroissement du transport d'eau douce et froide à travers le détroit de Fram dans les années 1960 s'est produit en même temps qu'une réduction dans l’échange méridien d'eau au-dessus de la crête Groenland–Écosse. Le déséquilibre résultant dans les flux de salinité et de chaleur à travers le détroit et au-dessus de la crête a aussi contribué à l'adoucissement des masses d'eau des mers nordiques et a intensifié la grande anomalie de salinité dans les mers nordiques. Le réchauffement des eaux atlantiques dans les mers nordiques et dans l'océan Arctique au cours des deux dernières décennies a eu un impact important sur la variabilité de ces deux bassins océaniques. Des études observationnelles et par modèle précédentes ont établi que le réchauffement de l'océan Atlantique subpolaire dans les années 1990 et le transport méridien de la masse d'eau atlantique dans les mers nordiques et dans l'océan Arctique ont contribué à ce processus. En même temps, les observations montrent que le réchauffement des eaux atlantiques dans les mers nordiques a commencé dans les années 1980 (c.–à–d. plus tôt que le réchauffement de l'océan Nord-Atlantique subpolaire). Les résultats du modèle suggèrent que ce processus a été déclenché par un déséquilibre dans les flux de chaleur latéraux à travers le détroit de Fram et au-dessus de la crête Groenland–Écosse. À la fin des années 1980, le transport des eaux atlantiques au-dessus de la crête Groenland–Écosse était plus fort que la normale alors que l’échange à travers le détroit de Fram était près de la normale. Le déséquilibre résultant dans les flux de chaleur latéraux à travers le détroit et au-dessus de la crête a réchauffé les mers nordiques et causé une augmentation de la température des eaux atlantiques parvenant à l'océan Arctique à la fin des années 1980 (c.-à-d. environ une décennie avant le réchauffement de la source d'eaux atlantiques dans l'océan Nord-Atlantique subpolaire). Donc, les résultats du modèle suggèrent que le déséquilibre dans les flux de chaleur et de salinité latéraux à travers le détroit et au-dessus de la crête reliant les mers nordiques à l'Atlantique Nord et à l'Arctique pourrait amplifier la variabilité interannuelle dans l'océan subarctique. 相似文献
11.
This paper provides a framework for integrated assessment of the impacts of climate change on natural resources and sets the stage for papers that follow in this volume. Integrated assessments are used to organize large quantities of technical information bearing on complex issues (environmental and others) in ways that facilitate application of the information in decision making and policy setting. Any integrated assessment must be based on the best available information. For that reason this paper includes a ‘primer’ on the current (and presumably best available) understanding of the science underlying climatic change. The remainder of the paper describes the component parts of one possible framework for integrated assessment. 相似文献
12.
To convert measurements of windspeed, eddy flux and scalar concentration into estimates of surface scalar exchange, we implicitly or explicitly assimilate the measurements into mathematical statements of the mass balance in a control volume on a representative patch of the surface. The form of this statement depends on the coordinate system in which it is written and the coordinate system should be chosen so that measurements can be used optimally. This requirement imposes a set of conditions on the coordinates. Here we perform a comparative analysis of some candidate coordinate systems, concentrating on the Cartesian and physical streamline systems. We show that over gentle topography there are definite advantages in working in streamline coordinates. Transforming measurements of vector and tensor quantities measured in the reference frame, s
i, of the anemometer into the reference frame, e
i, of the chosen coordinate system involves using the measured statistics of the wind field to define three Euler rotation angles. We compare the method in most common use, which employs the components of the mean wind vector and the Reynolds stress tensor to define these angles, with the more recent planar-fit method that uses instead an ensemble of mean wind vectors to define the rotations. We find that, in real flows, the standard method has a previously unrecognized closure problem that ensures that the third rotation angle defined using the stress tensor or scalar flux vector will always be in error and often give unphysical results. An alternative procedure is recommended. Finally, the relationships between measurements and model outputs are discussed. 相似文献
13.
