三维逆时偏移GPU/CPU机群实现方案研究

叠前逆时偏移是当前最为准确的地震成像方法,由于计算量大、存储量大等原因需要合适的实现策略和高效的计算平台.本文以高阶有限差分逆时偏移为基础,重点讨论了在GPU上实现需要解决的显存不足问题和人工边界问题.利用区域分解技术可以在当前GPU上高效地实现任意生产规模的三维逆时偏移成像,不会受到GPU显存规模的制约.常规最佳匹配层边界条件边界区域控制方程与内部区域差异较大,不适于GPU高速运算.本文在GPU上实现近似最佳匹配层(NPML)边界条件,使得高阶有限差分计算不需要分支判断,边界区域辅助波场的存储量也较低,保证了在GPU上进行波场传播的高效性.三维理论数据和实际资料成像结果表明了本文方法的正确性.     

Hydrothermal dolomitization of the carbonate Jurassic succession in the Provençal and Subbriançonnais Domains (Maritime Alps,North-Western Italy)

The present article illustrates a straightforward case of hydrothermal dolomitization, affecting Jurassic platform limestones of the Provençal and Subbriançonnais Domains (Maritime Alps, North-Western Italy). Dolomitized bodies are randomly distributed within the host limestone, and are commonly associated with dolomite vein networks and tabular bodies of dolomite-cemented breccias discordant with respect to bedding. Main dolomite types are a finely to medium-crystalline replacive dolomite and a coarsely-crystalline saddle dolomite occurring both as replacive and as cement. Stratigraphic constraints indicate that dolomitization occurred during the Cretaceous, in a shallow burial context, and was due to the circulation of hot fluids (temperature about 200 °C, as indicated by fluid inclusion microthermometry) through faults and related fracture networks. Hydrothermal dolomitization therefore indirectly documents a Cretaceous fault activity in the Maritime Alps segment of the European Tethyan passive margin.     

Global monsoon: Dominant mode of annual variation in the tropics

This paper discusses the concept of global monsoon. We demonstrate that the primary climatological features of the tropical precipitation and low-level circulation can be represented by a three-parameter metrics: the annual mean and two major modes of annual variation, namely, a solstitial mode and an equinoctial asymmetric mode. Together, the two major modes of annual cycle account for 84% of the annual variance and they represent the global monsoon. The global monsoon precipitation domain can be delineated by a simple monsoon precipitation index (MPI), which is the local annual range of precipitation (MJJAS minus NDJFM in the Northern Hemisphere and NDJFM minus MJJAS in the Southern Hemisphere) normalized by the annual mean precipitation. The monsoon domain can be defined by annual range exceeding 300 mm and the MPI exceeding 50%.The three-parameter precipitation climatology metrics and global monsoon domain proposed in the present paper provides a valuable objective tool for gauging the climate models’ performance on simulation and prediction of the mean climate and annual cycle. The metrics are used to evaluate the precipitation climatology in three global reanalysis products (ERA40, NCEP2, and JRA25) in terms of their pattern correlation coefficients and root mean square errors with reference to observations. The ensemble mean of the three analysis datasets is considerably superior to any of the individual reanalysis data in representing annual mean, annual cycle, and the global monsoon domain. A major common deficiency is found over the Southeast Asia-Philippine Sea and southeast North America-Caribbean Sea where the east–west land–ocean thermal contrast and meridional hemispheric thermal contrast coexist. It is speculated that the weakness is caused by models’ unrealistic representation of Subtropical High and under-represented tropical storm activity, as well as by neglecting atmosphere–ocean interaction in the reanalysis. It is recommended that ensemble mean of reanalysis datasets be used for improving global precipitation climatology and water cycle budget. This paper also explains why the latitudinal asymmetry in the tropical circulation decreases with altitude.     

中亚成矿域地质矿产研究的若干重要问题

我国新疆地处中亚成矿域的核心地区,具有得天独厚的地理和资源优势。在执行国家“十一五”科技支撑计划重点项目08课题并取得初步成果的同时,我们意识到中亚成矿域目前还存在如下关键科学问题：中亚成矿域的形成和演化在全球地质构造体系中的地位和作用;环巴尔喀什-西准噶尔成矿省的地质背景：是岛弧环境还是后碰撞环境形成了斑岩型矿床以及相关浅成低温热液型矿床？成吉斯-塔尔巴哈台山的地质演化及其对金属成矿作用的制约机制;天山和阿尔泰地区广泛发育的韧性剪切带对金成矿作用控制时限与区域构造演化的耦合问题：中地壳的韧性剪切带如何会聚成矿流体？晚古生代晚期火山岩和次火山岩中铜金多金属矿集区的形成和演化;印支期地质过程的成矿意义和地球动力学背景;中生代陆相盆地演化与能源资源形成的动力学过程。对这些科学问题的探讨必然带动中亚成矿域地质研究的深入,并取得矿产资源勘查的突破。     

云南滇池流域强烈灌溉条件下西芹大棚土壤水分动态特征

利用TRIME-T3型TDR仪土壤含水量测量系统和WM-1型负压计系统现场监测了强烈灌溉条件下整个作物生长期西芹大棚土壤水分、土壤负压(基质势)的动态变化;研究表明,不同深度土壤含水量受强烈灌溉的影响程度不同,0.3 m深度处受影响最大,1.0,2.0 m深度处受影响最小;受灌溉的影响,0.3,0.6,1.0 m深度处负压有所波动,其中0.3 m深度处负压的波动幅度最大;2.0 m深度处的土壤一直处于"饱和-非饱和"两种状态的转换之中;在地下水埋深为2.0 m左右,且上部土层的渗透性较差(饱和渗透系数仅为0.04 m/d)的情况下,地下水水位受灌溉的影响极小.     

