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1.
REN Shoumai LIU Yongjiang GE Xiaohong . Strategic Research Center of Oil & Gas Resources Ministry of L & Resources Beijing China . College of Earth Sciences Jilin University Changchun China 《东北亚地学研究》2009,(3):145-155
The latest sharp uplift of the Tibetan Plateau and adjacent mountains occurred at the end of the early Pleistocene. The uplift of the Plateau resulted from Late Mesozoic-Cenozoic compressional structure due to the subduction of the Indian Plate beneath the Asian continent. This event definitively effected the formation of basin-mountain relief, Cenozoic basin deformation, large scale aridity and desertification of western China. The Australasian meteorites impact event happened ca. 0.8 Ma ago, located in the triangle area of the Indian Ocean ridge （20°S/67°E）. The impact may have resulted in an acceleration of speeding of the Indian Ocean ridge pushing the Indian Plate to subduct rapidly northward. Thus, the impact event can give reasonable explanation for the dynamic background of the latest rapid uplift of the Tibetan Plateau and the continental deformation of western China and even of the Middle Asia. 相似文献
2.
自新生代印度板块的块持续碰撞与俯冲作用下,青藏高原经历了快速隆升与复杂的岩石圈改造过程,但高原现今的垂向动力学机制和地壳形变特征仍然存在争议。基于非均一有效弹性厚度的挠曲模型,利用地形和地球重力场模型数据,计算了青藏高原及邻区的挠曲均衡重力异常。结果显示,青藏高原的均衡重力异常在-120~90 mGal之间,高原中部为明显的正异常特征,边缘为显著的均衡负异常。极小值出现在青藏高原西北部及其相邻的帕米尔高原,极大值则出现在与之紧邻的喜马拉雅块体西北部。此外,在青藏高原北面和东面,塔里木盆地和四川盆地显示出大片的均衡正异常。这些特征说明青藏高原及邻区地壳现今处于非均衡的状态,在板块碰撞挤压作用下,老的块体地壳整体发生抬升,导致了均衡正异常特征;而年轻的造山区域,地壳形变主要表现为地表抬升与下地壳强烈增厚,形成了均衡负异常。在高原中部和北部,均衡调整方向与地壳垂向运动趋势相一致;但在高原南面（喜马拉雅块体）和东面（四川盆地）,均衡调整方向与地表形变观测结果相反。这说明印度板块碰撞与俯冲仍然控制着青藏高原南部、东部及其相邻块体的地壳形变过程,然而在更北的区域,地壳正通过均衡调整恢复均衡状态。 相似文献
3.
Introduction A set of reddish clay-silt-sized sediments named red clay underlying the Quaternary loess-paleosol sequence widely distribute in the Chinese Loess Plateau. The thickness of the red clay sediments ranges from decades of meters to over 100 m (Evan et al.1991,Mo and Derbyshire 1991, SUN et al. 1997&1998, DING et al. 1999, GUO et al. 2001, QIANG et al. 2001). Previous studies show that not only loess-paleosol (e.g.LIU et al.1985,AN et al.1990,DING et al.1992),but also red … 相似文献
4.
长江的发育演化尤其是东西贯通的时限问题,是百余年来地学界的焦点问题,金沙江水系的演化重组是长江演化中的关键一环。基于填充海拔的模型模拟以及物源示踪的梳理结果,讨论了金沙江在夷平面上南流汇入红河的可能性。结果显示当海拔填充至2 000~2 200 m时,金沙江水系格局发生重大变化,表现为金沙江在金江街一改东流之势,沿宾川盆地汇入古红河;古雅砻江在攀枝花附近转而向西,沿金沙江河谷经宾川盆地流入古红河,形成古红河的一级支流。推断哀牢山-红河断裂带、程海-宾川断裂带的活动及山体隆升特别是鸡足山的隆升可能阻断了上述南流泄口,切断了金沙江与红河的联系,从而形成今日江水东流的水系格局,这为古金沙江南流路径的研究提供了新的思路和方向。 相似文献
5.