通过分析《气候与能源2030政策框架》(以下简称《框架》)方案要点,认为欧盟2030年的减排目标相对2020年承诺目标更为积极,可再生能源目标略高于之前官方预期。由于东欧国家的参与,欧盟一方面获得了这些国家盈余的排放配额,帮助欧盟作为一个整体实现减排目标;另一方面,成员国经济发展水平差异增大,导致欧盟施行相对积极的环境政策阻力加大,未来大幅调整减排目标的可能性不大。《框架》目标将可能对2020年后国际碳市场需求预估产生影响,未来国际碳市场的健康运行,将不仅需要欧盟外的发达国家提出具有雄心的减排目标,也需要欧盟提高减排目标,增加其对于国际减排配额的需求;此外,欧盟辅助实现40%减排目标的相关生产标准和措施,可能对未来全球自由贸易产生影响,其他国家尤其是对外贸易依存度较高的发展中国家需要密切关注相关动向。《框架》方案所提出的以应对气候变化引领和促进经济发展、采用组合目标且针对不同目标采取不同实现形式、展现制定目标的透明度、充分考虑成员国差异等提法和操作方式值得中国借鉴。 相似文献
14.
Inviewofthecomplexnatureoftheexperimentalresearchonaftificialrainenhancementandthestrictrequirementsontheselectionofnaturalconditions,thepreparationofinstrumentationandthedesignofoperationscheme,apre-experimentisthereforeindispensableforaformalexperimenta… 相似文献
15.
采用线性倾向估计和非参数统计检验(Mann-Kendall)方法计算黄河流域78个气象站点12个月及年平均气温多年来的长期变化趋势,并在计算结果基本一致的前提下,重点对Mann-Kendall法的计算结果进行了分析.结果表明,黄河流域平均气温总体呈现上升趋势,这种趋势主要归因于1、2、12月气温的升高;气温上升趋势以12月份表现最明显,8月份表现最平缓;全流域年平均气温只有4个站点表现出下降趋势,不同月份变化趋势的地区分布亦有差异,并根据这些差异将流域进行了分区. 相似文献
16.
A physically based conceptual framework is put forward that explains why an increase in heavy precipitation events should be a primary manifestation of the climate change that accompanies increases in greenhouse gases in the atmosphere. Increased concentrations of greenhouse gases in the atmosphere increase downwelling infrared radiation, and this global heating at the surface not only acts to increase temperatures but also increases evaporation which enhances the atmospheric moisture content. Consequently all weather systems, ranging from individual clouds and thunderstorms to extratropical cyclones, which feed on the available moisture through storm-scale moisture convergence, are likely to produce correspondingly enhanced precipitation rates. Increases in heavy rainfall at the expense of more moderate rainfall are the consequence along with increased runoff and risk of flooding. However, because of constraints in the surface energy budget, there are also implications for the frequency and/or efficiency of precipitation. It follows that increased attention should be given to trends in atmospheric moisture content, and datasets on hourly precipitation rates and frequency need to be developed and analyzed as well as total accumulation. 相似文献
17.
Grassroots innovations emerge as networks generating innovative solutions for climate change adaptation and mitigation. However, it is unclear if grassroots innovations can be successful in responding to climate change. Little evidence exists on replication, international comparisons are rare, and research tends to overlook discontinued responses in favour of successful ones. We take the Transition Movement as a case study of a rapidly spreading transnational grassroots network, and include both active and non-active local transition initiatives. We investigate the replication of grassroots innovations in different contexts with the aim to uncover general patterns of success and failure, and identify questions for future research. An online survey was carried out in 23 countries ( N = 276). The data analysis entailed testing the effect of internal and contextual factors of success as drawn from the existing literature, and the identification of clusters of transition initiatives with similar internal and contextual factor configurations. Most transition initiatives consider themselves successful. Success is defined along the lines of social connectivity and empowerment, and external environmental impact. We find that less successful transition initiatives might underestimate the importance of contextual factors and material resources in influencing success. We also find that their diffusion is linked to the combination of local–global learning processes, and that there is an incubation period during which a transition initiative is consolidated. Transition initiatives seem capable of generalising organisational principles derived from unique local experiences that seem to be effective in other local contexts. However, the geographical locations matter with regard to where transition initiatives take root and the extent of their success, and ‘place attachment’ may have a role in the diffusion of successful initiatives. We suggest that longitudinal comparative studies can advance our understanding in this regard, as well as inform the changing nature of the definition of success at different stages of grassroots innovation development, and the dynamic nature of local and global linkages. 相似文献
19.
