Relationship of Arctic sea ice and Northern Hemispheric 500 hPa Polar vortices

Using the NCEP/NCAR reanalysis monthly 500 hPa height data on a 2.5 latitude-longitude grid and 1°×1° sea ice data,the polar vortex area,intensity index and arctic sea ice area index are calculated respectively,and the meridional distribution,period variation and the abrupts in the long range trend are analyzed to study their relationship.The results show that the meridional distribution of sea ice and polar vortex h-ave distinctive difference,the relative positions of them are different in the eastern and western hemispheres,and exept they have periods of 4 months,quasi half year,quasi year,4-5 years and 10 years commonly,and each of them has its own respective variation as well.The sea ice area is decreasing apparently since 1980's,so is the polar vortex area,but their abrupt changge time are different totally.The area of sea ice and polar vortex has prominent positive correlation,but the relationship of sea ice intensity,polar vortex intensity,polar vortex area is complicated.     

渤海地区平台结构设计环境条件选取分析

随着平台的使用年限增长,环境条件随着海洋环境的变化而变得日益恶劣,对于渤海地区,提出了是否采用100年一遇环境条件替换50年一遇环境条件进行结构设计.经过对渤海地区的部分中心平台和井口平台50年/100年环境条件对比分析,提出了对于渤海地区海上平台结构采用100年一遇环境条件替换50年一遇环境条件.     

Interannual variability in the biochemical composition of newly hatched larvae of the spider crab Maja brachydactyla (Decapoda,Majidae)

The spider crab Maja brachydactyla is an important commercial species in Europe and supports intensive fisheries in the NE Atlantic. A field survey was performed to assess long‐term and consecutive interannual (2005–2010) variation of the biochemical composition of newly hatched larvae of M. brachydactyla. Larval biochemical profiles differed significantly among years, with pronounced differences being recorded in 2010. Differences among batches of newly hatched larvae were mainly explained by the contribution of triacylglycerols and, to a lesser degree, by protein and lipid content. The use of different nutrition indices is discussed. The biochemical composition of newly hatched larvae from M. brachydactyla was highly variable, even though surveyed broodstock was obtained from the same local population and was always sampled during the same season. The unpredictable biochemical profiles of newly hatched larvae may condition their survival and recruitment. This largely overlooked aspect of larval variability should be considered in future fisheries management strategies and captive production of marine organisms that still rely on wild seeds.     

Self‐similar solution of a plane‐strain fracture driven by a power‐law fluid

This paper analyses the problem of a hydraulically driven fracture, propagating in an impermeable, linear elastic medium. The fracture is driven by injection of an incompressible, viscous fluid with power‐law rheology and behaviour index n?0. The opening of the fracture and the internal fluid pressure are related through the elastic singular integral equation, and the flow of fluid inside the crack is modelled using the lubrication theory. Under the additional assumptions of negligible toughness and no lag between the fluid front and the crack tip, the problem is reduced to self‐similar form. A solution that describes the crack length evolution, the fracture opening, the net fluid pressure and the fluid flow rate inside the crack is presented. This self‐similar solution is obtained by expanding the fracture opening in a series of Gegenbauer polynomials, with the series coefficients calculated using a numerical minimization procedure. The influence of the fluid index n in the crack propagation is also analysed. Copyright © 2002 John Wiley & Sons, Ltd.     

大倾角煤层分层综采再生顶板破断规律研究

针对大倾角厚软煤层下分层安全综采问题,结合淮南矿区潘北煤矿1212（3）大倾角厚软煤层分层综采下分层工作面地质与工程条件,综合运用基于数字散斑、声发射监测与分布式光纤传感技术的物理模拟试验、基于煤系地层赋存禀赋建模技术的数值模拟试验相结合的研究手段,开展了下分层开采再生顶板破断倾向分区演化、再生岩体变形声发射能量与光纤应变响应规律及应力分布特征研究。结果表明：再生顶板破断由其破断岩块滑移、低中位悬臂梁和高位铰接岩梁断裂组成,双梁破断是引起下分层支架失稳的关键所在。下分层中上部双梁破断声发射能量呈高度聚集且持续时间短,光纤感知低位悬臂梁破断且中上部光纤应变峰值高,下分层中上部是支架与再生顶板稳定性控制的重点区域。下分层下部再生顶板破断岩块充填密实且粒径小,是架间与架前岩块漏冒多发区域。下分层再生顶板中形成高应力组成的应力拱,距采空区高度约30 m,双梁破断主要发生在拱内,拱中岩体破断对支架具有一定的冲垮作用。     

中国冬半年最低气温概率分布特征

 根据1955-2005年中国160个站冬半年 (当年11月至翌年4月)平均最低气温资料,使用统计检验的方法,分析了近50 a中国冬半年最低气温的突变事实,在此基础上给出了气候变暖前后最低气温的概率分布,比较了变暖前后时段全国最低气温空间分布的差异。结果表明：1) 20世纪80年代末中国冬半年最低气温发生了显著突变,进入异常增暖时期,其增温程度比平均气温明显;2) 增暖后中国最低气温的概率分布发生了明显的变化,最低气温偏冷的概率显著减小,偏暖的概率明显增大;3)气候变暖后除西南地区最低气温上升幅度不显著外,其余地区均呈现显著增温趋势。     

锡林郭勒盟冬季降水分布特征及成因分析

利用气候相似性原理,按照天气系统影响划分气候区,分析锡林郭勒盟冬季降水分布特征及其成因。冬季降水分布特点与其他季节有所不同,西南部和东部各有一大值区,其原因主要是受河套气旋(倒槽)和蒙古冷涡影响造成,山地小气候也起到重要作用。西部地区70年代降水最多,其他地区降水最多的时期是在90年代,2000年以来降水有所减少,异常偏多或偏少的年份多集中于某个时期,具有一定的周期性。     

The study on the interannual variation and the mechanism of the south china sea monsoon

l.Intr0ductionTheonset0ftheSouthChinaSea(SCS)monsoonisasignofthecomingoftheAsianmonsoon.Inaverage,theonsetoftheSCSmonsoonisinthemiddleofMay,butitsstrengthandtheonsetdatediffergreatlyfromoneyeartoanother.TheanomaliesoftheSCSmon-soonhighlydePendonnotonIytheprecipitationinSCS,butalsotheanomaliesofthecircu-lationintheworld.WhyisthemonsoononsetearliestinSCS?Whatisthemechanismoftheonsetanditsvariation?Thisisascientificproblemthatisinterestedinbymeteorologistsbothathomeandabroad.TaoandChen…     

1999年上半年全世界地震灾害综述

１９９９年上半年全世界地震灾害总水平偏低,共发生Ｍｓ≥６地震４９次,其中Ｍｓ≥７地震３次。全世界地震造成的死亡人数总计为２１２８人,伤约６０００人;经济损失约１０亿美元。主要灾害地震发生在哥伦比亚、阿富汗、印度、伊朗和墨西哥 。     

天文准19年周期与西北降水

从天体运行周期角度分析发现,月亮等天体运行存在显著的准１９年周期。相应对年际气候变化有重要影响的厄尔尼诺事件也有准１９年周期,每１９年出现４～５个厄尔尼诺事件。在月赤纬最大值谷点年附近,西北区容易出现春旱;在月赤纬最大值峰点年附近,西北区春雨正常偏多