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The representative concentration pathways: an overview 总被引：20，自引：4，他引：16
Detlef P. van Vuuren Jae Edmonds Mikiko Kainuma Keywan Riahi Allison Thomson Kathy Hibbard George C. Hurtt Tom Kram Volker Krey Jean-Francois Lamarque Toshihiko Masui Malte Meinshausen Nebojsa Nakicenovic Steven J. Smith Steven K. Rose 《Climatic change》2011,109(1-2):5-31
This paper summarizes the development process and main characteristics of the Representative Concentration Pathways (RCPs), a set of four new pathways developed for the climate modeling community as a basis for long-term and near-term modeling experiments. The four RCPs together span the range of year 2100 radiative forcing values found in the open literature, i.e. from 2.6 to 8.5 W/m2. The RCPs are the product of an innovative collaboration between integrated assessment modelers, climate modelers, terrestrial ecosystem modelers and emission inventory experts. The resulting product forms a comprehensive data set with high spatial and sectoral resolutions for the period extending to 2100. Land use and emissions of air pollutants and greenhouse gases are reported mostly at a 0.5?×?0.5 degree spatial resolution, with air pollutants also provided per sector (for well-mixed gases, a coarser resolution is used). The underlying integrated assessment model outputs for land use, atmospheric emissions and concentration data were harmonized across models and scenarios to ensure consistency with historical observations while preserving individual scenario trends. For most variables, the RCPs cover a wide range of the existing literature. The RCPs are supplemented with extensions (Extended Concentration Pathways, ECPs), which allow climate modeling experiments through the year 2300. The RCPs are an important development in climate research and provide a potential foundation for further research and assessment, including emissions mitigation and impact analysis. 相似文献
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Malte Meinshausen S. J. Smith K. Calvin J. S. Daniel M. L. T. Kainuma J-F. Lamarque K. Matsumoto S. A. Montzka S. C. B. Raper K. Riahi A. Thomson G. J. M. Velders D.P. P. van Vuuren 《Climatic change》2011,109(1-2):213-241
We present the greenhouse gas concentrations for the Representative Concentration Pathways (RCPs) and their extensions beyond 2100, the Extended Concentration Pathways (ECPs). These projections include all major anthropogenic greenhouse gases and are a result of a multi-year effort to produce new scenarios for climate change research. We combine a suite of atmospheric concentration observations and emissions estimates for greenhouse gases (GHGs) through the historical period (1750?C2005) with harmonized emissions projected by four different Integrated Assessment Models for 2005?C2100. As concentrations are somewhat dependent on the future climate itself (due to climate feedbacks in the carbon and other gas cycles), we emulate median response characteristics of models assessed in the IPCC Fourth Assessment Report using the reduced-complexity carbon cycle climate model MAGICC6. Projected ??best-estimate?? global-mean surface temperature increases (using inter alia a climate sensitivity of 3°C) range from 1.5°C by 2100 for the lowest of the four RCPs, called both RCP3-PD and RCP2.6, to 4.5°C for the highest one, RCP8.5, relative to pre-industrial levels. Beyond 2100, we present the ECPs that are simple extensions of the RCPs, based on the assumption of either smoothly stabilizing concentrations or constant emissions: For example, the lower RCP2.6 pathway represents a strong mitigation scenario and is extended by assuming constant emissions after 2100 (including net negative CO2 emissions), leading to CO2 concentrations returning to 360 ppm by 2300. We also present the GHG concentrations for one supplementary extension, which illustrates the stringent emissions implications of attempting to go back to ECP4.5 concentration levels by 2250 after emissions during the 21st century followed the higher RCP6 scenario. Corresponding radiative forcing values are presented for the RCP and ECPs. 相似文献
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Global and regional evolution of short-lived radiatively-active gases and aerosols in the Representative Concentration Pathways 总被引：3，自引：0，他引：3
Jean-Fran?ois Lamarque G. Page Kyle Malte Meinshausen Keywan Riahi Steven J. Smith Detlef P. van Vuuren Andrew J. Conley Francis Vitt 《Climatic change》2011,109(1-2):191-212