To better understand the crustal deformation of the South China Sea Basin, we produce a mechanically consistent 2-dimensional model for observing regional velocity field in the South China Sea (SCS). We studied the dominating regional tectonic stress field by geodetic measurements and finite element analysis, the spatial variations of velocity field and strain field, and relative movements among different blocks, using a 2-dimensional model describing crustal deformation of the South China Sea Basin. Strain results show that the SCS is extending at present. The western part of SCS is opening gradually in NWSE direction from its northern margin to the south, but the eastern part of SCS is opening gradually from its central part to the north and south. In addition, we analyzed the plate kinematics to the deformation of the SCS, using a two-dimensional finite element model. Our simulations results are well explained by available geodetic data. The movement of SCS is resulted from interactions among Indian Plate, Pacific Plate, Philippine Sea Plate, and Eurasian Plate. 相似文献
6.
大陆岩石圈的增厚及对流剥离对青藏高原隆升的影响 总被引：1，自引：0，他引：1
伴随着印度板块对欧亚板块南缘的碰撞、挤压,青藏高原地壳及下伏地幔岩石圈的厚度增加了１倍。增厚岩石圈热结构的变化可导致高原海拨下降约１５００ｍ。其对流剥离并被较热的软流圈物质替代可用以解释青藏高原自８百万年或３百万年前开始的快速隆升。大陆岩石圈的增厚及热结构变化和对流剥离可能是青藏高原自９百万年前开始的夷平—快速隆升过程的主导控制因素。 相似文献
7.
????С???任??????2000??2007???й??????????????仯????????ò??С??????????μ??????????????仯???????????1?????С?????????????????2??????С??????????????????????????Ms8.0???????????3??????С???????????????????????????????????????????????????????????????????4??????С?????????????????????????????????????????????μ???塢?????????????????????????????? 相似文献
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9.
青藏高原东南缘位于印度板块与欧亚板块侧向汇聚部位,是检验碰撞造山动力学模型的理想场所。尽可能全面收集该区已有地球物理和新生代岩浆岩数据,探讨这些资料对碰撞造山带结构和物质组成的指示。结果表明:青藏高原东南缘不同部位的壳幔结构和组成存在较大差异。兰坪—思茅地块、保山地块和腾冲地块等的中地壳(15~30 km深度)普遍发育低速层,表明富水层或者部分熔融物质的存在,为青藏高原物质向东南流动提供了可能。部分熔融产物以大型剪切带内具有高Sr、低Nd同位素特征的淡色花岗岩脉为代表。但是,扬子板块同等深度下却发育高速层,其组成很可能是峨眉山玄武岩,它的存在阻隔了碰撞带物质向东流动。扬子板块和兰坪—思茅地块下地壳底部均出现呈条带状展布的高速体。根据新生代具有高Sr、低Y的岩石显示的下地壳源区特征,结合该区地质演化历史,将上述两套呈条带状展布的高速体分别解释为新元古代铁镁质弧岩浆岩和二叠纪—三叠纪铁镁质弧岩浆岩。青藏高原东南缘地幔各向异性存在明显南、北分区特征,在26°N以北表现为SN向,在26°N以南表现为近EW向。这一差异跟俯冲的印度板片撕裂有密切关系。该撕裂在综合地球物理剖面上显示为突变的印度板片俯冲角度,在地表表现为苦橄岩、煌斑岩、埃达克岩以及淡色花岗岩等的集中出露。这一新模型明显区别于前人的岩石圈拆沉和对流减薄等作用。 相似文献
10.
LIU Na CHEN Hongxia 《中国海洋大学学报(英文版)》2006,5(2):99-105
Using the monthly wind and sea surface temperature （SST） data, southern meridional atmospheric circulation cells associated with the Indian Ocean Dipole Mode （IOD） events in the Indian Ocean are for the first time described and examineS. The divergent wind and pressure vertical velocity are employed for the identification of atmospheric circulation cells. During the four different phases of the positive IOD events, the anomalous meridional Hadley circulation over the western Indian Ocean shows that the air rises in the tropics, flows poleward in the upper troposphere, sinks in the subtropics, and returns back to the tropics in the lower troposphere. The anomalous Hadley circulation over the eastern Indian Ocean is opposite to that over the western Indian Ocean. During positive IOD events, the meridional Hadley circulation over the eastern Indian Ocean is weakened while it is strengthened over the western Indian Ocean. Correlation analysis between the IOD index and the indices of the Hadley cells also proves that, the atmospheric circulation patterns are evident in every IOD event over the period of record. 相似文献
11.
