基于WebGIS的地震应急快速反应系统设计与实现     

余其鹏  汪波 《地震地磁观测与研究》2020,41(4):239-250

根据镇江地震地质情况及防震减灾工作实际，通过需求分析及系统整体设计，建立基于WebGIS的地震信息数据库管理系统。系统采用Oracle数据库、JavaScript语言、Tomcat网站服务器，开发了具有地方特色的地震应急处置快速反应系统，系统可实现震后快速评估、辅助决策、震后趋势分析、震后应急资料产出等功能。实际应用表明，该系统达到了低成本、高效率的预期目标。  相似文献   

扎格罗斯前陆盆地晚中新世快速剥露证据——来自磷灰石(U- Th)/He的约束     

李佳纬  孙继敏  吕丽星  张志亮  田晟辰  曹萌萌  李有生  苏柏 《地质学报》2020,94(12):3674-3688

伊朗扎格罗斯造山带是世界上最年轻的造山带之一，前人对其构造演化历史的研究尚存争议。前陆盆地蕴藏着丰富的造山带热史信息，为研究造山带的隆升和剥露历史提供了重要途径。本研究选取位于扎格罗斯前陆盆地前缘中部的Kuh- E Bedush向斜和Kuh- E Murdeh向斜翼部出露的第三纪陆相红层(Agha Jari组)为研究对象，共采集11个粗砂岩样品进行磷灰石(U- Th)/He测试分析。11个样品共得到38个单颗粒年龄，年龄区间为0. 8~79. 9Ma。大部分样品的单颗粒年龄比较分散，表明这些样品没有发生完全热重置。相反，位于Murdeh向斜剖面最底部的样品，(U- Th)/He年龄小于其对应的地层年龄，并且集中分布在8. 3~6. 8Ma，表明该样品发生了完全重置并记录了最后一次剥露事件的时间。因此，我们认为扎格罗斯前陆盆地于晚中新世~7. 5 Ma经历了一期快速剥露事件。此外，我们发现未重置的(U- Th)/He年龄大致分布在四个时间段：晚白垩纪—早古新世、早—中始新世、渐新世、早—中中新世。根据所得热年龄并结合前人研究设定了三种不同的热史，正演模拟结果与实际样品拟合较好，由此推断出前陆中部Agha Jari陆相红层沉积物可能来自于：①晚白垩世以来以蛇绿岩套为主的仰冲体持续剥露；②萨南达季- 锡尔詹变质带(SSZ)渐新世和中新世逐渐加速的剥露；③渐新世末堆积在仰冲体之上的同造山期砾岩，在中新世的大规模逆冲作用下重新剥露。  相似文献   

北极快速变化的生态环境响应   总被引：1，自引：0，他引：1  

陈建芳  金海燕  白有成  庄燕培  李宏亮  李杨杰  任健 《海洋学报》2018,40(10):22-31

北冰洋由于其特殊的地理位置，成为全球变化响应最为敏感的地区。本文聚焦北极海冰变化幅度最大的西北冰洋，从营养盐、叶绿素、浮游植物群落和沉积碳埋藏等变化来讨论海洋生态环境对北极快速变化的响应。尽管太平洋北向流和北极周边河流输入加强可以增加西北冰洋上层营养盐储库，但由于夏季硅藻旺发向沉积物迁出大量生源元素，使得上层营养盐相对亏损，部分海域存在显著的氮限制和硅限制。随海冰减退，尽管夏末海盆区浮游植物呈现小型化趋势，但西北冰洋总体上浮游植物现存量和初级生产力呈现增高的趋势；伴随叶绿素极大层下移、北扩，以硅藻为代表的生物泵过程得以更高效的运转。在沉积物埋藏的有机碳中，除原先北冰洋生态系统占据重要比份的冰藻外，硅藻等藻类的有机碳埋藏也逐渐增加。西北冰洋海洋初级生产力的增加不仅促进了生物泵的运转和碳的埋藏，而且给海洋生态系统提供了更多的食物来源。北极海域目前已成为全球碳源汇格局变化最大、海洋生态系统改变最显著的地区之一。  相似文献   

