Bringing greenhouse gas removal down to earth: Stakeholder supply chain appraisals reveal complex challenges     

《Global Environmental Change》2021

Greenhouse gas removal (GGR) approaches are considered essential in several projections to meet the climate mitigation ambition of the Paris Agreement. Biomass Energy with Carbon Capture and Storage (BECCS) and afforestation are included extensively in mitigation scenarios but there are concerns about the feasibility of these approaches. This was explored with stakeholders from industry, non-governmental organisations (NGOs) and policy who were involved in interviews and a one-day participatory workshop. Multicriteria mapping (MCM) methodology was used to appraise the ‘real-world’ feasibility of four specific greenhouse gas removal supply chains at a granular level in the UK context. The MCM analysis shows that afforestation performs better in comparison to three BECCS supply chains, on criteria such as business model, social acceptability, and environmental sustainability. This innovative application of the MCM methodology enables the abstract representations of GGR in integrated assessment models to be explored at a more granular level through a supply chain analysis and thus gain a deeper understanding of the issues facing these approaches. The data gathered allows a wide range of technical, environmental, social and political criteria to be systematically applied in appraising the practical performance of different future implementation options for afforestation and BECCS. If these GGR supply chains are to become a reality on the scale required for 1.5 °C global warming, factors such as global cooperation, land availability, and the longevity of policies and incentives were found to be major challenges.  相似文献   

蒙古东部冷涡造成河北中南部雹暴过程的地闪特征分析   总被引：3，自引：3，他引：0       下载免费PDF全文

连志鸾  高连山  李国翠  赵瑞金  赵彦厂 《高原气象》2009,28(1):186-194

应用地面闪电定位系统、多普勒雷达、加密自动雨量站资料,对2007年7月8～9日蒙古东部冷涡天气系统下,发生在河北中南部的两次雹暴过程进行了分析.结果表明:两次雹暴均产生大量地闪活动,且以负地闪占优势,闪电集中发生时段与强对流发生及维持时间相当.雹暴和强降水在时空分布上对应的地闪极性有明显差异,降雹发生在雹暴云团中正地闪最活跃的阶段,正地闪集中出现在强回波中心及其邻近区域,降雹点落在正地闪聚集区附近;对流性强降水云团中负地闪频繁发生,强降水区出现在负地闪密度高值中心附近,负地闪簇集区域预示着对流性强降雨的落区.多单体风暴中:闪电的频率及聚集区域主要取决于雷暴单体的数目、强度和相互接近的程度,其造成的强降雹主要发生在总地闪的活跃期.本次个例分析显示,总闪电频数跃增、正闪频数突增,仅先于降雹数分钟(几乎同时)发生.因此,根据闪电频数变化可监测对流强度的演变和冰雹天气的发生.  相似文献   

Luminosity characteristics of leaders in natural cloud-to-ground lightning flashes     

Yijun Zhang  Weitao Lu  Jun Li  Wansheng Dong  Dong Zheng  Shaodong Chen   《Atmospheric Research》2009,91(2-4):326-332

Using high-speed cameras, we have recorded the leaders contained in four natural negative cloud-to-ground (CG) lightning flashes in the summers of 2006 and 2007 at Conghua, Guangdong, China. It was found that the downward negative leaders preceding the first return stroke could propagate at quite different speeds. In one flash, the average speed of the downward negative stepped leader with no branches is about 2.2 × 10⁶ m s^− 1, while that of the other 3 flashes are all of the order of 10⁵ m s^− 1 with multilevel branches. The luminosity of the leaders shows an increasing tendency in propagating downward to the ground. For the leaders preceding the subsequent strokes, although all of them exhibit high speeds as reported previously. One subsequent leader exhibits an increasing speed from 5.2 × 10⁵ m s^− 1 to 1.7 × 10⁶ m s^− 1 during its propagation from about 1.26 to 0.36 km above the ground, and its luminosity also increased. The speed and luminosity of a leader between subsequent strokes of a natural lightning appear to decrease as it developed downward. Its speed ranges from 1.1 × 10⁶ to 1.1 × 10⁵ m s^− 1, with a height between 1.15 and 0.81 km above the ground.  相似文献   

