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341.
A precise monitoring of snow surface height in the region of Lambert Glacier basin-Amery Ice Shelf,East Antarctica 总被引:2,自引:0,他引:2
I.Allison 《中国科学D辑(英文版)》2005,48(1):100-111
The net surface snow accumulation on the Antarctic ice sheet is determined by a combination of precipitation, sublimation and wind redistribution. We present a one-year record of hourly snow-height measurements at LGB69 (70°50'S, 77°04'E, 1850 m a.s.l.). east side of Lambert Glacier basin (LGB), and 4 year record at G3 (70°53'S, 69°52'E, 84 m a.s.l.), Amery Ice Shelf (AIS). The measurements were made with ultrasonic sensors mounted on automatic weather stations installed at two sites. The snow accumulation at LGB69 is approximately 70 cm. Throughout the winter, between April and September, there was little change in surface snow height (SSH) at the two sites. The negative SSH change is due to densification at LGB69, and is due to both ablation and densification at G3. The strongest accumulation at two sites occurred during the period between October and March (accounting for 101.6% at LGB69), with four episodic increasing events occurring during 2002 for LGB69, and eight events during 1999-2002 for G 相似文献
342.
WANG Xueqin WANG Tao JIANG Jin & ZHAO Congju . Laboratory of Blown Sand Physics Desert Environment Cold Arid Regions of Environmental Engineering Research In-stitute Chinese Academy of Sciences Lanzhou China . Xinjiang Institute of Ecology Geography Chinese Academy of Sciences Urmqi China Correspondence should be addressed to Wang Xueqin 《中国科学D辑(英文版)》2005,(6)
Longitudinal dunes,also known as linear dunes,are the most widespread of all dune types,which occupy1/2to2/3of the total area in the world sand seas.They mainly occur in the southern part of Africa,Arabian Peninsular,Australia,Central Asia and North Af-rica-Middle East regions[1],in China they mainly ap-pear in the Gurbantnggt Desert.Many researches have been done on wind dynamics of the sand dune and its relations with environmental conditions[2—9],but comprehensive studies on sand … 相似文献
343.
WU Yaping ZHU Yuanlin GUO Chunxiang SU Qiang & MA Wei . School of Civil Engineering Lanzhou Jiaotong University Lanzhou China . State Key Laboratory of Frozen Soil Engineering Cold Arid Regions Environmental Engineering Research Institute Chinese Academy of Sciences Lanzhou China 《中国科学D辑(英文版)》2005,48(7)
In the construction of Qinghai-Tibet railway,to avoid diseases caused by frost heave and thaw col-lapse of frozen ground,besides the normal bridges over the rivers,a lot of dry bridge structures have been built to replace subgrade in the regions of high tem-perature and high ice content frozen soil.So,the problems on forming mechanism of bearing capacity of pile foundation in cold regions already become one of hot spot problems in frozen soil engineering.Freezing force and frost heave force ar… 相似文献
344.
LI Rongfeng YOU Xiaobao & Peter C. Chu . LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China . Department of Oceanography Naval Postgraduate School Monterey CA - USA 《中国科学D辑(英文版)》2005,48(7)
The classic Sverdrup theory suggests that the water movement in the central subtropical gyre of North Pa-cific be slowly westward or southwestward.In the late sixties of the20th century,the existence of a peculiar eastward narrow flow between20°N and25°N in spring was theoretically predicted.It was named the Subtropical Countercurrent(STCC),although direct observational evidences were not yet sufficient to con-firm whether or not such eastward flow between20°N and25°N was a persistent… 相似文献
345.
