青藏高原冬季积雪异常对东,南亚夏季风影响的初步数值模拟研究   总被引：10，自引：2，他引：10  

范广洲  罗四维 《高原气象》1997,16(2):140-142

利用一个耦合了简化的简单生物圈模式的大气环流谱模式（ＳＳｉＢ－ＧＣＭ），初步探讨了青藏高原冬季积雪异常对东、南亚夏季季风环流和降水的影响及其机理。结果表明，高原地区积雪增加将使随后地夏季东、南来季风明显减弱，主要表现为东、南亚季风区降水减少，索马里急流、印度季风的印度西南气流弱弱。另外，还提出欧亚大陆雪盖与整个高原雪盖和高原东部雪盖对东、南亚夏季风影响的敏感问题。与欧亚大陆雪盖相比，高原雪盖是影响  相似文献   

东亚冬季风的演变特征   总被引：5，自引：0，他引：5       下载免费PDF全文

丁一汇 《应用气象学报》1997,8(2):186-196

文章主要讨论了东亚冬季风和冷涌的演变特征，并与南亚作了对比，发现在东亚地区，冬季风演变主要表现为10月中旬经向环流的突变及9月初、11月中旬和1月末对流层低层温度的3次突变；而在南亚地区，经向环流的变化不如东亚地区明显，而且高层要先于低层变化，对流层低层温度存在2次突变。在整个冬季，东亚地区冷涌的演变过程，主要表现为南海地区冷涌在12月份出现最高频率，而西太平洋冷涌在1月份出现最高频率；南亚地区冷涌在12月份出现最高频率，但远小于东亚地区且衰减速度很快。另一个不同点是东亚地区的冷涌强度是往上衰减的，而南亚地区的冷涌强度则是往上增强的。这说明东亚冬季风和南亚冬季风的性质有较大的区别。  相似文献   

Partial melting during tectonic exhumation of a granulite terrane: an example from the Larsemann Hills, East Antarctica   总被引：23，自引：0，他引：23  

C. J. CARSON  R. POWELL  C. J. L. WILSON  & P. H. G. M. DIRKS 《Journal of Metamorphic Geology》1997,15(1):105-126

Anatectic migmatites in medium- to low-pressure granulite facies metasediments exposed in the Larsemann Hills, East Antarctica, contain leucosomes with abundant quartz and plagioclase and minor interstitial K-feldspar, and assemblages of garnet–cordierite–spinel–ilmenite–sillimanite. Qualitative modelling in the system K₂O–FeO–MgO–Al₂O₃–SiO₂–H₂O–TiO₂–O₂, in conjunction with various P–T calculations indicate that the high-grade retrograde evolution of the terrane was dominated by decompression from peak conditions of c. 7 kbar at c. 800 °C to 4–5 kbar at c. 750 °C. Extensive partial melting during decompression involved the replacement of biotite by the assemblage cordierite–garnet–spinel within the leucosomes. These leucosomes represent the site of partial melt generation, the cordierite–garnet–spinel–ilmenite assemblage representing the solid products and excess reactants from the melting reaction. The extraction and accumulation of this decompression-generated melt led to the formation of syntectonic pegmatites and extensive granitic plutons. Leucosome development and terrane decompression proceeded during crustal transpression, synchronous with upper crustal extension, during a progressive Early Palaeozoic collisional event. Subsequent retrograde evolution was characterized by cooling, as indicated by the growth of biotite replacing spinel and garnet, thin mantles of cordierite replacing spinel and quartz within metapelites, and garnet replacing orthopyroxene and hornblende within metabasites. P–T calculations on late mylonites indicate lower grade conditions of formation of c. 3.5 kbar at c. 650 °C, consistent with the development of late cooling textures.  相似文献   

人地系统动力学研究中的几个问题   总被引：1，自引：0，他引：1  

吴殿廷  葛岳静 《热带地理》1997,17(1):95-100

人地系统动力学研究是当前地理学研究的最主要领域，应从人的生存和发展需要出发，围绕人类活动的环境效应和人地协调发展主线选择研究对象，界定研究内容，采用物质能量守恒分析和统计分析相结合的方法，加强对人地相互作用机制的研究。  相似文献   

Geothermal Regime of Meso-Cenozoic Basins and Their Tectonic Background in East China     

 Zhuang XinguoZhuang XinguoGeothermal Regime of Meso-Cenozoic Basins  Their Tectonic Background in East ChinaFaculty of Earth Resources  China University of Geosciences  Wuhan  《中国地质大学学报(英文版)》1997,(1)

ＧｅｏｔｈｅｒｍａｌＲｅｇｉｍｅｏｆＭｅｓｏ－ＣｅｎｏｚｏｉｃＢａｓｉｎｓａｎｄＴｈｅｉｒＴｅｃｔｏｎｉｃＢａｃｋｇｒｏｕｎｄｉｎＥａｓｔＣｈｉｎａ＊ＺｈｕａｎｇＸｉｎｇｕｏＦａｃｕｌｔｙｏｆＥａｒｔｈＲｅｓｏｕｒｃｅｓ，ＣｈｉｎａＵｎｉｖｅｒｓｉｔ...  相似文献   

Reservoir Diagenesis Sequence and Framework in Intracontinent Rift Basin,East China     

