锋面北侧冷气团中连续降雹环境场特征及成因   总被引：2，自引：0，他引：2       下载免费PDF全文

许爱华  陈云辉  陈涛  张娟娟 《应用气象学报》2013,24(2):197-206

对2009年2月24日—3月5日我国南方锋面北侧冷气团中连续冰雹天气过程的环流形势和环境场特征及形成机理进行分析。此次冰雹过程是发生在我国南方典型的连阴雨天气形势背景下,欧亚中高纬度地区为两槽一脊形势,副热带高压偏强、中南半岛为低槽区,青藏高原有5次短波槽东移,中层700 hPa暖湿气流势力强盛。中层强西南暖湿气流在强锋区 (冷垫) 上抬升,形成我国南方典型的高架雷暴。高架雷暴的发生与中低层强温度锋区、中层700 hPa不低于20 m·s-1的西南急流、强风垂直切变、对流层中层较大的温度直减率、较低的0℃层高度 (4 km以下) 有关。  相似文献   

农牧交错带气候变化对土地利用的影响及对策——以内蒙古伊金霍洛旗为例     

马玉峰  高春香 《内蒙古气象》2013,(4):24-28

文章讨论了农牧交错带典型区域的气候变化特点,并运用GIS技术分析了区域土地利用变化。在此基础上,分析了气候变化对土地利用结构的影响,并提出了应对策略。这些对策将促进农牧交错带社会经济增长和生态环境的改善,对实现区域的可持续发展具有重要意义。  相似文献   

阿尔金造山带东段地质构造演化概论     

郑健康 《青海国土经略》1995,(2)

阿尔金造山带曾是一个早古生代拗拉槽,其两侧地质体具有极为相似的地质构造特征。该区构造演化可以概括为:晚太古代至早元古代处于底侵造壳阶段,经吕梁旋回发生克拉通化,出现中元古代稳定型盖层沉积。加里东旋回中叶,经过短暂的拗拉、裂陷,分裂的塔柴板块又重新聚合。华力西旋回该区以剥蚀夷平作用为主,仅在山间断陷或山前凹陷的局部地段沉积有上泥盆统磨拉石建造。石炭纪发生短暂小规模海侵。侏罗纪全区进入陆相发育阶段。区内岩浆活动频繁,燕山旋回为最高潮。在喜山旋回,随着印度板块与欧亚板块的碰撞,该区也被卷入青藏高原总体的巨大演变之中。早期由边缘断陷转化为大型断陷盆地,至上新世湖水淹没了大部地区;晚期,随着阿尔金迅速崛起,塔里木—柴达木板块再度分裂,南盘抬升,北盘下降。文章最后探讨了阿尔金左行斜滑地震断裂带的控震作用。  相似文献   

河南省地壳结构和深断裂简述     

邬雪雁  李进先 《河南国土资源》1995,(2)

利用重磁资料正反演计算，获得了一系列的地壳深部资料。多种资料综合反映了河南省深部构造的主要特征。本文论述了我省地壳层状结构的特点和深断裂带的划分。首次提出黄河南断裂带、驻马店－桐柏断裂带为超壳断裂带；确山－固始断裂带、南阳断裂带为地壳断裂带。  相似文献   

Pixel‐scale evaluation of SSM/I sea‐ice algorithms in the marginal ice zone during early fall freeze‐up     

