应用IAP9L-AGCM对2002年中国夏季气候的预测及效果检验

利用中科院大气所9层大气环流格点模式(IAP9L—AGCM)和IAP—ENSO预测系统对2002年中国夏季气候进行实时集合预测及其检验。结果显示，IAP9L—AGCM较好地预测出了2002年夏季我国大范围旱涝的分布形势，如华南、我国西部多雨，黄河和长江流域之间大范围干旱等；850hPa减弱的夏季风、青藏高原辐散中心以及北太平洋上空的异常气旋性环流中心亦被较好地预报出来；不足的是，模式对降水异常细致分布的预测能力有限。预测结果还表明，该模式对夏季(6—8月)平均降水的预报技巧要高于月平均状况，且月平均预报的准确度从6—8月依次递减。     

JOPENS数据库的平滑迁移

由于现使用的测震软件JOPENS系统是建立在MySQL数据库上的,MySQL数据库是面对中小型企业的开源数据库,其性能与稳定性都不及现在主流Oracle。阐述了在MetaMatrix的基础上,实现JOPENS数据库从MySQL到Oracle的平滑迁移。     

一个有限差分大气环流模式的并行效率

适合于大规模并行处理机（ＭＰＰ）的中国科学院大气物理研究所新一代九层大气环流模式（ＩＡＰ ９Ｌ ＡＧＣＭ）被发展成功。本文描述了并行模式的设计原则，给出了该模式的并行版本在我国几种主要的并行机上的并行执行效率数据。采用消息传递方式（ＭＰＩ）的区域分解方法用于实现程序的并行，结果表明，对于该模式，只有一维区域分解方法才能取得较好的并行可扩展性，即随着处理器的增加而能得到相应较好的并行加速比和并行效率。     

Intermittent chaos in nonlinear wave–wave interactions in space plasmas

There is increasing observational evidence of nonlinear wave–wave interactions in space and astrophysical plasmas. We first review a number of theoretical models of nonlinear wave–wave interactions which our group has developed in the past years. We next describe a nonlinear three-mode truncated model of Alfvén waves, involving resonant interactions of one linearly unstable mode and two linearly damped modes. We construct a bifurcation diagram for this three-wave model and investigate the phenomenon of intermittent chaos. The theoretical results presented in this paper can improve our understanding of intermittent time series frequently observed in space and astrophysical plasmas.     

Peculiar oscillations in the microwave emission of Jupiter during the impact of K fragment of comet Shoemaker-Levy 9

In this article we report the peculiar oscillations in the intensity of microwave (4.15 GHz) emission seen during the impact of K fragment of comet Shoemaker-Levy 9 on July 19, 1994. The oscillations begin at 10h 13m 25s UT suddenly with a frequency of ~0.3 Hz and gradually the frequency of these oscillations increases to ~ 1 Hz. The oscillations are not due to local atmosphere or the radio interference from signals of geostationary satellite. They are intrinsic to the microwave emission from Jupiter during the impact of K fragment. Peak-to-peak amplitude of the oscillations is about 34% of the total microwave emission from Jupiter. If we assume that only 50% of the microwave emission is non-thermal and only the non-thermal emission suffered oscillations, then the oscillations are about 68% of the non-thermal emission from Jupiter. The observations also indicate that there are three continuum enhancements during this event and periodic oscillations almost all through. The third enhancement was the largest and during this enhancement there were some additional aperiodic variations. The aperiodic variations were of the order of few minutes and were possibly generated by the gravity waves. The periodic oscillations could be synchrotron emission modulated by the plasma oscillation in the outer magnetosphere. kg]Key words     

Biostratigraphy,sedimentology and palaeobathymetry of Waulsortian buildups and peri-Waulsortian rocks during the late Tournaisian regression,Dinant area,Belgium

Recent revision of the biostratigraphy allows the recognition of a stratigraphic entity (here termed Freyrian) between the base of the Moliniacian stage and the base of the Viséan and simplifies sedimentological interpretation of late Tournaisian events around Dinant, in Belgium. Petrographic analysis of Freyrian rocks in Waulsortian buildups and peri-Waulsortian facies reveals a pattern of carbonate sedimentation related to the submarine topography developed by the buildups, and to sea-level changes. Graded beds and thin layers of grainstone in the predominantly fine-grained peri-Waulsortian sediments represent influxes derived mainly from nearby buildups during a period of shallowing. Using the sequence of foraminiferan assemblages which colonized the buildups as a stratigraphic scale, the earlier influxes are shown to have occurred only close to the presumed source, whereas later influxes extended further and marked the culmination of the shallowing phase. Deposition during the latter part of the Freyrian appears to have occurred in rather deeper, less disturbed water. The Moliniacian and Viséan boundary stratotypes, both in peri-Waulsortian facies, are critically assessed because almost all the stratigraphically useful foraminiferans occur in the rare grainstones resulting from sediment influxes. Tetrataxis was one of the few foraminiferans to colonize proximal peri-Waulsortian areas and appears to have ranged to a water depth of about 200 m. Downslope diachronism of colonization is interpreted as evidence of a sea-level fall of about 140 m and is used to draw a sea-level curve for this late Tournaisian regression. Using the same depth scale, microbial coating extended to about 300 m and its development appears to have been related to low sedimentation rates rather than photic conditions. © 1997 John Wiley & Sons, Ltd.     

