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1.
Cenozoic sedimentary records and geochronological constraints of differential uplift of the Qinghai-Tibet Plateau 总被引：14，自引：0，他引：14
KeXin Zhang GuoCan Wang Kai Cao Chao Liu ShuYuan Xiang HanLie Hong XiaoHu Kou YaDong Xu FenNing Chen YanNing Meng RuiMing Chen 《中国科学D辑(英文版)》2008,51(11):1658-1672
Geological mapping data (1:250000) in the Qinghai-Tibet Plateau and its adjacent regions reveal the sediment sequences, distribution and tectonic evolution of the 92 Tertiary remnant basins. Southern Tibet and the Yecheng area in Xinjiang, located at southern and northwestern margins of the Qinghai-Tibet Plateau, respectively, were parts of the Neo-Tethys remnant sea in the Paleogene. In southern Tibet, both the subabyssal and abyssal sequences occur at the Gyangze, Saga, Guoyala, and Sangmai areas. The deep-water facies successions outcrop in the west, whereas the shallow-water facies sequences in the east, indicating the east to the west retreat of the Neo-Tethys Ocean. The retreat of the Neo-Tethys Ocean in the east was contributed to the earlier tectonic uplift of the eastern Qinghai-Tibet Plateau. The uplift process of the Plateau from the Late Cretaceous to Pliocene is described as follows: During the Late Cretaceous, tectonic uplift of the Qinghai-Tibet Plateau occurred in the northeastern part and the configuration of the Qinghai-Tibet Plateau was characterized by rise in the northeast and depression in the west. In the Paleocene-Eocene interval, the Tengchong-Baingoin and Kuyake-Golmud areas experienced local tectonic uplifting, the West Kunlun uplift zone broadened easterly, the Qilian uplift zone broadened southerly, and the Songpan-Garzê uplift zone shrank easterly. The Oligocene configuration of the Qinghai-Tibet Plateau was characterized by mountain chains rising along its margins and sedimentary basins in the central part because of tectonic uplifts of the Gangdisê and the Himalaya blocks. Meanwhile, the Kunlun-Altyn-Qilian uplift zones have also broadened southerly and northerly. In contrast, the great uplift zones of the Gangdisê, the Himalaya, the Karakorum, and the Kunlun blocks characterize the paleogeographic contours of the Qinghai-Tibet Plateau during the Miocene-Pliocene. Additionally, the thermochronological data on tectonic uplift events in southern Tibet, West Kunlun Mountains, Altyn Tagh, eastern Tibet, and western Sichuan all suggest that the most intense deformation occurred at 13-8 Ma and since 5 Ma, respectively, corresponding to two great uplift periods in Neogene. As a result, turnover of paleogeographic configuration of the Qinghai-Tibet Plateau occurred during the Neogene, experiencing a change from high contours in the east in the pre-Oligocene to high contours in the west at the end-Pliocene. The uplift of the Qinghai-Tibet Plateau during the Cenozoic was episodic, and the uplifts of various blocks within the Plateau were spatially and chronologically different. 相似文献
2.
XingFeng Yang Xin Cheng YaNan Zhou Lun Ma XiaoDong Zhang ZhaoSheng Yan XiMing Peng HaiLun Su HanNing Wu 《中国科学:地球科学(英文版)》2017,60(1):124-134
Results of a systematic paleomagnetic study are reported based on Late Carboniferous to Early Permian sedimentary rocks on the north slope of the Tanggula Mountains,in the northern Qiangtang terrane(NQT),Tibet,China.Data revealed that magnetic minerals in limestone samples from the Zarigen Formation(CP^z)are primarily composed of magnetite,while those in sandstone samples from the Nuoribagaribao Formation(Pnr)are dominated by hematite alone,or hematite and magnetite in combination.Progressive thermal,or alternating field,demagnetization allowed us to isolate a stable high temperature component(HTC)in 127 specimens from 16 sites which successfully passed the conglomerate test,consistent with primary remnance.The tilt-corrected mean direction for Late Carboniferous to Early Permian rocks in the northern Qiangtang terrane is D_s=30.2°,I_s=-40.9°,k_s=269.0,a_(95)=2.3°,N=16,which yields a corresponding paleomagnetic pole at 25.7°N,241.5°E(dp/dm=2.8°/1.7°),and a paleolatitude of 23.4°S.Our results,together with previously reported paleomagnetic data,indicate that:(1)the NQT in Tibet,China,was located at a low latitude in the southern hemisphere,and may have belonged to the northern margin of Gondwana during the Late Carboniferous to Early Permian;(2)the Paleo-Tethys Ocean was large during the Late Carboniferous to Early Permian,and(3)the NQT subsequently moved rapidly northwards,perhaps related to the fact that the Paleo-Tethys Ocean was rapidly contracting from the Late Permian to Late Triassic while the Bangong Lake-Nujiang Ocean,the northern branch of the Neo-Tethys Ocean,expanded rapidly during this time. 相似文献
3.
