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991.
Clay mineral records of East Asian monsoon evolution during late Quaternary in the southern South China Sea 总被引:3,自引:2,他引:1
High-resolution clay mineral records combined with oxygen isotopic stratigraphy over the past 190 ka during late Quaternary from core MD01-2393 off the Mekong River in the southern South China Sea are reported to reconstruct a history of East Asian monsoon evolution. The dominating clay mineral components indicate a strong glacial-interglacial cyclicity, with high glacial illite, chlorite, and kaolinite contents and high interglacial smectites content. The provenance analysis indicates the direct input of clay minerals via the Mekong River drainage basin. Illite and chlorite derived mainly from the upper reach of the Mekong River, where physical erosion of meta-sedimentary rocks is dominant. Kaolinite derived mainly from active erosion of inhered clays from reworked sediments in the middle reaches. Smectites originated mainly through bisiallitic soils in the middle to lower reaches of the Mekong River. The smectites/(illite+chlorite) and smectites/kaolinite ratios are determined as mineralogical indicato 相似文献
992.
S-wave velocity and Poisson''''s ratio structure of crust in Yunnan and its implication 总被引:13,自引:2,他引:11
HU Jiafu SU Youjin ZHU Xiongguan & CHEN Yun Geophysical Department of Yunnan University Kunming China Seismological Bureau of Yunnan Province Kunming China Institute of Geology Geophysics Chinese Academy of Sciences Beijing China 《中国科学D辑(英文版)》2005,48(2):210-218
Receiver function of body wave under the 23 stations in Yunnan was extracted from 3-component broadband digital recording of teleseismic event. Thus, the S-wave velocity structure and distribution characteristics of Poisson's ratio in crust of Yunnan are obtained by inversion. The results show that the crustal thickness is gradually thinned from north to south. The crustal thickness in Zhongdian of northwest reaches as many as 62.0 km and the one in Jinghong of further south end is only 30.2 km. What should be especially noted is that there exists a Moho upheaval running in NS in the Chuxiong region and a Moho concave is generally parallel to it in Dongchuan. In addition, there exists an obvious transversal inhomogeneity for the S-wave velocity structure in upper mantle and crust in the Yunnan region. The low velocity layer exists not only in 10.0-15.0 km in upper crust in some regions, but also in 30.0-40.0 km in lower crust. Generally, the Poisson's ratio is on the high side, however it has a better co 相似文献
993.
Climatological distribution of lightning density observed by satellites in China and its circumjacent regions 总被引:14,自引:1,他引:13
MA Ming TAO Shanchang ZHU Baoyou & LU Weitao School of Earth Space Sciences University of Science Technology of China Hefei China 《中国科学D辑(英文版)》2005,48(2):219-229
The 0.5°×0.5°grid resolution distribution of lightning density in China and its circumjacent regions have been analyzed by using the satellite-borne OTD (Apr 1995-Mar 2000) and LIS (Dec 1997-Mar 2003) databases. It is shown that: (i) Firstly, the variability of the lightning density (LD) is particularly pronounced over the different subareas, 9 times greater over the south than the north side of Himalayas Mountains, 2.5 times greater over the eastern than the western area of China. While the maximum and minimum LD are respectively 31.4fl/km2/a (in Guangzhou region) and less than 0.2fl/km2/a (in the desert of western China). Secondly, the LD of China's continent regularly varies with latitude and distance off coast, which is consistent with annual mean precipitation in varying trend. In conclusion, the Qinghai-Tibet Plateau, the China's three-step staircase topography and the latitude are three important factors affecting macro-scale characteristics of the LD distribution, (ii) The regional differences 相似文献
994.
CHEN Hao ZHOU Jinxing CAI Qiangguo LU Zhongchen & LI Zhongyan Institute of Geographic Sciences Natural Resources Research Chinese Academy of Sciences Beijing China Institute of Forestry Science Chinese Academy of Forestry Science Beijing China Research Center for Eco-Environment Sciences Chinese Academy of Sciences Beijing China Computing Institute of Science Engineering North China Electric Power University Beijing China 《中国科学D辑(英文版)》2005,48(2):230-240
Threshold of environmental elements in drainage basin sediment yield refers to, under effect of climate, underlying surface and human activity, a turning point of abrupt changes in drainage sediment yield related to environmental element characteristics. Previous studies on threshold of sediment yield of relevant drainage basins were mainly concentrated on impact of natural zones with a few researches on impact of other environmental elements. Particularly studies on compound environmental element threshold in drainage basin sediment yield remain blank today. Studies indicate that sediment yield in drainage basins is affected by compound interactions and complex actions. Based on single element analysis, the present paper gives quantitatively compound threshold of environmental elements affecting sediment yield of the drainage basin between Hekouzhen and Tongguan in the middle Yellow River by the method of multi-variant, polynomial formula regression analysis. 相似文献
995.
