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21.
Mohammed Jaffal Azzouz Kchikach Jean-Pierre Lefort Lahoucine Hanich 《Comptes Rendus Geoscience》2002,334(4):229-234
A large number of seismic reflection lines and boreholes have been carried out in the Essaouira Basin by the oil industry. The present study concentrates on the reinterpretation of these data in the restricted area of Khemis Meskala, in order to better characterise the structure of the Cretaceous aquiferous system. The reflector corresponding to the bottom of the Vraconian formation has been identified on the different seismic sections. This horizon, which marks the base of the aquiferous system, was first digitised on time migration sections and then converted to depth sections using a suitable linear velocity law. The isobath map of the bottom of the Vraconian resulting from this study images the 3D geometrical structure of this horizon and shows that it is slightly folded in domes and basins. This document will be useful for rationalising the future hydrogeological researches that will be undertaken in the Khemis Meskala area. To cite this article: M. Jaffal et al., C. R. Geoscience 334 (2002) 229–234. 相似文献
22.
Applied Research Laboratories, The University of Texas at Austin (ARL:UT) has established a cross platform open source software
project called the GPSTk or the GPS Toolkit. The GPSTk consists of a library and collection of applications that support GPS
research, analysis, and development. The code is released under the terms of the Lesser GNU Public License. The GPSTk supports
a broad range of functionality. This includes reading and writing observations in standard formats, such as RINEX, BINEX,
and SP3, ephemeris evaluation, position determination, receiver autonomous integrity monitoring (RAIM), atmospheric delay
modeling, cycle slip detection and correction, and P-code generation. The GPSTk provides the core set of functionality that
is used for GPS research and development at ARL:UT. ARL:UT has been involved with satellite navigation since Transit (the
precursor to GPS) in the 1960s and is currently conducting research in a wide variety of GPS-related fields, including precise
surveys, monitor station networks, and ionospheric studies. The GPSTk is a community-wide resource for all users of GPS and
GNSS technology. Participation is welcomed in all areas including: bug reports, new algorithms, suggestions for improvement,
and contributions of additional functionality or applications. ARL:UT continually improves the library, shepherds community
participation, and is committed to the project’s development and maintenance.
The GPS Toolbox is a column dedicated to highlighting algorithms and source code utilized by GPS Engineers and scientists.
If you have an interesting program or software package you would like to share with our readers, please pass it along; e-mail
it to us at gps-toolbox@ngs.noaa.gov. To comment on any of the source code discussed here, or to download source code, visit
our website at . This column is edited by Stephen Hilla, National Geodetic Survey, NOAA, Silver Spring, Maryland, and Mike Craymer, Geodetic
Survey Division, Natural Resources Canada, Ottawa, Ontario, Canada. 相似文献
23.
本文以金苞花为例,尝试了组培苗从试管内到自然条件下安全养护的小气候环境模拟并获得成功,提出了“关键阶段,过渡阶段和适应阶段”的三段安全养护措施及其相应的气象条件。这对名贵花卉的商业性生产是有意义的。 相似文献
24.
本文通过成都城市发展前后气候要素变化的对比分析,探索了城市化对成都市气候影响的基本规律,并用统计方法得出了城市“热岛”强度(△T,△Tmin)与城市人口总户数及建成区面积密切相关的客观事实,为改善和治理成都城市气候提供了一定的依据。 相似文献
25.
稳定氯同位素的分馏作用有限,同位素比值变化小,测定精度要求高。在很长一段时期内,人们一直未能发现自然界稳定氯同位素组成的变化。随着测定技术的不断发展,氯同位素的分馏效应逐渐得到证实,并引起了人们的广泛关注。国内外学者已将氯同位素应用于海水、地表河流水、地下水、盐湖、古代蒸发岩(盐)和热液矿床等方面的地球化学研究中,对水体演化和矿床成因进行了较为深入的探讨和分析,并取得了一定的研究进展。这些研究工作充分表明氯同位素在水体演化和成矿理论研究以及矿产勘查等方面有着独特优势,尤其在我国开展蒸发岩(盐)氯同位素地球化学研究具有很大的发展潜力和广阔的应用前景。但氯同位素的应用地球化学研究目前尚处于发展时期,更深入的研究还有待于测定方法的进一步完善以及对不同地球化学体系氯同位素的系统测定和研究。 相似文献
26.