Using reanalysis data, the role of initial signals in the tropical Pacific Ocean in predictions of negative Indian Ocean Dipole (IOD) events were analyzed. It was found that the summer predictability barrier (SPB) phenomenon exists in predictions, which is closely related to initial sea temperature errors in the tropical Pacific Ocean, with type-1 initial errors presenting a significant west-east dipole pattern in the tropical Pacific Ocean, and type-2 initial errors showing the opposite spatial pattern. In contrast, SPB-related initial sea temperature errors in the tropical Indian Ocean are relatively small. The initial errors in the tropical Pacific Ocean induce anomalous winds in the tropical Indian Ocean by modulating the Walker circulation in the tropical oceans. In the first half of the prediction year, the anomalous winds, combined with the climatological winds in the tropical Indian Ocean, induce a basin-wide mode of sea surface temperature (SST) errors in the tropical Indian Ocean. With the reversal of the climatological wind in the second half of the prediction year, a west-east dipole pattern of SST errors appears in the tropical Indian Ocean, which is further strengthened under the Bjerknes feedback, yielding a significant SPB. Moreover, two types of precursors were also identified: a significant west-east dipole pattern in the tropical Pacific Ocean and relatively small temperature anomalies in the tropical Indian Ocean. Under the combined effects of temperature anomalies in the tropical Indian and Pacific oceans, northwest wind anomalies appear in the tropical Indian Ocean, which induce a significant west-east dipole pattern of SST anomalies, and yield a negative IOD event. 相似文献
4.
北太平洋对北极的半封闭状态和南太平洋对南极的开放状态是厄尔尼诺事件发生的构造基础，它导致北太平洋海表热能的积累和周期性向南太平洋输送，强潮汐振荡和火山喷发是其激发因素。 相似文献
5.
南印度洋副热带偶极模（Subtropical Dipole Pattern,SDP）是印度洋存在的另一种很明显的偶极型海温差异现象,在年际和年代际尺度上均有十分明显的表现.而目前有关印度洋海气相互作用的研究主要集中在赤道印度洋地区,针对南印度洋地区的工作还比较少,特别是有关南印度洋海温与ENSO（El NiDo-Southern Oscillation）事件关系的研究.本文初步探讨了年际尺度上南印度洋副热带偶极型海温变化差异与ENSO事件的关系,发现SDP与ENSO事件有密切的联系,SDP事件就像连接正负ENSO位相转换的一个中间环节,SDP事件前后期ENSO的位相刚好完全相反.进一步,本文通过分析SDP事件前后期海温、高低层风、低层辐合辐散、高空云量和辐射等的变化特征研究了南印度洋偶极型海温异常在ENSO事件中的作用,结果表明：SDP在ENSO事件中的作用不仅涉及海气相互作用的正负反馈过程,还与热带和副热带大气环流之间的相互作用有关,特别是与东南印度洋海温变化所引起的异常纬向风由赤道印度洋向赤道太平洋传播的过程等有十分直接的关系;同时,SDP对ENSO事件的影响在很大程度上还依赖于大尺度平均气流随季节的变换. 相似文献
6.
7.
Bai Peng Wang Jia Chu Philip Hawley Nathan Fujisaki-Manome Ayumi Kessler James Lofgren Brent M. Beletsky Dmitry Anderson Eric J. Li Yaru 《Ocean Dynamics》2020,70(7):991-1003
Ocean Dynamics - A partly coupled wave-ice model with the ability to resolve ice-induced attenuation on waves was developed using the Finite-Volume Community Ocean Model (FVCOM) framework and... 相似文献
8.