Continuing current in multiple channel cloud-to-ground lightning     

M.A. Ferro  M.M.F. Saba  O. Pinto Jr. 《Atmospheric Research》2009,91(2-4):399-403

In this study we analyze the effects of continuing current initiated by strokes following a new channel to ground in multiple stroke flashes using high-speed video records, electric field measurements from a fast antenna and lightning detection network data. We observed that the long continuing current initiated by a stroke that follows a new channel also obeys the pattern in the initiation of long continuing current suggested by Rakov and Uman [Rakov, V.A., Uman, M.A., 2003. Lightning: Physics and Effects, 687pp., Cambridge Univ. Press, New York.]. We also verify that the statement of Rakov and Uman [Rakov, V.A. and Uman, M.A., 1990. Some properties of negative cloud-to-ground lightning flashes versus stroke order, Journal of Geophysical Research. 95, 5447–5453.] reporting that: “...strokes initiating long continuing currents tend to have lower initial electric field peak than regular strokes” is valid for strokes that create a new channel to ground and are followed by long continuing current (CC). Apparently the reduction of peak current value (I_p) when the stroke is followed by a long CC is stronger than the I_p increase that is commonly observed when strokes follow a new channel. We also find that the “exclusion zone” proposed by Saba et al. [Saba, M.M.F., Pinto, O. Jr., Ballarotti, M.G., 2006a. Relation between lightning return stroke peak current and following continuing current, Geophysical Research Letters 33, L23807, doi:10.1029/2006GL027455.] is valid for new channels initiating CC, and finally we verify that a number of strokes in the same channel larger than four or the existence of a long CC current do not always consolidate the channel in a multiple stroke flash.  相似文献   

Comparative analysis of the initial stage in two artificially-triggered lightning flashes     

J. Yang  X. Qie  Q. Zhang  Y. Zhao  G. Feng  T. Zhang  G. Zhang 《Atmospheric Research》2009,91(2-4):393-398

The initial discharge stages of two flashes during the Shandong Artificially Triggering Lightning Experiment (SHATLE) are analyzed based on the synchronous data of the current and close electromagnetic field. For a lightning flash, named 0503, the wire was connected, not electrically, but via a 5 m length of nylon, with the lightning rod; while for another, named 0602, the wire was connected with the rod directly. Results show that the discharge processes of the initial stage (IS) in flash 0503 are quite different from that of the usual classical-triggered flash 0602 and altitude-triggered flashes. A large pulse with a current of about 720 A resulted from the breakdown of the 5 m air gap during flash 0503, and the corresponding electric field at 60 m from the lightning rod was 0.38 kV/m. The upward positive leaders (UPLs) propagated continuously from the tip of the rocket after this breakdown. The geometric mean (GM) of the UPL peak current was 23.0 A. Vaporization of the wire occurred during the initial continuous current (ICC) stage and the largest current pulse was about 400 A. Compared with triggered flash 0503, the discharge processes of IS in flash 0602 were simple, only two large pulses similar to each other occurred before dart leader/return stroke sequences. The peak current of the first pulse was 2.1 kA and its corresponding electric field and magnetic field at a distance of 60 m from the lightning rod were 0.98 kV/m and 7.03 μT, respectively. During the second pulse, the wire disintegrated. The current decreased to the background level at the moment of the wire disintegration. The current of the second pulse in triggered flash 0602 was 2.8 kA, and the corresponding electric field and magnetic field at 60 m from the lightning rod were 1.22 kV/m and 9.01 μT, respectively.  相似文献   

前陆冲断带的后期演化:负反转与再次冲断          下载免费PDF全文

马晓鸣何登发  吴晓智赵振宇 《地质科学》2010,45(4):1066-1077

和什托洛盖盆地位于准噶尔西北缘冲断推覆体之上,是一个在中生代由区域应力场性质发生改变时形成的负反转盆地。盆内沉积盖层厚度可达5000 m,由下侏罗统八道湾组、三工河组,中侏罗统西山窑组、头屯河组以及新生界组成。盆地内断裂发育,可划分为控制盆地格局和构造带展布的北东东向断裂和起调节作用的北西向断裂两组,依据分界断裂可将盆地划分出北部断褶带、中央坳陷带和南部斜坡带3个一级构造单元和7个二级构造单元。盆地的形成演化主要经历了3个时期：印支期在边界断裂不均衡冲断活动下形成盆地雏形; 燕山早期是盆地主要发育期,以大规模沉降作用为主; 燕山晚期-喜马拉雅山期是盆地的改造期,现今的构造格局基本形成并在喜马拉雅山期后定型。  相似文献   