地震速报区域的自动确认——以内蒙古测震台网为例     

张珂  王鑫  郝美仙  苏柱金  刘芳 《中国地震》2019,35(4):753-761

针对当前省级区域测震台网在判别边界地震是否需要速报的问题，基于内蒙古自治区行政区域的边界数据，利用几何学中包络线原理，在Matlab中将内蒙古地震速报范围以包络线的形式呈现，解译Msdp地震分析软件的数据接口，实现内蒙古地震速报区域在Msdp软件中的自动确认；对比分析地震速报区域自动确认功能的结果与现阶段手动量取方式判别地震事件是否需要速报的结果，表明地震速报区域的自动确认可提高速报业务软件系统的自动化程度，简化地震速报工作的操作流程，减少速报用时，提高速报工作的准确度。  相似文献   

春季季风间期赤道东印度洋浮游植物光合生理特征     

袁超  徐宗军  张学雷  韦钦胜  王辉武  王宗灵 《海洋学报(英文版)》2019,38(6):83-91

Phytoplankton physiologies are dynamic and have sensitive responses to the ambient environment. In this paper,we examine photosynthetic physiologies of phytoplankton communities with Phyto-PAM in the eastern equatorial Indian Ocean during the spring inter-monsoon. Environmental parameters were measured to investigate the coupling between phytoplankton photosynthetic physiologies and their habitats. During the cruise, the water column was highly stratified. The mixed layer extended to about 75 m and was characterized by high temperature(28°C) and low nutrient level. The F_v/F_m values and chlorophyll a(Chl a) concentrations were lower at the surface, as consequences of nutrient depletion and photo-inhibition. Subsurface Chl a maximum(SCM) occurred between 75 and 100 m, and had the highest F_v/F_m values. The formation of SCM was a balance between nutrient availability and light limitation. The SCM may contribute significantly to pelagic food web and primary production in the water column. Phytoplankton in different layers encountered different light, trophic and hydrographic dynamics and evolved distinct photosynthetic characteristics. Despite of co-limitation of nutrient limitation and photo-inhibition, phytoplankton in the surface layer showed their acclimation to high irradiance, had lower light utilization efficiencies(α: 0.061±0.032) and could exploit a wide range of light irradiance. Whereas, phytoplankton in the SCM layers presented the highest light utilization efficiencies(α:0.146±0.48), which guaranteed higher photosynthetic capacities under low light level. These results provide insights into phytoplankton photo-adaption strategies in this less explored region.  相似文献   

Exploring future changes in smallholder farming systems by linking socio-economic scenarios with regional and household models     

《Global Environmental Change》2014

We explore how smallholder agricultural systems in the Kenyan highlands might intensify and/or diversify in the future under a range of socio-economic scenarios. Data from approximately 3000 households were analyzed and farming systems characterized. Plausible socio-economic scenarios of how Kenya might evolve, and their potential impacts on the agricultural sector, were developed with a range of stakeholders. We study how different types of farming systems might increase or diminish in importance under different scenarios using a land-use model sensitive to prices, opportunity cost of land and labour, and other variables. We then use a household model to determine the types of enterprises in which different types of households might engage under different socio-economic conditions. Trajectories of intensification, diversification, and stagnation for different farming systems are identified. Diversification with cash crops is found to be a key intensification strategy as farm size decreases and labour costs increase. Dairy expansion, while important for some trajectories, is mostly viable when land available is not a constraint, mainly due to the need for planting fodders at the expense of cropland areas. We discuss the results in relation to induced innovation theories of intensification. We outline how the methodology employed could be used for integrating global and regional change assessments with local-level studies on farming options, adaptation to global change, and upscaling of social, environmental and economic impacts of agricultural development investments and interventions.  相似文献   

Transforming agricultural land use through marginal gains in the food system     

《Global Environmental Change》2019

There is an increasing need for transformational changes in the global food system to deliver healthy nutritional outcomes for a growing population while simultaneously ensuring environmental sustainability. However, such changes are subject to political and public constraints that usually allow only gradual, incremental changes to occur. Drawing inspiration from the British cycling team’s concept of marginal gains, we show how transformation might be reconciled with incremental changes. We demonstrate that a set of marginal food system changes acting to increase production efficiency, to reduce losses or to adjust diets could collectively reduce the agricultural land required globally for food production by 21%, or over a third given higher adoption rates. The results show that while all categories of action are important, changes in consumer choices in Europe, North America and Oceania and in the supply-chain in Africa and West and Central Asia have the greatest potential to reduce the land footprint of the food system.  相似文献   

