季风低压诱发2018年8月广东特大暴雨过程分析

利用NCEP/FNL再分析资料和中尺度数值模拟方法探讨2018年8月27日—9月1日季风低压环境下广东特大暴雨过程的形成成因。利用扰动天气图方法分析发现,季风低压和西南急流为此次广东暴雨过程提供了有利的水汽条件和能量条件。熵变零线位置与降水落区位置有较好的对应,零线处能量有最大累积,有利于暴雨的发生发展,对预报暴雨降水落区有一定的指示意义。为进一步验证季风低压的影响机制,构建不同季风低压尺度的敏感性试验,即通过滤去季风低压环流中的扰动分量来改变季风低压的强度。结果表明：暴雨强度与季风低压尺度和强度存在密切的关系。当季风低压强度较强时,暴雨过程总雨量强;当季风低压强度较弱时,降水大为减少甚至无降水。诊断分析指出,能量螺旋度指数能够较好反映出不同情形下降水发生发展,在季风低压背景下,暴雨区能量螺旋度指数较大,降水强度较强。反之,随着季风低压强度减弱,能量螺旋度指数减小,降水减弱。     

A simulation study on risks of pedestrian evacuation from flooded staircases of different slopes in the underground space

Natural Hazards - To quantitatively assess the risks of pedestrian evacuation through staircases with different slopes when a flood intrudes into the underground space, a numerical model was...     

中全新世以来南极宇航员海的古生产力演变

本文通过对南极宇航员海ANT36-C4-05岩心的放射性核素²¹⁰Pb、AMS¹⁴C测年、XRF岩心扫描、多参数物性扫描和主、微量元素的测试分析,重建了该海区中全新世(6 500 Cal a BP)以来的古生产力演变及其制约因素。研究结果表明,中全新世以来宇航员海古生产力波动较强,其演变趋势与南极气温变化基本一致,受海冰范围变化制约较大。在6 500~5 200 Cal a BP期间宇航员海古生产力随着温度升高和海冰范围减小而快速上升;在5 200~3 350 Cal a BP期间宇航员海的古生产力处于高值期,波动较小;在3 350~2 000 Cal a BP期间随着温度降低和海冰范围的扩大,硅质、钙质生产力下降;在2 000~0 Cal a BP期间古生产力水平变化复杂,变化程度相较于之前小。同时,中全新世以来宇航员海区沉积记录较好地反映了5 500 Cal a BP冷事件、DACP冷事件、MWP暖期和LIA冷事件的气候变化,受冷、暖事件影响导致的古生产力的变化最为明显。     

气象产品的广义联合偏差修正方法及其应用

卫星气象产品、气候模式预测数据通常与地面观测数据存在偏差,为保证数据的可靠性和合理性,需要对其进行偏差校正,但偏差校正过程往往受具体区域气象特征、方法本身假定等因素的影响,导致修正效果不佳。为此,本文提出一种广义联合偏差修正方法,相较于现有研究最常用的单变量QM修正方法以及固定多变量修正顺序的JBC修正方法,该方法充分考虑到流域尺度降水和气温双变量的时空相关性,并结合其对径流的主导作用对变量修正顺序进行动态调整,实现了QM法和JBC法的优势互补。在澜沧江-湄公河流域的应用表明：考虑降水、气温相关性可显著改善降水和温度极值的修正效果,尤其是5、6月份,修正后气象与实测数据的纳什系数提升了0.5以上;考虑气象要素的修正次序显著降低了修正后的降水和温度频率分布及均值偏差;利用修正后的气象数据驱动分布式水文模型时,部分月份的径流模拟精度提升了54.3%。     

知识经济与区域可持续发展

分析了知识经济和知识产业的特点。从知识产业的零排放概念对环境保护的意义,信息产业发展对城市可持续发展的作用,生物工程农业与区域可持续发展的关系,微生物技术为基础的废弃物资源化产业对大气环境的保护,新能源与节能产业对经济可持续发展的作用等方面阐述了知识产业的发展在区域可持续发展中的重要意义。     

探索虚拟城市

本文重点讨论了虚拟城市的涵义及其来由,同时简要地论及虚拟城市的功能,如对城市规划方案讨论、评价,城市功能虚拟化和城市运行评价等。     

专家笔谈:知识经济与地理学发展

编者按　伴随世界性科学技术高速发展,以计算机应用软件为代表的知识经济（智力经济）扑面而来,信息产业在国民经济发展中的地位日益重要。这是信息时代到来的标志,是“科学技术是第一生产力,科技进步是经济发展的决定性因素”的现实体现。面对信息时代的新气息,我们地理科学工作者应解放思想,更新观念,吸收新鲜血液,抓住机遇,迎头赶上信息时代的步伐,把一个生机勃勃的地理科学带入２１世纪。但是,如何发挥地理科学的现有优势,尽快形成适应时代需要的新的优势,值得全国地理学工作者深入思考,认真研究,系统探讨。为此,本刊从…     

A coupled high-resolution hydrodynamic and cellular automata-based evacuation route planning model for pedestrians in flooding scenarios

Flooding is now becoming one of the most frequent and widely distributed natural hazards, with significant losses to human lives and property around the world. Evacuation of pedestrians during flooding events is a crucial factor in flood risk management, in addition to saving people’s lives and increasing time for rescue. The key objective of this work is to propose a shortest evacuation path planning algorithm by considering the evacuable areas and human instability during floods. A shortest route optimization algorithm based on cellular automata is established while using diagonal distance calculation methods in heuristic search algorithms. The Morpeth flood event that occurred in 2008 in the UK is used as a case study, and a highly accurate and efficient 2D hydrodynamic model is adopted to discuss the flood characteristics in flood plains. Two flood hazard assessment approaches [i.e., empirical and mechanics-based and experimental calibrated (M&E)] are chosen to study human instability. A comprehensive analysis shows that extreme events are better identified with mechanics-based and experimental calibration methods than with an empirical method. The result of M&E is used as the initial condition for the Morpeth evacuation scenario. Evacuation path planning in Morpeth shows that this algorithm can realize shortest route planning with multiple starting points and ending points at the microscale. These findings are of significance for flood risk management and emergency evacuation research.

     

专家笔谈:知识经济与地理学发展

编者按　伴随世界性科学技术高速发展,以计算机应用软件为代表的知识经济（智力经济）扑面而来,信息产业在国民经济发展中的地位日益重要。这是信息时代到来的标志,是“科学技术是第一生产力,科技进步是经济发展的决定性因素”的现实体现。面对信息时代的新气息,我们地理科学工作者应解放思想,更新观念,吸收新鲜血液,抓住机遇,迎头赶上信息时代的步伐,把一个生机勃勃的地理科学带入２１世纪。但是,如何发挥地理科学的现有优势,尽快形成适应时代需要的新的优势,值得全国地理学工作者深入思考,认真研究,系统探讨。为此,本刊从…     

Oomycetes and fungi: important parasites on marine algae

Considering that the field is largely unexplored and its importance to aquaculture, outline of oomycetes and fungi parasiting on marine algae was provided in this paper, including 15 species of oomycetes, six species of chytrids, 31 Ascomycota species and one species of mitosporic fungi. In natrue, both the oomycetes and chytrids frequently occurred and induced prevalences of disease which could destroy the populations of host plants greatly. However, the parasites in Ascomycota on algae have never occurred as epidemics so far. Some issues relating to the field were discussed such as performing tests to satisfy Koch''s postulates, investigations of host specificity, interactions between host and parasite and the potential effects of environmental factors on occurrence of a disease, which are urgent in need of further investigations.