Li ZhongInstitute of Geology  Chinese Academy of Sciences  Beijing Sun YongchuanDepartment of Petroleum Geology  China University of Geosciences  Wuhan  《中国地质大学学报(英文版)》1997,(1)

ＲｅｓｅｒｖｏｉｒＤｉａｇｅｎｅｓｉｓＳｅｑｕｅｎｃｅａｎｄＦｒａｍｅｗｏｒｋｉｎＩｎｔｒａｃｏｎｔｉｎｅｎｔＲｉｆｔＢａｓｉｎ，ＥａｓｔＣｈｉｎａ＊ＬｉＺｈｏｎｇＩｎｓｔｉｔｕｔｅｏｆＧｅｏｌｏｇｙ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ...  相似文献   

Lithospheric Stretching,Subsidence and Thermal History Modeling: Application to Yinggehai,Qiongdongnan and Songliao Basins in East China   总被引：3，自引：0，他引：3  

Lin ChangsongDepartment of Energy Resources  China University of Geosciences  Beijing Li SitianFaculty of Earth Resources  China University of Geosciences  Wuhan Zhang QiminWest Nanhai Oil Company  Zhanjiang Zhang 《中国地质大学学报(英文版)》1997,(1)

ＬｉｔｈｏｓｐｈｅｒｉｃＳｔｒｅｔｃｈｉｎｇ，ＳｕｂｓｉｄｅｎｃｅａｎｄＴｈｅｒｍａｌＨｉｓｔｏｒｙＭｏｄｅｌｉｎｇ：ＡｐｐｌｉｃａｔｉｏｎｔｏＹｉｎｇｇｅｈａｉ，ＱｉｏｎｇｄｏｎｇｎａｎａｎｄＳｏｎｇｌｉａｏＢａｓｉｎｓｉｎＥａｓｔＣｈｉｎａ＊Ｌｉ...  相似文献   

Lower-crustal rifting in the Rukwa Graben, East Africa     

Ming Zhao  Charles A. Langston  rew A. Nyblade  Thomas J. Owens 《Geophysical Journal International》1997,129(2):412-420

An M_w 5.9 earthquake occurred in the Lake Rukwa rift, Tanzania, on 1994 August 18, and was well recorded by 20 broad-band seismic stations at distances of 160 to 800 km and 21 broad-band stations at teleseismic distances. The regional and teleseismic waveforms have been used to investigate the source characteristics of the main shock, and also to locate aftershocks that occurred within three weeks of the main shock. Teleseismic body-wave modelling yields the following source parameters for the main shock: source depth of 25 ± 2 km, a normal fault orientation, with a horizontal tension axis striking NE-SW and an almost vertical pressure axis (Nodal Plane I: strike 126°–142°, dip 63°–66°, and rake 280°–290°; Nodal Plane II: strike 273°–289°, dip 28°–31°, and rake 235°–245°), a scalar moment of 4.1 times 10¹⁷ N m, and a 2 s impulsive source time function. Four of the largest aftershocks also nucleated at depths of 25 km, as deduced from regional sPmp–Pmp times. The nodal planes are broadly consistent with the orientation of both the Lupa and Ufipa faults, which bound the Rukwa rift to the northeast and southwest, respectively. The rupture radius of the main shock, assuming a circular fault, is estimated to be 4 km with a corresponding stress drop of 6.5 MPa. Published estimates of crustal thickness beneath the Rukwa rift indicate that the foci of the main shock and aftershocks lie at least 10 km above the Moho. The presence of lower-crustal seismicity beneath the Rukwa rift suggests that the pre-rift thermal structure of the rifted crust has not been strongly modified by the rifting, at least to depths of 25 km.  相似文献   

The transition from people''s property to private property: Consequences of the restitution principle for urban development and urban renewal in East Berlin''s inner-city residential areas     

Bettina Reimann 《Applied geography (Sevenoaks, England)》1997,17(4):301-313

The constitutional decision to return to their original owners all real-estate property in East Germany that had either been expropriated or placed under state administration (the restitution principle) has had significant consequences for urban development and urban renewal. Experiences from East Berlin's innercity residential areas illustrate the effects on the state of repair of housing, the character of residential neighbourhoods, the tenants living in the areas affected, and the future structure of real-estate ownership. The case studies reveal a picture of a contradictory development of residential neighbourhoods, including shifting power relations and new polarizations, especially between tenants and landlords.  相似文献   

FARMING THE FOREST EDGE: VULNERABLE PLACES AND PEOPLE AROUND KIBALE NATIONAL PARK,UGANDA     

LISA NAUGHTON-TREVES 《Geographical review》1997,87(1):27-46

ABSTRACT. Subsistence farmers near Kibale National Park, Uganda, fear and resent many wildlife species. In this article I compare records of crop damage by wildlife and livestock with local complaints about the worst animals and the most vulnerable crops. I discuss the concordance and discrepancies in complaints versus actual damage in light of physical parameters of risk and of social factors that shape perceptions and vulnerabilities. Crop losses were greatest at the edge of the forest, where immigrants are disproportionately represented. State proprietorship of wildlife amplifies local vulnerability and constrains traditional coping strategies, such as hunting.  相似文献