本文着重分析了青藏高原500hpa高压因伊朗高压脊东伸、分裂产生过程中和东移过程中,西风带波动、印度季风低压以及100hpa层流型的一系列变化,从而说明青藏高原500hpa高压产生和东移的环流背景。 相似文献
12.
热带海洋热状况是影响中国气候变化的主要因子之一,为了研究热带次表层海温如何影响中国气候,通过相关计算和合成分析等方法讨论了热带太平洋至印度洋次表层海温异常对中国东部夏季降水和温度的影响。结果表明:当冬季赤道东印度洋至西太平洋次表层海温偏暖(偏冷),中印度洋和东太平洋次表层海温偏冷(偏暖),夏季,长江中下游地区降水偏少(偏多),华南、华北和东北大部地区降水偏多(偏少);中国东部大范围高温(低温)。其可能的影响途径为,东亚夏季风环流对热带次表层海温异常的响应导致了其年际变化,进而引起中国东部夏季气候的异常分布。 相似文献
13.
By using Season-reliant Empirical Orthogonal Function (S-EOF) analysis, three dominant modes of the spatial-temporal evolution of the drought/flood patterns in the rainy season over the east of China are revealed for the period of 1960-2004. The first two leading modes occur during the turnabout phase of El Nino-Southern Oscillation (ENSO) decaying year, but the drought/flood patterns in the rainy season over the east of China are different due to the role of the Indian Ocean (IO). The first leading mode appears closely correlated with the ENSO events. In the decaying year of El Nino, the associated western North Pacific (WNP) anticyclone located over the Philippine Sea persists from the previous winter to the next early summer, transports warm and moist air toward the southern Yangtze River in China, and leads to wet conditions over this entire region. Therefore, the precipitation anomaly in summer exhibits a ’Southern Flood and Northern Drought’ pattern over East China. On the other hand, the basin-wide Indian Ocean sea surface temperature anomaly (SSTA) plays a crucial role in prolonging the impact of ENSO on the second mode during the ENSO decaying summer. The Indian Ocean basin mode (IOBM) warming persists through summer and unleashes its influence, which forces a Matsuno-Gill pattern in the upper troposphere. Over the subtropical western North Pacific, an anomalous anticyclone forms in the lower troposphere. The southerlies on the northwest flank of this anticyclone increase the moisture transport onto central China, leading to abundant rainfall over the middle and lower reaches of the Yangtze River and Huaihe River valleys. The anomalous anticyclone causes dry conditions over South China and the South China Sea (SCS). The precipitation anomaly in summer exhibits a ’Northern Flood and Southern Drought’ pattern over East China. Therefore, besides the ENSO event the IOBM is an important factor to influence the drought/flood patterns in the rainy season over the east of China. The third mode is positively correlated with the tropical SSTA in the Indian Ocean from the spring of preceding year(-1) to the winter of following year(+1), but not related to the ENSO events. The positive SSTA in the South China Sea and the Philippine Sea persists from spring to autumn, leading to weak north-south and land-sea thermal contrasts, which may weaken the intensity of the East Asia summer monsoon. The weakened rainfall over the northern Indian monsoon region may link to the third spatial mode through the ’Silk Road’ teleconnection or a part of circumglobal teleconnection (CGT). The physical mechanisms that reveal these linkages remain elusive and invite further investigation. 相似文献
14.
区域气候模式RegCM3对中国夏季降水的模拟 总被引：5，自引：0，他引：5
利用意大利国际理论物理中心（ICTP）最新发布的区域气候模式RegCM3检验我国包括青藏高原地区夏季降水的模拟能力。初始值及边界值取自美国国家环境预测中心（NCEP）和国家大气中心（NCAR）的全球再分析资料。模式积分时间为2005年5月1日到2005年8月31日,考虑到模式的“spin-up”时间,只对6月1日-8月31日的模式结果进行分析。模式水平分辨率取为60km,范围包括整个青藏高原在内的我国及周边地区（14°-55°N,70°-140°E）。结果表明：RegCM3具有模拟我国夏季降水主要分布特征的能力,尤其在观测站点稀少的青藏高原地区可提供局地降水分布的较可靠信息。模式较好地模拟了包括整个青藏高原在内的我国区域降水的月际尺度变化和空间分布等基本特征,但对我国东南地区的夏季降水模拟能力有待进一步提高。 相似文献
15.
