印度洋地区异常海温的偶极振荡与中国降水及温度的关系   总被引：42，自引：15，他引：42  

肖子牛  晏红明  李崇银 《热带气象学报》2002,18(4):335-344

利用1951-1997年近47年的印度洋海温距平场资料以及相应中国160站降水资料，通过相关普查得出，印度洋地区东西海温的偶极振荡与中国6-8月汛期的降水有较好的相关关系，特别是前期3-5月份的印度洋地区东西海温的偶极指数与中国6-8月降水的相关较好。分析1958-1995年NCEP 500hPa北半球高度场资料发现，印度洋偶极指数与欧亚中高纬度地区的高度场异常有密切的联系，其中印度洋偶极指数IODI负位相年有明显的PJ波列存在，印度洋偶极海湿异常很可能是通过PJ波列来影响中国的降水。同时，对印度洋地区海温偶极指数和中国地区温度的相关分析表明，印度洋地区海温偶极指数与冬季中国南部地区的温度也有较好的相关关系。  相似文献   

西南季风期间斯里兰卡降水的年代际、年际变化及其与热带印度洋的联系     

W. A. E. LAKSHANI  张广隶  王鑫 《南京气象学院学报》2018,10(3):282-289

本文主要研究了1979—2016期间斯里兰卡在西南季风期间降水的年代际、年际变化以及与印度洋海温的联系.首先用经验正交的方法分析了斯里兰卡以及周边地区降水的时空分布,发现前两个模态能够解释超过70%的方差.其中第一模态为均一模态,且其PC1以及斯里兰卡7 a滑动平均降水序列都有年代际变化,降水异常在2000年前后异常偏多和偏少.通过合成分析发现2000年之后降水的异常减少与热带西部、中部印度洋的暖海温异常有关.暖海温异常通过调整经向环流引起了斯里兰卡上空的下沉运动,抑制了降水.在第二模态中,负的信号出现在斯里兰卡大部分地区,只有在斯里兰卡北部海角很小地区出现了正的信号.PC2表现出了年际变化,且与热带东南印度洋海温异常有显著的关系.通过Gill-Matsuno响应,热带东南印度洋海温异常造成热带北印度洋上空的气旋性环流异常,引起了水汽的辐合,从而利于降水.  相似文献   

Mineralogical Characterization of Graphite Deposits from Thodupuzha-Kanjirappally Belt, Madurai Granulite Block, Southern India   总被引：1，自引：0，他引：1  

K.R. Baiju  M. Satish-Kumar  H. Kagi  C.G. Nambiar  M. Ravisankar 《Gondwana Research》2005,8(2):223-230

Graphite from deposits occurring in the high-grade metamorphic rocks and their larteritized equivalents of the Thodupuzha-Kanjirappally Belt in Madurai Granulite Block, southern India is structurally fully ordered (crystallite size, Lc₍₀₀₂₎ ranging from 469 to 749 Å), possess high degree of graphitization (DG value ranging from 105 to 267 Å) and reflect crystallization at high temperature (700±100°C). Raman spectra of graphite display profiles corresponding to high crystallinity and high structural ordering. The high temperature crystallinity characteristics of graphite were not obliterated during retrogression of granulites to amphibolite facies gneisses. Preliminary carbon stable isotope results show a spread in isotope values from —11.8 to —26.8 %, which suggest more than one sources for carbon. The lighter carbon isotope values are suggestive of biogenic origin, whereas the heavier ones are probably fluid precipitated graphite.  相似文献   

Mesoproterozoic Reworking of Palaeoproterozoic Ultrahigh-temperature Granulites in the Central Indian Tectonic Zone and its Implications   总被引：3，自引：0，他引：3  

BHOWMIK  S. K.; SARBADHIKARI  A. BASU; SPIERING  B.; RAITH  M. M. 《Journal of Petrology》2005,46(6):1085-1119