Numerical modeling with application to tracking marine debris 总被引：1，自引：0，他引：1
Potemra JT 《Marine pollution bulletin》2012,65(1-3):42-50
This paper describes different numerical models of ocean circulation the output of which can be applied to study patterns and pathways of drifting marine debris. The paper focuses on model output that is readily available rather than on numerical models that could be configured and run locally. These include operational models from the US Navy (the Navy Layered Ocean Model (NLOM), Coastal Ocean Model (NCOM), and Hybrid Coordinate Ocean Model (HYCOM)), data assimilating reanalysis models (the Simple Ocean Data Assimilation (SODA), the Global Ocean Data Assimilation Experiment (GODAE) models), and the European Center for Medium-Range Weather Forecasts (ECMWF) ocean reanalysis (Ocean Reanalysis System, ECMWF/ORA-S3). The paper describes the underlying physics in each model system, limitations, and where to obtain the model output. 相似文献
9.
利用SODA次表层海温再分析资料和卫星遥感海面高度异常数据,分析了热带太平洋和印度洋温跃层海温之间的联系,提出了太平洋-印度洋温跃层海温异常联合模(PITM)的概念、并定义了该联合模指数.结果表明,联合模指数具有准两年和3~5年的年际变化周期以及2011-2012年的年际变化周期,并具有季节锁相和振幅不对称等特征.联合模的演变过程与温跃层海温异常(TOTA)的发展和传播过程紧密相联:在太平洋,TOTA一般从西太平洋出发沿赤道(5°S-5°N)向东传播,到达东太平洋之后折向北,再沿10°N-14°N纬度带向西传播到达太平洋西岸并向赤道西太平洋扩展,形成一条回路;南太平洋也有类似回路但信号较弱;在印度洋,则主要沿8°S-12°S纬度带向西传播,到达西岸后折向北,然后迅速沿赤道(1.25°S-1.25°N)向东扩展,也形成一条回路.对NCEP/NCAR再分析风场资料的合成分析则表明,联合模的演变过程与大气环流尤其是纬向垂直环流(Walker环流)的变化密切相关,联合模的正位相对应着赤道印度洋区域顺时针的Walker环流以及赤道太平洋区域逆时针的Walker环流;而联合模的负相位则有相反的情况.此外,联合模演变过程中,TOTA的传播发展与850 hPa异常纬向风的传播发展有很好的相关. 相似文献
10.
Global upper ocean heat content and climate variability 总被引：3，自引：2，他引：1
Peter C. Chu 《Ocean Dynamics》2011,61(8):1189-1204
Observational data from the Global Temperature and Salinity Profile Program were used to calculate the upper ocean heat content
(OHC) anomaly. The thickness of the upper layer is taken as 300 m for the Pacific/Atlantic Ocean and 150 m for the Indian
Ocean since the Indian Ocean has shallower thermoclines. First, the optimal spectral decomposition scheme was used to build
up monthly synoptic temperature and salinity dataset for January 1990 to December 2009 on 1° × 1° grids and the same 33 vertical
levels as the World Ocean Atlas. Then, the monthly varying upper layer OHC field (H) was obtained. Second, a composite analysis was conducted to obtain the total-time mean OHC field ([`([`(H)])] \bar{\bar{H}} ) and the monthly mean OHC variability (
[(\textH)\tilde] \widetilde{\text{H}} ), which is found an order of magnitude smaller than
[^(\textH)] \widehat{\text{H}} . Third, an empirical orthogonal function (EOF) method is conducted on the residue data (
[^(\textH)] \widehat{\text{H}} ), deviating from
[(\textH)\tilde] \widetilde{\text{H}} +
[(\textH)\tilde] \widetilde{\text{H}} , in order to obtain interannual variations of the OHC fields for the three oceans. In the Pacific Ocean, the first two EOF
modes account for 51.46% and 13.71% of the variance, representing canonical El Nino/La Nina (EOF-1) and pseudo-El Nino/La
Nina (i.e., El Nino Modoki; EOF-2) events. In the Indian Ocean, the first two EOF modes account for 24.27% and 20.94% of the
variance, representing basin-scale cooling/warming (EOF-1) and Indian Ocean Dipole (EOF-2) events. In the Atlantic Ocean,
the first EOF mode accounts for 49.26% of the variance, representing a basin-scale cooling/warming (EOF-1) event. The second
EOF mode accounts for 8.83% of the variance. Different from the Pacific and Indian Oceans, there is no zonal dipole mode in
the tropical Atlantic Ocean. Fourth, evident lag correlation coefficients are found between the first principal component
of the Pacific Ocean and the Southern Oscillation Index with a maximum correlation coefficient (0.68) at 1-month lead of the
EOF-1 and between the second principal component of the Indian Ocean and the Dipole Mode Index with maximum values (around
0.53) at 1–2-month advance of the EOF-2. It implies that OHC anomaly contains climate variability signals. 相似文献
11.
