长生命史冷涡影响下持续对流性天气的环境条件

利用云图和NCEP 1°×1°再分析资料,对生命史长达9天的冷涡系统的云图形态、移动轨迹、强度变化及其长久维持的原因进行了分析;并对比分析该冷涡影响下的持续对流性天气与冷涡分裂的冷空气、湿度层结及水汽条件的关系,探讨对流性天气的预报着眼点和不稳定参数阈值。主要结论:(1)连续9天对流性天气分别出现在冷涡涡旋云系头部的南部或东南部。强的对流过程时,云顶TBB温度在-40～-72℃;弱的对流过程时,云顶TBB温度在-40℃以上。(2)东亚阻塞高压两侧高涡度区的正涡度平流交替补充冷涡对正涡度的损耗,是冷涡长久滞留维持的主要原因。(3)冷涡在长生命期中是动态的,冷涡中心距研究代表点的距离与对流性天气的强弱有关;对流层中层V分量能敏感地反映冷涡分裂的冷空气活动情况。(4)随着对流性天气的持续,低空湿度层逐渐增厚,而850～700 hPa相对湿度≤60%的相对于区始终存在;975 hPa水汽通量的大小和方向反映来自渤海的水汽输送状况。(5)强天气威胁指数SWEAT和风暴相对环境螺旋度SREH在判断对流性天气的强度方面比常用的不稳定参数效果好。     

Tectonic ore-controlling in the middlesouthern segment of Da Hinggan Ling, Northeast China

1INTRODUCTION THEMIDDLE SOUTHERNSEGMENTOFDAHINGGANLING ISONEOFTHEIMPORTANTORE CONCENTRATEDAREASOFCHI NA.INRECENTYEARSGREATSTRIDESHAVEBEENMADEIN THEORETICALGEOLOGICALRESEARCHANDGEOLOGICALEXPLOITA TION(SHAOJI’ANETAL.,1998,1999;ZHANGLUQIAOET AL.,1998;XIAOCH…     

Late Quaternary sinistral slip rate along the Altyn Tagh fault and its structural transformation model

The Altyn Tagh Fault (ATF) is a major boundaryfault on the northern margin of the Qinghai-TibetanPlateau and is also the longest sinistral strike-slip faultat a lithospheric scale in the Eurasian Plate. Its exis-tence has directly affected regional features of neotec-tonics, topography, geomorphology, Quaternary geol-ogy, recent crustal deformation, seismicity, climatechange and ecological environment for fauna and florain China[1—6]. The sinistral slip on the ATF and activethrusting-fo…     

长江正源区可持续发展对策探讨

长江源区自然环境恶劣，生态脆弱，资源较缺乏，居民生活贫困，区域经济的发展和生态环境的保护面临着严峻的挑战。综合分析源区的现状和有利条件，认为旅游资源具有得天独厚的优势，如果加强基础设施建设，逐渐使牧民从散居到聚居，以旅游业为龙头，带动第三产业的发展，促进居民生活方式的多元化，提高居民生活质量和思想素质，树立环保意识，逐渐摆脱对草地的过分依赖，自觉保护生物多样性，优化和重建生态环境，从而实现人和自然的协调发展，步入可持续发展的轨道。     

Late Paleozoic adakites and Nb-enriched basalts from northern Xinjiang, northwest China: Evidence for the southward subduction of the Paleo-Asian Oceanic Plate

Abstract   Volcanic rocks consisting of adakite and Nb-enriched basalt are found in the early Devonian Tuoranggekuduke Group in the northern margin of the Kazakhstan-Junggar Plate, northern Xinjiang, northwest China. The geochemical characteristics of the andesitic and dacitic rocks in this area resemble that of adakites. The relatively high Al₂O₃, Na₂O and MgO content and Mg^♯ values indicate that the adakites were generated in relation to oceanic slab subduction rather than the partial melting of basaltic crust. A slightly higher SrI and a lower ɛ _Nd( t  = 375 Ma) compared to adakites of mid-oceanic ridge basalt (MORB) imply that slab sediments were incorporated into these adakites during slab melting. The Nb-enriched basalt lavas, which are intercalated in adakite lava suite, are silica saturated and are distinguished from the typical arc basalts by their higher Nb and Ti content (high field strength element enrichment). They are derived from the partial melting of the slab melt-metasomatized mantle wedge peridotite. Apparently, positive Sr anomalies and a slightly higher heavy rare earth element content in these adakites compared to their Cenozoic counterparts indicate that the geothermal gradient in the Paleo-Asian Oceanic subduction zone and the depth of the Paleo-Asian Oceanic slab melting are between those of their Archean and Cenozoic counterparts. The distribution of the adakites and Nb-enriched basalts in the northern margin of the Kazakhstan-Junggar Plate, northern Xinjiang, indicates that the Paleo-Asian Oceanic Plate subducted southward beneath the Kazakhstan-Junggar Plate in the early Devonian period.     

Research on the Application of Residual Apparent Polarization to Surveying Deep Jiaojia-type Gold Mines

The theory and equations of the residual apparent polarization method are proposed and described in this article. Based on studies of existing mines, the residual apparent polarization ηα^sy, calculated from the induced-current middle-gradient apparent polarizations ηα^sy at large and small electrode spaces over the known deep Jiaojia-type gold mines, have been shown to separate the effects of mines from the anomalous polarizations generated from the strongly altered rocks in fracture zones.     

基于遥感GIS的安塞油田水源井有利区预测

安塞油田地处干旱缺水地区,通过分析确定项目区找水目标层--白垩系下统洛河组砂岩和侏罗系中下统延安组砂岩,确定了井位部署原则,利用遥感技术提取了砂岩裂隙密集带,在Arcview GIS平台下分析,得到水源井部署有利区.     

基于卫星编队InSAR时间同步对系统性能影响分析

基于卫星编队的InSAR系统是一个多基雷达系统，依靠卫星编队构型形成干涉所需的基线。系统在一发多收的工作模式下，协同工作的雷达间必须建立时间同步、相位同步和空间同步。本文根据卫星编队条件下InSAR高程测量的要求，对时间同步的要求进行了研究，在此基础上，分析了时间同步对InSAR系统性能的影响。     

地壳形变观测与地震前兆一般性问题的讨论

从构造变形及破裂成核的角度来看, 强地震前形变异常理应出现在地震震源附近, 而许多连续形变观测事实与这种认识往往是相矛盾的.本文研究了攀枝花多次形变异常结束后10天内的首发中强地震与异常之间的相关性, 发现西北地区2000-2005年5.9级以上地震震中(绝大多数作为异常后的首发地震)分布具有较好的规律性.本文揭示的事实对于认识形变观测与前兆本质、实验场区连续形变观测台网建设及物理预测方法探索等都提供了新的可能性.     

气象资金安全使用的初步探讨

从经济学角度出发,介绍了目前事业单位财务监管的弱化,在日常的财务管理中存在的问题及由此带来的风险,并分析了上述问题存在的主要原理,给出了加强财务监管的相关对策,降低财务风险,从而有效保障气象部门资金安全和科学使用。