1994年南海夏季风爆发的数值模拟和分析研究   总被引：9，自引：1，他引：8  

吴池胜  王安宇  冯瑞权  古志明 《大气科学》2001,25(4):455-464

1994年南海夏季风建立于5月第一候,利用MM5成功地模拟了这一过程,并通过敏感性试验,讨论了中纬度系统和中南半岛及其附近地区的积云对流对夏季风环流建立的影响,结果表明:(1)南下接近副热带一定强度的中纬度槽-锋系统的强迫,可引起南海地区副热带高压脊的减弱东撤,因而有利于南海夏季风的建立;(2)东移的中纬度高压脊与南亚高压的同相叠加是触发夏季风建立的重要因子之一,它引起南亚高压中心迅速北移至中南半岛的北部;(3)中南半岛及其附近地区的积云对流加热,对南海地区夏季风环流的建立也有重要的影响.  相似文献   

Distribution ofBe andBe in the Pacific Ocean     

M. Kusakabe  T.L. Ku  J.R. Southon  J.S. Vogel  D.E. Nelson  C.I. Measures  Y. Nozaki 《Earth and Planetary Science Letters》1987,82(3-4)

The vertical distributions of¹⁰Be and⁹Be at three locations in the Pacific (25°N, 170°E; 17°N, 118°W; 3°S, 117°W) are presented. The results show that both isotopes exhibit nutrient-like profiles. From the surface to the bottom, the increase for¹⁰Be is two- to threefold and that for⁹Be is about fivefold. While the inter-station variations in surface water concentrations may reach a factor of two, deep-water values tend to be much more uniform averaging about 2000 atoms/g for¹⁰Be and 30 pM for⁹Be. A similar situation applies to the¹⁰Be/⁹Be ratio; it varies approximately from 1 to 3 × 10⁻⁷ (atom/atom) at shallow depths but tends toward a value close to 1.1 × 10⁻⁷ in the deep ocean. The variation of¹⁰Be/⁹Be can be viewed as resulting from the fact that¹⁰Be in a given parcel of water consists of two components: recycled and primary. The recycled component is that part of¹⁰Be which has reached tracer equilibrium with⁹Be, as opposed to the primary component which, upon entering the sea from the atmosphere, has yet to equilibrate with⁹Be through particle cycling and mixing processes. It is estimated that 70% to nearly 100% of¹⁰Be at the three stations are being recycled, and the recycled beryllium bears an atomic ratio of¹⁰Be/⁹Be close to 1 × 10⁻⁷. The oceanic residence time of Be is of the order of 1000–4000 years, comparable to or slightly longer than the ocean mixing time.  相似文献   

Be in a deep-sea core: implications regardingBe production changes over the past 420 ka     

J.R. Southon  T.L. Ku  D.E. Nelson  J.L. Reyss  J.C. Duplessy  J.S. Vogel 《Earth and Planetary Science Letters》1987,85(4)

The influx of¹⁰Be into a globigerinid ooze core (CH72-02) from the eastern North Atlantic has been studied. This core contains a depositional record of the first 11 δ¹⁸O stages covering the last 423 ka. It is shown that the marine deposition of¹⁰Be is strongly influenced by the sedimentation of clays. Clay particles appear 10 times more efficient than the carbonate component as a carrier in bringing¹⁰Be to the bottom sediments. In core CH72-02, the deposition rates of¹⁰Be averaged over each oxygen-isotope stage for the past 11 stages show a scatter of ±40% about the mean value of 6.6 × 10⁸ atoms cm⁻² ka⁻¹. However, after correction for changes in lithology, the data show that the production rate of¹⁰Be over the same period has varied no more than ±25%, and the variations are not systematic in that high or low¹⁰Be production appear to be associated with either cold or warm climates. On the time scale of this investigation (intervals of ca. 50 ka over the last 420 ka, with resolutions as fine as 10 ka for portions of the record), it is unlikely that the shielding effect of the solar wind has deviated by more than ±25% or the geomagnetic field intensity has deviated by more than a factor of 1.6 from their long-term averages.  相似文献   

GPS控制测量和精密导线在隧道定向中的应用     

邹进贵  童魁  朱勇超 《测绘信息与工程》2014,(2):42-44

针对隧道测量中的难点问题,提出了运用GPS测量手段和精密导线测量的方法来解决特长隧道定向问题;依托全球卫星定位系统建立高等级控制网,得到准确的控制点坐标;研发的基于测量机器人的多测回测角软件用于隧道内导线测量,减轻隧道内作业强度,提高了测量精度。  相似文献   