ABSTRACTAs increasing evidence shows that the risks of climate change are mounting, there is a call for further climate action (both reducing global emissions, and adaptation to better manage the risks of climate change). To promote and enable adaptation, governments have introduced, or are considering introducing, reporting on climate risks and efforts being taken to address those risks. This paper reports on an analysis of the first two rounds of such reports submitted under the UK Climate Change Act (2008) Adaptation Reporting Power. It highlights benefits and challenges for reporting authorities and policymakers receiving the reports that could also inform other countries considering such reporting. For reporting authorities, benefits arise from the reporting process and resulting reports. These benefits include elevating climate risks and adaptation to the corporate level and with stakeholders, alongside facilitating alignment and integration of actions within existing risk management and governance structures. For policymakers, reporting provides enhanced understanding of climate risks and actions from a bottom-up perspective that can be integrated into national-level assessments and adaptation planning processes. The identified challenges are those related to capacity and process. These include limited risk and adaptation assessment capacities; relevance of climate change risks and adaptation in the context of other urgent risks and actions; reporting process effectiveness and robustness; and the provision of effective and sufficiently comprehensive support, including feedback. Key policy insights Effective adaptation reporting needs to be designed and delivered so as to enhance the value of the reporting process and resulting reports both for those reporting and those receiving the reports, as well as from the broader policy perspective. Providing a positive and supportive reporting environment is critical to encourage participation and facilitating contiuous learning and improvement, while also facilitating delivery of policy-relevant adaptation reports. Contributions of adaptation reporting can be enhanced by an inclusive reporting requirement involving a broader organizational mix that enables more effective risk management and reporting that reflects associated (inter)dependencies and consistency with the more comprehensive post-2015 resilience agenda (Paris Agreement, Sendai Framework for DRR and UN Agenda 2030 SDGs). 相似文献
20.
以灵活性跳点格式和时间分解算法为重点, 介绍了IAP (中国科学院大气物理研究所) AGCM-4的动力框架, 并用R-H (Rossby-Haurwitz) 波和Held-Suarez方案对框架进行了检验。结果表明: 高纬灵活性跳点格式很好地保持了普通跳点格式的各种性质, 未产生计算紊乱现象, 可在一定程度上增大时间步长, 在未采用滤波处理时增大时间步长的效果更为显著; 时间分解算法, 即将平流过程与适应过程分开计算, 二者都采用3次非线性迭代积分方案, 在N=5和N=10 (N为平流过程时间步长与适应过程时间步长的比值) 的情况下, 可分别节省CPU时间10.7%和19.9%; R-H波检验表明, 在积分的前80天, 框架较好地保持了R-H 4波的波形, 总有效能量仅衰减0.1%, 从第80天开始, 风场波形开始变形和破碎, 对应的动能和总能量也开始急剧衰减, 至第365天, 总有效能量衰减约8%, 此时, 风场和高度场亦变得较平直。经分析, 第80天R-H波破碎的主要原因是平流项的计算误差使R-H波失稳, 而其后的高度场和风场的变平直是典型的旋转适应机制; Held-Suarez方案检验也证明该框架是可靠的。 相似文献
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