CAUSAL ANALYSIS AND NUMERICAL MODELING OF THE INSHORE INTENSIFICATION OF SUPER TYPHOON “HATO”     

于鑫  郑腾飞  万齐林  肖辉  刘显通  王婷 《热带气象学报(英文版)》2019,25(3):293-303

This paper comprehensively analyzes the characteristics and cause of the inshore intensification of super typhoon "Hato", the 13 th super typhoon in 2017. The aspects of typhoon structure, evolution of large-scale circulation and physical quantity field are analyzed using observation data from the Guangdong Automatic Station, Shenzhen Doppler Radar data, NCEP 1°×1° reanalysis data, NCEP 0.25°×0.25° sea surface temperature(SST) data, etc.Additionally, in order to investigate the influence of SST change on the intensity of "Hato", the WRF model and ECMWF 0.125°×0.125° reanalysis data are combined to conduct 3 sensitivity tests on"Hato". The results show that the favorable conditions for inshore intensification of "Hato"included the strengthening and westward extension of the subtropical high, continuous increase of low level moisture transport, an anomalous warm SST area north of 20°N in the South China Sea, an extreme divergence value in the northern South China Sea exceeding 6 ×10-5 s-1, and vertical environmental wind shear between 1.1 m/s-4.8 m/s. The intensity of"Hato"was very sensitive to changes in SST. When the SST rose or dropped by 2℃, the minimum central pressure of the typhoon changed by about 13 hPa or 11 hPa,respectively. SST indirectly influenced the intensity of the typhoon through affecting latent heat transport and sensible heat transport.  相似文献   

台湾地形对台风Meranti(1010)经过海峡地区时迅速增强的影响研究   总被引：3，自引：1，他引：2  

薛霖  李英  许映龙  王蕾  戴高菊 《大气科学》2015,39(4):789-801

台风在趋近大陆过程中强度一般衰减, 但Meranti(1010)北上进入台湾海峡过程中却迅速加强, 且在登陆福建时达到最强。采用中国气象局台风资料、NCEP GFS 0.5°×0.5°再分析资料及台湾雷达资料, 结合中尺度数值模式WRF(The Weather Research and Forecasting Model)开展台湾地形敏感性试验, 研究Meranti进入台湾海峡过程中的结构变化及迅速加强机理。结果表明:台湾地形是Meranti迅速加强的一个重要影响因子。Meranti北上过程中, 一方面通过台湾岛地形分流作用及其背风坡效应在台湾海峡内诱生中尺度涡旋, 形成正负相间的涡度分布, 激发出与台风相关的扰动波列。地形强迫抬升及扰动波列可加强垂直运动和积云对流, 有利于台风对流发展。另一方面, 台湾地形还通过改变环境气流使台风高空辐散场加强, 环境风垂直切变减小, 形成有利于台风发展的环流背景。比较不同高度台湾地形试验中台风动能收支发现, 台湾地形激发的扰动波列和积云对流增强了次网格尺度系统与台风间能量的交换, 成为Meranti登陆前迅速加强的主要动能源。  相似文献   

福建省热带气旋暴雨突然增幅特征分析     

蔡义勇  王宏  郑秋萍 《湖北气象》2015,34(1)

利用2007—2013年福建省区域自动站和基本气象站小时降水观测资料,确定精细时空尺度上热带气旋暴雨突然增幅的阈值标准,分析暴雨突然增幅的时空分布特征及其与同期热带气旋之间的关系。结果表明:满足1 h、3 h和6 h暴雨突然增幅的热带气旋个例数随时间分辨率的降低而明显减少;3 h突增个例数主要出现在6—10月,且个例数和突增次数年分布总体呈上升趋势,突增次数日变化呈现"三峰型",高值区位于17—20时;暴雨突然增幅的热带气旋大多数在福建中南部沿海登陆,且不同的热带气旋中,强度较弱时发生突增次数较多,极值最大;暴雨突然增幅大多数发生在热带气旋登陆后24 h、距中心400 km内、西南方向,与登陆路径有关。对比分析了热带气旋登陆福建前后暴雨突然增幅的特征,发现登陆中部的热带气旋个数最多、暴雨突增次数也最多;热带气旋登陆后暴雨突增次数明显比登陆前多。  相似文献