Late Palaeozoic mineralization and tectonic evolution of the West Junggar metallogenic belt,Central Asia: constraints from Re–Os and 40Ar/39Ar geochronology

ABSTRACT

The West Junggar Metallogenic Belt (WJMB) is located between the Tianshan fault system and the Ertix fault system in the western part of the Central Asian Metallogenic Domain (CAMD). The belt features widespread late Palaeozoic granitic plutons, strike-slip faults, and porphyry copper and orogenic gold deposits. We collected nine molybdenite samples from the Baogutu III–IV Cu–Mo deposit and the Suyunhe Mo–W deposit, and 12 granitoid samples from the Jiaman, Kangde, Kulumusu, Bieluagaxi, Hatu, Akbastau, Miaoergou, Baogutu, Karamay, and Hongshan plutons in the WJMB. Molybdenite Re–Os dating gives metallogenesis ages of 312.7 and 299.7 Ma for the Baogutu III–IV and Suyunhe deposits, respectively. ⁴⁰Ar/³⁹Ar thermochronology yields biotite ages ranging from 326 to 302 Ma and K-feldspar ages from 297 to 264 Ma, indicating a regional medium-temperature cooling history in the WJMB during the late Carboniferous to middle Permian. By integrating these data with previous zircon U–Pb, amphibole ⁴⁰Ar/³⁹Ar, and zircon and apatite fission-track ages, we reconstruct the whole thermal history of the WJMB, which includes late Palaeozoic intrusive magmatism, porphyry Cu and W–Mo mineralization, and late Mesozoic tectonic uplift and exhumation of the WJMB. The regional ⁴⁰Ar/³⁹Ar cooling ages are consistent with the timing of regional sinistral strike-slip faulting, thereby indicating the tectonic significance of the cooling ages. We suggest that the biotite ⁴⁰Ar/³⁹Ar ages represent the static cooling of the granitic plutons after emplacement, since the ages are consistent with the U–Pb ages of the plutons. Thereafter, the oldest K-feldspar ⁴⁰Ar/³⁹Ar age may record the initiation of sinistral strike-slip movement on the Darabut, Mayile, and Baerluke faults. The regional faulting resulted in significant uplift of the WJMB during the early and middle Permian.     

综合物探方法在内蒙古某铅锌矿勘查中的应用

在内蒙古某铅锌矿勘查中,采用地质、化探、激电法、EH-4电磁测深等综合方法,取得了较好的地质找矿效果。建立了物化探"两高一低二边"(即高极化率、铅锌多金属元素质量分数高,低电阻率积磁场梯级带、视电阻率梯级带)的综合找矿模型,结合地质因素,对在该地区找寻构造破碎蚀变岩型的铅锌多金属硫化物矿体(矿化体),具有明显的指导作用。     

吊舱式直升机频率域电磁系统 在北京密云红光铁矿的勘查效果

新引进的IMPULSE吊舱式直升机频率域电磁、磁综合系统是新型的数字化宽带系统,通过分析该系统在北京密云红光铁矿进行的试验勘查结果,其中包括电磁、磁场的剖面和平面特征,以及其转换的视电阻率和电阻率深度断面特征,并与以往Tridem固定翼电磁系统所测量的结果进行对比,证实了IMPULSE系统比Tridem系统具有较好的分辨率和较大的勘探深度,在矿产和水文勘查中具有显著的勘查效果。     

Parallel Computing of a Climate Model on the Dawn 1000 by Domain Decomposition Method

ＰａｒａｌｅｌＣｏｍｐｕｔｉｎｇｏｆａＣｌｉｍａｔｅＭｏｄｅｌｏｎｔｈｅＤａｗｎ１０００ｂｙＤｏｍａｉｎＤｅｃｏｍｐｏｓｉｔｉｏｎＭｅｔｈｏｄ①ＢｉＸｕｎｑｉａｎｇ（毕训强）ＩｎｓｔｉｔｕｔｅｏｆＡｔｍｏｓｐｈｅｒｉｃＰｈｙｓｉｃｓ，ＣｈｉｎｅｓｅＡ...     

我国大地重力学和固体潮研究进展

地球重力学是研究重力场时空分布及其物理机制的一门学科．地球重力场的空间分布通常可用于三个方面：一是空间科学和大地测量学，主要是利用地表的重力观测对在其上测得的几何量加以归算，以及给出重力场的高空赋值以修正卫星和近地飞行器的轨道；二是反演地球内部结构，主要是三维密度的不均匀分布，并对诸如地慢对流等作约束；三是勘探在时间变化方面，最主要影响来自固体潮，当然还有许多内部力源导致动力学效应．本文着重对我国大地重力研究和固体潮研究的进展作一回顾．