ENSO cycle and climate anomaly in China 总被引：2，自引：0，他引：2
The inter-annual variability of the tropical Pacific Subsurface Ocean Temperature Anomaly (SOTA) and the associated anomalous atmospheric circulation over the Asian North Pacific during the El Ni o-Southern Oscillation (ENSO) were investigated using National Centers for Environmental Prediction/ National Center for Atmospheric Research (NCEP/NCAR) atmospheric reanalysis data and simple ocean data simulation (SODA). The relationship between the ENSO and the climate of China was revealed. The main results indicated the following: 1) there are two ENSO modes acting on the subsurface tropical Pacific. The first mode is related to the mature phase of ENSO, which mainly appears during winter. The second mode is associated with a transition stage of the ENSO developing or decaying, which mainly occurs during summer; 2) during the mature phase of El Ni o, the meridionality of the atmosphere in the mid-high latitude increases, the Aleutian low and high pressure ridge over Lake Baikal strengthens, northerly winds prevail in northern China, and precipitation in northern China decreases significantly. The ridge of the Ural High strengthens during the decaying phase of El Ni o, as atmospheric circulation is sustained during winter, and the northerly wind anomaly appears in northern China during summer. Due to the ascending branch of the Walker circulation over the western Pacific, the western Pacific Subtropical High becomes weaker, and south-southeasterly winds prevail over southern China. As a result, less rainfall occurs over northern China and more rainfall over the Changjiang River basin and the southwestern and eastern region of Inner Mongolia. The flood disaster that occurred south of Changjiang River can be attributed to this. The La Ni a event causes an opposite, but weaker effect; 3) the ENSO cycle can influence climate anomalies within China via zonal and meridional heat transport. This is known as the "atmospheric-bridge", where the energy anomaly within the tropical Pacific transfers to the mid-high latitude in the northern Pacific through Hadley cells and Rossby waves, and to the western Pacific-eastern Indian Ocean through Walker circulation. This research also discusses the special air-sea boundary processes during the ENSO events in the tropical Pacific, and indicates that the influence of the subsurface water of the tropical Pacific on the atmospheric circulation may be realized through the sea surface temperature anomalies of the mixed water, which contact the atmosphere and transfer the anomalous heat and moisture to the atmosphere directly. Moreover, the reason for the heavy flood within the Changjiang River during the summer of 1998 is reviewed in this paper. 相似文献
16.
The distribution and variability of simulated chlorophyll concentration over the tropical Indian Ocean from five CMIP5 models 总被引：1，自引：0，他引：1
Performances of 5 models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) in simulating the chlorophyll concentration over the tropical Indian Ocean are evaluated. Results show that these models are able to capture the dominant spatial distribution of observed chlorophyll concentration and reproduce the maximum chlorophyll concentration over the western part of the Arabian Sea, around the tip of the Indian subcontinent, and in the southeast tropical Indian Ocean. The seasonal evolution of chlorophyll concentration over these regions is also reproduced with significant amplitude diversity among models. All of 5 models is able to simulate the interannual variability of chlorophyll concentration. The maximum interannual variation occurs at the same regions where the maximum climatological chlorophyll concentration is located. Further analysis also reveals that the Indian Ocean Dipole events have great impact on chlorophyll concentration in the tropical Indian Ocean. In the general successful simulation of chlorophyll concentration, most of the CMIP5 models present higher than normal chlorophyll concentration in the eastern equatorial Indian Ocean. 相似文献
17.