Mesozoic-Cenozoic tectonic transition in Kuqa Depression-Tianshan, Northwest China: Evidence from sandstone detrital and geochemical records 总被引:2,自引:0,他引:2
LI Zhong GUO Hong WANG Daoxuan & LIN Wei . Institute of Geology Geophysics Chinese Academy of Sciences Beijing China . Tarim Oilfield Branch CNPC Korla China . Hefei University of Industry Tunxilu Hefei China 《中国科学D辑(英文版)》2005,48(9):1387-1402
Succeeding to multiply collisions of different blocks in Late Paleozoic[1―5], complex intracontinental structural deformation occurred in the Tianshan area during Mesozoic-Cenozoic[6―16], which controlled coeval basin-range evolution and resulted in intensive modi- fication and adjustment of the Paleozoic oil-gas reser- voirs[17―19]. The Kuqa Depression is a secendary struc- tural unit of the Tarim basin, in which Mesozoic- Ce- nozoic deposits occur in thickness of 6000―7000 m. The Kuq… 相似文献
346.
With the acceleration of industrialization, coal- burning atmospheric pollution is getting more and more serious in many regions in China. However, there are only about ten odd years literature records about pollution in some large and mid-sized cities, where the atmosphere has perhaps been polluted for several decades, and therefore it is difficult to know the process and characteristic of pollution, and diffi-cult to evaluate its damage to environment. Lacustrine sediment, a natural record w… 相似文献
347.
HU Ping YIN Xiulan ZHAO Linghu & LI Dien . Department of Earth Sciences China University of Geosciences Wuhan China . Northeastern Illinois University Chicago IL USA . China Institute of Geo-Environmental Monitoring Beijing China . Division of Chemistry Los Alamos National Laboratory Los Alamos NM USA 《中国科学D辑(英文版)》2005,48(11)
A large amount of nuclear wastes has been pro-duced due to nuclear weapon development and nuclear electricity generation. One possible resolution for the disposal of the nuclear wastes is to seal them in an underground repository, which requires detailed knowledge on the mobility, chemical behavior and immobilization of radionuclides in underground water. In addition, toxic heavy metals are extensively present in ground and underground water, how to immobilize and remedy these toxic heavy meta… 相似文献
348.
HE Yongfeng & CHEN Xiaofei . Department of Geophysics School of Earth & Space Sciences Peking University Beijing China . North-West Institute of Nuclear Technology Xi’an China 《中国科学D辑(英文版)》2005,48(12):2118-2122
Since the sign up of CTBT (Comprehensive Test Ban Treaty), the nuclear monitoring and distinguishing has gained great attention by the treaty countries. Seismology is one of the primary technical means available for monitoring compliance to a CTBT. However, there does not exist a single criterion, so far, that can effectively distinguish explorations from earthquakes. It has been known that source time function (abbreviated to STF) of an underground nuclear explosion contains important p… 相似文献
349.
地面观测到的物理场变化可表示成X=X1+X2+X3。式中,X1和X2分别为地球内部过程和外部过程决定的场分量,X3为干扰量(技术和仪器等的干扰)。7.1磁场变化与太阳系行星旋转周期的关系太阳系包括9颗大行星,根据行星形成特性分为两种主要类型:一是类地行星,除地球外,包括水星、金星、火星;二是木星类行星(巨星),包括木星、土星、天王星和海王星。表7.1列出了行星的若干特征。由表可见,地球和火星自转周期几乎一样,火星昼夜比地球昼夜长41分钟,金星和水星自转极慢,金星周期为584个地球日,水星为116个地球日。类地行星平均加权密度为5.14g/cm3,巨… 相似文献
350.
当今世界所有工业发展国家关于安全以及居民、地区、国民经济工程设施对人为灾害和自然灾害的防护问题,已成为没有地理和民族界限的最重要的社会经济、人口学和生态研究问题。因此,建立与地震安全性保障有关的国家科技课题是极为重要的。在哈萨克斯坦,研究人员拓展了地震监测系统构思,在其基础上制定了优先问题的计划:——研究地震危险性评定的方法学和编制不同比例尺的地震区划图以作为进行建设和合理利用土地的标准文件。——研究地震发生地点、强度和时间预报的方法,建立地震活动性和地震预报的地震监测系统。——研究监测的方法学,对有… 相似文献