2019年6月黄河口6次局地冰雹实例分析

利用常规气象资料、多普勒雷达资料、加密自动气象站资料及第五代欧洲中心再分析资料(ERA5),分析了2019年6月发生在黄河口地区的6次局地冰雹天气过程。结论如下：1）6次降雹过程是在有利的环境条件下产生的,大尺度影响系统是东北（华北）冷涡与横槽、中纬度高空槽;冰雹天气即将发生前,对流层低层多存在逆温,有对流抑制,对流有效位能在1 000 J·kg-1以上,环境比较干,0 ℃层与-20 ℃层之间的厚度在1.8～2.3 km,两温度层的高度较经验值偏低。2）雹暴云在发生发展阶段存在最大组合反射率（MaxREF）、回波顶高（ET）和垂直累积液态水含量（VIL）的迅猛跃增;6次雹暴云气柱内冰水含量偏多,且积累迅速,液态水含量较少,雨水含量最少,因而造成降雹时多伴有弱降水。3）雹暴云的中层风场特征表现为雷达径向风的水平切变与垂直切变,而在对流层低层则表现为风向辐合与风速脉动。4）6次冰雹天气发生的地点多在黄河口的沿岸地区;特殊的地理位置有利于在对流层低层形成中尺度风场辐合线,在有利的环流背景下,可激发局地对流或使移入的雷暴云得到迅猛发展,这是导致该地对流频发的原因。     

Developments in the characterisation of waste materials for environmental impact assessment purposes

The characterisation of waste is entering a new phase with the latest developments of characterisation leaching tests and associated modelling capabilities. The currently applied too simple testing approaches lead to poor choices in waste management. With the increased insight in release controlling processes chemical speciation aspects can be addressed even in the most complex and heterogeneous waste materials. From a composition perspective materials may be highly variable, but often materials are far more consistent in their leaching behaviour. This aspect should be exploited more extensively as it holds the key to treat waste materials in such a way that long term solutions are achieved rather than reaching temporary gains.     

基于随机森林模型的珠江三角洲30 m格网人口空间化

人口空间化是实现人口统计数据与其他环境资源空间数据融合分析的有效途径。本文选取夜间灯光数据、道路网数据、水域分布数据、建成区数据、数字高程模型和地形坡度数据作为影响珠江三角洲人口分布的变量因子,利用随机森林模型对珠江三角洲2010年人口数据进行了30 m格网空间化,并将模拟结果与三个公开数据集作精度对比,最后基于随机森林模型的变量因子重要性分析珠江三角洲人口空间分布的影响因素。结果表明：本文模拟整体精度达到82.32%,均优于WorldPop数据集以及中国公里网格人口数据集,接近GPW数据集,而且在人口密度中等区域模拟精度最高;通过对变量因子重要性进行度量,发现夜间灯光强度是珠江三角洲人口分布的最重要指示性指标,到水域的距离、到建成区的距离和路网密度对珠江三角洲人口分布均具有重要作用。利用随机森林模型结合多源信息能够实现高空间分辨率的人口空间化,可为精细化城市管理提供重要数据源,也可为相关政策决策制定提供支持。     

生态地球化学预测预警若干问题探讨

回顾了生态地球化学危害效应的作用机理,提出了区域地球化学调查-地球化学环境监测-机理研究相结合的生态地球化学预测预警基本思路。根据当前中国多目标区域地球化学调查和生态地球化学评价工作的现状,举例说明了土壤重金属元素累积、土壤环境变化、生态效应机理的若干研究方法,提出了预测预警成果体现的若干建议。     

长江三角洲NB5孔第四纪地层划分及环境变化信息

长江三角洲北翼NB5孔做了古地磁测试、~(14)C测试及ESR测试结果,对古地磁变化特征进行了总结分析,结合区内其他钻孔的对比,对钻孔第四纪地层划分及所反映的古气候环境进行了探讨。结果表明:46 m处为全新世底界,163 m为中更新世顶部,240 m左右为早更新世顶部,354 m为早更新世底部。其中,海相层有2个,位置在2~47m,125~163 m。分别对应于Ⅰ(Qh)镇江海侵,Ⅲ(Q_p~(3-1))昆山海侵。据晚更新世以后沉积物粒度变粗及磁化率所反映的巨大变化特征,提出中更新世晚期、晚更新世初期为长江主泓流经本区的时间,并认为此或与塑造中国现代地貌的共和运动造成的青藏高原再次强烈隆升有关。     

Robustness and the Paradox of Bridging Organizations: The Exit Problem in Regional Water Governance Networks in Central America