In the southern periphery of the Sausar Mobile Belt (SMB), thesouthern component of the Central Indian Tectonic Zone (CITZ),a suite of felsic and aluminous granulites, intruded by gabbro,noritic gabbro, norite and orthopyroxenite, records the polymetamorphicevolution of the CITZ. Using sequences of prograde, peak andretrograde reaction textures, mineral chemistry, geothermobarometricresults and petrogenetic grid considerations from the felsicand the aluminous granulites and applying metamorphosed maficdyke markers and geochronological constraints, two temporallyunrelated granulite-facies tectonothermal events of Pre-Grenvillianage have been established. The first event caused ultrahigh-temperature(UHT) metamorphism (M₁) (T 950°C) at relatively deepercrustal levels (P 9 kbar) and a subsequent post-peak near-isobariccooling P–T history (M₂). M₁ caused pervasive biotite-dehydrationmelting, producing garnet–orthopyroxene and garnet–rutileand sapphirine–spinel-bearing incongruent solid assemblagesin felsic and aluminous granulites, respectively. During M₂,garnet–corundum and later spinel–sillimanite–biotiteassemblages were produced by reacting sapphirine–spinel–sillimaniteand rehydration of garnet–corundum assemblages, respectively.Applying electron microprobe (EMP) dating techniques to monazitesincluded in M₁ garnet or occurring in low-strain domains inthe felsic granulites, the UHT metamorphism is dated at 2040–2090Ma. Based on the deep crustal heating–cooling P–Ttrajectory, the authors infer an overall counterclockwise P–Tpath for this UHT event. During the second granulite event,the Palaeoproterozoic granulites experienced crustal attenuationto 6·4 kbar at T 675°C during M₃ and subsequentnear-isothermal loading to 8 kbar during M₄. In the felsic granulites,the former is marked by decomposition of M₁ garnet to orthopyroxene–plagioclasesymplectites. During M₄, there was renewed growth of garnet–quartzsymplectites in the felsic granulites, replacing the M₃ mineralassemblage and also the appearance of coronal garnet–quartz–clinopyroxeneassemblages in metamorphosed mafic dykes. Using monazites frommetamorphic overgrowths and metamorphic recrystallization domainsfrom the felsic granulite, the M₄ metamorphism is dated at 1525–1450Ma. Using geochronological and metamorphic constraints, theauthors interpret the M₃–M₄ stages to be part of the sameMesoproterozoic tectonothermal event. The result provides thefirst documentation of UHT metamorphism and Palaeo- and Mesoproterozoicmetamorphic processes in the CITZ. On a broader scale, the findingsare also consistent with the current prediction that isobaricallycooled granulites require a separate orogeny for their exhumation. KEY WORDS: Central Indian Tectonic Zone; UHT metamorphism; counterclockwise P–T path; monazite chemical dating  相似文献   

BOOK REVIEWS     

《The Professional geographer》1988,40(4):471-499

Books reviewed in this article: USA, Eine Geographische Landeskunde , Vol. I, Der Grossraum in Strukturellem, Wandel, 3rd Ed. Helmut Blume . Introduction to Remote Sensing . James B. Campbell . The Sounds of People and Places: Readings in the Geography of American Folk and Popular Music . George O. Carney , ED. Development and Underdevelopment . John Cole . Mobility and Employment in Urban Southeast Asia: Example from Indonesia and the Philippines . Michael A. Costello , Thomas R. Leinbach , AND Richard Ulack . Soviet Asia: Economic Development and National Policy Choices . Leslie Dienes . The Third World City . David Drakakis -Smith . Scholars' Guide to Washington, DC for Cartography and Remote Sensing Imagery (maps, charts, aerial photographs, satellite images, cartographic literature and geographic information systems). Ralph E. Ehrenberg . Population and Development in the Third World . Allan AND Anne Findlay . The Early Mapping of Hawaii . Gary L. Fitzpatrick . Energetics of Physical Environment: Energetic Approaches to Physical Geography . K. J. Gregory , ED. Wildland Recreation: Ecology and Management . William E. Hammitt and David N. Cole . Agricultural Commercialization and Government Policy in Africa . J. Hinderink AND J. J. Sterkenburg . The Dynamics of American Housing . James W. Hughes AND George Sternlieb . Thailand: Buddhist Kingdom as Modern Nation State . Charles F. Keyes . Resolving Locational Conflict . Robert W. Lake , ED. Lands at Risk in the Third World: Local-level Perspectives . Peter D. Little and Michael M. Horowitz , EDS. Nathaniel Southgate Shaler and the Culture of American Science . David N. Livingstone . Regions: The Economics and Politics of Territory . Ann R. Markusen . Wetlands . William J. Mitsch and James G. Gosselink . Historical Geography: Progress and Prospect . Michael Pacione , ED. Loess and Periglacial Phenomena . Marton P$eacsi and Hugh M. French , EDS. Regional Management of Metropolitan Floodplains, Experience in the United States and Abroad . Rutherford H. Platt , ED. Human Cartography: Mapping the World of Man . Janos Szegö . Atlas of Great Lakes Indian History . Helen H. Tanner , ED. The Botany of Mangroves . P. B. Tomlinson . Urban Spatial Traffic Patterns . Rodney Vaughan . The Night After … Climatic and Biological Consequences of a Nuclear War . Yevgeni Velikhov , ED. Industrial Geography . H. D. Watts . Dictionary of Quotations in Geography . James O. Wheeler and Francis M. Sibley . Vermont Townscape . Norman Wiliams , Jr. , Edmund K. Kellogg and Peter M. Lavigne .  相似文献   