Granulitic lunar meteorites offer rare insights into the timing and nature of igneous,metamorphic and impact processes in the lunar crust.Accurately dating the different events recorded by these materials is very challenging,however,due to low trace element abundances(e.g.Sm,Nd,Lu,Hf),rare micrometerscale U-Th-bearing accessory minerals,and disturbed Ar-Ar systematics following a multi-stage history of shock and thermal metamorphism.Here we report on micro-baddeleyite grains in granulitic mafic breccia NWA 3163 for the first time and show that targeted microstructural analysis(electron backscatter diffraction)and nanoscale geochronology(atom probe tomography)can overcome these barriers to lunar chronology.A twinned(~90°/401)baddeleyite domain yields a ~(232)Th/~(208)Pb age of 4328 ± 309 Ma,which overlaps with a robust secondary ion mass spectrometry(SIMS)~(207)Pb/~(206)Pb age of 4308 ± 18.6 Ma and is interpreted here as the crystallization age for the igneous protolith of NWA 3163.A second microstructural domain,2μm in width,contains patchy overprinting baddeleyite and yields a Th-Pb age of 2175 ±143 Ma,interpreted as dating the last substantial impact event to affect the sample.This finding demonstrates the potential of combining microstructural characterization with nanoscale geochronology when resolving complex P-T-t histories in planetary materials,here yielding the oldest measured crystallization age for components of lunar granulite NWA 3163 and placing further constraints on the formation and evolution of lunar crust. 相似文献
27.
Ekaterina Batchvarova Xiaoming Cai Sven-Erik Gryning Douw Steyn 《Boundary-Layer Meteorology》1999,90(1):1-20
The purpose of this paper is to test the ability of two quite different models to simulate the combined spatial and temporal variability of the internal boundary layer in an area of complex terrain and coastline during one day. The simple applied slab model of Gryning and Batchvarova, and the Colorado State University Regional Atmospheric Modelling System (CSU-RAMS) are tested by comparison with data gathered during a field study (called Pacific '93) of photochemical pollution in the Lower Fraser Valley of British Columbia, Canada. The data utilised here are drawn from tethered balloon flights, free flying balloon ascents, and downlooking lidar operated from an aircraft flown at roughly 3500 m above sea level. Both models are found to represent the temporal and spatial development of the internal boundary-layer depth over the Lower Fraser Valley very well, and reproduce many of the finer details revealed by the measurements. 相似文献
28.
应用旅游地理学在中国的进展 总被引:10,自引:0,他引:10
应用旅游地理学是地理学变革时期的产物,是适应旅游业的发展需要,地理学与园林、建筑、旅游等学科相互交叉、渗透的结果。应用旅游地理学研究的中心是区域旅游开发。为了完成这一任务,地理工作者应投身旅游实践中去,发挥地理学的优势,联合其他学科,在旅游开发中做出贡献。 相似文献
29.
在揭示海洋气象学学科归属问题和影响的基础上,通过对相关学科内涵和外延的综合分析,厘清了海洋气象学学科归属。海洋气象学归属于大气科学比归属于海洋科学更适合其发展。厘清海洋气象学学科归属的关键是理解海洋-大气相互作用的多尺度特征。未来海洋气象学的发展极大地依赖于海上高科技探测技术、实地和遥感观测的综合应用、中小尺度海-气相互作用理论、多层次大气-海洋耦合模式,由此需要加强更小尺度的海洋-大气相互作用研究。分析结果可供大气科学和海洋科学科研、教学、业务、管理人员参考。 相似文献
30.