In this paper, we discuss the results of 2000?C2100 simulations following the emissions associated with the Representative Concentration Pathways (RCPs) with a chemistry-climate model, focusing on the changes in 1) atmospheric composition (troposphere and stratosphere) and 2) associated environmental parameters (such as nitrogen deposition). In particular, we find that tropospheric ozone is projected to decrease (RCP2.6, RCP4.5 and RCP6) or increase (RCP8.5) between 2000 and 2100, with variations in methane a strong contributor to this spread. The associated tropospheric ozone global radiative forcing is shown to be in agreement with the estimate used in the RCPs, except for RCP8.5. Surface ozone in 2100 is projected to change little compared from its 2000 distribution, a much-reduced impact from previous projections based on the A2 high-emission scenario. In addition, globally-averaged stratospheric ozone is projected to recover at or beyond pre-1980 levels. Anthropogenic aerosols are projected to strongly decrease in the 21st century, a reflection of their projected decrease in emissions. Consequently, sulfate deposition is projected to strongly decrease. However, nitrogen deposition is projected to increase over certain regions because of the projected increase in NH3 emissions. 相似文献
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Christophe E. Menkes Matthieu Lengaigne Patrick Marchesiello Nicolas C. Jourdain Emmanuel M. Vincent Jér?me Lefèvre Fabrice Chauvin Jean-Francois Royer 《Climate Dynamics》2012,38(1-2):301-321
This paper evaluates the performances of four cyclogenesis indices against observed tropical cyclone genesis on a global scale over the period 1979–2001. These indices are: the Genesis Potential Index; the Yearly Genesis Parameter; the Modified Yearly Convective Genesis Potential Index; and the Tippett et al. Index (J Clim, 2011), hereafter referred to as TCS. Choosing ERA40, NCEP2, NCEP or JRA25 reanalysis to calculate these indices can yield regional differences but overall does not change the main conclusions arising from this study. By contrast, differences between indices are large and vary depending on the regions and on the timescales considered. All indices except the TCS show an equatorward bias in mean cyclogenesis, especially in the northern hemisphere where this bias can reach 5°. Mean simulated genesis numbers for all indices exhibit large regional discrepancies, which can commonly reach up to ±50%. For the seasonal timescales on which the indices are historically fitted, performances also vary widely in terms of amplitude although in general they all reproduce the cyclogenesis seasonality adequately. At the seasonal scale, the TCS seems to be the best fitted index overall. The most striking feature at interannual scales is the inability of all indices to reproduce the observed cyclogenesis amplitude. The indices also lack the ability to reproduce the general interannual phase variability, but they do, however, acceptably reproduce the phase variability linked to El Ni?o/Southern Oscillation (ENSO)—a major driver of tropical cyclones interannual variations. In terms of cyclogenesis mechanisms that can be inferred from the analysis of the index terms, there are wide variations from one index to another at seasonal and interannual timescales and caution is advised when using these terms from one index only. They do, however, show a very good coherence at ENSO scale thus inspiring confidence in the mechanism interpretations that can be obtained by the use of any index. Finally, part of the gap between the observed and simulated cyclogenesis amplitudes may be attributable to stochastic processes, which cannot be inferred from environmental indices that only represent a potential for cyclogenesis. 相似文献
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垄行作物玉米方向亮温野外测量中视场角影响的简单分析 总被引：3，自引：4，他引：3
基于透视原理、地面试验中对于较高目标的观测存在着一定的偏差。这种偏差随传感器高度、观测角度、视场角大小、观测位置等多个因素改变。由于垄行作物空间结构和温度分布的复杂性 ,在采用较大视场角测量方向亮温的地面实验中 ,将不可避免地存在着误差。采用一个简化的三分量二维结构模型对这种误差进行初步的分析与估算。亮温三分量分别为植被、被阳光照到的亮土和植被阴影下的暗土。作物的结构简化为剖面为矩形的无限长平行体。通过对这三个分量在传感器视场中面积权重的计算来模拟目标结构、传感器高度、位置、视场角大小、观测角度等因素对测量结果产生的影响。模拟结果表明 ,在垂直观测中 ,视场中的植被权重往往被高估 ,偏差随传感器高度的降低急剧增加。在倾斜观测中 ,由于一种互补效应的产生 ,偏差被限制在一个较低的范围内。经过分析 ,减小误差的最有效办法是提高传感器高度。最后 ,实验数据与模拟结果进行了比较。恰当地选取模型输入 ,两种数据能非常好的吻合。 相似文献
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Matthieu Kretzschmar Thierry Dudok de Wit Jean Lilensten Jean-Francois Hochedez Jean Aboudarham Pierre-Olivier Amblard Frederic Auchère Said Moussaoui 《Acta Geophysica》2009,57(1):42-51
The knowledge of solar extreme and far ultraviolet (EUV) irradiance variations is essential for the characterization of the
Earth’s upper atmosphere. For a long time, this knowledge has been based on empirical models, which are themselves based on
proxies of the solar activity. However, the accurate modeling and prediction of the Earth’s upper atmosphere necessitate to
improve the precision on the irradiance and its variations below about 200 nm. Here, we present a review of recent works made
by the authors that aim at quantifying the irradiance variability at these wavelengths, and that lead to new way of monitoring
the solar EUV/FUV irradiance spectrum. In more details, it is shown that the quantification of the high level of redundancy
in the solar spectrum variability allows to envisage measuring only a small portion of the spectrum without losing essential
knowledge. Finally, we discuss what should and could be measured in order to retrieve the solar extreme and far ultraviolet
spectrum. 相似文献
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