Bridging organizations facilitate a range of governance processes, including cooperation and social learning, and are theorized to be a key component of robust governance systems. In this article, we use node removal simulations to test structural hypotheses of robustness in a regional water governance network in Central America. We investigate the response of network measures supporting core governance processes to the targeted removal of bridging organizations and other actors, which we compare to random and centrality-based simulations. The results indicate removing bridging organizations has a greater impact on the network than any other type of actor, suggesting bridging organizations are critical to the robustness of the governance system. Furthermore, network structures supporting cooperation may be less robust than structures facilitating social learning. We conclude with policy implications of the research findings as they relate to the exit problem in governance systems with a large presence of international development actors.     

Applying the Political Geography of Scale: Grassroots Strategies and Environmental Justice

The grassroots environmental movement often protests locally unwanted land uses. Many grassroots groups have, however, expanded their agenda to the scale of environmental justice. Explanations for this scale transformation include historical circumstances, individuals' radicalization through activism, and the growth of environmental justice networks. This case study, grassroots environmentalists' opposition to a proposed electricity transmission line in Monroe County, WV, explores another explanation: appeals for environmental justice are also a strategic response to siting regulatory procedures. With concepts emerging from the political geography of scale, I interpret the Monroe Countians' efforts and show how their strategies link the grassroots scale with that of environmental justice.     

西部中国沙棘叶片稳定碳同位素组成的空间特征及其气候意义

分析了西部中国沙棘（Hippophate rhamnoides sinensis）叶片稳定碳同位素组成特征及其与环境因子之间的关系。结果表明,中国沙棘叶片δ13C值在-30.40‰~-24.91‰之间变化,平均值约为-27.62‰,属于C3植物。随纬度和经度的升高,中国沙棘叶片δ13C值明显升高,而随海拔的升高而降低,具有明显的空间分布特征。中国沙棘叶片δ13C值与温度没有明显的关系,随蒸发量和日照时间的升高而升高,随降水量的升高有降低趋势,具有明显的气候意义。表明中国沙棘具有较高的水分利用效率,水分是控制中国沙棘δ13C值变化或生长的主导因子。     

THE MESOSCALE CONVECTIVE SYSTEMS ACROSS THE TAIWAN STRAIT AND NEIGHBORING AREAS DURING IOP608 OF HUAMEX

The paper gives the distributions of the daily mean temperature of black body of satellite infrared images from June 7 to 10, 1998 during HUAMEX and examines 14 meso-α-scale convective systems and a number of meso-b-scale convective systems using the satellite infrared images at 1-h intervals. The mesoscale convective systems on June 7 and 9, which resulted in severe rainstorm over the middle of Taiwan and the estuary region of the Pearl River (Zhujiang R.), are emphatically analyzed. The serial development of mesoscale convective systems is revealed by the distributions of the black body temperature of satellite infrared images. The environmental conditions in which many mesoscale convective systems continuously occurred are diagnosed. The visualizing tool, LiveView, displays the link between the upper and lower horizontal wind fields and the vertical circulations and 3-dimensional trajectories of moist air motions, based on the data of objective analyses.     

三峡水库香溪河鱼类群落结构特征及历史变化

由于自然和人为因素的影响,三峡水库鱼类资源一直在发生变化,为掌握三峡水库蓄水后典型支流香溪河鱼类群落的现状及历史变化,于2020年7月—2021年4月使用多网目复合刺网和地笼对香溪河鱼类群落进行实地采样,并结合历史数据进行比较分析。研究期间共采集到鱼类55种,隶属于7目14科,鲤科鱼类种类数最多,以杂食性鱼类和湖泊定居性鱼类为主,优势种为贝氏?(Hemiculter bleekeri)、短颌鲚(Coilia bratchygnahus)、似鳊(Pseudobrama simoni)和翘嘴鲌(Culter alburnus),其相对重要性指数(IRI)分别为5502、3828、2567和1109。鱼类物种多样性指数在春季最高,夏季最低。刺网单位捕捞努力量渔获个体数和单位捕捞努力量渔获量在夏季最高,冬季最低。与三峡水库蓄水前相比,香溪河鱼类中长江上游特有鱼类减少4种,外来鱼类增加3种。湖泊定居性种类持续增加,喜流水性种类减少,鱼类优势种发生较大变动。2020—2021年香溪河鱼类组成与1987年的相似性指数为0.29,与2012—2013年的相似性指数为0.53,反映三峡水库蓄水前后香溪河...