Heating status of the Tibetan Plateau from April to June and rainfall and atmospheric circulation anomaly over East Asia in midsummer 总被引:20,自引:0,他引:20
DUAN Anmin LIU Yimin & WU Guoxiong State Key Laboratory of Numerical Modeling for Atmospheric Sciences Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China 《中国科学D辑(英文版)》2005,48(2):250-257
Based on the 1958-1999 monthly averaged reanalysis data of the National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) and the rainfall data of 160 Chinese surface stations, the relationship between rainfall and the atmospheric circulation anomaly over East Asia (EA) in July and the sensible heating (SH) over the Tibetan Plateau (TP) from April to June (AMJ) is investigated by using the rotational experimental orthogonal function (REOF) method. The results show that the TP is an isolated heating source in this period. The lagged correlation analysis between the first rotational principal component (RPC) of SH over the TP in May and rainfall of EA in July demonstrates that strong SH over the TP before July leads to a positive rainfall anomaly over the TP, the valley between the Yangtze River and Huaihe River, and the regions south and southeast of the TP, and the Sichuan Basin and Yunnan-Guizhou Plateau, but less rainfall anomaly over the regions north, northeas 相似文献
996.
An integrated decision method for prediction of tropical cyclone movement by using genetic algorithm 总被引:2,自引:0,他引:2
YANG Yuanqin & WANG Jizhi . National Meteorological Center Beijing China . Chinese Academy of Meteorological Sciences Beijing China 《中国科学D辑(英文版)》2005,48(3):429-440
Typhoon disaster is one of the most influentialnatural disasters. The strong storm surge of Bangla-desh cyclone, which happened in November 1970,resulted in 300000 deaths. Asia and the western Pa-cific can be regarded as an area where is affected mostseverely by the disasters of tropical storms[1]. Themost important thing is to improve the accuracy oftyphoon tracks prediction internationally. Lande-sea,C.[2] pointed out that for a successful forecast oftropic cyclone (TC) tracks, it is not … 相似文献
997.
ZHAO Wenzhi WANG Zhaoyun HE Haiqing ZHANG Mingjie WANG Hongjun WANG Yunpeng & QIN Yong . Research Institute of Petroleum Exploration & Development PetroChina Beijing China . PetroChina Exploration & Production Beijing China . Department of Geology Lanzhou University Lanzhou China . Guangzhou Geochemical Institute Chinese Academy of Sciences Guangzhou China . China University of Mining Technology Xuzhou China 《中国科学D辑(英文版)》2005,48(4):441-453
It has been proven in exploration practice that thecarbonates in China not only can generate hydrocar-bons, but also form commercial reservoirs. The car-bonates are different from clastic rocks in view of theirdeposition environment as well as their sedimentaryand diagenetic processes. Therefore, the evaluationcriteria and hydrocarbon generation mechanism forcarbonates can not be the same as that for clasticrocks, and it is important to establish a special hydro-carbon generation mechanism and… 相似文献
998.
Influencing domain of peripheral sources in the urban heavy pollution process of Beijing 总被引:1,自引:0,他引:1
Multiple cities in a diveloped economic area may consist of a city cluster,and the difusion and mixing of its pollutants result in the effect of pollutants plume between cities and the large-scale regional pollution diffusion phenomenon.The distant transfer and diffusion of pollutants occurs when massive aerosols are affected by the dynamic porcess of large-scale circulations.Research suggesten that the life span of aerosol particles whose diameters are about 1 um is the longest.The longevity … 相似文献
999.
Geochemical discriminations of sandstones from the Mohe Foreland basin,northeastern China: Tectonic setting and provenance 总被引:5,自引:0,他引:5
Andrey A. Sorokin 《中国科学D辑(英文版)》2005,48(5):613-621
The Mohe region near the border area of China with Russia is in Heilongjiang Province. Topographically the area consists of lower mountains or hills situated at the northern end of the Da Hinggan Mountains. Struc-turally the Mohe basin rests on the north margin of the Ergun Block, and the Mongol-Okhotsk Orogen is lo-cated to the north of the basin. Due to poor access conditions and good vegetation coverage, previous researches on the basin are much weak with few spe-cial geological inves… 相似文献
1000.
PENG Runmin ZHAI Yusheng WANG Zhigang & HAN Xuefeng . Key Laboratory of Lithospheric Tectonics Lithoprobing Technology Ministry of Education China University of Geosciences Beijing China . Inner Mongolia Geological Prospecting Institute Ministry of Chemical Industry Hohhot China Correspondences should be addressed to Peng Runmin 《中国科学D辑(英文版)》2005,48(6):822-833
Since the mid-1980s,Tanyaokou large Zn-Cu-Fe sulfides deposit,located at the southwest end of Langshan-Zhaertaishan-Bayan Obo Mesoproterozoic metallogenic belt in the west section of the northern margin of the North China Platform[1?9](Fig.1),has been confirmed to be submarine volcanic exhalative-sedimentary metamorphosed deposit hosted in the miogeosynclinal mud-carbonaceous formation of the Langshan Group(LG)[1],or submarine volcanic exha-lative-deposition-altered deposit[2]or stratabo… 相似文献