地理学视角下土地利用/覆被分类发展探讨     

王志华  郜酷  杨晓梅  苏奋振  黄翀  石铁柱  颜凤芹  李贺  张慧芳  吕宁  潘婷婷 《地理研究》2022,41(11):2946-2962

随着对地观测和互联网技术的发展,地理大数据时代正在到来,其多尺度、长时序、多模态等海量“超”覆盖数据为土地利用/覆被（Land Use/Land Cover, 简称LULC）分类及变化检测带来巨大的机遇,支撑着新时代人、地两大系统相互作用关系的认知和实践。然而,多数地理学者认为地理学基本原理与核心思想并未因为大数据的到来而发生本质性变化。所以,从地理学基本原理角度理解LULC分类的发展,尤其在地理大数据时代的发展方向,不失为一条可行的途径。为此,本文从区域、尺度、综合三方面的地理学基本原理视角将LULC分类技术的发展划分为地球观测数据匮乏阶段、人类行为数据融合阶段以及地理大数据“超”覆盖阶段分别探讨分析,以期主动把握LULC分类技术及应用的未来发展趋势。研究结果显示：在地球观测数据匮乏阶段,LULC分类多以类型还不丰富的遥感数据源,在空间分辨率较低的像元尺度上,进行以地表覆被状态为主的分类;发展到人类行为数据融合阶段,LULC分类在城市区域率先出现了对地观测数据和人类行为数据相融合,在街区尺度上进行以空间功能异质性划分、识别为主导的城市功能区分类;在地理大数据“超”覆盖阶段,LULC分类将实现多尺度协同、面向全空间的功能异质性划分,并在主体功能的基础上融合“社会-经济-自然”多维定量属性,本文称之为“空间场景”。希望本文的探讨能够为地理大数据时代LULC分类的新技术发展和新产品应用提供有益启示。  相似文献   

东濮凹陷文70断裂带构造与油气富集规律研究     

吴超  朱俊强  王宁  王库  吴信龙 《华北地质》2014,37(3)

文70断裂带位于东濮凹陷中央隆起带文留构造带南部,油藏受文东、文70和文147三条东倾的断层控制,为东倾的断层和一系列西倾的断层形成的断块。断层切割关系复杂,造成断层组合多解性强;另外油藏含油层系多,油藏较小,油水关系复杂,油藏成因、富集规律及控制因素不明确,油藏动用困难。针对区带存在问题,运用精细地层划分与对比、RFT测试资料、HDT测井资料和三维地震解释等新技术和新方法,在强调整体解释的基础上,重点解剖了文70断裂带各断层的空间展布及组合关系,落实了构造形态和圈闭特征,并对所形成构造圈闭的含油气性及潜力进行了详细分析。结果认为,文70断裂带油气成藏主要受构造控制,发育下生上储、自生自储和古生新储三种成藏组合模式。  相似文献   

Geological evolution of the Gulf of Saros,NE Aegean Sea     

Çağatay  M. N.  Görür  N.  Alpar  B.  Saatçılar  R.  Akkök  R.  Sakınç  M.  Yüce  H.  Yaltırak  C.  Kuşcu  I. 《Geo-Marine Letters》1998,18(1):1-9

 The Gulf of Saros is an Upper Miocene transtensional basin in NW Anatolia, formed by the interaction between the North Anatolian Fault and the N-S extensional tectonic régime of the Aegean. The present configuration of the basin evolved mainly during the Plio-Quaternary under the increased activity of the North Anatolian Fault. During the late Miocene-late Quaternary, no sedimentation took place on the shelves. After this long hiatus, an important change in tectonic style about 0.2 Ma BP allowed sedimentation to resume in the gulf. Received: 14 February 1997 / Revision received: 12 November 1997  相似文献   

Nonlinear Rayleigh wave inversion based on the shuffled frog-leaping algorithm     

Cheng-Yu Sun  Yan-Yan Wang  Dun-Shi Wu  Xiao-Jun Qin 《应用地球物理》2017,14(4):551-558

At present, near-surface shear wave velocities are mainly calculated through Rayleigh wave dispersion-curve inversions in engineering surface investigations, but the required calculations pose a highly nonlinear global optimization problem. In order to alleviate the risk of falling into a local optimal solution, this paper introduces a new global optimization method, the shuffle frog-leaping algorithm (SFLA), into the Rayleigh wave dispersion-curve inversion process. SFLA is a swarm-intelligence-based algorithm that simulates a group of frogs searching for food. It uses a few parameters, achieves rapid convergence, and is capability of effective global searching. In order to test the reliability and calculation performance of SFLA, noise-free and noisy synthetic datasets were inverted. We conducted a comparative analysis with other established algorithms using the noise-free dataset, and then tested the ability of SFLA to cope with data noise. Finally, we inverted a real-world example to examine the applicability of SFLA. Results from both synthetic and field data demonstrated the effectiveness of SFLA in the interpretation of Rayleigh wave dispersion curves. We found that SFLA is superior to the established methods in terms of both reliability and computational efficiency, so it offers great potential to improve our ability to solve geophysical inversion problems.  相似文献   

基于正交各向异性介质理论的地应力地震预测方法   总被引：1，自引：1，他引：0       下载免费PDF全文

马妮  印兴耀  孙成禹  宗兆云 《地球物理学报》2017,60(12):4766-4775

地应力是评价页岩气储层是否可压裂成网的重要参数.利用地震资料进行地应力参数预测可以根据水平应力差异比(DHSR,Differential Horizontal Stress Ratio)值大小来判断.现阶段计算水平应力差异比主要基于具有对称轴的横向各向同性介质理论,即HTI介质假设,欠缺对页岩中实际大量存在的VTI特征的考虑.本研究同时考虑页岩气地层VTI和HTI特征的作用,利用正交各向异性介质岩石物理关系,推导出水平应力差异比与弹性参数及各向异性参数之间的关系.首先,在分析应力应变本构方程的基础上,对正交各向异性介质(OA)的本构方程进行推导,通过胡克定律一般形式获得正交各向异性介质的应力和应变关系;其次,利用该应力和应变关系推导出最大水平应力、最小水平应力和水平应力差异比与地层弹性参数和各向异性参数的关系并定义了参数正交各向异性水平应力差异比(ODHSR,Orthorhombic Differential Horizontal Stress Ratio);最后,对正交各向异性水平应力差异比ODHSR与具有水平对称轴的横向各向同性介质的DHSR进行了对比,证明了本文的正交各向异性水平应力差异比(ODHSR)计算公式.  相似文献