胡尖山油田长9段储层孔隙结构表征及影响因素分析

通过岩心观察、普通薄片、铸体薄片、扫描电镜以及压汞测试等分析手段,对胡尖山油田长9段储层岩石学、物性和孔隙结构表征及控制因素等方面进行研究。研究表明,长9段储层岩性以岩屑长石砂岩和长石岩屑砂岩为主,储集空间以剩余粒间孔为主,喉道较细,物性较差,属于低孔低渗储层。利用分形维数结合压汞参数对储层孔隙结构进行表征,基于此将目的储层划分为4类,建立不同类型储层测井响应,明确不同类型储层的平面分布。认为沉积和成岩作用控制孔隙结构的形成,其中沉积作用是影响储层孔隙结构的先决条件,而成岩作用是决定储层孔隙结构特征的关键因素。压实和胶结作用对孔隙结构起破坏作用,溶蚀作用则改善储层孔隙结构。以上研究成果对研究区长9段储层的分类评价及下一步的油气勘探具有指导意义。

     

基于OCCI的空间数据库几何对象实现方法

海量空间数据的高效访问和操作是 GIS平台和应用系统开发的核心技术。本文分析了 Oracle数据库管理系统所提供的访问接口 OCI、OCCI及对象类型转换工具 OTT的特性 ,基于 OCCI和 OTT技术提出了一种面向对象的访问及操作 SDO几何对象的方法 ,并通过实例讨论了实现过程。该方法利用 SDO几何模型作为 Oracle服务端的几何对象载体 ,在客户端通过继承 SDO几何对象实现自定义几何对象模型 ,避免了 SDO几何对象与用户定义几何对象之间的空间数据转换过程 ,有利于扩展自定义空间数据模型。同时 ,自定义几何对象可以充分利用Oracle Spatial提供的空间操作与整合功能 ,加速 GIS软件平台研发过程。     

Discovery of the largest impact crater field on Earth in the Gilf Kebir region, Egypt

Using orbital imaging radar, we have detected a large number of circular structures in the southwestern Egyptian desert, covering more than 4500 km² close to the Gilf Kebir plateau in sandstones of Upper Cretaceous. Fieldwork confirmed that it is a new impact crater field: 13 craters from 20 m to 1 km in diameter were studied. The impact origin is confirmed by the observation of shock-related structures, such as shatter cones and planar fractures in quartz grains of breccia. Considering the extension of the crater field, it was possibly created by several meteorites that broke up when entering the atmosphere. To cite this article: P. Paillou et al., C. R. Geoscience 336 (2004).

Résumé

À partir d'images satellites issues de systèmes radar, nous avons détecté un grand nombre de structures circulaires dans le Sud-Ouest du désert égyptien, s'étendant sur plus de 4500 km² à l'est du plateau du Gilf Kebir, dans des grès du Crétacé supérieur. Une étude sur le terrain a permis de vérifier qu'il s'agit d'un champ d'impacts météoritiques jusque là inconnu : 13 structures, d'un diamètre compris entre 20 m et 1 km, ont été reconnues comme cratères d'impact. La présence d'un grand nombre de cônes de percussion et de brèches dans lesquelles des quartz choqués à structures planaires ont été observés confirment l'hypothèse de l'impact. Considérant l'extension du champ d'impact, il a probablement été créé par plusieurs météorites qui se sont fragmentées dans l'atmosphère terrestre. Pour citer cet article : P. Paillou et al., C. R. Geoscience 336 (2004).     

Elemental abundance analyses with DAO spectrograms: XXX. The middle B through early A stars ξ2 Ceti (B9 III), 21 Aquilae (B8 II‐III), ι Aquilae (B5 III), and ι Delphini (A2V)

This series of high quality elemental abundance analyses of mostly main‐sequence band normal and peculiar B, A, and F stars defines their properties and provides data for the comparison with the analyses of somewhat similar stars and with theoretical predictions. Most use high dispersion and high S/N (≥ 200) spectrograms obtained with CCD detectors at the long camera of the Coudé spectrograph of the 1.22‐m Dominion Astrophysical Observatory telescope. Here we reanalyze 21 Aql with better quality spectra and increase the number of stars consistently analyzed in the spectral range B5 to A2 by analyzing three new stars for this series. In the early A stars the normal and non‐mCP stars have abundances with overlapping ranges. But more stars are needed especially in the B5 to B9 range. ξ² Cet on average has a solar composition with a few abundances outside the solar range while both 21 Aql and ι Aql have abundances marginally less than solar. The abundances of ι Del are greater than solar with a few elements such as Ca being less than solar. It is an Am star (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)