Electrostatic ion-cyclotron waves in a plasma with heavy negative ions     

S.-H. Kim 《Planetary and Space Science》2008,56(11):1552-1559

Results of a laboratory study of electrostatic ion-cyclotron (EIC) waves in a plasma containing K⁺ (39 amu) positive ions, electrons and C₇F₁₄⁻ (350 amu) negative ions are presented. Excitation of the fundamental and higher harmonic light and heavy ion EIC modes was observed. The presence of heavy negative ions in the plasma has a significant effect on the excitation of the light ion EIC modes. The results may be relevant to the understanding of plasma wave properties in plasmas containing negative ions, such as those found in the Earth's ionosphere, the solar system, and, in particular, near Saturn's moon Titan, where an abundance of heavy negative ion species has recently been discovered [Coates, et al., 2007. Discovery of heavy negative ions in Titan's ionosphere. Geophys. Res. Lett. 34, L22103].  相似文献   

横向各向同性介质和斜方介质各向异性参数的约束条件   总被引：4，自引：2，他引：2       下载免费PDF全文

李磊  郝重涛 《地球物理学报》2011,54(11):2819-2830

Thomsen提出的横向各向同性(TI)介质各向异性参数(α0、β0、ε、δ、γ)是各向异性理论研究和实际资料处理中的常用参数,Thomsen参数的取值必须符合物理学定律和实际地学情况,随意的取值可能导致无意义乃至错误的结果.本文根据热力学定律和弹性常数的物理意义,结合大量的实测数据,提出常见TI介质的Thomsen参...  相似文献   

Phytoplankton growth and microzooplankton grazing in the continental shelf area of northeastern South China Sea after Typhoon Fengshen   总被引：1，自引：0，他引：1  

Linbin Zhou  Yehui Tan  Liangmin HuangJianrong Huang  Huaxue LiuXiping Lian 《Continental Shelf Research》2011,31(16):1663-1671

Dilution experiments were used to investigate the phytoplankton growth and microzooplankton grazing in the continental shelf area of northeastern South China Sea during 30 June and 7 July, 2008, occurring about a week after Typhoon Fengshen. We detected negative phytoplankton growth rates (−0.03 to −2.02 d⁻¹) and measured grazing rates of microzooplankton on phytoplankton in size-fractionations of 20-200 μm (1.25±0.44 d⁻¹), 3-20 μm (1.48±0.63 d⁻¹) and <3 μm (1.02±0.42 d⁻¹). Results showed significant correlations between phytoplankton growth and microzooplankton grazing rates, between phytoplankton and ciliate abundance, and between the dominant phytoplankton Thalassionema nitzschioides and the dominant ciliate Helicostomella longa (p<0.05). Phytoplankton decay, due to nutrient-limited conditions occurring with the fading of upwelling and spreading of freshwater plume after Typhoon Fengshen, may account for negative phytoplankton growth rates in this study. Synergism in the specific size-selective grazing of various species, including ciliates and heterotrophic dinoflagellates, may contribute to similar grazing rate on phytoplankton in different size-fractionations, at the integrated level. Interactions between phytoplankton and microzooplankton, including grazing selectivity, top-down and bottom-up control between phytoplankton and microzooplankton may contribute to these findings. Our results indicate that under conditions of negative phytoplankton growth microzooplankton grazing may reduce energy loss from the epipelagic waters by retrieving energy from the decaying phytoplankton community.  相似文献   

北京及其周边地区闪电活动的时空特征   总被引：3，自引：2，他引：1       下载免费PDF全文

李京校  宋海岩  肖稳安  杜晓宾  郭凤霞 《大气科学学报》2013,36(2):235-245

利用具有总闪观测能力的SAFIR3000在2005-2007年对北京及周边地区(天津、唐山、廊坊等)的观测资料,分析了该地区云闪和地闪时空分布特征.结果表明:云闪高发时段在15:00-次日00:00,峰值在19:00,高发月份在6-8月,峰值在7月;云闪空间分布高值区在北京东北部、天津北部、承德西南部一带,约为30次/(km2·a);云闪平均高度(海拔高度)日变化差异不大,季节变化夏季最高,冬季最低;高度在9～10 km的云闪最多,占云闪总次数的10.97％.地闪高发时段、月份、地闪高值区(密度约为5次/(km2·a))与云闪基本相似,不同之处在于云闪日分布多为单峰,而地闪为双峰,云闪高值时段开始与结束时间均比地闪早;云闪空间分布高值区密度约为地闪的6倍.3 a平均正闪占地闪总数百分比为16.44％,夏季该百分比较低,春秋季较高,其月际变化与正闪次数月际变化相反.总闪时空分布特征和云闪更为相似,总闪高值区分布和卫星探测得到的基本一致.  相似文献