Two modes of dipole events in tropical Indian Ocean 总被引：1，自引：0，他引：1
By analyzing the distributions of subsurface temperature and the surface wind stress anomalies in the tropical Pacific and
Indian Oceans during the Indian Ocean Dipole (IOD) events, two major modes of the IOD and their formation mechanisms are revealed.
(1) The subsurface temperature anomaly (STA) in the tropical Indian Ocean during the IOD events can be described as a “<”
-shaped and west-east-oriented dipole pattern; in the east side of the “<” pattern, a notable tongue-like STA extends westward
along the equator in the tropical eastern Indian Ocean; while in the west side of the “<” pattern, the STA has opposite sign
with two centers (the southern one is stronger than the northern one in intensity) being of rough symmetry about the equator
in the tropical mid-western Indian Ocean. (2) The IOD events are composed of two modes, which have similar spatial pattern
but different temporal variabilities due to the large scale air-sea interactions within two independent systems. The first
mode of the IOD event originates from the air-sea interaction on a scale of the tropical Pacific-Indian Ocean and coexists
with ENSO. The second mode originates from the air-sea interaction on a scale of the tropical Indian Ocean and is closely
associated with changes in the position and intensity of the Mascarene high pressure. The strong IOD event occurs when the
two modes are in phase, and the IOD event weakens or disappears when the two modes are out of phase. Besides, the IOD events
are normally strong when either of the two modes is strong. (3) The IOD event is caused by the abnormal wind stress forcing
over the tropical Indian Ocean, which results in vertical transports, leading to the upwelling and pileup of seawater. This
is the main dynamic processes resulting in the STA. When the anomalous easterly exists over the equatorial Indian Ocean, the
cold waters upwell in the tropical eastern Indian Ocean while the warm waters pileup in the tropical western Indian Ocean,
hence the thermocline in the tropical Indian Ocean is shallowed in the east and deepened in the west. The off-equator component
due to the Coriolis force in the equatorial area causes the upwelling of cold waters and the shallowing of the equatorial
India Ocean thermocline. On the other hand, the anomalous anticyclonic circulations and their curl fields located on both
sides of the equator, cause the pileup of warm waters in the central area of their curl fields and the deepening of the equatorial
Indian Ocean thermocline off the equator. The above three factors lead to the occurrence of positive phase IOD events. When
anomalous westerly dominates over the tropical Indian Ocean, the dynamic processes are reversed, and the negative-phase IOD
event occurs.
Supported by National Natural Science Foundation of China (Grant No. 40776013), National Basic Research Program of China (Grant
No. 2006CB403601) and the Knowledge Innovation Project of Chinese Academy of Sciences (Grant No. KZCX-SW-222) 相似文献
12.
13.