Byong Jun Hwang  David G. Barber 《水文研究》2006,20(9):1909-1927

Observed reduction in recent sea ice areal extent and thickness has focused attention on the fact that the Arctic marine system appears to be responding to global‐scale climate variability and change. Passive microwave remote‐sensing data are the primary source underpinning these reports, yet problems remain in geophysical inversion of information on ice type and concentration. Uncertainty in sea‐ice concentration (SIC) retrievals is highest in the summer and fall, when water occurs in liquid phase within the snow–sea‐ice system. Of particular scientific interest is the timing and rate of new ice formation due to the control that this form of sea ice has on mass, energy and gas fluxes across the ocean–sea‐ice–atmosphere interface. In this paper we examine the critical fall freeze‐up period using in situ data from a ship‐based and aerial survey programme known as the Canadian Arctic Shelf Exchange study combined with microwave and optical Earth observations data. Results show that: (1) the overall physical conditions observed from aerial survey photography were well matched with coincident moderate‐resolution imaging spectroradiometer data and Radarsat ScanSAR imagery; (2) the shortwave albedo was linearly related to old ice concentration derived from survey photography; (3) the three SSM/I SIC algorithms (NASA Team (NT), NASA Team 2 (NT2), and Bootstrap (BT)) showed considerable discrepancies in pixel‐scale comparison with the Radarsat ScanSAR SICs well calibrated by the aerial survey data. The major causes of the discrepancies are attributed to (1) the inherent inability to detect the new thin ice in the NT and BT algorithms, (2) mismatches of the thin‐ice tie point of the NT2 algorithm, and (3) sub‐pixel ambiguity between the thin ice and the mixture of open water and sea ice. These results suggest the need for finer resolution of passive microwave sensors, such as AMSR‐E, to improve the precision of the SSM/I SIC algorithms in the marginal ice zone during early fall freeze‐up. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

南秦岭勉略蛇绿构造混杂带辉长辉绿岩类微量-稀土元素地球化学   总被引：2，自引：0，他引：2  

赖绍聪 《地球科学与环境学报》2005,27(3):5-9

应用元素地球化学方法．研究了勉略带中辉长辉绿岩的相关特征．结果表明．勉略蛇绿构造混杂带内的辉长岩属高铝强碱质辉长岩类，是地幔橄榄岩部分熔融的产物。辉绿岩墙群属强碱铝质基性岩类，过渡族元素蛛网图与辉长岩类几乎完全相同，其不相容元素与辉长岩类总体趋势相一致．反映了一种递进岩浆演化趋势。因此，本区辉长岩与辉绿岩墙群具同源岩浆分异演化的地球化学特征．其均为勉略蛇绿岩的重要组成端元。  相似文献   

TEMPORAL SPATIAL VARIATION CHARACTERISTICS OF CRUST DEFORMATION OF ACTIVE TECTONIC BLOCKS IN NORTH CHINA     

Xu Caijun  Li Zhicai  Wang Hua 《大地测量与地球动力学》2003,23(Z1)

1　IntroductionTomonitorthecurrentcrustalmotionandearthquakehazardsinNorthChinaarea,theFirstCrustalMonitoringandApplicationCenter (FC MAC)oftheChinaEarthquakeAdministration(CEA)hasestablishedaGlobalPositioningSystem(GPS)monitoringnetworkinNorthChinaandtheCapital(Beijing)Circlearea .TheobservedstationsaremainlydistributedinthenorthernpartofNorthChinaandCapitalCirclearea (Fig .1 ) .Theregionisbetween 1 0 7°Eand 1 2 2°E (about 1 40 0km) ,andbetween 33°Nand 42°N (about 80 0km) .…  相似文献   

河南省西峡北部金矿分布特征浅析     

杨崇辉  韩志勇  张寿广  卢欣祥  董有  常秋玲 《河南国土资源》1994,(4)

从剪切带及原岩建造分析入手，论述了工作区内金矿的分布特征和主要控矿因素。区内的金矿床（点）无论其物质来源和时代如何，就其空间位置而言绝大多数金矿直接产在剪切变形变质带─—脆性及脆－韧性剪切带中。Ｆｅ／（Ｆｅ＋Ｍｇ）高比值的容矿岩石有利于金的沉淀富集。  相似文献   

The Vardar ophiolite: a continuous belt under the Axios basin sediments     

L. G. Kiriakidis 《Geophysical Journal International》1989,98(2):203-212

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横断山区地质构造分区     

潘裕生 《山地学报》1989,(1)

位于青藏高原东南部的横断山区,是我国东部环太平洋区与西部古地中海区间的交接过渡地带,也是我国地质结构最为复杂的一个区域。作者根据1981—1985年在当地考察资料,将本区分出5条具洋壳性质的强变形构造带,2块具陆壳性质的地块,它们相间并列。文章论述了各条块的发育特征及区域演化历史。  相似文献