戚伟 《地球信息科学学报》2019,21(8):1198-1206
研究青藏高原城镇化格局的时空分异及其影响因素,有利于推动青藏高原现代人类活动时空过程的认知,对青藏高原就地就近城镇化及可持续发展具有参考意义。根据历次人口普查数据,本研究构建青藏高原县市尺度城镇化空间数据集,参考城镇化发展阶段,采用LISA空间类型划分法和空间计量回归模型,系统分析1990-2010年青藏高原内部城镇化格局的时空分异特征及影响因素。主要结论包括：① 青藏高原整体城镇化水平偏低,2017年底,青藏高原主体部分青海省和西藏自治区的常住人口城镇化水平分别为53.07%和30.8%,低于全国同期水平的58.52%,但青藏高原内不乏高水平城镇化地区,而且各地区间城镇化水平的空间差异缩小;② 青海西部柴达木盆地是高水平城镇化集聚区,羌塘地区是低水平城镇化集聚区,地级行政中心所在县市多呈现自身高、周边低的城镇化格局;③ 与内地相似,第二、三产业从业机会是推动青藏高原城镇化发展重要因素,社会公共服务资源对城镇化拉动作用开始凸显。研究结果可以为青藏高原人类活动研究和青藏高原就地就近城镇化可持续发展政策提供参考。 相似文献
18.
气候变化情景下极端降水事件的频次和强度预估呈增加趋势,这会导致全球部分地区极端降雨诱发地质灾害风险的增加。本文基于中国降雨诱发地质灾害易发性模型和不同地貌分区的累积事件降雨量-降雨历时阈值曲线,采用最新的CMIP6全球气候模式多模式集合结果,基于全球温升目标情景的视角,从地质灾害空间易发性和发生频次两方面,探讨温升情景下中国地质灾害危险性的可能变化及其对暴露人口的潜在影响。结果表明,CMIP6多模式集合预估的多年平均降水在温升1.5℃和2.0℃情景下相比基准时期可能增加5.4%～9.5%,导致中等至极高地质灾害易发区范围预估增加0.33%～0.74%,由于预估的极端降水事件增加,地质灾害发生频次预估增加7.0%～11.2%,进一步综合未来人口空间分布,潜在地质灾害暴露人口可能增加6.20亿人次（18.90%）和4.26亿人次（12.97%）。各地貌分区未来情景下地质灾害危险性预估增加且存在显著的空间异质性,温升2.0℃情景下中等至极高易发性范围相比基准时期增加0.71%～1.28%,地质灾害发生频次预估增加1.2%～15.6%,其中,青藏高原区地质灾害危险性增加最明显。综合考虑未来人口... 相似文献
19.
青藏高原冬季降水的气候特征认识对高原冬季雪灾的防御有着重要意义。基于青藏高原54个气象站1971~2010年冬季(12~2月)逐月降水量资料,利用现代统计方法分析了青藏高原冬季降水的时空分布特征及突变现象,利用经验正交函数(EOF)和旋转经验正交函数(REOF)概括出高原冬季降水的6种主要空间分布型以及区域性特征进行分析。结果表明:冬季降水分布不均匀,偏东偏南部降水量相对较多,冬季降水在12月最少,2月最多;EOF对青藏高原地区冬季降水分解为6种模态,全区一致型、南北部型、东西部型、川西型、高原腹地型和西部型模态;EOF第1模态时间系数表明高原大部分地区冬季降水在20世纪90年代有显著增加、且存在14年左右的周期变化特征。REOF分析表明,高原地区冬季降水的局地特征显著,而高原腹地与中东部地区变化特征显示了高原冬季降水的主要变化特征,与EOF分析第1模态的变化特征较为一致。 相似文献
20.
Previous research has defined the index of the Indian-Pacific thermodynamic anomaly joint mode (IPTAJM) and suggested that
the winter IPTAJM has an important impact on summer rainfall over China. However, the possible causes for the interannual
and decadal variability of the IPTAJM are still unclear. Therefore, this work investigates zonal displacements of both the
western Pacific warm pool (WPWP) and the eastern Indian Ocean warm pool (EIOWP). The relationships between the WPWP and the
EIOWP and the IPTAJM are each examined, and then the impacts of the zonal wind anomalies over the equatorial Pacific and Indian
Oceans on the IPTAJM are studied. The WPWP eastern edge anomaly displays significant interannual and decadal variability and
experienced a regime shift in about 1976 and 1998, whereas the EIOWP western edge exhibits only distinct interannual variability.
The decadal variability of the IPTAJM may be mainly caused by both the zonal migration of the WPWP and the 850 hPa zonal wind
anomaly over the central equatorial Pacific. On the other hand, the zonal migrations of both the WPWP and the EIOWP and the
zonal wind anomalies over the central equatorial Pacific and the eastern equatorial Indian Ocean may be all responsible for
the interannual variability of the IPTAJM. 相似文献