Multi-scale variability of the tropical Indian Ocean circulation system revealed by recent observations 总被引：1，自引：0，他引：1
Ke HUANG Dongxiao WANG Weiqiang WANG Qiang XIE Ju CHEN Lingfang CHEN Gengxin CHEN 《中国科学:地球科学(英文版)》2018,(6)
The tropical Indian Ocean circulation system includes the equatorial and near-equatorial circulations, the marginal sea circulation, and eddies. The dynamic processes of these circulation systems show significant multi-scale variability associated with the Indian Monsoon and the Indian Ocean dipole. This paper summarizes the research progress over recent years on the tropical Indian Ocean circulation system based on the large-scale hydrological observations and numerical simulations by the South China Sea Institute of Oceanology(SCSIO), Chinese Academy of Sciences. Results show that:(1) the wind-driven Kelvin and Rossby waves and eastern boundary-reflected Rossby waves regulate the formation and evolution of the Equatorial Undercurrent and the Equatorial Intermediate Current;(2) the equatorial wind-driven dynamics are the main factor controlling the inter-annual variability of the thermocline in the eastern Indian Ocean upwelling;(3) the equatorial waves transport large amounts of energy into the Bay of Bengal in forms of coastal Kelvin and reflected free Rossby waves. Several unresolved issues within the tropical Indian Ocean are discussed:(i) the potential effects of the momentum balance and the basin resonance on the variability of the equatorial circulation system, and(ii) the potential contribution of wind-driven dynamics to the life cycle of the eastern Indian Ocean upwelling. This paper also briefly introduces the international Indian Ocean investigation project of the SCSIO, which will advance the study of the multi-scale variability of the tropical Indian Ocean circulation system, and provide a theoretical and data basis to support marine environmental security for the countries around the Maritime Silk Road. 相似文献
14.
Zygmunt Kowalik William Knight Tom Logan Paul Whitmore 《Pure and Applied Geophysics》2007,164(2-3):379-393
A numerical model for the global tsunamis computation constructed by Kowalik et al. (2005), is applied to the tsunami of 26 December, 2004 in the World Ocean from 80°S to 69°N with spatial resolution of one
minute. Because the computational domain includes close to 200 million grid points, a parallel version of the code was developed
and run on a Cray X1 supercomputer. An energy flux function is used to investigate energy transfer from the tsunami source
to the Atlantic and Pacific Oceans. Although the first energy input into the Pacific Ocean was the primary (direct) wave,
reflections from the Sri Lankan and eastern shores of Maldives were a larger source. The tsunami traveled from Indonesia,
around New Zealand, and into the Pacific Ocean by various routes. The direct path through the deep ocean to North America
carried miniscule energy, while the stronger signal traveled a considerably longer distance via South Pacific ridges as these
bathymetric features amplified the energy flux vectors. Travel times for these amplified energy fluxes are much longer than
the arrival of the first wave. These large fluxes are organized in the wave-like form when propagating between Australia and
Antarctica. The sources for the larger fluxes are multiple reflections from the Seychelles, Maldives and a slower direct signal
from the Bay of Bengal. The energy flux into the Atlantic Ocean shows a different pattern since the energy is pumped into
this domain through the directional properties of the source function. The energy flow into the Pacific Ocean is approximately
75% of the total flow to the Atlantic Ocean. In many locations along the Pacific and Atlantic coasts, the first arriving signal,
or forerunner, has lower amplitude than the main signal which often is much delayed. Understanding this temporal distribution
is important for an application to tsunami warning and prediction. 相似文献
15.
The Mw = 9.3 megathrust earthquake of December 26, 2004 off the northwest coast of Sumatra in the Indian Ocean generated a catastrophic
tsunami that was recorded by a large number of tide gauges throughout the World Ocean. Part 1 of our study of this event examines
tide gauge measurements from the Indian Ocean region, at sites located from a few hundred to several thousand kilometers from
the source area. Statistical characteristics of the tsunami waves, including wave height, duration, and arrival time, are
determined, along with spectral properties of the tsunami records. 相似文献
16.