发展地理信息产业的几项措施     

向宗藩  黄杨 《地理信息世界》2001,(1)

地理信息产业是为国民经济和社会发展提供地理信息服务的一项公益性事业。测绘部门是地理信息产业形成的基础与主导。论述了地理信息产业在国民经济和社会发展中的地位和作用 ,分析其现状 ,提出了一些亟待解决的问题及其对策。  相似文献   

球面正压大气的不稳定与南亚夏季风爆发动力机制的探讨     

张铭  朱敏  张立凤 《大气科学》2006,30(2):193-201

通过球坐标正压原始方程谱点的计算,发现南亚夏季风爆发前有正压不稳定发生,不稳定罗斯贝波其最大增幅位于南半球的西风急流处,可向低纬传播并能在低纬激发出旺盛的积云对流,该积云对流可造成已失稳的大气基本场发生重大调整,从而导致南亚夏季风的爆发.  相似文献   

Back to the Future? Privatisation and the domestication of water in the Copperbelt Province of Zambia, 1900-2000     

Barbara Mwila Kazimbaya-Senkwe 《Geoforum》2007,38(5):869-885

In Zambia’s Copperbelt as in most of the developing world, the water sector is undergoing reforms targeted at promoting an active participation of the private sector. Conventional wisdom suggests that the private sector will be better able to achieve universal access as opposed to the public sector which hitherto has failed to deliver. Using archival materials from the Copperbelt Province, this paper however argues that in countries like Zambia where economic enterprise was driven by private capital, access to water has always been tied to an active involvement of the private sector. The full story of failure to provide universal access to potable water cannot be told without examining this historical role of the private sector and its relationship with the public sector. At the same time, contemporary policy debates can benefit from the resonance of historical debates around economic efficiency, demand management, health and access in the production and consumption of water.  相似文献   

Mapping of b-value Beneath the Shillong Plateau     

P.K. Khan   《Gondwana Research》2005,8(2):271-276

The seismic parameter ‘b’ has been computed over rectangular grid of dimension 0.3° ' 0.8° at four depths range: 0-13 km (first layer), 13.1-26 km (second layer), 26.1-39 km (third layer) and 39.1-52 km (fourth layer) beneath the Shillong Plateau area. The four depths were carefully selected based on the crustal structure and distribution of hypocentres. The dimension of each grid was chosen so as to have enough events that can represent the b-value at the respective layer. Finally, two-dimensional mapping was done at these depth-levels considering the respective b-value over each grid. This analysis includes viz., low b-value all through the first layer, and a trend of increasing b-value, which was initially towards north, changes to northwest. Eastern and western parts of the second and third layers document almost moderate b-values, whereas the north-south-oriented central part of layer second is apparently dominated by low b-values, which seems to divide the area broadly into three parallel zones based on b-values. In the deeper part (fourth layer) beneath the Shillong Plateau a moderate b-value that was initially trending towards north becomes high near the northeastern part. This phenomenon may be associated with higher heterogeneity of the medium, and interestingly, this region lies between the lower crust and upper mantle, possibly documents lower degree of seismic coupling, where the Shillong Plateau is being supported by the strong Indian lithosphere at these depths. In addition, minima were noted towards the southern parts of layers first, second and third, which may presumably be related with steeply Bouguer gravity anomaly. It is thus less clear that the occurrence of earthquakes beneath the Shillong Plateau whether is attributed to faults or lineaments at intermediate to deeper level. However, a correlation between high b-values in few parts of each layer and deep-seated minor faults cannot be ruled out.  相似文献   

印度板块向欧亚板块俯冲碰撞的新模式及其对青藏高原构造演化的影响   总被引：2，自引：0，他引：2  

周征宇  廖宗廷 《沉积与特提斯地质》2005,25(4):27-32

青藏高原南部与北部的断裂带走滑方向不同，断裂带在高原东、西两侧的展布规律和构造运动方式也存在极大的差异。通过高原南缘横向地球物理特征的对比，发现该地区东、西两侧深部岩石圈结构存在明显不同，表明印度次大陆向欧亚大陆俯冲碰撞的方式和强度在横向上差异明显。在充分利用高原地质研究最新成果的基础上，提出印度次大陆向欧亚大陆碰撞前地壳增厚及斜向碰撞是造成上述地质现象的根本原因，并由此对青藏高原构造演化的一些特点作了新的解释和探讨。  相似文献