D. D. Singh 《Pure and Applied Geophysics》1997,150(1):53-73
—Rayleigh and Love waves generated by sixteen earthquakes which occurred in the Indian Ocean and were recorded at 13 WWSSN stations of Asia, Africa and Australia are used to determine the moment tensor solution of these earthquakes. A combination of thrust and strike-slip faulting is obtained for earthquakes occurring in the Bay of Bengal. Thrust, strike slip or normal faulting (or either of the combination) is obtained for earthquakes occurring in the Arabian Sea and the Indian Ocean. The resultant compressive and tensional stress directions are estimated from more than 300 centroid moment tensor (CMT) solution of earthquakes occurring in different parts of the Indian Ocean. The resultant compressive stress directions are changing from north-south to east-west and the resultant tensional stress directions from east-west to north-south in different parts of the Indian Ocean. The results infer the counterclockwise movement of the region (0°–33°S and 64°E–94°E), stretching from the Rodriguez triple junction to the intense deformation zone of the central Indian Ocean and the formation of a new subduction zone (island arc) beneath the intense deformation zone of the central Indian Ocean and another at the southern part of the central Indian basin. The compressive stress direction is along the ridge axis and the extensional stress manifests across the ridge axis. The north-south to northeast-south west compression and east-west to northwest-southeast extension in the Indian Ocean suggest the northward underthrusting of the Indian plate beneath the Eurasian plate and the subduction beneath the Sunda arc region in the eastern part. The focal depth of earthquakes is estimated to be shallow, varying from 4 to 20 km and increasing gradually in the age of the oceanic lithosphere with the focal depth of earthquakes in the Indian Ocean. 相似文献
17.
The stability of the mean ocean level was investigated using the T/P altimeter data of 1993-1997 in 39 blocks of about 30° by 30°: 20 blocks forming the Pacific Ocean, 10 the Atlantic, and 9 blocks in the Indian Ocean. The 1993-1997 yearly means were found to be nearly constant, the computed linear terms came out as: (0.9±1.3) mm/year for the Pacific, (0.3±1.1) mm/year for the Atlantic, (–0.7 ± 1.4) mm/year for the Indian Ocean. No SST model was used in the solution. 相似文献
18.
Ocean Dynamics - Wave climate is important for marine disaster prevention and marine development. The East China Sea is open to the Pacific Ocean and is considered to be greatly affected by swells.... 相似文献
19.
B. H. Vaid C. Gnanaseelan P. S. Polito P. S. Salvekar 《Pure and Applied Geophysics》2007,164(8-9):1765-1785
The sea-surface height anomalies derived from Simple Ocean Data Assimilation (SODA) during 1958–2001, Topex/Poseidon satellite
during 1993–2001 and the SODA heat content anomalies (125 m depth) during 1958–2001 are filtered into annual and biennial
Rossby wave components using a two-dimensional Finite Impulse Response filter. The filtered Rossby wave components (both annual
and biennial) in the southern Pacific and Indian Oceans have considerable strength and variability. The propagation of annual
and biennial Rossby waves in the Indonesian through-flow region [12.5°S–7.5°S] of the Indian Ocean is in phase with the southern
Pacific Ocean waves. So it is speculated that the Pacific Ocean influences the Indian Ocean, especially through the region
17.5°S to 7.5°S and thus the southern Pacific Rossby waves could be an unexplored contributor to the Indian Ocean Rossby waves.
We also carried out Fast Fourier Transform (FFT) and wavelet analysis on the tide gauge sea-level data along the Australian
coast to support our claim. Filtered annual and biennial components of SODA heat content anomalies (125 m depth) also support
these findings. 相似文献
20.
Isaac V. Fine Evgueni A. Kulikov Josef Y. Cherniawsky 《Pure and Applied Geophysics》2013,170(6-8):1295-1307
We use a numerical tsunami model to describe wave energy decay and transformation in the Pacific Ocean during the 2011 Tohoku tsunami. The numerical model was initialised with the results from a seismological finite fault model and validated using deep-ocean bottom pressure records from DARTs, from the NEPTUNE-Canada cabled observatory, as well as data from four satellite altimetry passes. We used statistical analysis of the available observations collected during the Japan 2011 tsunami and of the corresponding numerical model to demonstrate that the temporal evolution of tsunami wave energy in the Pacific Ocean leads to the wave energy equipartition law. Similar equipartition laws are well known for wave multi-scattering processes in seismology, electromagnetism and acoustics. We also show that the long-term near-equilibrium state is governed by this law: after the passage of the tsunami front, the tsunami wave energy density tends to be inversely proportional to the water depth. This fact leads to a definition of tsunami wave intensity that is simply energy density times the depth. This wave intensity fills the Pacific Ocean basin uniformly, except for the areas of energy sinks in the Southern Ocean and Bering Sea. 相似文献